Benchmark Helps Select Best Technique for Sand Control in Field Development

Abstract

This article, written by Editorial Manager Adam Wilson, contains highlights of paper IPTC 16449, ’Production-Integrated Sand-Control Benchmark for Field Development,’ by Keng Seng Chan, SPE, Danny Chong, SPE, Rahim Masoudi, SPE, Mohamad B. Othman, SPE, and Norbashinatun Salmi Bt M. Nordin, Petronas, prepared for the 2013 International Petroleum Technology Conference, Beijing, 26-28 March. The paper has not been peer reviewed. This paper shares the engineering approach used to determine where and when sand control was needed in offshore Malaysia on the basis of geomechanical sand-free critical-drawdown-pressure (CDP) evaluation for the selected well type, configuration, and completion. The decision to implement a proper method of sand control can be made by comparing the CDP with the minimum drawdown pressure (MDP) required to meet the target production rate. Sand-control-method selection was based not only on the sand-particle-size distribution, well life, and mode of well production but also on maximizing oil and gas recovery per well. Introduction The challenge in Malaysia was to design and implement a sand-control completion that could maximize well productivity with a stable wellbore under perceivable changing offshore production conditions implemented at the lowest cost. The objectives of setting up the sand-control benchmark for the Malaysian field were To reduce the sand-control completion costs by greater than 50% To drive a sand-control well-design culture change for developing cost-effective well completions for sandstone reservoirs To determine selectively where, when, and what sand control is needed in the developing reservoirs To enable well-placement and reservoir-penetration-trajectory design to maximize sand-free-production drawdown pressure To optimize the use of expensive sand-control methods To estimate sand critical erosion pressure drawdown Fig. 1 shows a carefully developed workflow. Maximizing CDP For a well designed to penetrate target reservoir sand, the sand-free CDP should be evaluated for the entire potential producing interval following the designed reservoir-penetration trajectory. Because the geomechanical properties change with pore pressure, this evaluation must be conducted for the whole life cycle. For cased-hole completion, perforation orientation and phase angle can be optimized to increase the CDP. More effectively, CDP can also be increased by increasing well inclination for the same sand. In some sands, the CDP can be affected strongly by water production. After water breakthrough, the rock strength and friction angle that affect sand consolidation and stability of sand structure at and near the wellbore may be dramatically reduced. Moreover, when formation sands contain significantly high amounts of water-reactive shale, the whole wellbore can collapse. CDP can then become very small, or even zero. High pressure drawdown could cause wellbore and even completion mechanical failure.