Investigation of Cementing Quality Control Factors in Large-Diameter Salt Cavern Gas Storage Wells: A Comprehensive Analysis of Displacement Efficiency and Cement Sheath Integrity

Abstract To enhance cementing displacement efficiency in large-diameter salt cavern gas storage wells, this study systematically analyzes critical factors including casing centrality and Cement slurry parameters (rate, plastic viscosity, yield stress, fluidity index and consistency index). The results establish the following optimal operational parameters: (1) the flow rate ( Q ) should exceed 1.6 m 3 /min; (2) the cement yield stress ( τ 0) should be at least 3.91 Pa; (3) the fluidity index ( n ) should be range from 0.7 to 0.92; (4) the consistency index ( K ) should rang from 0.3 to 0.8 Pa·s n ; and (5) the casing centrality should be no less than 90%. Furthermore, a systematic investigation was conducted to evaluate the impacts of key parameters - including elastic modulus of cement sheath, cyclic injection-production pressure, casing dimensions (diameter and wall thickness), and cement sheath thickness - on cement sheath integrity. The results reveal that:(1) the elastic modulus of the cement sheath should be maintained below 5.9 GPa; (2) optimal casing wall thickness ranges between 10 to 20 mm; (3) both the casing internal pressures ( P i ) and the casing inner diameter ( D i ) must be controlled under 35 MPa and 283.5 mm respectively; and (4) the cement sheath requires a minimum thickness of 40 mm.