Doubling the Production from a Mature Reservoir in North Kuwait-Challenges, Achievements & Lessons Learnt

Abstract

Abstract Sabiriyah Lower Burgan is a clastic reservoir in North Kuwait on continuous production for the last 45 years. The reservoir, on active water drive, has its inherent problem of rapid increase in water cut, the production performance of wells declining drastically after water cut level of 40%. Many wells became idle in the past, with overall well efficiency (ratio of flowing to total number of wells) of 60%. The formal strategy for production had been focused on "keeping the active perforations away from water". Attempts were made in the past neither to install any artificial lift nor to have a campaign for water shut off/new technology applications. In order to double production within 6 months from the reservoir, extensive review of the performance, intelligent analysis of existing wells, identification of production enhancement opportunities vis-à-vis mapping resources needed, horizontal wells/ ESP installation for the first time, more ambitious ESP implementation than was comprehended earlier; proactive process to quickly evaluate/ implement rig/ rigless workovers; drill/ complete/ connect new wells on priority and the opportunistic utility of newly drilled wells slated for overlying reservoirs in Lower Burgan were the cornerstone of the strategy. This strategy also proved to be a gap-filler to supplement production gaps, if any, resulting due to delays in water injection projects for other reservoirs. The interlinked workflow processes were developed for other reservoirs with ambitious goal of similar magnitude. The strategy was implemented during 2010–11 with a jump in production to twice the base level. The challenge was carried forward to sustain the oil rates with controlled water cuts. Proposed paper is a reflection of a quantum change in the mindsets of the professionals to re-prioritize & re-focus on the reservoir management of mature reservoirs and accordingly align the resources to enhance the production delivery at Gathering centre. Background Sabiriyah Lower Burgan(SA LB) is a clastic reservoir on continuous production for the last 45 years. It is a prolific reservoir with natural aquifer support. The crude oil quality produced from the reservoir is of light quality with an average API gravity of about 33 degree and % Sulphur of less than 2.8%. The reservoir has cumulatively produced about 40%of reserves so far. The long term production aspirations from SA LB to the asset is quite significant, with expected peak production of about three time the present levelonce the ESP plan is fully operational and planned infill drilling is complete, as per the forecast from simulation models. The reservoir had been under production with all producers on natural flow at a daily rate of about 50,000 bopd (for the last 3–4 years), with average water cut of about 29%.