Flowing Material Balance and Rate-Transient Analysis of Horizontal Wells in Under-Saturated Coal Seam Gas Reservoirs: A Case Study from the Qinshui Basin, China

Two phase flow and horizontal well completion pose additional challenges for rate-transient analysis (RTA) techniques in under-saturated coal seam gas (CSG) reservoirs. To better obtain reservoir parameters, a practical workflow the two RTA technique is presented to extract information by of production data an CSG reservoir. This includes flowing material balance (FMB) improved form (water + gas) RTA. At stage reservoirs, FMB was developed original water in-place (OWIP) permeability. involves application appropriate productivity equation representing relative position drainage area. Then, also investigated introducing concept area influence (AI), which enables calculation saturation during transient formation linear flow. Finally, simulation field examples are validate demonstrate proposed techniques. Simulation results indicate that accurately predicts OWIP permeability when selected. The methods demonstrated Qinshui Basin, China.