Gauging And Gauging Equipment For Oil & Gas Production

Tracking oil production is vitally important for lease pumping, particularly smaller operations where every penny counts. Regularly gauging the stock tanks is an important part of tracking your production, as it gives you an quick look at how your system and the well is behaving, as well as allowing you to track production over time.

The tank battery is the center of most lease pumping operations, and is most likely going to be the center of most of your work day as well. Gauging stock tanks and water tanks should be a regular part of your routine. A sudden change in production is usually a hint that something is wrong. A jump in production can be an indication of a change in the well, or a even a leak in the water disposal system. Falling production is obviously a concern, and can cause a number of different malfunctions.

Routine is an important part of the lease pumper’s day, as there are many things that have to be checked and measured on a lease pumping operation. Other parts of a routine day include things like a visual inspection. That should perhaps be the first thing you do, and you can start as soon as you drive onto the lease. Signs of a water or oil leak may be the first sign that a pipe or tank has a hole. Other things that are a good idea to check include the height of fluid in sight glasses, the pressure in the various parts of the tank battery, the amount of water being produced, and if there is any oil in the water system.

 

Gauging Equipment

The gauge line is one of the most important pieces of equipment, and it will be covered in more detail below. However, there’s a number of other tools that can make the process of gauging easier. A particular problem is gauging the amount of water beneath the oil in a stock tank.

Gauging

Figure 1. Water gauging paste. (courtesy of WL. Walker Company)

One option is a water gauging paste like Kolor Kut. The paste is brown in color, but will change to bright red when it comes in contact with water. It can be applied to the gauge line above and below the depth of the estimated water level. When the tape is pulled back, the water level can be accurately measured.

Gauging

Figure 2. An example of a specific type of thief, called a Tulsa thief. Pictured are two options, one with a glass cylinder and one made from brass. (courtesy of WL. Walker Company)

The other option is to use a tool called a thief. This is a small cylinder that is dropped into the tank. Heavier oil and other elements like paraffin and asphalt will often sink to the bottom of the oil, but still be light enough to float on the water. When lowered to the bottom of the tank, the thief will capture a sample of the bottom. You can then spread the sample out and see, by looking carefully, where the heavier oil turns to sediment and water.

 

The Gauge Line

The gauge line consists of a measuring tape, a plumb bob to pull the tape down, and a frame to hold it all. While this may seem like a fairly simple piece of equipment, it is a precise measuring tool and has to be treated carefully. In addition, a line wiper will be needed to clean the line after use.

Gauging

Figure 3. A couple different gauge line examples. (courtesy of WL. Walker Company)

The measuring line itself can either be chrome or black (also labeled as nubian). Chrome tapes are generally better for heavier oils as the oil is darker and so the line stands out better. When using a chrome tape to gauge lighter weight oils, the tape may need to be dusted to get an accurate reading. Black lines work better for lighter colored, lighter weight oils. It’s also the better choice for gauging distillates, which is so clear the fluid may appear as clear as water. Black lines may need to be dusted when gauging distillates, as they evaporate quickly. The same may be true for water.

Gauging

Figure 4. An example gauge line. (courtesy of WL. Walker Company)

The tapes are reeled onto frames, of which three sizes are available. The smallest size holds tapes of 18, 25, 33 feet in length. The medium sized frame holds tapes of 50, 66, and 75 foot long measuring tapes. The largest size holds 75 and 100 foot tapes, which are used for measuring the deepest tanks. The majority of lease pumpers will be working with one of the two smaller frames.

Gauging

Figure 5. A few of the different plumb bob options available. (courtesy of WL. Walker Company)

A typical plumb bob is a brass cylinder about ¾ of an inch in diameter, and weighing about 20 ounces. The plumb bob pulls the tape to the bottom of the tank, and it’s length is included in the tape’s depth measurement. At the bottom of the tank, below the thief hatch, will be a striker plate. This is added to the tank bottom to protect it against the consistent banging of the plumb bob on the bottom, which can eventually punch through causing leaks. There are a few different styles of plumb bob out there, though they all function basically the same.

Gauging

Figure 6. An example of a Little Joe, a device used for wiping oil from the gauging line. (courtesy of WL. Walker Company)

Rather than letting oil drop from the line back into the stock tank, you should use a line wiper, also known as a Little Joe, to clean the plumb bob and measuring tape. After the line is used to gauge the tank, the Little Joe collects oil so that it can be added back to the supply. This saves both the oil and the cost of using rags to clean the line.

 

How To Gauge A Tank

You should already have some idea of the oil and water levels in your tanks. This will be based on a few different factors, but mostly the previous day’s measurements and what you expect the well to produce. Ideally, the estimate should be within about ¼ inch of the actual measurement. Keeping track of measurements is important, so in addition to the lease records, it’s a good idea to keep another notebook just for gauge measurements. Called a greasebook, this should be something you can keep in your pocket, while still being able to hold several months’ records.  

When wells are far apart and only produce small amounts, visiting each tank battery every day may not be necessary. In that case, gauging can be done every other day. It’s an approach that allows more time for maintenance and repairs, and sometimes is a better way to go.

 

Gauging Oil Tanks

The gauge line does have to be carefully handled, and you should make sure the thief hatch can’t close on the measuring tape while it’s in the tank. That can cause a kink in the line, ruining it. You can lower the tape directly into the center of the hatch, or let it slide over the hatch’s edge. The line should be slowed before it reaches the bottom of the tank, so that it is lowered gently.

You may have to raise and lower the line a few times before the plumb bob actually touches bottom. This action, called spudding, has to be done carefully to get an accurate reading. Jerking or bouncing the line will cause the plumb bob to lean and oil to splash up the line. Learning to gauge the tank accurately is a crucial skill, and one that should be practiced until readings become consistent. Even then, your measurements may differ slightly from others, particularly the buyer of your oil. If the reading is off by the estimated amount by a large margin, the gauge measurements should be done again.

Even if the measurements are close to what you predicted, it’s usually a good idea to also measure the water tanks and get a clear idea of how much water has flowed through your system. Checking sight glasses and meter readings is also good practice.

The Last Talk

This week, after spending the last four weeks working with my fellow Oklahoma Panhandlers as we all try to recover from the fires that devastated us here, I wanted to talk about human connection and how that connection to others and other “beings” impacts all of us, even those of us who like to think we tough oil field guys.

So this week, hunker down in your pumpin’ truck with your cell phone over lunch and join us for “At the well”; stories from several pumpers who have met some out of the ordinary creatures as well as people they likely wouldn’t have met in any other location.

 

“The last talk”

Meet Panhandle contract pumper Brent Stahlman. He’s been a pumper for well over 20 years now. While the job of pumpers, especially contract pumpers can be rather solitary, Stahlman tells of us two meetings that took place at well sites that will endure in his memory forever.

“Well, there was a rancher I knew who owned cattle on the land that this well was on,” Stahlman said. “one day, my daughter Lindsey had gone with me and we had found this orphan calf. Well, we called this guy and he told us he didn’t have time to take care of an orphan calf and so he gave that calf to Lindsey.”

That meeting happened about a week before Stahlman said he ran into the man once again when he turned into the well location.

“I sat and visited with this guy who, other than the week before, I had not seen in a long time. I used to go to school with him,” he said. “We ended up visiting for about two hours that day.”

It was just a rare chance to catch up with a friend on a day when the weather was just right for leaning against a pickup and talking about all kinds of things.

“Then I found out that two weeks later he committed suicide,” Stahlman said. “It was just unbelievable that I could set and visit with someone and I could not know that he had problems like that. It just makes you think, how did I miss that?”

For Stahlman, the memory of that day the two men talked and laughed about old times together still haunts him. He plays the conversation back in his mind, searching for clues, much like a war-time code-breaker, looking for the code hidden within his friend’s conversation that day. If he had just been able to decipher the code at that moment,  maybe it could have allowed him to help his friend.

