致密气藏储层开发过程中套管应力分布影响规律研究  

Study on influence law of casing stress distribution in tight gas reservoir development

作　　者：杨钊[1] 孙锐 Yang Zhao;Sun Rui(College of Petroleum Engineering,Northeast Petroleum University,Daqing 163318,China)

机构地区：[1]东北石油大学石油工程学院,黑龙江大庆163318

出　　处：《能源与环保》2022年第6期1-9,共9页CHINA ENERGY AND ENVIRONMENTAL PROTECTION

基　　金：中石油创新基金资助项目(2019D-5007-0205)。

摘　　要：目前各大油田套损现象严重,研究套管受力非常迫切。利用离散元与有限元分析方法,建立了套管—水泥环—地层组合体系模型,模拟裂缝密度、裂缝夹角、水泥环缺失厚度、多缺口夹角、套管偏心下水泥环厚度及其弹性模量、断层滑移对套管的应力分布影响情况。结果表明,套管应力随着裂缝密度的增加呈现增大的趋势,套管应力随着次级裂缝与主裂缝间夹角的增大呈现增大的趋势;套管应力随着地应力差值的增加呈现不断变大的趋势,当地应力差值相同时,随着水泥环单缺口缺失厚度增加,套管越容易发生损坏,水泥环双缺口夹角为60°及三缺口夹角75°时,套管应力值最大。当套管存在偏心,偏心率为0.037、0.074、0.111时,随着水泥环厚度的增加,套管应力呈现不断变大的趋势;当偏心率为0.148时,套管应力随着水泥环厚度增加而减小,水泥环对套管保护能力随其弹性模量的增大而增强。套管应力随着断层滑移的增大而增大,而增速在不断放缓。At present,casing damage is serious in major oilfields,and it is very urgent to study casing stress.Using discrete element and finite element analysis method,the casing-cement ring-formation combination system model was established to simulate the influence of crack density,crack angle,cement ring missing thickness,multi-notch angle,cement ring thickness and its elastic modulus under casing eccentricity and fault slip on the stress distribution of casing.The results showed that:the casing stress increases with the increase of crack density,and the casing stress increases with the increase of the angle between the secondary crack and the main crack.The casing stress shows a trend of increasing with the increase of in-situ stress difference.When the local stress difference is the same,the casing is more prone to damage with the increase of the missing thickness of the cement ring single notch.When the double gap angle of the cement ring is 60°and the three gap angle is 75°,the casing stress largest.When the eccentricity of casing is 0.037,0.074 and 0.111,the stress of casing increases with the increase of cement sheath thickness.When the eccentricity is 0.148,the stress of casing decreases with the increase of cement sheath thickness,and the protection ability of cement sheath to casing increases with the increase of elastic modulus.The casing stress increases with the increase of fault slip,and the growth rate is slowing.

关 键 词：有限元 离散元 裂缝密度 裂缝夹角 水泥环缺失 套管偏心 断层滑移 

分 类 号：TE37[石油与天然气工程—油气田开发工程]