Experimental Evaluation of the Succession Sequence During Commingled Production in a Tight Gas Reservoir

With the continuing development of tight multilayer reservoirs, commingled production technology has been widely adopted for multilayer tight gas reservoirs and coalbed methane co-production. This paper assembles the cores with different physical properties in single-core, three-core, and four-core modes in tandem. Different core combinations are used to conduct experiments on single-layer production, direct co-production, and sequential and timing co-production to evaluate the behavior and characteristics during co-production. When the core is combined complexly, the recovery factor decreases significantly after half the pressure reduction. The gas production difference between high and low-permeability layers forms an interlayer interference and is superimposed on the effect of seepage resistance. As a result, the high-permeability layer recovery factor is greatly influenced. Furthermore, the core is combined complexly, and the high-permeability layer has a higher contribution ratio to the output gas. Additionally, it is easy to obtain the maximum gas production by selecting the combination timing of developed and undeveloped formations with the same pressure.