But no matter how much he does this, no code emerges. No secret messages pop out from the conversation that is now six years old. And it leaves him feeling a kind of helplessness that defies description.

These days, Stahlman admits, he tries harder to make real connections and he also says this friend, who had obviously been in so much pain, also changed his rigid, black and white thinking regarding what it means spiritually when someone takes their own life.

“Before, I had always looked at suicide as an extremely selfish….but he wasn’t a selfish guy. And the way I was raised, I was always taught that committing suicide was an automatic ticket to Hell,” he said. “Then this happened and you think, what causes that? What kind of Hell must they already be feeling? And then you find out later that there was a lot of family history of that and it gives you pause. And  then you just know, it can be genetic just like cancer.”

That last talk with his friend in the two weeks preceding his death with a pumping unit chug, chug, chugging in the background, changed Stahlman forever. He has given up the idea that he thinks he knows God’s mind regarding suicide. And he realizes that sometimes, there is something a little more important than getting to the next well.

“You know, I don’t pump that well anymore. But I drive by it every day and each time I drive by it, I think about him.”

Thank you Brent Stahlman for being courageous enough to share that story with us.

By the way, when Brent and I were talking about this story, he added a fun story of another encounter he had at one of his wells that I felt compelled to share.

 

It was a dark and not-so-stormy-night

Like most contract pumpers, Stahlman has a level of flexibility that allows him to, every once in a while, pause his day and do something with the family. On this particular day, he went to Oklahoma City with his lovely wife Ginger.

They went shopping, which makes me wonder why a man would allow his wife to take him shopping. But Ginger is a pretty fun gal. So it could be that he really enjoys just shopping with his wife…anything’s possible.

So when they returned, it was late. And like any pumper worth his salt, he got out and pumped his wells.

“So I came back and by the time I started checking wells, it was pitch black,” he said. “So here I was, in the middle of nowhere, completely alone down on the Beaver River.”

He said he got out of the pickup and there was no moon.

He found his way to his meter house to get some readings. He had opened the door on the meter house and was juggling a small flashlight and a pen while writing down the numbers, when all of a sudden;

“Someone grabbed the back of my shirt,” he said. “I jumped so bad that I tripped and fell over on my back and when I did I shined my flashlight up at what had just grabbed me.”

Turns out, the monster that had grabbed the back of Stahlman’s shirt was a giant goat. he said the goat looked at him with an expression that said, “What? Was I wrong to do that?”

Last Talk

“I had noticed, when I would go to that well, that I was having trouble with something that was chewing the wires,” he said. “I had never seen him though and it was a huge pasture and so I assumed it was calves.”

Now days the two are friends. When Stahlman heads down to the well, he looks for the old show goat, who he now knows is living out his days in that meadow.

And every time he sees the old goat, he scrubs his old gnarly head with his hands and reminds him how lucky he was that on that night after the shopping trip, he had not worn his pistol.

 

Spirit pumper

Panhandle Oil and gas pumper Donnie Crigler is a manly man. No really…this is a guy who is like 6 foot 3 inches of growly bear manliness and no one can really know anything else other than that about him. He forbids it.

Donnie was a fellow pumper and until perhaps today, after he reads this, was a good friend over the years. But I have to share his story. It’s too good.

When I started pumping at the same company as he did and he finally decided that I might not be such a bad old gal, he told me a story.

You see, when Donnie began in the oil field, he had a mentor – another big, strapping guy who was an experienced pumper by the name of Mark.

Over the years, Mark helped Donnie with every kind of problem that developed on his wells. We all know that sometimes the best way to figure out what is ailing a well is to bounce our ideas off of another person who can see, in their mind’s eye, what we are looking at.

That’s the kind of friendship that developed between these two. It was a friendship born of clogged bleed tubes on constant bleed dumps, swamped separators and compressors that wouldn’t run in the cold. It was two friend pumpers who worked shoulder to shoulder with a 36 inch pipe wrench, pulling off a Kimray. It was cussing Field Direct because that program won’t let you show negative oil when you have a stock tank leakage that drains a foot of product.

But one thing Mark was always telling Donnie was to “slow down”.

“And then, as a joke, I would speed up,” Donnie said laughing.

We all know that in the oilfield, slow is fast. If you are focused on what you are doing, you spend less time at your site and you are safer.

I may be wrong, but I got the feeling that this calm-minded guy would say it in a really slow way. I didn’t know Mark, but I can almost see him, moving his hand in a downward motion while he says it.

And then one day, Mark wasn’t there anymore.

“It was on a Thursday and I was off when he had his heart attack,” Donnie said. “The day before we had worked and he was there and the next day, he was gone.”

For anyone who has ever worked with a good pumper, you know what a loss that is. Working in the oil field is lonely for a lot of reasons. But one of the reasons is because it is damn hard to find a friend who you can trust. Like it or not, this industry can be full of a lot of people who cannot be trusted. So when you find one, you truly have struck real gold.

Over that weekend, Donnie said he couldn’t get Mark off his mind. He said he had gone to sleep on Saturday night and something had woken him up.

That’s when he said he saw Mark standing in front of him.

Donnie told me this story about five years ago. And he said that Mark said only one thing during that spirit visit.

“Slow down”.

And then, he was gone.

~ Rachael Van Horn aka “Wench with a Wrench”

The Basics Of Working A Lease In Oil & Gas Production

Time management is an important skill in most situations, but for a lease pumper it can be vital. Spending your time wisely can make the difference between turning a profit and falling short, or between turning a small profit and a much larger one. Because lease pumpers often work on their own, you’ll be in charge of your own schedule and what you spend your time on each day. Routine, habit, and planning ahead can all help to make sure you’re using that time well.

 

The Working Day

You’ll need to put together a routine that works well for you, but devoting the morning to small, daily tasks is a good way to go. Getting that stuff out of the way allows you to focus on larger projects later in the day.

The first thing to get out of the way is a visual inspection of the site and equipment. This starts as soon as you drive onto the lease. Keep your eyes open for things like leaking lines or rusty equipment, and you may end up spotting a lot of problems early on. The lease should be kept clean and free of trash and debris to make this sort of look-around as easy as possible. It’s possible you may see small bolts or washers on the ground around a failing piece of equipment.

Sight glasses should also be checked, and the level of liquid in each measured. Tying string around the level or otherwise marking it can give a clear indication if the level changes. If the amount of oil in a vessel increases, that can indicate an increase in the amount of water, or that water has been trapped in an oil line.

Part of the visual inspection is also listening; a malfunctioning pump or engine will usually sound different, and paying attention is worthwhile. Gauging tanks should be done daily, and possibly several times throughout the day.

If wells don’t pump constantly, it’s usually good to be around for at least some of the time they’re operational. Starting a pump at the beginning of your work day is a good idea. If pumps are running on schedule, that’s a good sign the electrical and automation systems are working. Pumps not turning on when they should is obviously a big hint that something’s wrong. Watching the pumps in action can often be a good idea, as well, as loosening fittings or failing equipment can sometimes be more clear.

 

How To Approach The Lease

Even before you get to the site, your attitude will often determine how successful you are. Self motivation is key, as is a sober approach and a good work ethic. Obviously liking your job is helpful and nice, but most parts of the job are going to be tedious, difficult, and dirty. Taking pride in a job well done, then, is going to get you further than having lots of fun.

Habitually maintaining your tools and equipment will save you a lot of money. Another key skill is knowing what purchases will ultimately be worth it, and which are going to be a waste of money. That will often require some research, which is something that is generally a good idea when running a pumping operation; techniques and equipment advance constantly and keeping up to date should be a priority. Understanding what’s under your feet is also vital, as understanding how the reservoir you’re tapping will behave can help anticipate problems and opportunities.

