Experimental Simulation on the Influencing Factors of Sand Production in H Gas Storage, Xinjiang, China

Affected by the complex operation mode of strong injection and strong production, sand production can seriously affect the life cycle and peak shaving capacity of gas storage. In this paper, combined with the actual production situation of China's largest gas storage (H Gas Storage), the effect of the gas flow rate, production pressure difference, formation pressure drop, permeability, and water saturation on sand production was systematically analyzed via an indoor sand production simulation experiment. The results showed that from the initial flow rate of 1.88 L/min to a critical flow rate of 3.87 L/min, the core permeability and the stage sand production continued to increase; however, during the flow rate from 3.87 to 8.58 L/min, the core permeability and the stage sand production decreased gradually. The whole process showed that only a small amount of free sand was produced in the early anhydrous production stage. Proper sand production in this stage can make the rock permeability and the gas production grow to a certain extent. But when the gas flow rate reached 3.87-8.58 L/min, pore throats were blocked by sand particles of large sizes. When all sand particles were carried away by the gas flow, no sand production occurred and the rock permeability remained unchanged. In this experiment, the critical pressure difference was 5 MPa. Under the same production pressure difference, the greater the rock permeability, the greater the stage sand production; similarly, under the same rock permeability, the greater the production pressure difference, the greater the stage sand production. In the case of high rock permeability, sand production occurred when the displacement pressure difference was 2 MPa. For the formation pressure drop, sand production occurred when the effective stress reached 10 MPa; furthermore, when the effective stress reached 16.5 MPa, the stage sand production reached the largest value; finally, when the effective stress reached 28 MPa, no sand production occurred anymore. Sand production was easy to occur in cores containing water, which was related to the hydration and swelling of clay minerals, the increase of seepage resistance in gas-water two-phase fluids, and the increase of shear stress in pore throats.

Abstract licence: CC BY-NC-ND

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