Reinjection management evaluation in Karaha Bodas field 2022

Abstract

The Karaha Bodas Field features a two-phase system with a vapor fraction ranging from 50% to 98%, which is tapped by five production wells. As of 2022, the field includes one injection well, namely KRH-1.A, with an injection flow rate of approximately 60-100 tph. Geochemical monitoring has indicated an increase in dryness in KRH-A.1, as well as in wells originating from the Talaga cluster (TLG-C.1 & TLGC.2), due to the absence of reinjection fluid contributing to the production wells. This observation is further supported by the findings of the 4D microgravity monitoring study, which reveals areas with reduced mass around the production wells in the Karaha Bodas Field. This trend aligns with the limited occurrence of micro-earthquake events around production wells. The Karaha Bodas Field presents challenges owing to its relatively high decline rate, patchy structure, and low-to-medium permeability. An inter-well connectivity study was conducted using the KRH-1.A injection well to confirm these indications. After six months of studies, it has become evident that there is no connectivity between the injection and production wells. The absence of reinjection fluid support for production wells has led to a decline in production by 9% annually. Tracer results also underline the absence of a structured path towards production wells or the presence of poor permeability due to the patchy structure, which is a contributing factor to the significant decline in output. To address this challenge, a modification in the injection strategy is imperative, involving the addition of the injection wells KRH-A.3 & KRH-B.3.