Maximum-Reservoir-Contact-Wells Performance Update: Shaybah Field, Saudi Arabia

Abstract

Summary This paper is an update on previous SPE technical papers (Saleri et al. 2003; Saleri et al. 2004) highlighting the results of 25 maximum-reservoir-contact (MRC) wells drilled in the Shaybah field either as new wells or as part of a workover strategy to convert existing weak 1-km single-lateral wells to MRC wells with reservoir contacts ranging from 5 to 9 km. Shaybah field in Saudi Arabia, a low-permeability reservoir overlain by a large gas cap, was developed initially in 1996 with 1-km single-lateral horizontal wells to drain hydrocarbon while reducing gas coning effectively. A step-development approach of increasing reservoir contact to improve well productivity and performance was the basis for the MRC concept. To date, results from 25 MRC wells have indicated a four-fold increase in well productivities and a three-fold decrease in unit-development cost when compared to the 1-km single-lateral wells. A useful byproduct of MRC drilling is the enhancement achieved in reservoir characterization. In addition to MRC wells, smart technologies such as down-hole-flow-control systems (smart completions), expandable liners, and production equalizers were deployed in Shaybah field. These technologies have improved well performance and recovery greatly. Smart controls assisted in optimizing production from each lateral in a multilateral (ML) well in the event of premature gas or water coning. In addition, downhole smart completions improved well productivity in ML wells with a better well-cleanup process. Production equalizers that were deployed in high-gas/oil-ratio (GOR) wells reduced gas coning and improved well productivity. To date, more than 21 expandable liners have been deployed as enablers to a workover strategy to convert single-lateral wells to ML/MRC wells, thereby providing a platform for installation of downhole-flow-control systems.