All these traits add up to getting as large a return on your investment of money and time as is possible, which is the goal of any lease pumper. The key thing to understand when working for yourself is that every minute you slack off, you’re just creating more work for yourself later. All the time you take off work because you’d rather be doing other things equates to money that doesn’t end up in your pocket.

 

Planning Larger Tasks

Some aspects of running a lease have a strict schedule. If you’re selling oil by truck transport, everything has to be ready before the truck arrives. Likewise, the leasing company usually expects to be paid on time.

Other aspects, including a great deal of the day-to-day work on a lease, may not have a deadline or schedule. A lot of things will just need to get done at some point, before too long has passed. Checking and changing oil and filters needs to happen regularly, but there’s no specific date by which, if it’s not done, the engine will stop working. Scheduling these sorts of tasks actually can become more important, rather than less so. Otherwise things can slip and routine maintenance is left undone until there’s an emergency, which is always more expensive in both money and time.

Regular maintenance should be planned and tracked in records kept for the lease. These sorts of tasks include checking and changing oil and filters, lubricating bearings, tightening belts, and so forth for every engine and pump on the lease. Records should also be kept of the amounts pumped each day for each well.

Other tasks include regular cleaning of tank bottoms, testing wells, and chemically treating the oil.

 

Cleaning Tank Bottoms

The company who buys your oil generally require that tank bottoms are kept clean, as dirty tanks can affect the quality of the oil sold. At the beginning of the month, the stock tanks emptied by the previous month’s sale should be circulated so that they’re as clean as possible for the next month’s oil production. Any oil and the emulsion that has collected needs to be sent back through the treating system so that the oil can be separated. You may have to do that a few times before the tank is clean enough. Oil in the stock tanks can also be regularly circulated during the month to help keep tank bottoms clean. Sometimes, you’ll have to pump water into the tank in order to get emulsion flowing.

 

Testing Wells

Wells should be tested monthly, and precise records kept. This is the best way to gauge how a well is performing. The same day of the month should be chosen for each well, so that a good comparison can be made to earlier measurements.

 

Chemically Treating Oil

A key part of the treatment process is adding chemicals to the oil produced from the well. This will need to be done on a regular basis. This can help the chemical treatment process efficient, and also use up less of the chemicals. Moving the oil and thus further mixing the chemical can help with treating it, so circulating oil sitting in stock tanks can also be helpful.

Utility Pumps For Oil & Gas Production

Lease pumping uses a lot of pumps; it’s right there in the name. It’s possible that you’re using a pump as part of the downwell system. However, pumps will probably perform many other important task around your operation. Knowing a few basics is all you need to keep things running smoothly and save yourself some money.

Pumps are designed for specific types of tasks, and so there may be a few different types of pumps around. Some will be able to pump fluid with all sorts of gravel and debris, called trash, without a problem. Other pumps aren’t able to handle that, and it can be damaged by trash. Pumps can exert a range of pressures, with the three general types being low, medium, and high pressure. Pumps can also be classed by how they operate mechanically, with the two most common types being positive displacement and centrifugal.

 

Basics of Pressure

Pumps move fluid or gas by mechanically pushing it around, thereby creating the pressure that shoves it down the pipe or line. If you’re wanting to learn about pumps, you’re basically looking at systems designing to create and use pressure, so understanding a bit about pressure is helpful.

Gas, and to some extent fluid, will expand to fill whatever container it is put in. When it expands it presses on the walls of the container, which is referred to as gas pressure. When gas is placed into a large container, there’s less of it pressing out over a larger area, and therefore there is a lower gas pressure. If the same amount of gas is placed in a smaller container the gas pressure is higher, in the same way that the same number of people will fill a smaller room more tightly.

The point of compressing gas is usually to get it to do work. Gas and fluid will move from a higher pressure area to a lower pressure one. In the process it can move stuff and provide control or power. The lower pressure that draws higher pressure in is called a vacuum. An example of that is the stroke cycle of the internal combustion engine. As the piston moves down for the intake stroke, it draws air and fuel into the vacuum, the area of low pressure, that the motion creates. Forcing more gas into a container to take up less space is referred to as gas compression. Compressing air is essentially the same process, forcing more air into a small container to increase the pressure.

The pressure at sea level is about 14.7 pounds per square inch. That means that the air in the atmosphere above any spot at sea level weighs about 14.7 pounds. As you move upward, say hiking up a mountain, there’s less atmosphere above you and so there is less pressure. Lower areas have a higher air pressure.

Most pressurized lines and tanks will have a pressure or gas gauge. A common unit of measurement for gauges is inches of mercury, abbreviated as in. Hg, or known as inches of vacuum. With that system, the pressure is measured by a mercury within a graduated sight tube. While at sea level pressure is 14.7 psi, it’s measured at 29.92 inches of vacuum. Unlike atmospheric pressure, the vacuum can’t be increased beyond that amount.

Pumps

Figure 1. Side by side comparison of the same pressure measured as psia and psig.

Gauges in the US are usually measured in pounds per square inch, or psi. You may also sometimes see pressure measured in psig and psia. These are actually two different measurements. Pounds per square inch gauge, or psig, measures the pressure of what’s inside the line or tank compared to the local atmosphere’s pressure. Pounds per square inch absolute, or psia, measures pressure against a vacuum, and so the local pressure is included in that measurement. For example, a standard car tire at sea level will be pressurized to 35 psig, or 35 psi above the local pressure of 14.7 psi. That same car tire would be measured as 49.7 psia, as it’s the 35 pounds of the car tire’s pressure, plus the 14.7 pounds of the atmosphere’s pressure.

 

Common Uses For Pumps

Pumps do a lot of jobs around a lease operations, and it’s not unlikely that some creativity will occasionally be required. There are some things that pumps will be used for, however, no matter where you go.

 

Circulating Pump

Circulating pumps are going to be found in the majority of tank batteries. As the name implies, the pumps are used to circulate the oil and fluids in order to keep tank bottoms clean. It will also be used for a number of other tasks in the tank battery. Larger pumping operations will usually have a circulating pump as a permanent part of the tank battery. That pump is often electrically powered. A single-cylinder gasoline pump is a common choice when electricity isn’t available or uneconomical.

Smaller operations may have a hand carried or trailer mounted pump that can be moved from one tank battery to the next. Ideally, a pump of this sort should be easy for one person to use and transport. Units with pump and motor together are convenient for that reason.

Pumps

Figure 2. A circulating pump and control box designed as a permanent part of the tank battery.

Circulating pumps will be hooked into the system at the stock tanks’ drain, and then looped back around to the beginning, after the separator and before the heater-treater, gun barrel, or any other vessels used for cleaning the oil. This allows oil to be sent through the system for further cleaning, and also keeps it moving so that heavier elements don’t sink to the bottom. It may also be sometimes necessary to pump fluid the other direction.

Basic maintenance for these pumps includes replacing old packing, or lubricating bearings. The engine that powers the pump will need regular engine maintenance, like changing the oil and tightening or changing belts. A common problem with gasoline powered engines is a clogged carburetor, which can be caused by rust or other trash in the fuel tank.

 

Air Compressor

Natural gas is produced by many wells and so is a natural choice whenever you have a system that uses pressurized gas for control or power. However, it’s a choice that may end up costing you more than you save. There are a range of potentially corrosive chemicals in natural gas that are difficult to remove. Systems can be damaged, clogged, or otherwise broken by using natural gas for an extended period. Air compressors are not that expensive, and compressed air has many fewer problems when used as a source of power.

Pumps

Figure 3. An example of an air compressor for a tank battery, used for an automated control system.

Most air compressors on lease pumping operations run off electricity. Maintaining the compressor is therefore fairly straightforward. The oil should be checked and changed regularly, and it should be noted that the oil needed for a compressor will likely be different from that required by most engines. Belts need to be kept at the correct tension. Air filters need to be kept clean in compressors to keep efficiency up, and the compressor will also likely collect water through condensation. The other major concern in a compressed air system is leaks, which can cause slow downs and other problems. Air compressors are usually automatic, to supply the system with pressure as it requires, so maintenance requirements are usually low.

