摘要
为了研究开窗侧钻过程中铣锥下移对胶结面、水泥环失效面积和套管应力状态的影响,以开窗侧钻过程中套管、水泥环和地层组合系统为研究对象,考虑水泥环与套管和地层之间的胶结力以及铣削过程中载荷的传递,采用有限元方法建立接触单元以模拟各部分之间的胶结状态,建立了套管组合系统三维有限元模型。通过分析组合系统的泵压和交变钻压等载荷作用,得到了套管应力、胶结面状态、水泥环完整度以及组合系统固有频率的响应情况。计算结果表明:在给定井况时,第二胶结面的剥离距离(7.05 m)大于水泥环破坏失效距离(5.75 m),同时整个开窗侧钻过程中套管应力处于动态变化,在铣削位置处应力达到最大值;泵压由10 MPa增加到19 MPa时,胶结面失效区域增加了0.20 m,水泥环失效区域减少了0.30 m;水泥环厚度由40 mm增加到70 mm时,胶结面失效区域增加了0.45 m,水泥环失效区域减少了0.30 m。研究成果可为研究老井开窗侧钻过程中结构响应状态提供理论参考。
During sidetracking,the downward movement of milling cone will influence the cementing surface,cement sheath failure area and casing stress state.To study this,taking the combination system of casing,cement sheath and formation during sidetracking as the study object,considering the cementation force between cement sheath,casing and formation and the load transfer during milling,a contact element was established by using finite element method to simulate the cementation state of each part,and a three-dimensional finite element model of casing combination system was established.The responses of casing stress,cementing surface state,integrity of cement sheath and natural frequency of the combined system were obtained by analyzing the loads of the combination system such as pump pressure and alternating weight on bit.The calculation results show that the peeling distance of the second cementing surface(7.05 m)is larger than the failure distance of cement sheath(5.75 m)under given well conditions.Meanwhile,the casing stress changes dynamically during the whole sidetracking process,and the stress reaches the maximum value at the milling position.When the pump pressure increases from 10 MPa to 19 MPa,the cementing surface and the cement sheath failure area increase by 0.20 m and decrease by 0.30 m,respectively.When the thickness of cement sheath increases from 40 mm to 70 mm,the cementing surface and the cement sheath failure area increase by 0.45 m and decrease by 0.30 m,respectively.The research results provide a theoretical reference for studying the structural responses of old wells during sidetracking.
作者
欧阳勇
申昭熙
白明娜
段志锋
丁宇奇
Ouyang Yong;Shen Zhaoxi;Bai Mingna;Duan Zhifeng;Ding Yuqi(Oil and Gas Technology Research Institute,PetroChina Changqing Oilfield Company;National Engineering Laboratory for Exploration and Development of Low Permeability Oil and Gas Fields;CNPC Tubular Goods Research Institute;State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials;School of Mechanical Science and Engineering,Northeast Petroleum University)
出处
《石油机械》
北大核心
2022年第7期34-42,共9页
China Petroleum Machinery
基金
中国石油重大科技专项“侧钻井技术示范与推广”(2019D-4209)
黑龙江省博士后基金项目“基于多场耦合的储罐内爆断裂破碎多米诺效应与罐群安全间距研究”(LBH-Q20082)。
关键词
套管组合系统
开窗侧钻
结构响应
胶结强度
水泥环失效
CCF(casing,cement sheath and formation)combination system of
sidetracking
structural response
cementation strength
cement sheath failure
