Consolidation and LACT in the SACROC Unit
Authors: Mathis James W. 
Published: December 2007

Installation of full-scale consolidation and lease automatic-custody-transfer oil delivery stations was commenced in the SACROC unit during 1957. By Feb., 1963, all the 42,000 BOPD production was being delivered through 12 LACT units. Equipment used in the LACT installations is of varied manufacture and design. Oil deliveries through the LACT units range from approximately 1,000 BID at the smallest station to 12,000 BID at the largest. Both dump-tank meters and positive displacement meters are used. History of the development of the SACROC unit consolidation and LACT program and the operating experience for the various types of installations are presented.

Introduction

The Kelly-Snyder field, Scurry County, Tex., was discovered in Nov., 1948. The producing formation, the Canyon Reef limestone, lies at a depth of about 6,600 to 6,900 ft. Development of the field proceeded at a rapid pace until it was essentially completed by the end of 1953. The field now contains 1,316 wells overlying approximately 52,000 oil-productive acres. In Dec., 1950, the Scurry Area Canyon Reef Operators Committee was formed, this name later being abbreviated to SACROC, and unitization studies were begun in Jan., 1951. Unitization of the major portion of the field became a reality on March 1, 1953, when SACROC unit began operation. The unit now contains 1,256 wells and approximately 50,000 productive acres, which overlie about 99 per cent of the productive formation of the Kelly-Snyder field. Initially, the operation of SACROC was under the supervision of a Unit Manager's Office, and the field was divided into three segments, each operated by one of the working interest owners-Standard Oil Co. of Texas, Mobil Oil Co. and Sun Oil Co. On May 1, 1962, after amendment and ratification of the Unit Operating Agreement, Standard Oil Co. of Texas became the unit operator. At the time SACROC became effective in 1953, there were approximately 400 active tank batteries within the area of the Kelly-Snyder field operated by the unit. Unitization made it possible to consider extensive tank-battery consolidation. By 1957 pressure-maintenance operations had resulted in stabilized producing conditions. Facilities had been installed to collect and return all produced water to the Canyon reef reservoir. Some consolidation work on a small scale had been done in the unit prior to 1957 as it became desirable to combine manifolds because of water line extensions and other field operating conditions. During the latter part of 1957 a full-scale program of consolidation of producing facilities and installation of automatic custody transfer equipment was commenced in SACROC unit. By Feb., 1963, all the 42,000 BOPD production from unit wells was collected into 12 central batteries and was being delivered to five pipeline companies through automatic-custody-transfer units. Experience in the unit has shown that it is economically feasible to replace conventional producing facilities with automatic-custody-transfer equipment in a developed field. In addition to improving operating efficiency, the centralization of producing facilities into large central batteries has made it economically feasible to collect and sell tank vapors which previously would have been vented to the atmosphere. Delivery of oil through LACT units has virtually eliminated breathing and filling losses which occurred in normal storage of oil in stock tanks without vapor control. As a result of the LACT installations, the amount of oil stored, closing stock, above ground in the unit has been reduced from approximately 160,000 bbl in March, 1957, to approximately 47,000 bbl since March, 1963.Representatives of a number of the working interest owners in SACROC contributed to the planning of the consolidation and LACT program. Early work and planning were done at a time when automatic custody transfer of oil was in the early stages of development. The five pipeline companies which gather unit oil have furnished assistance and have been very cooperative throughout the development of the consolidation and LACT work. Both dump-tank type units and PD meters have been installed and operated. LACT units are now operated which handle approximately 1,000 BOPD at the smallest station to 12,000 BOPD at the largest. The purpose of this paper is to discuss the development of the consolidation and LACT program in the unit, to describe the equipment used, and to discuss the results obtained from the program.

JPT

P. 751ˆ