 

Gas Compressor

Gas can be used for many things around the lease, but using a gas compressor has more to do with keeping excess gas out of the air, collecting it, and potentially selling it. They’re used when a tank battery is closed to a populated area, or if large quantities of gas are likely to be produced. These compressors are usually automatic, using low pressure systems for control. Altogether, this is referred to as a vapor recovery unit.

The compressor collects the gas, compresses it, and then sends it to a natural gas sales system. Along the way, the gas is passed through a scrubber to remove any mist suspended in the gas, which is later routed back to the stock tanks.

The vapor recovery unit has a lubricating system which must kept filled and checked. Keeping records on how much oil you’re using over time can be a good way to catch problems before they become serious. It also allows you to determine how often you’ll need to add oil to keep the system topped up.

The Basics Of Maintaining Engines For Oil & Gas Production

There are probably going to be several engines around a typical lease pumping operation. Obviously, there’s the engine in the truck that gets you out to the lease site. There may also be generators if the lease is far from electrical lines, or as a backup power source. They can power pumps, and do a number of other vital jobs. The engines on the lease may run constantly, and so the ability to maintain and repair the engines around the site is an important one. This is particularly true with smaller and wildcat operations, when even small expenses can have an impact on profitability.

 

Engine Basics

Just about every modern engine is an internal combustion engine, meaning it’s powered by small, constant explosions. Gas and air are mixed within the engine, in the cylinder, and then compressed by a piston. With some engines, a small spark ignites the mixture. In diesel engines, the compression is enough to cause the explosion. The piston is driven down by the explosion, which turns a crank and provides power.

In four cycle engines, the piston moves four times per explosion. There are also two cycle engines which moves two times per explosion, but four cycle engines are more common. The first downstroke is the intake stroke, during which air and fuel are drawn into the cylinder through the intake valve. When the piston approaches the bottom of the cylinder, the intake valves open. In the first upstroke, called the compression stroke, the fuel and air mixture is forced upward and compressed into 1/10 the original volume. This heats the mixture.

The compressed mixture is ignited by the spark plug and the piston is forced down in the power stroke by the explosion. The cylinder is now filled with the byproducts of the explosion, which are forced out in upward exhaust stroke through the exhaust valve.

Each step must happen at the correct moment for the engine to be as efficient as possible. Engine timing is an important part of how the engine works, and a mis-timed engine will often cease to work altogether.

Engines

Figure 1.  Single cylinder engines are common around oilfields. This one has a large flywheel to provide smooth power. (courtesy Arrow Specialty Co., Inc.)

A large number of the engines around the operation will be single cylinder engines, meaning they’ll have only one cylinder and piston. Circulating pumps often are powered by single, vertical cylinder engines, and larger horizontal, cylinder engines are used to power mechanical pumps for some wells. Single cylinder engines that operate pumps usually are slower and have large flywheels. The flywheels use momentum to even out the power generated by the single cylinder engine. For the single cylinder engine, everything is kept relatively simple. There’s a single spark plug and a simplified electrical system. The sheave, which attaches to a belt to provide power to the pump or other piece of equipment, is usually larger and revolves at a slower speed.

Engines

Figure 2. To the left of the picture you can see a single cylinder engine using gas produced from the well as fuel.

Engines with multiple cylinders have correspondingly more complex requirements when it comes to electrical and fuel systems, and may need a separate battery, voltage regulator, coil and more for each cylinder. Multi-cylinder engines also usually have a smaller flywheel and so run much more quickly.

 

Maintenance

Maintaining a working engine is always preferably to repairing a broken one. The ability to performance basic, or even more complex, maintenance on the engines around your operation is a useful skill. Some things require the services of a shop with specialized equipment and specific know-how. Most problems having to do with the piston, cylinder, or valves are going to fall into this category. Most regular maintenance and some basic repairs can be done with a basic understanding of how each system works.

 

Electrical System

The electrical system in your car powers the radio, and probably the locks and windows. For most engines around the lease, however, the electrical system is used just to provide the spark which ignites the fuel in the cylinder. The spark is provided by the spark plug. Spark plugs must be the right size and within the right temperature range. These can include standard, hot, and cold. The points on the spark plug must also be set to the correct gap setting for the engine.

Most engines will have use a magneto to provide the spark for the explosion. These will have the points built directly into the magneto, as well as the condenser, distributor, and coil. Low tension magnetos are also available and are less prone to problems, but are more expensive. Solid state ignitions are also available.

The starter is provided with electricity either by the electrical grid or a battery. Batteries should also be cared for so that they last as long as possible. That includes protecting them from weather and extremes of temperature.

Other parts of the electrical system for an engine can include an alternator or generator, distributor, voltage regulator, and whatever wiring is needed.

 

Oil and Lubricating System

Oil is used to prevent friction throughout the engine, and it’s circulated throughout the engine outside of the cylinder. The amount of oil and the pressure at which it’s run through the system are two critical aspects of the lubricating system. The oil amount is measured by the level of oil in the engine. A safety measure is included in the form of a float and switch. If the oil level drops too low, the engine will shut down. A similar, but more complex, safety system shuts the engine down if the oil pressure falls too low.

The correct weight of oil must also be used for each engine. Weight in this case refers to the oil’s viscosity, or how easily it flows. 10 weight oil flows much more quickly than 40 weight oil, and oil will flow at different weights depending on its temperature, so it will often be labeled with 2 numbers. Oil that is 10-40 will flow as fast as a 10 weight oil when it’s cold, but will travel as slowly as a 40 weight oil when it’s hot.

Oil will also have a number of different additives in it, so the oil is doing more than providing lubrication. Some additives will improve the viscosity so that the oil sticks to the engine parts and does a better job of preventing friction. Other additives prevent rust or help to clean the engine. Oil and the additives it can contain will breakdown over time, especially when exposed to heat.

The oil and the oil filter will need to be replaced regularly. When doing so, you should use the correct weight and type of oil for each different engine.

 

Antifreeze and Coolant System

The coolant system removes heat from the engine by circulating water and antifreeze. The coolant then is run through a radiator that is open to passing air. The air draws heat from the coolant in the radiator, so that it can be cycled back into the engine to be used again. The temperature of the coolant is monitored, and if it gets too hot the engine is automatically shut down.

As the coolant used in most engines is water, it is in danger of freezing in cold weather. To prevent that, antifreeze is added to the water. The main component in almost all antifreeze is ethylene glycol. It’s also effective as a rust inhibitor and as a lubricant for the coolant system. Antifreeze also has a higher boiling point, at 263 degrees Fahrenheit, so that the coolant transfers heat more efficiently. While it’s unlikely for the coolant to freeze during a hot summer, it’s wise to continue to add antifreeze for other benefits it has.
The standard ratio of water to antifreeze is 1/3, or one part antifreeze to two parts water. That mixture is optimized for freezing temperatures to 0 degrees Fahrenheit. Different mixtures are better for other climates. The table below offers some mixtures optimized for a range of temperature ranges.

Ratio of Antifreeze Ratio of Water % of Antifreeze Freezing point

(in Fahrenheit)

Boiling point

(in Fahrenheit)

1 3 25 +10
2 1 33 0
20 7 35 -3
5 2 40 -12 258
20 9 45 -22
1 1 50 -34 263
20 11 55 -48 266

Fuel

The fuel that an engine uses will determine a lot about how it functions. An engine powered by gasoline will need a carburetor or fuel injector. Engines using other possible fuels like butane or natural gas will also need carburetors. Diesel engines will need a fuel injection system. You’ll have to maintain engines powered by many different fuels, so it’s a good idea to be familiar with as many as possible.

