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
The Tank Battery
THE CRUDE OIL SALES SYSTEM
Figure 1. Components of the crude oil sales system are marked with an S.
G-1. The Oil Sales System.
The oil sales system (Figure 1) is one part of the tank battery system that must meet specific regulations. This is because a part of the oil contained in the vessel is owned by the well operator, but some of it belongs the mineral rights owner(s). The oil purchaser, pipeline, or transportation company pays each of these parties separately for the oil purchased. Regulations governing the accumulation and sale of crude oil are very rigid to protect the interests of both parties. All valves below the liquid level line may be required to have seals on them, but the sales valves have recorded seals that cannot be removed without accounting for every seal. These seals are placed on the sales valves by the crude oil purchaser, and, if any are removed, they may have to be saved and 10G-2 turned in to the office for accounting to the transportation company as to why it was removed. The sales line openings are usually located 12 inches above the bottom of the tank. This provides sufficient room below the opening for the emulsion that accumulates on the bottom and cannot be sold. The normal field tank has sales openings for 4-inch pipe and, normally, 4-inch pipe is used in the full sales system.
G-2. Selling Oil by Truck Transport.
Oil is sold by transport when a pipeline is not available or the cost of installing a pipeline cannot be justified. The transport truck supplies the flexible hoses utilized to complete the connection from the truck to the line opening. A good truck driver will not lose more than a few drops of oil when the loading has been completed. The tank battery pictured in Figure 2 has two tanks, one for water and one for storing produced oil. The two lines are connected to the tank at the 12-inch level. The oil tank has a seal that was placed on it by the contracted oil purchaser, but if the water tank has a seal, it would be put on by the oil operator. Figure 2. A tank battery set up for transporting oil by truck. Both tanks have separate lines and a box to catch any spilled oil or water from the loading process. Most operators require their lease pumper to be present when oil is sold. When water is hauled, it is not necessary that the lease pumper be present. A mailbox (Figure 3) is provided for the convenience of the transport driver and the lease pumper so that they can communicate with each other. The transport driver has a place to leave the load ticket, and the pumper can communicate where and when the next load will be available. Figure 3. A mailbox is provided to allow communication between the transport driver and the lease pumper. Note that a riser is located to the left of the oil sales line valve on both tanks. This allows the tanks to be switched from the ground and reduces the amount of time that the lease pumper must spend near the thief hatch opening, especially when the tank contains a high level of hydrogen sulfide. A grounding post is provided near the hose connection box to give the truck driver a good, stable connection to ground the truck before the oil or water loading process begins. This reduces the possibility of a spark occurring in the area of the liquid opening.
G-3. Selling Oil with the LACT Unit.
Selling oil by the use of a Lease Automatic Custody Transfer Unit (Figure 4) is an ideal method for selling oil. In this system, the oil sales line is always left open to the stock tanks. The stock tank then acts as a surge tank since the LACT will operate intermittently. As fluid builds up in the tank, a switch sends a signal to the LACT unit so that it will come on and begin selling oil. As the fluid gets low in the tank, it will shut the unit in, and no more oil will be sold until the level comes back up and the cycle begins again. The sale cycle will continue as long as the tank battery is producing pipeline oil. This term indicates that the BS&W level is low enough for the oil to be acceptable. If the BS&W level should get high enough that the oil is no longer acceptable pipeline oil, the BS&W diverter valve will open and send the oil back to the heater/treater. The detector probe on the riser of the inlet line of the unit will continue to reject the purchase of additional oil until pipeline oil is again detected. At that time the detector probe will send a signal to the diverter valve to change to the sales position, and sales will begin again. The reading on the sales meter will be recorded daily. The BS&W sampler must be blended or mixed periodically and the average determined. This correction factor will be effective for all oil sold since the last time that it was averaged. Since the oil contained in the sampler is owned by the production operator, the sample will be circulated back into the upstream sales line or stock tank. A second factor that must be used to determine how much oil has been sold is the positive displacement meter test. The number should approach 1.0000 but will generally be a little over or a little under, such as 0.9997 or 1.0009. These tests are performed by a meter testing company using a trailer-mounted meter prover or a master meter with its own meter factor. The oil sales opening is normally placed one foot above the bottom of the tank. The primary automatic on/off control switch for the LACT unit is usually installed on the side of the tank approximately 2 feet off bottom. This allows the pump to operate without danger of drawing natural gas into the sales lines. For safety purposes a secondary control switch may be placed 1-2 feet above the primary switch. This added safety generally results in a dependable system. Figure 4. Two views of a Lease Automatic Custody Transfer System.