Lease Pumper's Handbook Published
by the Commission on Marginally Producing
Oil and Gas Wells of Oklahoma, First
Edition 2003 Written by Leslie V. Langston
Table of Contents Introductions A. Cover
Sheet Book Title B. Publishing Information
First Edition, 2003
The Lease Pumper's Handbook
Published by the Commission on Marginally Producing Oil and Gas Wells of Oklahoma, First Edition 2003 Written by Leslie V. Langston Table of Contents Introductions A. Cover Sheet Book Title B. Publishing Information First Edition, 2003
Written by Leslie V. Langston
Publishing Information. First Edition, 2003. C. Foreword. Rick Chapman, Executive Director (1996-2000) Commission on Marginally Producing Oil and Gas Wells, State of Oklahoma. D. Dedication. John A. Taylor, Chairman (1992-1998) Commission on Marginally Producing Oil And Gas Wells, State of Oklahoma. E. Author’s Introduction. Leslie V. Langston, Author, First Edition F. Commission Introduction. Liz Fajen, Executive Director, Commission on Marginally Producing Oil and Gas Wells, State of Oklahoma.
The Lease Pumper’s Handbook
Testing, Treating, and Selling Crude Oil
SELLING CRUDE OIL
D-1. Preparing to Sell the Oil.
Preparing to sell a tank of oil requires substantially more work than the actual sale itself. If the gauger thinks the pumper is careless in preparing the tank for the sale and the oil must frequently be rejected, the gauger will be more inclined to refuse the oil. A turndown should be a rare event. Some leases have very difficult treating problems. Every lease has its own treating characteristics. Turndowns are bad for both the pumper and the transport gauger. The gauger must always have a back-up load to pick up in event of a turndown. However, this alternate load may be many miles away, causing the gauger to haul one less load that day. His company and possibly the gauger will make less money. The three conditions that must usually be met for acceptance are: · A full load is available. · The bottom is a minimum of 4 inches below the outlet connection. · The BS&W throughout averages 1% or less. End of the month oil sales overload. If a tank of oil is almost full and the end of the month is approaching, the tank should be sold. This will allow the employer to receive his payment for the oil a month earlier than if the pumper waited until next month. Most employers appreciate the pumper selling all oil possible this month. However, all pumpers in your area will also think the same thing. As the end of the month approaches, the gauger or purchaser is flooded with requests and not all can be honored. Tank runs should be reasonably scheduled in advance with your purchaser to prevent this problem. Full tanks normally carry a priority over almost full tanks with your gauger at the end of the month.
D-2. Selling Oil Requirements for a full transport load.
Crude oil purchasers usually require the accumulation of a full truckload (Figure 1) or tank full of oil before purchase. The two reasons for this requirement are safety and cost. Figure 1. Selling oil by truck transport.
· Safety. It is difficult to transport a partial load of liquid safely. When the transport turns a corner, oil will climb up the wall of the tank and with excessive speed can turn the truck and trailer over. When the transport goes up or down inclines, the liquid rushes back and forward with a powerful force. Although the trailer tank is built with baffles to help withstand these forces, the safe trailer is a full one. · Cost It costs the same amount to haul or pump into a pipeline regardless of whether the tank is full or not. It is a matter of economics to require a full load before purchasing it. Selling split loads. It is difficult to sell less than a full load of oil. However, most purchasers will accommodate emergencies such as a hole in the tank or problems with a vessel. Possibly there is another tank nearby that will allow the transport to be fully loaded. Occasionally when there is a partial load of condensate and the weather is hot, the evaporation will equal and even exceed the production. The lease pumper must recognize such problems and search for reasonable solutions. Communication with the gauger. Each area may have a different method of communicating to the gauger that there is a load of oil ready for sale. Some oil transported by pipeline still uses a visual cueing system of metal markers at the tank battery. As gaugers make their rounds, they put the oil on line when they drive by. These days, however, requests are usually called in by radio or telephone. Regardless of the system used, adequate notice should be given to the gauger. The note jar. Every tank battery should have a note jar (Figure 2). This can be as simple as a pint or quart clear glass jar with two holes punched in the lid. The lid is wired to the outside of the tank walkway steps, creating an efficient mailbox. When the gauger puts a tank on the transport line, a note is usually put in the jar with the top reading. After the tank of oil is sold, a copy of the run ticket is left in the jar if the pumper is not present. Different companies have different policies regarding the witnessing of gauges and selling oil. Figure 2. Glass jar for pumper-to-gauger communications when selling oil. Witnessing the oil sale and the rejection notice. When the gauger rejects the tank of oil for purchase, a rejection notice on a printed form is placed in the tank battery note jar, and a copy possibly turned in to the purchasing company. The form will list reasons the load was unacceptable, date, pumping company name, lease and tank number. Some companies require the pumper to witness every step of the purchase or rejection. Even if not required, it is still a good practice. Sometimes it is necessary for top gauges to match. If the ambient temperature is warmer than the tank of oil, the gauged volume will increase. If it is lower, the gauged volume will decrease. This is a normal situation. If the pumper last gauged yesterday, the level will almost certainly always be slightly different today.
D-3. Seals and Seal Accounting.
