Belida is an oil field that has been producing for almost 20 years. A tight and thin reservoir (10-15 ft thick), the Intra Barat Sand (IBS), is present between the two main producer reservoirs within the thick Barat Formation Shale formation. Although recognized as a potentially productive interval, this thin formation was not considered of sufficient commercial significance to justify development in the early production phase of the field. To optimize the recovery from a thin oil column is a challenging task. In many cases, horizontal wells have been the solution. Appropriate well location and vertical placement within the sand body are the keys to optimize reserve recovery. In 2005, IBS development started with a carefully placed 2500 ft horizontal section well which has subsequently successfully produced oil without water production. Following successfully drilling the initial horizontal development well, a decision was made to drill additional horizontal wells beyond what was considered to be the current well drainage areas. Logging While Drilling (LWD) technology was used to geologically “steer” horizontal wells in real time within the thin oil column. However, it is still difficult to guarantee the optimum placement near the top of the reservoir due to the existing uncertainty in the location of the top of the sand. This paper describes the technical assessment and successful implementation of horizontal wells in a thin oil column. A comprehensive and extensive well planning exercise was completed for the initial well placement study. This was then used in combination with integrated LWD, real time monitoring of petrophysical parameters and analysis of dip information to steer the well. As a result, the accurate well placement needed to effectively recover oil beyond the existing well drainage areas and enhance the production sustainability was achieved. Accurate horizontal well placement is considered to be essential for further development of the thin Intra Barat Sand reservoir in the Belida Field.
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