气顶砂岩油藏型储气库运行上限压力和库容量定量评价研究

Quantitative evaluation of maximum operating pressure and storage capacity for gas-top sandstone reservoir-type gas storage

提高运行上限压力是增加储气库工作气量最直接、最有效且综合效益最优的方案。通过在矿场井中原位实测得到的最小主应力,对冀东南堡油田1-29气顶砂岩油藏型储气库的运行上限压力和库容量进行了定量评价,研究结果表明:基于最小主应力准则,盖层发生拉张破坏对应的上限压力最低,即根据实测最小主应力确定南堡油田1-29储气库的运行上限压力为27.2 MPa。基于有效库容计算模型,综合考虑气层含水量、残余水和边缘孔隙以及油层的波及系数、气驱液效率和含油空间利用率等因素,将上限压力从原始地层压力22.5 MPa提升到27.2 MPa,储气库的有效库容从15.46×10^(8)m^(3)增加到18.14×10^(8)m^(3),库容量增加约17.3%,预期可显著提升储气库的经济效益。研究成果对其他地下储气库运行上限压力和库容量定量评价具有一定参考价值。

[Objective]The maximum operating pressure for underground gas storage facilities designed for oil and gas reservoirs,both constructed and under construction in China,is currently set at the original formation pressure.There have yet to be successful cases of overpressure operation,which significantly impacts the economic benefits of converting depleted oil and gas reservoirs into underground gas storage facilities.This article aims to evaluate the maximum operating pressure and storage capacity of the Nanpu 1-29 gas storage facility from the perspective of the ultimate bearing capacity of cap layers and faults,with the goal of effectively enhancing the construction benefits of the facility.[Methods]The evaluation of the maximum operating pressure for the Nanpu 1-29 gas storage facility in eastern Hebei is based on the minimum principal stress measured in situ in the mining wells.Different effective porosity calculation methods are employed to quantitatively evaluate the effective storage capacity of gas and oil reservoirs,as well as the incremental capacity after pressure boosting operation,based on their development differences.[Results]The evaluation of the maximum operating pressure for the Nanpu 1-29 gas storage facility indicates that the minimum principal stress of the cap layers determined by the in-situ measurements in the mining wells is 34.00 MPa.Based on the tensile failure criteria determined by the minimum principal stress,the maximum operating pressure for the tensile failure of the cap layer is 27.20 MPa.Combined with the maximum safe injection pressure corresponding to shear failure of the cap layer(30.60 MPa)and the maximum safe injection pressure corresponding to unstable slip of the fault(27.60 MPa),the final maximum operating pressure for the Nanpu 1-29 gas storage facility is determined to be 27.20 MPa.Based on the effective storage capacity calculation model,considering factors such as the water content of the gas reservoir,residual water and edge porosity as well as the coefficient of influence,the efficiency of gas-driven fluid,and the utilization rate of oilcontaining space,the maximum operating pressure increased from the original formation pressure of 22.50 MPa to 27.20 MPa.The practical storage capacity of the gas storage facility increased from 15.46×10^(8)m^(3)to 18.14×10^(8)m^(3),an increase of approximately 17.3%.[Conclusion](1)The construction of gas storage facilities can be re-evaluated for the maximum operating pressure based on the minimum principal stress measured in situ in the mining wells,and overpressure design can be conducted under appropriate conditions.(2)Overpressure design can effectively increase storage capacity and improve the economic benefits of reservoir construction.[Significance]The research results have a certain reference value for the quantitative evaluation of the maximum operating pressure and storage capacity of other underground gas storage facilities,and are expected to significantly improve the economic benefits of overpressure-designed reservoir-type gas storage facilities in China.