AN INTEGRATED EVALUATION MODEL OF KAJI-SEMOGA FIELD WATER INJECTION SYSTEM, INCLUDING SUBSURFACE AND SURFACE FACILITIES

摘要

A water injection (WI) system plays a significant role for an oil field that is experiencing liquid lifting with high water cut and production via waterflooding method. Kaji-Semoga field is an oil field with an average water cut of 93% and liquid lifting of 180,000 BLPD. In order to achieve the targeted oil production, it is a priority to increase the liquid lifting rate. Artificial lift conversions, additional wells through infill drilling and field station upgrading have been implemented to optimize oil production. Furthermore, the water injection system handles produced water to be injected as part of a field strategy to improved reservoir seep. In addition, optimized lifting capacity eliminates oil deferment caused by water handling constraints. An integrated evaluation model of Kaji-Semoga water injection system was created to optimize water injection rate and to de-bottleneck the water flow system. A surface facilities model was developed and simulated using integrated surface- subsurface software to evaluate the surface facilities constraint. Production surveillance, analysis and forecasting software was utilized to record the hall- plot performance history of water injection wells (WIW) to identify subsurface constraints. Based on the simulation results, some activities consisting of well stimulations, water injection pump optimization and the installation of additional pipeline network were executed. The contribution of these activities to the field water injection system was then evaluated. As a result, manifold system pressure has decreased from 1100 psig to 1050 psig, whilst average water injection rate has increased from 168,200 BWPD to 172,800 BWPD and monthly VRR (Voidage Replacement Ratio) has increased from 0.911 to 1.048 for Kaji Field. Total Kaji-Semoga field liquid lifting capacity has increased from 179,000 to 184,500 BLPD. Elimination of oil deferment of 236 BOPD (caused by shutting in high water cut wells due to water handling constraint) has been achieved.