No abstract

New completion practices currently are being developed and tested in California. This paper describes a recent technique using smaller gravel, coated screens, and a viscous polymer-carrying fluid to complete a well in these unconsolidated formations. Results are encouraging, as is evidenced by the oil production of wells redrilled and completed with this new technique. Introduction The Huntington Beach field is a major oil accumulation lying on the California coastline approximately 20 miles southeast of Los Angeles. Fig.1 shows the location of the Huntington Beach field in the Los Angeles basin, with the offshore area of the field crosshatched. Currently, three of the zones are producing by waterflood, one by cyclic steam producing by waterflood, one by cyclic steam injection, and three on primary production. A drilling program is planned for the one zone not being program is planned for the one zone not being produced. produced. During the last 50 years, there has been a transition toward more efficient oil recovery techniques in the Huntington Beach field. To achieve this end, many drilling and production problems have been overcome. Major production problems are due to (1) the complex geology, (2) the highly deviated wells, (3) the unconsolidated formation, and (4) the corrosive nature of the injection and formation water. Because we cannot alter the geology or the need to drill the wells directionally, we have concentrated our efforts on extending the life of the field by effective sand and corrosion control.The zones where the most recent of these new completion techniques have been initiated are the Upper and Lower Jones zones, both under waterflood. Fig. 2 depicts a cross section of the offshore field. Previous Completion Techniques Previous Completion Techniques Wells drilled from 1930 to 1960 were completed for primary production. These wells usually were primary production. These wells usually were completed with 6 5/8-in. slotted liners in a 7 5/8-in. hole.Full-scale waterflooding began in the early 1960's, and gravel flow packing was initiated to control sand production from the high gross rates from waterflooding. production from the high gross rates from waterflooding. This technique was typical of California-type completions. An 8 5/8-in. protection casing was run and cemented at the top of the oil-bearing zone. The zone was drilled and underreamed to 15 in, and a 6 5/8-in. slotted liner was installed. The liners typically had slots cut 2 in. long, 0.060 in. wide, on 6-in. centers, and in a staggered 28-row pattern. The wells were gravel packed conventionally with various completion fluids as the carrying medium and using 6-9 or 8-12 Tyler mesh gravel. This work mas done using sand control designs of Schwartz.Using these successful techniques, Aminiol U.S.A. Inc. engineered the third largest waterflood (450,000 BWPD) in the U.S. The large volumes of water have created other problems.Corrosion was so severe that some liners would fail in 1 to 2 years, which allowed entry of gravel and formation material into the wellbore. Many different coatings were applied to these liners to combat corrosion and thereby lengthen the life of these wells. Results seemed encouraging after much experimentation. JPT P. 757