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.