 

Gasoline

Just like your car, the gas you put in the engines on your lease should be of the right type and grade. Using the wrong grade of fuel can lead to reduced efficiency, as well as some longer term problems.

Gas can come with a number of different additives that do many of the same things as those added to oil. Some will prevent acids from forming through condensation. Carburetors can become clogged over time, so some additives are designed to help clean them. Water in the fuel line can lead to rust or freezing damage, so some additives help water pass through the system harmlessly.

Some will also improve the performance of the engine. Octane improvers will slow down the burning of the fuel-air mixture in the cylinder. That allows the power generated to be used more effectively, and also reduces the wear on the engine itself. Higher octane fuels can lead to better performance and a cleaner engine, but are also usually more expensive.

 

Diesel

Diesel powered engines don’t use spark plugs, as the heat generated by the piston compressing the air is enough to ignite the fuel. Fuel is injected at the moment the piston reaches the top of the cylinder and burns instantly. Because of the heat that is generated, diesel fuel has oil mixed into it as lubricant. Steel expands when hot, so diesel engines aren’t built with tolerances as close as gasoline engines. They’ll make more noise when they’re first started up and grow quieter as the engine heats up. Diesel engines have glow plugs that heat up the air in the cylinder so that the engine will start.

 

Natural Gas

Gas is an obviously appealing power source, particularly when it’s a product of the well you’re pumping. Gas from the well will often contain a lot of water. This has to be removed from the gas before it can be used as fuel. When you’re using the gas directly from the well, you’ll need to pass it through a regulator, so that it’s at the correct pressure for your system. The gas can then be passed through a wash tank to remove water.
Water in the fuel system can freeze in cold weather. It will condense out of the gas and the collect in low points in the system, eventually blocking the line. Adding a small, custom modified tank to the system to collect the moisture can help prevent blockages, as long as the water is blown out of the tank regularly.

Engines

Figure 3. The layout of a natural gas fuel system, showing the flow from well to engine including all major components.  (courtesy Arrow Specialties, Co., Inc.)

In Figure 3, you can see an example layout of the system. A scrubber and tank may be needed when supplying an engine with gas. The scrubber will remove water, though if the gas supply is dry enough to be used as fuel you don’t need to add a scrubber to the system. The volume tank will keep the fuel supply steady and the pressure steady; 6 or 7 ounces of pressure is usually required.

Larger engines will have a greater fuel need, and so a second volume tank may be needed. The rise, the pipe projecting upward in Figure 3 between scrubber and volume tank, is used to prevent a sudden rise in pressure or amount of gas.

Lease Electrical System and Motors In Oil & Gas Production

The electrical system on your lease is usually a vital part of the operation. The electricity it provides can power pumps and other equipment for producing and treating oil. The system will also provide power for lights, tools, and even a few conveniences like a radio. The cost of supplying the lease with electricity is the responsibility of the pumper, as it’s considered a cost of the pumping operation. The electrical system itself and the maintenance it requires will also be left to the pumper, and so it’s useful to understand some basics about the electrical system and electrical power.

 

Electrical Basics

Electrical power can either be direct current (DC) or alternating current (AC). With direct current, electricity flows one way consistently in a circuit. With alternating current, the flow of the electricity changes directions. How often the direction changes is the cycle rate, which in the US is 60 cycles per second. Other countries may have other cycle rates. It’s important to use both the correct type (DC vs. AC) and the correct cycle electricity for each piece of equipment.

Likewise, it’s important to use the correct voltage for a particular piece of equipment. Most household electrical systems are at 110 volts, with some bigger appliances like washers and driers drawing 220 volts. Larger equipment on a pumping lease may use as much as 440 volts. Using the incorrect voltage, cycle, or using DC power when you should be using AC, can all damage equipment, sometimes in dangerous ways. The electrical plugs for some equipment, and electrical outlets, will often have a different arrangement to prevent the use of an incorrect electrical supply.

Electricity will most likely not arrive at the lease site at the correct voltage, as electricity is transmitted long distances at several thousand volts. That’s obviously way too much for any equipment on the lease. Electricity in long distance lines is also three-phase (which has to do with the construction of the wire), while electricity will need to be single phase to be used on the lease. The voltage and phase will need to be changed using a transformer. The amperage, or amount of work the electricity can do, will be stepped up in a direct relationship to the stepping down of the voltage.  The transformer will usually be on a power pole, and hooked directly into the lease electrical system.

 

The Electrical System

The lease electrical system is really part of a larger electrical grid, starting with generators operated by the power company, and then sent to consumers through electrical lines. Though a pumping operation may use more electricity than a home, it’s still a small portion of the overall electrical grid. If you ever lose power on the lease, you’ll most likely need to contact the power company to let them know.

Electricity is distributed around the lease by electrical lines. Most leases will use a three overhead electrical lines, though a four line system is also used for some operations. Lines are run using electrical poles and fuses and any transformers that are needed.

Electrical System

Figure 1. Three lines and fuses on an electrical pole.

Electrical System

Figure 2. The second fuse from the right has been tripped.

There are three fuses on the pole for the three lines (with a four line system needing four fuses). The fuses are spring loaded so that it will fall when tripped, and can be easily seen. Examples of the fuses can be seen in Figures 1 and 2. In Figure 1, 3 functioning fuses can be seen. In Figure 2, you can see that one of the fuses has been tripped. When a fuse is tripped, you should shut in any equipment that is powered by that line. A blown fuse means a problem with the flow that could lead to damaged equipment. Contacting the power company should be your next step. They usually understand that power loss is a major problem and will act quickly.

 

Automation

One of the chief uses of the electrical system is powering automation systems on the lease site. This is particularly true of larger operations that depend to a greater extent on computer control. For smaller operations, automation usually consists of a control box with timers and fuses.

 

Control Boxes

For safety reasons, high electrical lines should drop to ground level and be run underground. A safe distance outside the well servicing area, the line should run down the pole to a fuse box with a disconnect lever that can electrically isolate the site. The line continues down and is buried in galvanized conduit and run to where it’s needed on the site. Electricity is routed through a control box before being sent to equipment.

In Figure 3, you can see a control box near the upper right. Electricity comes up from the bottom, flows toward the upper right where the control switch is located. The three round tubes at the front and on the lower half of the box are equipment fuses. Above them is a breaker arm, which can electrically isolate the equipment the box controls if there needs to be maintenance. There’s a wire to ground the box, as well, in case of lightning strikes or other surges. Wires hook the electrical supply to a small transformer which changes the electricity to 110 volts, and from there it powers the control switch.

The switch can be set manually to on or off, or to automatic to follow a schedule preset on a timer clock. The clock has three fuses. It also connects to a power motor, which will start equipment at times the clock is set. When that period ends, power is shut off.
The control box will have a few fuses and a reset button, both of which protect it against heat and electrical surges. It’s usually possible, with some basic knowledge, to solve the majority of problems you run into.

Electrical System

Figure 3. Control box and two timers.

Timers

Timers can be divided into two broad types. The time clock is mounted in a metal box about six inches wide by ten inches high and three inches deep. Rather than having a standard, analogue 12 hour face, it shows 24 divisions of one hour. Half the clock is white to indicate day, and half black to indicate night. For most timers of this sort, the day is divided into 15 minutes chunks when the equipment is either on or off. Depending on your needs and the wells production volumes, you can set the timer to run equipment at different times of the day.

A percentage timer works a little bit differently. Rather than running the equipment at specific times of the day, it will turn it on at certain times so it will run a percentage of the whole day. A timer will run for a particular period, usually between 15 minutes and an hour. You can then set the timer to turn things on for a percentage of that period. For example, a timer set to run 33% of the time on a 15 minute timer will turn equipment on for 5 minutes out of every 15.

