Production Optimization Strategies for a Gas Field under Declining Reservoir Pressure Conditions

Abstract

Declining reservoir pressure is a major challenge affecting gas production sustainability in mature gas reservoirs. This study investigates production optimization strategies for the MnaziBay Gas Field under declining reservoir pressure conditions using an Integrated Production Modelling approach. The gas field is estimated to contain 1036 Bscf of gas reserves produced from the Miocene reservoir formations, and currently operates with five producing wells, MB-1, MB-2, MB-3, MB-4, and MS-1X  at a field production rate of 130 MMscfd over a contractual period of 16 years. Four optimization scenarios were investigated, including the existing production system, application of surface compression, perforation of additional reservoir zones, and drilling of infill wells, with reservoir performance, well deliverability, and surface production network behaviour analysed using MBAL, PROSPER, and GAP simulation software. The existing five-well configuration was found capable of maintaining the plateau for only 4.49 years, representing merely 28% of the contractual target. Among the perforation scenarios assessed, the configuration employing 4-inch tubing at a separator pressure of 725 psi yielded the most favourable outcome, extending the plateau duration by 12.54 years, from 6.24 years to 18.78 years, demonstrating the significant potential of accessing additional productive layers.