Publications

Kotabatak field, as a part of Sumatra Light Oil field of Chevron Pacific Indonesia, has been in production since 1952. Productive oil sands in Kotabatak field are found in Bekasap Formation, which accounts for more than 75% of field reserve and Telisa Formation, which makes up the remaining reserve. Telisa formation has shown very low recovery factor and low to moderate effective oil permeability, usually below 50 md. Fracturing jobs has been successfully performed for the last 6 years to increase the productivity from Telisa formation. Since 2009 several project have been performed to improve the performance of fractured wells. Several changes also have been implemented to increase the effective fracture conductivity and length. Water base high temperature delayed borate crosslinked fluids is usually utilized in fracturing treatment in Telisa formation. Initial attempts to increase fracture conductivity centered in changing proppant type (natural sand to ceramic) and proppant size (20/40 to 12/18). The amount of proppant ranged from 160,000 to 200,000 lbm depending on formation permeability and reservoir thickness. Proppant flowback control methods have been incorporated as last stage in a number of fracturing jobs. Proppant flowback need to be prevented to avoid near-wellbore conductivity decrease and to avoid future expenses due to Electrical Submersible Pump failure caused by proppant intrusion. * Chevron Pacific Indonesia ** Schlumberger In 2010, a new approach to fracturing treatment using unconventional shaped proppant was introduced. This proppant is a new high strength ceramic with a cylindrical rod shape. The two main benefits of this new proppant are enhanced proppant pack conductivity and improved proppant flowback control. This paper covers the candidate selection process, fracture design, treatment execution, treatment evaluation and production results of the first three hydraulic fractures executed using unconventional shaped proppant in Telisa formation. A production comparison with offset wells using conventional proppant is also presented. After six months of production, the three wells fractured with unconventional shaped proppant produced ~25% more oil per net pay compared to offset wells fractured with conventional proppant. Additionally, these wells have not shown any proppant flow back even without the use of flowback control method, eliminating the need of extra workover interventions.