Matrix Acidizing Optimization for Screened Sandstone Formation at High-Rate Gas Well of Deepwater GWK-8

Abstract

Deepwater GWK-8 is a gas well in deep sea with 1500 meters water depth and a deviated well with a sandstone formation that has good permeability, potentially high-rate gas well, high reservoir pressures, and large reservoir size. This well is expected to immediately ramp up production at optimal productivity through Floating Production Storage and Offloading (FPSO) in Makassar Strait. For a gas well at deep-water exploration must be commercially viable, it needs to achieve optimal production rate. Gas production initially was not meet the expectations, so it needed to be optimized by one of stimulation method that suitable for this well is matrix acidizing. Sandstone formation is screened by Shape Memory Polymer (SMP) sand control system and matrix acidizing is carried out to optimize the deliverability of gas well by dissolving formation impurities and normalize damage in the wellbore. Methodology of this study begins with collecting data on reservoir data, formation lithology, completion, and well-testing. The optimization of matrix acidizing process is based on initial well-testing results where skin (s) of pre-acidizing is 46 with a permeability (k) is 51.4 mD. The matrix acidizing process uses mud acid (HCl-HF) for upper zone of deepwater GWK-8 that has been installed Shape Memory Polymer (SMP) sand control at the pay zone area. Based on well-testing of post-matrix acidizing, successfully proven in reducing the skin number (s) from 46 to 10, increasing permeability (k) from 51.4 mD to 120 mD, and increasing productivity from 30 MMSCFD to 44 MMSCFD.