 

Motors

Like other electrically equipment, electric motors usually need to be provided with a voltage of 110, 220, or 440. Depending on the size and operating specifications of the motor, they might run at 1100, 1400 or 1725 rpm, though motors have a wide range of speeds.

Electrical System

Figure 4. An example of a motor and control box. The motor can be wired to run at three different speeds.

An electric motor for a pump will normally have three groups of three wires connecting to the electrical system. Each group will be attached to a single wire from the control box. The direction the motor runs can be changed by switching two of the wire groups. The motor will have a plate on it which indicates how to hook up the motor.

There are motors that can be hooked up to either 220 or 440 volts. The plate with instructions will indicate if that’s the case, and how to wire the motor for each option.

 

Using Electricity Safely

Electricity is obviously useful, but it can also be dangerous if it’s not handled with caution. Safety procedures as well as good worksite habits are essential. Most often at a pumping well, you’re working by yourself, so it’s important to take responsibility for your own welfare. You’re going to have to replace tripped fuses, perform basic maintenance, and even due some simple rewiring if needed. There’s a few general rules which should be followed in every situation. Make sure that you’re always shutting off and isolating any electrical system from the power supply before you begin working on it. Where insulated gloves when handling electrical lines. Know what you’re doing before you start, and take a conservative attitude when it comes to risky situations.  

 

Operating Costs

One of the chief considerations when setting up your electrical system is the cost, both of assembling the system and the ongoing cost of using electricity. Power consumption is going to be a significant expense, and it can turn a marginally profitable well into one not worth working.

In return for running a power line to the lease, power companies will commonly require a 5 year commitment with a minimum amount billed. It’s possible to manage the cost of electricity by understanding how power companies charge. At peak usage times, for example during the workday, a power company will usually charge more. If the demand for electricity across the whole grid goes up, they’ll also increase their rates.

By taking advantage of lower cost time periods, you can help to manage the expense for your operation. Most pumps use less electricity when they’re up and running than when they first start. Timing things so a pumping cycle starts during a lower rate time period can show savings. Run equipment that draws less power, such as a circulating pump, during peak hours. Pumping the well and other high drawing activities can be scheduled for off-peak hours. Other pumpers and the operations manager should be able to provide some guidance on how to manage your electricity consumption.

Tank Battery Design In Oil & Gas Production

The tank battery is likely to be the largest part of your above-ground operation. Its job is to clean and store oil you pump until it’s ready to be sold. It’s makeup will depend on a number of factors, but primarily on the quality and quantity of the oil you produce.

Fluid produced from a well will include the oil you’d like to sell, and usually a number of other things as well. That will usually include natural gas, water, sediment, and other petroleum products like paraffin and asphalt. All of these have to be separated from each other before each can be sold, and that separation will be done by equipment in the tank battery. Most will at least include a separator, for breaking out natural gas. A heater-treater or gun barrel may also be necessary if you need to remove water and sediment from the oil.

The amount of fluid produced will determine the size of the tank battery, and the size of the lines and tanks. The amount and pressure of the natural gas produced determines the makeup of the gas system. Likewise the amount of water, and its potential to corrode lines or tanks, dictate the water system setup. The sales system for selling by pipeline is different from one for selling by truck. All of these different needs have to be met by the tank battery.

The tank battery can end up being somewhat complex. However, each part is used to solve a specific problem, or set of problems. If you’re thinking about designing your own tank battery, looking at a few examples of how those problems have been solved in the past can provide some useful insight.

 

A Basic Tank Battery

Tank Battery Design

Figure 1. This tank battery sells directly to a pipeline, and therefore doesn’t need stock tanks.

Some wells actually produce oil ready to sell, right out of the ground. When you’re pumping oil of that quality, the needs your tank battery has to meet are fairly simple. The battery in Figure 1 is an example of this sort of operation. Eleven different wells all feed into this one battery, which consists of a separator to remove gas and a sales system that’s connected directly to a pipeline using an LACT Unit. The separator is a large horizontal model to handle the volume of the wells that flow into it. This is fully automated and computer controlled, and therefore doesn’t need supervision. Instead, monitors sound alarms if problems are encountered.

Tank Battery Design

Figure 2. The header for the tank battery in Figure 1. Pictured is the conical oil-saver hopper used for recovering residue oil.

The header for this system is shown in Figure 2. As the separator is the only tank in the tank battery, there’s just two larger separator lines (with positive choke valves, heading to the upper left) and a smaller test line. Below the positive choke valves is the oil-saver hopper, where residue oil can be poured to be injected back into the system.

 

Single Vessel Tank Battery

Tank Battery Design

Figure 3. A tank battery consisting of just one vessel.

When a well isn’t producing any water and there isn’t enough gas to be captured and sold, the tank battery can be just one vessel for storing oil prior to it being sold. Other types of operations may have a similar setup, such as a gas well that doesn’t produce any water or condensate. It could also be the water tank from a gas producing well. In many cases, there’s no way to know without checking the details of the well.

Tank Battery Design

Figure 4. A tank battery with just one vessel. In this case, it’s a custom, shop-made gun barrel.

You may only need one vessel when a well produces small amounts. In Figure 4, you can see a shop-made gun barrel being used with a covered pit. The gun barrel is a vessel designed to remove water and sediment from oil. This setup includes a backpressure valve on the gas line, which helps to prevent loss due to evaporation. In addition to the loss of volume, it also lowers the weight of the oil.

 

Multiple Vessel Tank Battery

Tank Battery Design

Figure 5. A tank battery that includes a gun barrel at the left, a water tank and two stock tanks.

Most lease pumpers will have to deal with separating water sediment from the oil before it can be sold. The amount of water and sediment that needs to be removed determines the number, size, and kind of that equipment. In Figure 5, you can see a tank battery that includes a gun barrel, on the far left. There is also two stock tanks and a water tank. A walkway crosses the lower three tanks, and there’s a ladder to the top of the gun barrel, all intended to make access to and testing of the contents easy.

Tank Battery Design

Figure 6. In this tank battery, there are larger, 500 bbl stock tanks, two tall heater-treaters, and two sales meters for gas.

Other wells may need more complex setups. In Figure 6, you can see a tank battery that includes 2 heater-treaters, but no gun barrel. The smaller heater-treater in Figure 5, to the right, is a test vessel. Like gun barrels, heater-treaters use gravity and some other natural forces to separate water from oil. Heater-treaters also use heat to aid in the separation. This arrangement is most likely necessary because the oil is producing heavier oil, with an API gravity of 30 or lower. The addition of heat increases the efficiency of the separation process. In some cases, a gun barrel might also be required to give water more time to break out.

Each tank battery is going to be designed around the well and what comes out of it, which means that each tank battery is unique. Any design that meets the needs of the operation and is laid out in a clear and efficient way, however, is going to be a good design.

How To Sell Your Oil & Gas Production

Sales System

Figure 1. Diagram of a tank battery. The sales system is labeled with an S.

The goal of any pumping operation is obviously to sell oil. Once the fluid produced from the well has been separated, and the crude oil has had enough sediment and water removed to meet the buyer’s standard, it’s ready to be sold. The sales system is everything after the stock tank, all of the lines that bring the oil to the transport system.

Obviously, this is an important part of the operation, and of the tank battery. This is particularly true as the sales system has to meet standards set by specific regulations. It’s where the interests of the pumper, the owner of the mineral rights, and the buyer of the oil all meet, and so the regulations are very strict to protect all concerned.

 

Common Requirements For The Sales System

The valves on the sales system are usually required to be sealed when not in use. Seals can be flat, locking the valve, or use wire and a lead seal. They’ll usually have some information on them, including the name of the purchasing company and a serial number. All these seals have to be accounted for, and if you remove one for any reason, you should hang on to it. You’ll almost certainly be required to return it and explain why it was removed.

