Experimental Study on Areal Flowing During Depletion of a High-Pressure Heterogeneous Gas Reservoir

Experiments to characterize the constant-rate gas depleted production behavior in core samples were performed to study the areal gas flowing mechanism of a high-pressure low-permeability heterogeneous gas reservoir, including a newly designed long-core experiment on areal heterogeneity constant-rate gas depleted production considering fracturing. In the experiments, the fluid pressure increased up to 45 MPa, and the cores of the near-wellbore high permeability area before and after fracturing and the cores of the low permeability non fractured area were connected in series to simulate the gas flowing process of the dual-area composite gas reservoir. When the irreducible water saturation is considered, the gas permeability in a high permeability area cater fracturing increased threefold. Experimental results indicated that the pressure difference in the near-wellbore high permeability area decreased rapidly after fracturing and increased in the low permeability area. The recovery:factor of each area increased titter fracturing. Fracturing could have a significant effect on increasing the recovery factor when the average permeability is relatively low. The greater the gas rate, the higher is the built-up pressure alter shut-in. Fracturing in the near-wellbore area may cause a significant decrease in the shut-in built-up pressure value.