Case History of Yakin Field: Its Development and Sand Control

Abstract

Summary This paper deals with the development of the Yakin field in East Kalimantan, Indonesia, with emphasis on the sand control methods used. Implementation of an effective sand control program ensured the successful development of this field. Gravel-packed wells had substantially lower production decline rates than the initial completions without gravel packs. Control of sand production also has been demonstrated by the lack of production also has been demonstrated by the lack of sand problems during the 4 1/2 years since the sand control program was initiated. During this time there have been no submersible pump failures associated with sand production. production. The successful sand control program was achieved by a well-coordinated and cooperative effort of drilling, reservoir engineering, production research, and service company personnel. Establishment of communication among all people involved, starting early in the planning process and continuing through the rig operations to the process and continuing through the rig operations to the final production phase, coupled with intensive training at all levels of responsibility, on-site supervision, and quality control were important factors in the success of the development program. Introduction The Yakin field was developed as a joint venture between Pertamina and Union Oil Co. of Indonesia within the terms of a production-sharing contract. The field is located approximately 4 miles offshore East Kalimantan. The field was discovered in April 1976 with the drilling of the Yakin No. 2 well. Yakin structure is a north-northeast-trending anticline, bordered on the north by a normal fault and on the west by a reverse fault. The reservoir is of marine origin, ranging in age from late Oligocene to early Miocene. The main sand has a closure of about 250 acres and an average thickness of 60 ft. The crude oil gravity ranges from 13 to 25 deg. API. More complete reservoir properties of Yakin field are shown in Table 1. The field was developed in two major stages. The earlier development, Phase 1, was completed such that oil recovery from the field could be accelerated. Despite some problems associated with rapid development, early Phase 1 completions provided the experience to allow for Phase 1 completions provided the experience to allow for the proper equipment to be ordered and installed in Phase 2. Phase 2 completions designed to control the sand problems experienced in Phase 1 were started in April 1977. problems experienced in Phase 1 were started in April 1977. Drilling and testing of early wells indicated that sand control would be required to deplete the reservoir efficiently. Sand produced during drill stem testing and low recovery of sidewall cores indicated a poorly consolidated formation sand. The initial three wells of Phase 1 were completed without sand control. Two wells eventually sanded out and the other one was produced at a reduced rate to stop the sand production. These three wells later were worked over and recompleted with inside-casing gravel packs. All the subsequent wells of Phase 2 were completed with open hole gravel packs. In Phase 2 were completed with open hole gravel packs. In some completions the gravel was resin-coated. A brief summary of the overall production characteristics of the Yakin wells is included in Table 2 and Fig. 1. Since a sand-control completion is more complex than a conventional completion, a team approach was initiated to ensure a successful job. A successful sand control project requires that everyone involved has a full knowledge and a thorough understanding of the "do's and don'ts" from the planning stage through the actual sand control job to the production stage. JPT P. 23