Reservoir Management in the Means San Andres Unit

Abstract

Summary The Means field provides an opportunity to observe the evolution ofreservoir management to meet ever-changing economic and technical challenges asthe field has been produced by primary, secondary, and tertiary methods. Reservoir management at Means has consisted of an ongoing but changingsurveillance program supplemented with periodic major reservoir studies toevaluate and make changes to the depletion plan. Current operations are anintegrated program of CO2 injection, infill drilling, and waterflooding. Todate, the tertiary project has performed above expectations. project hasperformed above expectations. Introduction The Means field in Andrews County, TX was discovered in 1934 and developedon 40-acre spacing. Reservoir management techniques began within 1 year ofdiscovery and have become increasingly complex as operations have changed fromprimary to secondary to tertiary. In 1963, a major portion of the field wasunitized as the portion of the field was unitized as the Means (San Andres)Unit (MSAU). Several papers described specific programs for papers describedspecific programs for the field. This paper describes the evolution ofreservoir management at Means. This paper concentrates on the reservoirdescription, infill drilling with pattern modification, and reservoir surveyportions of reservoir management. Reservoir portions of reservoir management. Reservoir description methods have evolved from the relatively simpletechniques used in the 1930's to the recent use of high-resolution seismic toimprove pay correlation between wells. The importance of reservoir continuityin determining well spacing and injection patterns is discussed for bothsecondary and patterns is discussed for both secondary and tertiary operations. Although surveillance has always been an integral part of reservoir managementin the Means field, a much more detailed plan was developed for surveillance ofthe CO2 tertiary project. Field Discovery and Development The Means (San Andres) field is located about 50 miles northwest of Midland, along the eastern edge of the Central Basin platform (Fig. 1), and lies in atrend of San platform (Fig. 1), and lies in a trend of San Andres productionthat extends for more than 100 miles in a northwest-southeast direction. Thefield was discovered in 1934 and by the early 1950's was developed on 40-acrespacing with approximately 300 wells in the MSAU area.