Unleashing Full Production Potential of Mature-Water Coning Sensitive-OilField through Simple Reservoir Simulation and Artificial Lift Installation

摘要

X field was discovered in 2001 and started producing in 2003.The formation is limestone supported withlarge aquifer.Main challenge is that wells must be produced with critical rate limitation,if a well is producedtoo hard,water coning and water breakthrough can occur,then oil production will disappear,as happenedin one of X's well.In 2011,several wells were becomes ceased-to-flow due to an increase in watercutvalue,then pumping units were installed on these wells.However,due to recurrent mechanical downholeproblems which limit effective production days,a new initiative is required to overcome these issues.Afterthorough analysis,ESP was chosen as best-fit artificial lift considering its versatility in deviated wells andhigh deliverability.In 2017,pilot phase of ESP implementation started in X-D4 well,which gave 150 BOPDaverage oil gain.Learning from the success of X-D4,comprehensive production strategy using ESP isconsidered crucial for optimum recovery.To support this strategy,an integrated optimization study with reservoir simulation model was usedinstead of analytical method to obtain more reliable production forecast.History matching was carriedout from initial production data in 2003,a good match in liquid-oil-water-pressure data was successfullyobtained,but poor match was occurred on gas production rate,this was ignored due to high uncertainty ongas measurements.The outcomes of simulation study were ESP well candidates,optimum production ratetarget and proper timing of ESP installation.The next step was the preparation of ESP which consists of thedesign and procurement of ESP.Following the ESP installation plan,it was also decided to increase powergeneration capacity at current surface facilities.Currently,7 out of 10 ESPs have been installed.Power plant upgrading and overhead line installation tosupport ESP have also been carried out.The average oil gain obtained was 700 BOPD with cumulative of160 MBO (from 2017-until 2018).This optimization case will contribute 1.5 MMBO additional reservefrom”do nothing”case.Economic evaluation shows a very good viability with significant additional grossrevenue.This optimization project has succeeded in reducing oil deferment from ceased-to-flow wells andextending the field's life.Good collaboration between each part (subsurface and surface)in this project has succeeded in producing significant oil gains.Continuous monitoring is still needed to further matchoptimization forecast with actual conditions.Long-term plans,some improvements are still needed in thereservoir model,one of which is OOIP value,there is a possibility that the actual X OOIP is bigger thanthe one in the reservoir model.