The tank openings for the sales lines are usually about 12 inches from the bottom of the tank, allowing room for emulsion to collect there. Sales lines are usually 4-inch diameter pipe.

 

Transporting By Truck

Trucks are common when a pipeline isn’t economical, or can’t be run for some other reason. The truck will connect to the sales system using flexible hoses, and while there can be some loss it’s usually quite small. There should be a grounding post near the sales opening for the driver to connect to, which will help to prevent sparks.

Sales System

Figure 2. A sales system set up to sell by truck transportation.

In Figure 2, you can see the sales lines for a tank battery, as well as the tank for holding sales oil and a water tank. This operation is also set up to dispose of water through truck transportation, and so there are lines to the water tank as well. These lines are at the standard 12 inch height. The sales oil tank is sealed, as is required. There’s also a riser, which you can see to the left of the sales oil line valve. That allows the valve to be controlled from the ground, so you don’t have to spend as much time near the thief hatch. Fumes there, particularly when there’s hydrogen sulfide, can be dangerous.

Sales System

Figure 3. A mailbox near openings to allow truck transport. This allows you to exchange receipts and other paperwork.

You’ll usually need to be there when the truck driver is hooking up the sales tank. However, that’s not usually the case when water is being trucked out. A mailbox is shown in Figure 3, so that the you and the lease pumper can communicate and leave paperwork.  

 

Transporting By Pipeline

The sales system will often lead directly to a pipeline owned by the purchasing company. With this setup, using a Lease Automatic Custody Transfer (LACT) Unit allows oil to automatically sent through the sales system and sold. The stock tanks that feed into the sales system essentially act as surge tanks, then, with crude oil flowing into the stock tanks until enough oil of sufficient quality has been collected. The LACT Unit will activate and sell oil through the pipeline. When the level of oil eventually falls low enough, the LACT Unit will shut in the tank. There’s usually two switches inside the tank to activate the LACT Unit, one about 2 feet off the bottom, and a second one or two feet higher. This setup prevents gas from being sucked into the sales line, and is generally pretty reliable.

Sales System

Figure 4. A LACT Unit from two angles.

Water Systems In Gas & Oil Production

Water Systems

Figure 1. A diagram of the water disposal system, and the circulating system. Water flow lines are marked W.

It’s common for the fluid pumped from a well to contain some amount of water, particularly in reservoirs that are driven by water pressure. As production volumes grow, and through the life of the well, the volume of water produced will increase. As the proportion of water in the fluid grows, specific vessels for separating water are going to be needed. The water that is separated out can be useful, and the equipment needed for handling it can also have more than one use. Understanding the equipment, other uses for it, and how to handle produced water are all important.

The heater-treater and gun barrel (also known as wash tank) are two common vessels used for separating out water, as well as gas, from the oil. There is also some other, more specialized equipment that can be used.

 

Water In The Heater-Treater And Gun Barrel

Both of these vessels use gravity and a few other natural reactions to separate the oil, water, and gas. They don’t require any power, but merely time and a certain amount of liquid pressure to keep the fluid flowing.

Water Systems

Figure 2. A heater-treater, showing inlet and outlet lines, as well as the water leg.

Crude oil enters through the inlet on the upper right side of the vessel in Figure 2. As it does, gas flash separates, meaning that it leaves the water within a relatively short period of time. Oil and water flows through a downcomer line to the bottom of the tank. The gas line is at the very top, then leading to the right, and pipes out natural gas released from the fluid. Oil floats to the top and the heavier water flows out through the drain at the bottom. Cleaned oil, which has had gas and water removed, flows out through the lowest right line, the closest in to the tank.

The water passes through the water leg, which is the small tower to the left. It consists of a larger pipe, a narrower pipe running inside the larger one, and a wider compartment at the top. Water flows from the drain up through the narrower pipe to the larger space at the top. Additional gas separates at this point. A small line runs from the the compartment to the top of the tank, equaling the pressure between the two. Water flows over the top of the smaller pipe, and then down into the outside leg and then to a dump valve.

Raising and lowering the water leg will change the water level inside the tank, also changing the amount of oil held in it. This can have an effect on the efficiency of separation, so while adjustments are sometimes necessary, it’s important to be aware of the consequences of those adjustments.

Both water in the water disposal line and clean oil in the oil flow line are both held to a height of about 4 feet above dump valves. These valves are usually controlled by a weight on a lever arm, which can be adjustable. Adjustments are generally unusual. The valves don’t control the height of the water in the tanks, only what’s held in the out flowing lines. The amount of liquid held in the tanks is controlled by height of the outlet lines on the tank.

Gun barrels operate in generally the same way as heater-treaters, lacking only a firebox to add heat to the separation process. Figure 3 shows an example of a gun barrel, with the emulsion entering an inlet on the left of the flume, the tower beside the tank. Gas breaks out at the top in the large compartment, and the liquid drops below where it enters the gun barrel and is then spread across the bottom. The clean oil flows out through the line near the top left of the tank and is piped to the stock tanks.

Water Systems

Figure 3. Gun barrel with a water leg on the right.

The water leg in this example is actually the thicker pipe attached to the top and right side of the gun barrel tank. Water is drained through the lower tank outlet on the side, and then up a smaller inner tube within the larger visible pipe. It then overflows at the top and is piped to the water disposal tank. The connection at the top is used to equalize pressure and stabilize the water leg. There’s also a support arm extending from the side of the tank and holding the pipe with saddle clamps. Some pipes, particularly plastic or fiberglass, need more support to keep the line stable, which helps prevent leaks.

 

Circulating Pump And Systems

Once oil reaches the stock tanks, it may need to be circulated back through the heater-treater or other vessels to continue to remove water and sediment. Circulating the fluid can also help to keep the bottoms of tanks clean. The circulating system pumps the oil from the stock tanks and back to the other vessels, which is necessary as the stock tanks are at the end of a gravity fed system.

For smaller operations, the circulating pump will usually be operated manually. As an operation grows and volume increases, that can become impractical and so automation is used. That usually requires some investment in upgraded equipment. However, it is worth it as the amount of time, equipment, and chemicals needed for separating the larger amounts of oil are reduced.

With automation, there is always the possibility that an error or malfunction could lead to a spill. In high volume operations where automation is more common, spills can be large and extremely costly. When using automation, keeping your equipment well maintained is vital.

The circulating pump can also be used to pump fluid for other purposes, including moving water for waterflood operations or disposal. It can be used to empty a vessel for inspection or cleaning, refill empty vessels, and for filling a tank prior to sale. It’s flexibility will depend on the system’s complexity. Some circulating systems are fairly basic and have only a few functions. Others are designed to be able to do more. The circulating system can’t be used for everything, but there are a few problems it is commonly used to solve.

 

Common Uses Of A Circulating Pump

The most basic problem a circulating system address is a rise in the amount of sediment and water in the oil. That has to be lowered before the oil can be sold, so the oil is circulated back through the separating vessels. As is explained below, care should always be taken that the vessels can handle the additional volume.

Water Systems

Figure 4. You can see the circulating pump in the background of this picture, next to the heater-treater. Also pictured are a stock tank and drain lines.

It’s also helpful to be able to drain any tank using a circulating pump. Tanks and lines will need be maintained and repaired many times in the course of pumping a well. Connecting the circulating pump to a tank’s drain allows you to empty the vessel fairly easily if you need to access the interior. Otherwise, emptying a vessel can be a time wasting pain.

Another common use is also helping to keep the bottoms of tanks clean. A regular circulation of oil through the system can help with this. But you’ll probably have to dedicate some time to cleaning tanks’ bottoms, which may require additional tubing that can be lowered into the tank and some other equipment. The circulating pump can make this operation easier.

A good circulating system should allow you to manage your water pumping and disposal needs while still allowing normal separation operations. The water outlet from those vessel should continue to feed into the water disposal tank, as that’s a gravity feed flow and therefore doesn’t need pumping.

