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 downhole-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. Introduction The MRC-well concept that was started in early 2002 by Saudi Aramco was based on the horizontal-well technology as a disruptive technology (Saleri et al. 2003) to challenge the current practice with the objective of improving well performance and ultimate recovery. An MRC well is defined as a well with a minimum aggregate reservoir contact of 5 km either as a single-lateral or ML configuration. The concept that was first tested in the Shu'aiba carbonate reservoir of the Shaybah field has been extended to cover several fields and rock types in both onshore and offshore environments. The majority of MRC wells were drilled initially as trilateral configurations; this configuration is now being challenged. Quad- and pentalateral well types are being drilled to improve well performance further by increasing well productivity index (PI) and, thus, lowering the drawdown pressures, resulting in high well potentials and improved long-term performance of sweep and recovery. Just as in the mid-1990s the oil and gas industry began using horizontal-well applications as the norm; today, Saudi Aramco is leading the way in deploying MRC wells across several of its fields to ensure improved well performance and ultimate recovery. In this paper, we discuss the performance of Saudi Aramco MRC wells over the past 4 years, including the different implemented technologies, and assess future uses of smart completions.

Prototype Test of an All-Electric Intelligent-Completion System for Extreme-Reservoir-Contact Wells

“…One MRC example in the Shaybah field was in a low-permeability carbonate oil reservoir overlain by a very large gas cap. In the remote Rub' al Khali desert, the Shaybah field-development practices have continuously evolved in an effort to reduce gas coning and improve oil recovery (Saleri 2002;Saleri et al 2003). Initial development in 1998 used numerous 1-km single-lateral horizontal wells.…”

“…These wells were extended to 2-to 3-km single-lateral horizontal wells by 2000, then to MRC multilateral (ML) wells by 2002, and to MRC ML wells equipped with hydraulic flow-control valves by 2004 (Salamy et al 2006). The drivers for increased reservoir contact and downhole control included lower unit-development costs, higher well productivity, higher cumulative-oil production before gas breakthrough, and control of production after breakthrough (Saleri 2002;Salamy et al 2006Salamy et al , 2008. Saudi Aramco has more recently embarked on extreme-reservoir-contact (ERC) wells with reservoir contact frequently exceeding 10 km by increasing both the number of laterals and their lengths.…”

Pushing Maximum Reservoir Contact Applications to New Limits in Tight Facies: A Case Study of Middle East's Highest Reservoir Exposure Producer

“…This well type was deployed in reservoirs with low to medium rock permeability. The development of MRC wells technology in Saudi Aramco started in 2002 (Salamy et al 2008;Al-Thuwaini et al 2009). The extended reservoir contact of these extended reach wells allowed lower pressure drawdown, and as a result, GOR levels were stabilized between the years 2004 and 2009.…”

Production Gain and Optimization through the Implementation of Smart Well Completion Technology in Saudi Aramco, Case Study

“…As a result of that, it was decided to utilize the existing smart completion to revive the dead laterals independently and uniform the flow contribution across the laterals of the well. Isolating individual laterals concentrates reservoir energy to the tested lateral (Salamy et al, 2008). Each of the non-flowing laterals was revived successfully and individually by also reducing the back pressure on the well.…”

“…When data from individual laterals were analyzed, optimal valve settings were chosen to ensure the best production from the well. Dead laterals were restored by inducing only that lateral to the production system and concentrating the energy of the reservoir to that specific lateral (Salamy et al, 2008). In addition, laterals that cut water were restricted to decrease water production and decrease hydrostatic head in the wellbore.…”