应用数学和力学2025，Vol.46Issue(12)：1571-1583,13.DOI:10.21656/1000-0887.450247
环空固相沉降对深水圈闭压力的影响机制及预测模型研究
Study on the Influence Mechanism of Annular Solid Phase Settling on Deepwater Trapped Pressure and the Prediction Model
摘要
Abstract
In deepwater oil and gas production operations,accurately predicting the annular trapped pressure is of decisive significance for ensuring the safety of oil and gas wells,optimizing the production process,and ex-tending the service life of oil and gas wells.The water-based annular fluids were investigated and the density and thermophysical property parameters under various settlement times were systematically tested,and the in-fluence law of solid-phase settlement on the fluid parameters was sorted out.Based on the law of constant-vol-ume thermodynamics,in view of key factors such as solid-phase settlement and dynamic changes in the thermo-physical property parameters of the fluids,a calculation method for the multi-annular coupled trapped pressures applicable to gas wells was proposed.Through comparison of the calculation results of this method with the measured trapped pressure data at the underwater wellhead,the maximum error between the 2 is only 8.91％.With a typical offshore gas production well as a specific example,a program was developed with the.Net lan-guage to solve and operate the constructed model.The results show that,the solid-phase settlement has an ex-tremely significant effect on the density of the annular fluid.With the continuous increase of the settlement time,the fluid density shows an obvious downward trend.After a 7 d test,the drilling fluid density gradually decreases from the initial value of 1.7 g/cm3 to 1.23 g/cm3 and tends to be stable,with a density reduction of up to 27.65％.With the well depth increase,the gas production rate rise,the isobaric expansion coefficient uplift and the drilling fluid isothermal compression coefficient growth,the annular trapped pressure always shows an increasing trend.Under the condition of the same thermophysical property of the fluid,the annular trapped pressure is particularly affected by the closed volume of the annulus.The trapped pressure in the 1st annulus is 23.2 MPa,that in the 2nd is 15.53 MPa,and that in the 3rd is 7.69 MPa.In addition,the comparison of the tub-ing displacement at the wellhead with that at the bottom of the well indicates that,the maximum tubing dis-placement at the wellhead decreases from 1.69×10-6 m to 6.1×10-7 m,and the tubing displacement at the well-head is about 2.77 times that at the bottom.The accurate solution of the annular trapped pressure can provide an extremely crucial theoretical basis and data support for practical engineering operations such as checking the pipe string safety factor,evaluating the wellhead uplift risk,and optimizing the cement return height design,and effectively contribute to the safe and efficient development of deepwater oil and gas production operations.关键词
深水气井/环空圈闭压力/等压膨胀系数/固相沉降/环空压力Key words
deepwater gas well/annular trapped pressure/isobaric expansion coefficient/solid-phase settle-ment/annular pressure分类
数理科学引用本文复制引用
孔祥伟,温帅,谢广宇,吴红建..环空固相沉降对深水圈闭压力的影响机制及预测模型研究[J].应用数学和力学,2025,46(12):1571-1583,13.基金项目
国家人才专项基金(SQ2022QB05933) （SQ2022QB05933）
