基于有限元法的井底应力场随井底压差变化规律研究  

Study on the variation law of bottom hole stress field with bottom hole pressure difference based on finite element method

作　　者：席境阳 XI Jingyang(Drilling Technology Research Institute of Shengli Petroleum Engineering Corporation Limited,Sinopec,Dongying Shandong 257000,China)

机构地区：[1]中石化胜利石油工程有限公司钻井工艺研究院,山东东营257000

出　　处：《钻探工程》2021年第5期60-68,共9页Drilling Engineering

基　　金：中石化工程公司科技项目“干热岩开发关键技术研究”(编号:SG18-06K)。

摘　　要：岩石破碎是钻头与井底岩石相互作用的结果,井底应力场是决定钻头破岩效果的重要因素。本文利用有限元数值模拟手段探讨了特定地应力条件下井底压差对井底岩石应力的影响规律。研究表明,降低井底压力可以减小井底岩石的等效应力、改变岩石的应力状态,有利于钻头破碎岩石。井底平面上井眼中心附近的岩石最易破碎,越靠近井壁岩石所受的应力越大,在近井壁地带0.8R(R为井眼半径)附近,会出现明显的应力集中现象,这使得该区域的岩石最难破碎。本文的研究成果为研究最经济、最有效的钻井工艺和破岩技术提供理论依据,为破岩工具的优化设计提供参考。The crushing of the rock is the result of the interaction between the drill bit and the bottom hole plane rock,and the bottom hole stress field is an important factor determining the rock fragmentation effect of the drill bit.In this paper,the finite element numerical simulation method is used to discuss the regular pattern of bottom hole pressure difference on bottom hole plane rock stress under specific ground stress conditions.To consider that reduce the bottom hole pressure can reduce the equivalent stress of rock,changing the stress state of rock,which is conducive to rock breaking by bit.At the same time,it is concluded that the rock near the center of the borehole is the most easily broken,and the rock stress value near the borehole wall is the largest.There will be obvious stress concentration near the borehole wall 0.8R(R is the radius of the borehole),which makes the rock in this area the most difficult to break.It provides theory basis for the study of the most economical,effective drilling and breakage rock technology.

关 键 词：有限元法 应力场 井底压力 岩石破碎 

分 类 号：TE21[石油与天然气工程—油气井工程] P634[天文地球—地质矿产勘探]