基于水泥环完整性分析的许用套管内压力解析计算方法

发布时间：2018-04-15 04:28

本文选题：水泥环 + 应力　；参考：《天然气工业》2017年07期

【摘要】：现有的油气井套管—水泥环—地层系统的应力分析模型可用于求解井筒系统应力分布及水泥环破坏条件,虽然对探讨水泥环完整性受套管内压力变化的影响起到了重要作用,但均未能给出许用套管内压力解析计算公式。为此,基于均匀水平地应力条件下的套管—水泥环—地层系统的应力分析解析模型,针对多种水泥环破坏形式,推导出了受其作用下的水泥环径向开裂、剪切破坏、胶结面剥离等破坏条件的许用套管内压力解析计算公式。研究结果表明:(1)按水泥环径向开裂和剪切破坏条件分别求出最大允许套管内压力,推荐采用二者中的较小值作为最大许用套管内压力;(2)按水泥环胶结面剥离条件求出最小允许套管内压力,推荐将其作为许用套管内压力。结论认为,套管内压力升高可能导致水泥环径向开裂和剪切破坏,套管内压力及温度降低可能导致水泥环胶结面剥离,应综合考虑水泥环破坏条件合理确定出最大和最小许用套管内压力。
[Abstract]:The existing stress analysis model of casing, cement ring and formation system in oil and gas wells can be used to solve the stress distribution of wellbore system and the failure condition of cement ring, although it plays an important role in probing into the influence of casing pressure on the integrity of cement sheath.However, no analytical formula for calculating the internal pressure of allowable casing can be given.Therefore, based on the analytical stress analysis model of casing, cement sheath and stratum system under uniform horizontal ground stress, the radial cracking and shear failure of cement sheath under the action of various failure forms of cement ring are deduced.Analytical formula of allowable casing pressure for fracture conditions such as peeling of cementing surface.The results show that the maximum allowable casing pressure is obtained according to the radial cracking and shear failure conditions of cement ring.It is recommended that the minimum allowable casing pressure be used as the maximum allowable casing pressure / / 2) and that the minimum allowable casing pressure be obtained according to the condition of cement ring cementing surface stripping, and that it be used as the allowable casing internal pressure.It is concluded that the increased pressure in the casing may lead to radial cracking and shear failure of the cement ring, and the decrease of the pressure and temperature in the casing may lead to the exfoliation of the cemented surface of the cement ring.The maximum and minimum allowable casing pressure should be determined by considering the failure condition of cement sheath.
【作者单位】：中国石油大学(华东)石油工程学院;中国石油新疆油田公司;
【基金】：国家科技重大专项课题(编号:2016ZX05022-002) 国家自然科学基金面上项目(编号:51674284)
【分类号】：TE256

【参考文献】