Integrated Solution for Development Carbonate Reservoir: Challenges and Mitigation in a Workover Operation

Abstract The work discusses a unique challenge in designing a horizontal well in the matured field that always comes with a multiple contingencies plan, from drilling, geology, reservoir management, and completion. Therefore, the topic presented in this paper is based on a holistic approach to tackle all potential uncertainties related to drilling operations toward production management. Limited data for wells previously drilled in the same area is gathered with associated uncertainties, and trajectory deepened in some wells to appraise and collect additional data. The well was completed lately to evaluate the reservoir potential, performance sustainability, reservoir drive, production around the area, etc. The workflow is set with some potential mitigation in place that includes using the latest rotary steerable system BHA during drilling of both- inclined sections including landing and horizontal trajectory into one section. The well was completed using complex LWD triple combo and sonic measurements aiming to overcome the uncertainty in formation evaluation. The process used proactive geosteering technology to enhance geosteering in the lateral section. The well was drilled in 3 runs, starting with the kickoff/ whipstock assembly, continuing with the curve section with high dogleg severity (10.4 deg dogleg), then completing with the horizontal section. The geosteering strategy has been applied successfully by implementing the landing strategy with model compare update technique and correlation. The well successfully landed 5ft TVD below the top reservoir. The reservoir was expected to be 1-2 deg dipping down; however, the reality was down to 5-6 deg dipping. The well was geosteered proactively to avoid the risk of exiting the top of the reservoir and completed with good net to gross in the reservoir. The sonic measurement was used to evaluate the formation strength for geomechanical study and contingency fracturing plan if the reservoir porosity was tighter than expected. This project implemented new technology and a novel approach to mitigate project uncertainty. The case studies are reviewed in which the application of innovative LWD services has played a fundamental role in providing new insight into the reservoir character and led to successful well placement.