A Lease Consolidation, Telemetering and Supervisory Control Project

Abstract

Abstract Pan American Petroleum Corp. has applied the latest techniques of tank battery consolidation and automation to control oil production from the East Texas field. A major part of this project was the consolidation of 93 leases comprising 913 wells under a central automatic custody transfer (ACT) system. This consolidation makes maximum use of the pipeline company's crude-gathering system that also handles and commingles the production from 45 outside-operated leases run by conventional tank-gauging methods. The second part of the project is a data acquisition, telemetering and computer-interfaced supervisory control system. The central control for this system is located in Tyler about 40 miles west of the East Texas field. Lease production is scheduled, controlled, accumulated and formally reported from the central control, which also monitors equipment operations and relays malfunctions to pumper patrols. Introduction The East Texas automation project includes 974 wells on 101 leases covering a 55 sq mile area in the north half of the East Texas field. About 95 percent of the wells are flowing and produce pipeline oil. The remainder are produced by electrically operated pumping units. Oil production in the field is obtained from the Woodbine sand at a depth of approximately 3,300 ft. It has been producing for 30 to 35 years and has a remaining estimated life of 70 years. Average well density is less than 5 acres/well. Because of this density and because of the depth of the sand, the top allowable is 20 B/D, subject to market demand factors. The average well produces its allowable when flowing on a schedule of approximately 30 minutes/ day, 3 days a week. History of Automation Project Phase 1 During 1955, each well on the majority of the flowing well leases was equipped with electrically operated hydromotor valves, automatic tank switching equipment on the tanks and electric clock time controllers. This was the first phase in changing from manual to automatic operation. Each lease was placed on clock control (Fig. 1). Clock control is partially used in the present system. The 24-hour electric clocks were located at each well and connected with a two-wire, 110-v power loop originating at the tank battery. A 7-day clock located at the battery energized the loop for a 24-hour period on specified producing days and turned the power off on nonproducing days. Each 24-hour clock ran the entire 24-hour period the loop was energized. In turn, these clocks energized the circuit containing the hydromotor well control valve (or the pumping unit controller) at predetermined periods within the scheduled producing day. All wells on a lease were flowed in a continuous sequence and were scheduled to allow an overlap in flowing periods of about 5 minutes to obtain gas flow measurement to the gasoline plants. Phase 2 During the next 10 years of operation in the field, the lease automatic custody transfer (LACT) unit was developed and lease production was commingled through consolidation of batteries by use of the positive displacement (Pd) meter. On pipeline oil-producing leases, oil production was commingled in a surge tank prior to sale through a LACT unit. On water-producing leases, the oil was commingled prior to treating. By the end of 1964, about 15 percent of the area was under consolidated battery and LACT unit operation. This phase in automating the field was motivated by the need to replace oil storage tanks that had been in service since the field was discovered. JPT P. 12ˆ