A problem to be aware of when both these operations are underway at the same time is overflow, or build up of one or the other liquids. You’re pumping oil into the tank, so you want to make sure you keep the in and out flows balanced. Otherwise, you may end up pumping too much oil, forcing more water out of the tank than you want, which leads to a drop of separating efficiency. In some cases, you may begin to lose oil down the water disposal line. That sort of loss of balance can be a big problem, and should be addressed immediately.

You can also end up with too much of one kind of fluid for a few other reasons. Some are caused by errors in design, such as water lines that aren’t big enough for the flow or an incorrectly set water leg. Others are errors in operation, such as circulating oil for too long or not allowing the vessels to reach a balance after circulating. Some stem from changes in production, such as lower production, or a change in the weight of the water being pumped.

 

Water Disposal Tank

Water disposal tanks are usually fiberglass, and have some sort of cover to keep wildlife out. A small operation’s tank will hold one transport load of about 250 barrels of water. These tanks are about 8 feet tall, and may have guy lines or other equipment to keep them stable. Larger operations need greater holding capacity, and may have 20 ft tall tanks capable of containing a couple thousand barrels of water. The tanks will need to be inspected for water level regularly, so some sort of access stairway or ladder is necessary.

Water Systems

Figure 5. The water disposal line from a gun barrel’s water outlet. This flows to the water disposal tank.

Water in the disposal tank can be reused for some purpose in the pumping operation. With those operations, a blanket of oil may be maintained over the water to prevent the water contacting oxygen in the air, which can lead to corrosion.

 

Water Disposal

Water, if not used elsewhere in the operation, is usually injected back down a well to keep the reservoir’s pressure. For smaller operations, there’s simply a pump that sends water to an injection well.

Water Systems

Figure 6. An example control unit for water injection.

If that’s not possible, water may be hauled by truck to an injection well. A single load will be between 160 and 200 barrels. You may have to pay to have this water trucked and disposed of, if you’re not running your own water injection or waterflood operation.

Equipment For Handling Crude Oil In Oil & Gas Production

Crude Oil

Figure 1. A diagram of a tank battery with crude oil lines marked with an O.

Crude oil is what you have after natural gas has been separated from fluid pumped out of a well. It includes oil, other petroleum products such as paraffin, and water. The crude oil system and lines are everything in the tank battery after the separator, including stock tanks, heater-treaters, and other tanks and lines. When you’re laying out a tank battery for your operation, it’s helpful to keep a few standards and regulations, as well as some useful tips, in mind.

Standard practice is to have a line piping the separator’s output directly to the stock tank. You can use a diverter manifold to add line openings to specific tanks and equipment, like a gun barrel or heater-treater. That allows you to choose whether to send the oil to a stock tank, or first run it through some additional steps to remove more water.

 

Specialized Vessels

Once crude oil has been diverted into a specialized vessel like a heater-treater, it will often have to follow a separate path back to where it is held in the stock tanks. When you’re producing fluid that contains a low to medium weight oil and has heavier petroleum products, a heater-treater is most likely to be the first specialized vessel.

 

The Heater-Treater

As a heater-treater may sometimes burn gas to heat crude oil as part of the separation process, it has some special safety considerations. First, the heater-treater’s firebox should be fitted with a flame arrestor. In addition to this, a heater-treater should be at least 100 feet from the nearest hatch through which gas could escape. That means you’ll need to lay out a little more line when placing a heater-treater.

Crude Oil

Figure 2. Heater-treaters and their inlet and outlet lines. Though it’s hard to tell in a black-and-white photo, the lines are color coded so they can be easily identified.

Figure 2 shows a couple of standard heater-treaters with their inlet and outlet lines. On the left is a heater-treater built according to a standard layout, where it’s fairly straightforward to identify the lines. The inlet would be the highest line on the right side, and the second highest line being an oil outlet. The water drain is near the bottom on the left, and the gas line is seen at the top. The placement of these lines is determined by their use and the operation of the vessel.

The heater-treater to the left has lines all in a single row. Starting at the right, the lines are: the inlet, the gas line, oil outlet, and the line leading to the water disposal tank. While it may be hard to figure out which line is which by just looking at the picture, where all you can see is the tank, it’s usually much easier to understand each line in the context of the tank battery. Often, you can follow a line from one vessel to the next to understand its purpose. Even when the line is buried, it’s usually possible to understand what it’s being used for. It may require you to access the buried line and, with a flashlight appropriate for working around oil and gas, trace the lines and outlets.

The operation of a standard heater-treater is fairly straightforward. Crude oil flows in through the inlet, and is directed through a downcomer near the bottom. Oil rises, past the heating element, and through a number of plates that act as baffles. At each step, water falls to the bottom where it is drained, and oil floats to the top and then flows out of the tank. Horizontal heater-treaters operate somewhat differently, using electricity to increase the vessel’s efficiency.

 

The Gun Barrel

A gun barrel is used to remove additional water from the oil. A line can be run to an inlet at the top of the gun barrel. Another arrangement that is popular, and increases the efficiency of a gun barrel somewhat, is to use an external side boot. Figure 3 shows an example of the side boot setup. With that, oil comes from the line, enters the bottom of the 2-inch pipe, and flows up to the larger container at the top. That’s the flash separator, where more gas is separated from the fluid. The fluid then travels down to enter the gun barrel about 12 inches from the bottom. In Figure 3, you can see that the side boot has a number of additional braces so that the gun barrel is supporting the top.

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Figure 3. Gun barrel with a side boot inlet.

Once the oil enters the gun barrel, it hits a spreader which disperses the oil across the tank. Oil floats to the top while water sinks to the bottom and is drained.

 

The Stock Tanks

Once the crude oil has finished its trip through any specialized vessels, it is routed back to a stock tank for holding. Most often, the outlet line from the gun barrel will lead right to a stock tank. The distance for this is generally short, as it’s helpful to keep these tanks all in close proximity for a number of reasons. In Figure 4, you can see an example of a gravity feed line from a gun barrel to a stock tank. You’ll want to make sure this line is big enough to handle your production volumes.

Crude Oil

Figure 4. A line flowing from a gun barrel to a stock tank. The line is closed in this case, as the valve’s handle is perpendicular to the pipe.

 

Stock Tanks and Selling

Stock tanks are where oil is held, the last place it’s routed to on the lease. It seems like it should just stay there and stop moving around at that point, but in reality it can be helpful to put equalizer lines across your stock tanks. These are lines that protrude from high on the side of the tank, and allow oil to flow between two tanks. If one stock tank is full, rather than overflowing, the oil is sent through the equalizer line to the next stock tank. These lines also make it easy to automatically top off each tank, as one tank will fill completely before oil flows to the next.

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Figure 5. The first type of equalizer line, which runs directly to the next stock tank.

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Figure 6. The second sort of equalizer line, where oil can be directed to specific tanks.

In the two pictures, you can see two methods of adding equalizer lines to your stock tanks. With the method Figure 5 shows, oil can only flow to the stock tank that’s directly connected. For the second arrangement, valves can be opened and closed to send oil to a specific tank. This method requires more room for piping and valves, and isn’t always possible due to the tight spaces created by walkways, lines, and other tanks.

The goal, ultimately, is to produce oil and get it in a state fit to be sold. When that happens, there’s a bit of a process that has to be followed. A number of valves are required to be locked closed to isolate the stock tank, a seal has to be inserted.

Seals come in two general types. One locks to itself, and the other uses wire and a soft lead seal. Both the inlet for oil and the drain line will most likely be sealed for the selling process. A seal will have some information on it, such as a serial number and the company buying the oil.

Once the oil in the sales tank has been sold, everything is returned to normal operating state, and a seal is again placed on the sales outlet. Keeping track of the seals is vital, as they will need to be kept track of and occasionally returned to the pipeline company.