There are two types of seals in common use (Figure 3). The most commonly used type for years has been a flat, narrow metal style that must be pushed through a dart in order to be installed correctly. Figure 3. Two styles of tank seals. The second style is a soft wire that has a lead head. The wire is run through a small hole, then doubled back and run through it again. The wires are pulled tight, and the lead is crimped to hold it in place. The wire must be cut in order to remove the handle or open the valve. When a tank of oil is sold by transport or by pipe line, the seal on the sales line valve on the front of the tank must be cut, removed, and the number on the seal recorded. At the end of the sale a new seal is placed through the dart, and the valve is resealed until the next sale. These seals are put on the tank by the purchasing company and usually have the name of the company imprinted in raised letters on the seal. The seal must be cut in order to remove it. If this seal must be removed for any reason, the owner of the seal should be notified. If the oil is sold by transport, the regulations for cutting the seal may not be critical. If the oil is sold by pipeline, a witness from the pipeline company may need to be present for removal and replacement of the seal. If the oil is sold by transport, the seal on the sales line valve will possibly be the only seal used. If the oil is sold by pipeline, the valve may be open from six hours to two days, so before the sales line valve is opened, the drain line on the back and the inlet valve must be sealed. These seals must remain in place until after the sales line valve has been closed and the seal replaced. The run ticket. The run ticket (Figure 4) is proof of an oil sale, listing the purchaser, date of the purchase, seller, method of transportation, lease location, lease name, tank battery, and other information. Figure 4. A run ticket. 13D-4 The tank number at the battery is usually assigned by the oil purchasing company. Tank numbers are in order from left to right when facing the tank battery. If the numbers are not in sequence, this usually implies that a tank has been replaced or has had a problem that required the capacity to be restrapped. The run ticket illustrated in Figure 4 shows that the tank had a capacity of 210 barrels, and the 15-foot tank contained 13 feet, 5 and no quarter inches. Since the bottom of the equalizer would be at about the 14 foot level, the tank was within 6 inches of maximum capacity. The 4-inch pipeline connection is 1 foot high, and the oil was pulled down to 1 foot, 6 and 2/4 inches. To pull the oil down to this level, the transport driver would have had to slow the pump suction down at about the two foot level, then keep lowering the suction speed to prevent air from being sucked in. It would take too long to lower the level using this procedure. The BS&W level was 5¼ inches and was 2½ inches below the maximum allowed level. The observed gravity of 38.3 is below 40 gravity, so there may have been a small price reduction for lower gravity. The BS&W level throughout the tank was 4/10 of one percent, well below the 1% allowed. The observed temperature on the thermometer was 72° F. The temperature on the hydrometer was also 72°. There would be a small volume adjustment for temperature correction. The truck drove 132 miles round trip to haul the oil, and it took from 11:50 until 12:20, or 30 minutes to load the oil. This is a long distance to travel if the oil must be rejected. There are 533 numbers difference in the number of the seal that was removed and the number of the one replaced. This is a marginally producing well. A check for payment will be made the following month. Typically, the royalty owed to the mineral rights owner will be mailed directly to this owner and the operator’s share will be mailed to the operator.
D-4. Selling Oil by Use of the LACT Unit and Surge Tanks.
The best method for selling crude oil is by use of the lease automatic custody transfer (LACT) unit (Figures 5 and 6). Figure 5. The LACT Unit. Oil travels left to right through this system. The control panel is visible in the background. Figure 6. A picture of a second LACT unit. The two lines in the foreground are for the prover loop. 13D-5 Oil can be produced to the LACT unit by use of the oil line that comes over the top of the tank, and the LACT sales line is left open at all times. As oil is produced into the stock tank, it rises and a level controller turns on an electric motor in the LACT unit. As the oil is sold and the level of oil lowers, the level controller turns the LACT unit off. The stock tank will act as a surge tank to achieve this objective. The first component of the LACT unit is a liquid transfer pump. The purpose of this pump is to place the fluid under approximately 30 pounds of pressure. This reduces the amount of gas that may break out while the oil is in the LACT unit and allows a positive displacement meter to operate accurately. The last component before the pipeline company’s system is a backpressure valve to maintain this pressure. As the oil travels up through the riser, the BS&W percentage is constantly monitored. The BS&W monitor controls a diverter valve. As the oil moves across the top of the riser, it passes through a screen and air eliminator. As it moves across and downward, a sample of oil is diverted into the sampler tank for BS&W analysis. BS&W is never monitored on a horizontal line because the liquids separate and stratify. As the liquid return horizontal, it passes through a three-way diverter valve. If the oil is not sellable, it is diverted back through the treating facilities. If it is pipeline grade oil, it will continue through the positive displacement meter, the prover manifold, and the backpressure valve. At this point it is now owned by the pipeline company. The prover loop determines the accuracy of the positive displacement meter. As pumps wear, they usually pump more fluid than is indicated on the meter reading. After the meter is tested, a correction factor is given to the lease operator and the oil purchaser. The reading is always close to 1.0000. A typical reading might be 0.998 or 1.0015. The gauger and the pumper will periodically meet at the LACT unit and blend the oil in a sample container and work a sample. They will then empty the sampler tank back into the sales line and read the meter. These figures, along with the temperature correction and correction meter number, will determine the oil sales since the last average to be computed. Hot oiling. It may become necessary to call for a hot oiler, a truck mounted with a propane heater to treat the oil. Cold oil is pulled from the tank bottom, heated, then put back into the tank. This thins the oil, melts paraffin back into a liquid state, and allows water to fall out. Chemicals can be added to assist in reducing surface tension on the droplets of water. Oil movement also assists in this treating. Hot oil is more difficult and dangerous to pump because of the change in viscosity and the danger of ignition of vapors coming off the heated oil. Some truck transport companies may not purchase the oil after hot oiling until it has cooled to less than 100° F. It is to the advantage of the production company to sell the crude oil as quickly as possible after hot oiling in order to sell more paraffin and remove it from the system so that it cannot congeal and cause problems again in the tank.