大庆油田嫩二段底部标准层进水后的黏滑变形计算模型  

Calculation model of stick-slip deformation of Nen2 bottom datum bed after water inflow in Daqing Oilfield

作　　者：李丹[1] LI Dan(No.1 Oil Production Plant,Daqing Oil Field Co.Ltd.,CNPC,Daqing 163001,Heilongjiang)

机构地区：[1]中国石油大庆油田有限责任公司第一采油厂,黑龙江大庆163001

出　　处：《长江大学学报（自然科学版）》2021年第5期56-65,共10页Journal of Yangtze University(Natural Science Edition)

基　　金：国家科技重大专项“致密油储层岩石力学性质与影响压裂裂缝延伸因素研究”(2016ZX05046004-004)。

摘　　要：大庆油田嫩二段底部(以下简称“嫩二底”)标准层高压进水改变了其力学状态,使其形成滑移的条件发生变化。为研究进水压力对标准层滑移的影响,基于区域间地层压差作用下的地层位移解析解,推导了标准层断裂前、后的垂向正应力与剪切应力计算公式;考虑长期注采条件下地层存在反复多次滑移的实际情况,运用黏滑理论建立了标准层断裂后层面残余剪切应力与滑移量计算模型,计算了不同进水条件下地层的滑移临界条件与滑移量。研究表明,在区域间地层压力差的作用下形成滑移后,在标准层断裂面上会有部分剪切应力未完全释放,标准层进水后,会使标准层形成滑移的区域间压差值降低,标准层滑移后断裂面的残余剪切应力降低,形成更大的剪切应力释放,使标准层更易滑移、滑移量更大。大庆油田嫩二底标准层进水后的黏滑变形计算方法可为标准层剪切套管损坏的有效防控提供理论依据。The high-pressure water inflow of the datum bed at the bottom of the second member of Nen in DaqingOilfield(hereinafter referred to as“Nen2 bottom”)changed its mechanical state and the slip condition.In order to study the influence of inflow pressure on the slip of standard layer,based on the analytical solution of formationdisplacement under the action of pressure difference between regions,the calculation formula of vertical normal stress and shear stress before and after the fracture of datum bed was derived;considering the actual situation of repeated slip of formation under the condition of long-term injection and production,the calculation model of residual shear stress and slip amount of datum bed after the fracture were established by using stick-slip theory.The critical slipcondition and slip amount under different water inflow conditions were calculated.The results show that after the slip is formed under the action of inter-regional formation pressure difference,some shear stress on the fracture surface of the datum bed will not be released completely.After the datum bed is flooded,the pressure difference between the slip regions of the datum bed will be reduced,and the residual shear stress on the fracture surface will be reducedafter the datum bed slips,resulting in greater release of shear stress,which makes the datum bed easier to slip and larger slip amount.The calculation method of stick-slip deformation of nen2 bottom datum bed after water inflow in Daqing Oilfield can provide theoretical basis for effective prevention and control of shear casing damage of datum bed.

关 键 词：标准层 套管损坏 区域压差 剪切变形 黏滑变形 计算模型 

分 类 号：TE931[石油与天然气工程—石油机械设备]