The influence of alternating load on sand production law of injection/production wells of underground gas storages

Periodic variation of production pressure in underground gas storages can generate alternating loads acted on skeleton rocks. Under alternating loads of intensive injection and production, rocks will be damaged and their mechanical properties will change. And as a result, the stability of borehole wall and skeleton rock will be impacted and sand production will be induced. In this paper, the sand production law of injection/production wells under the alternating load of intensive injection and production was experimentally simulated. Then, the sand production index formula was modified by using rock damage amount, loading times, loading frequency and other parameters. Finally, the sand production risk of injection/ production wells was analyzed and the sand production time was predicted. In this way, the influence law of injection/production cycle on sand production of injection/production wells was figured out. By virtue of the modified sand production index formula, the sand production period and degree of injection/production wells can be predicted. And it also plays an effective role in guiding the selection of early sand control completion mode of injection/production wells in underground gas storages and formulating reasonable production system to control sand production of injection/production wells so as to ensure the smooth operation of underground gas storages.