Attic Oil Recovery by Steam Displacement

Abstract

This paper was prepared for the 43rd Annual California Regional Meeting of the Society of Petroleum Engineers of AIME to be held in Bakersfield, Calif., Nov. 8–10, 1972. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon requested to the Editor PETROLEUM ENGINEERS JOURNAL is usually granted upon requested to the Editor of the appropriate journal, provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers Office. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract The Metson Pool of the Midway-Sunset Field in California is a steeply dipping, viscous oil reservoir. Steam-type thermal recovery operations have been in progress in the pool for seven years. Cyclic steam stimulation efforts have been designed to take advantage of both natural and induced productive mechanisms. These cyclic operations have proven effective in all but the extreme updip sections of the formation. An attic steam injection program was initiated as a pilot project in October, 1970 and has since been expanded to include six steam injection wells across the updip edge of the formation. The short term objective of this program is to economically displace and recover oil at the top of the structure by conventional steam flood mechanisms. The long-term objective is to accelerate recoveries from downdip cyclic operations by repressuring and stimulated gas drive mechanisms. A special operating technique has been introduced to this program that allows better control of the development of the steam zone and better use of the beneficial effects associated with steam channeling. HISTORY The Metson Pool of the Midway-Sunset Field is located in Sections 23 and 24, T11N, R23W, SBB and M, Kern County, California. The discovery well was completed in 1953 pumping 10.5 deg. API oil at a rate of 27 BPD. pumping 10.5 deg. API oil at a rate of 27 BPD. Development drilling for primary production was limited due to the low oil rates. The Metson sand is of Miocene Age and is encountered at an average depth of 1,050 feet. The sand has a 30% porosity and permeabilities ranging from 1 to 4 darcies. The average dip of the productive sands is 70 degrees. productive sands is 70 degrees. Cyclic steam stimulation was introduced as a recovery process in late 1965. Response to initial stimulation efforts was good with most wells exhibiting oil rates in excess of 100 BPD after steaming and yielding oil-steam ratios for individual cycles of 0.8–1.3. However, cyclic response declined as the number of cycles progressed. progressed.