Publications

Charlie sand is a major production contributor reservoir in the Alpha field. It is characterized by high average permeability (500-3000 mD) and active aquifer support. After put on production for years, this reservoir shows some coning phenomena in existing producing wells and its oil column has also recently identified much thinner (~15-25 ft) in newly drilled wells than that in old wells (~40-50 ft). To continue improving oil recovery factor in this reservoir, it is realized that producing from directional wells are not effective enough because of its rapid increase characteristics in watercut trend during productions. A horizontal well project targeting this reservoir is conducted with an objective to improve production performance and recovery from this sand. This paper is purposed to provide a lesson learned of how managed horizontal well placement can improve production performance in this type of high permeability and active water drive reservoir from Charlie Sand in the Alpha field. Horizontal well pilots are conducted targeting this Charlie sand. Subsurface evaluation is conducted by focusing on identifications of key elements that are potentially play significant impacts to productions. The identified subsurface key elements are stratigraphic heterogeneity, reservoir property changes and oil saturation distribution. These key subsurface elements are used to drive critical well execution plan including both horizontal well trajectory exercises and Logging While Drilling (LWD) selections. The integrated works of subsurface evaluation and well execution plan are purposed to ensure successful placement of horizontal wells with optimum standoff to prevent early water coning. The pilot wells are successfully landed on the low-quality part located at top of the Charlie sand with optimum standoff along lateral section. The wells are currently on productions. The productions show good performance indicated by significant improvement in Water Oil Ratio trend compared to directional wells. In addition, the oil rate deliveries of the horizontal wells also significantly increase compared to those of recent directional wells. The success of the pilot projects to improve production performance from this typical water coning impacted Charlie sand has become a lesson learned and can be leveraged across other fields in the Central Sumatra Basin.