Rejuvenate Brown Field with the Characteristic of Lenses Reservoirs and Securing New Wells Net Present Va l u e U p b y P e r f o r m i n g I n -House Holistic Study

Abstract

S-Structure, an area operated by PT PERTAMINA EP, has been producing oil and gas since 1976 and located in Upper Kutai Basin which is famous with lenses reservoir characteristics. Inspite of the challenges S-Structure faced in 2013 until early 2018 where production decline was severe and 5 previous drilled wells were considerably dry, it awoke again by a successful 989-bopd-drill well in 2019. There were two Final Investment Decisions (FID) made to finally effectuate drilling again in S-Field. Nonetheless, the first FID was a concern due two unexpected shale out and unprognosed gas layers and accordingly contributed minus Net Present Value (NPV) and the second FID consisting of 15 new well candidates got cancelled. Therefore, this study was conducted to tackle this hesitation. Subsequent to implemented method, we got approval for the 2 FID. The analysis was safely done without incidents and secure 15 wells to still be viable to drill. We divided S-Structure into sectors of Graben, West Panel, and East Panel which have their own behaviors, properties and productivity and we set minimum distances over offset wells afterwards. Within almost a year there were 5 new wells POP-ed with the total NPV and reserves realization are USD 7.58 million and 483 thousand stock tank barrels oil respectively. The method implemented is thorough and well suited with small tanks in such S-Strcuture. The result somehow creates positivity and encouragement to all members to stay striving towards profitable and efficient  development strategy. New well proposals are designed through static and dynamic model generally speaking. However, it has always been a different approach when it comes to lenses reservoir type. There are plethora of costly methods to reduce subsurface uncertainties, yet during the time of the field is considered marginal, efficiency is the most profound and considerable action. Therefore, this method was developed consistently in-house with almost zero investment budget.