储气库井油套环空压力影响因素分析

针对储气库注采井密闭环空带压问题，开展了储气库注采井在生产管柱内温度、压力变化时，密闭环空压力计算模型的研究。首先，根据储气库现场实际简化井身结构，建立了密闭环空分析模型。其次，采用管柱弹性力学平面应变理论、物质的热胀冷缩性质及流体PVT状态方程，建立了数理解析模型。最后，根据某井的基础数据得出储气库注采井生产管柱内温度变化是形成密闭环空压力的主要影响因素这一认识；在只考虑温度、压力变化对保护液影响的情况下，可以满足现场工程要求，误差小于5%，计算结果与现场数据吻合较好。计算方法便于现场的环空压力快速预估。

Analysis of Factors Influencing the Casing-tubing Annular Pressure of Gas Reservoir Wells

Due to the problem of sustained casing pressure in the trapped annulus of gas reservoir injection-production wells, we develop a calculation model for sustained casing pressure under changing temperature and pressure of the production tubular column. An analysis model is first established for the trapped annulus according to a site-specific simplified structure of the actual gas reservoir. Next, based on the plane strain theory of elasticity, the thermal expansion and contraction properties of the material and the PVT equation of state for fluids, a mathematical analysis model is constructed. Finally, when the raw well data is considered, it is clear that the temperature change in the gas reservoir injection-production well is the main factor affecting the formation of the annular pressure. When only the effects of temperature and pressure on the protecting fluid are considered, this protocol meets the engineering requirements on site, with an error less than 5% and calculated results in good agreement with field data. This method facilitates the rapid prediction of annulus pressure in the field.