常规测井三向应力计算方法研究

大庆油田注水开发油藏套管损坏的主要原因是长期高压注水造成的区域或局域孔隙压力不平衡,导致地层滑动或地层应力集中释放的结果,套损预测的关键是有效地求取地层应力参数.首先以地层测试资料为标准,利用常规测井建立了水淹油藏孔隙压力计算方法,进而以交叉偶极子声波测井解释结果为相对标准,给出了水平主应力与孔隙压力关系,实现了常规测井计算水平主应力方法,为油水井地层应力求取提供技术保证.通过5口井交叉偶极子声波测井资料检验,平均相对误差5%,最大绝对误差1.1 MPa,基本满足工程要求.

On Calculating Method of Three-component Stress with Conventional Logging Data

The oil-exploration in recent decades shows that the main reasons for causing casing damages in water-flooded reservoir of Daqing oilfield are the area or local area unbalanced pore pressure created from long-period high-pressure injection which in turn leads to formation sliding or ground stress concentrated relief,the key for casing-damage predication is to derive formation stress parameter(effectively).First of all,based on formation testing data,established is a method of calculation of water-flooded zone through conventional logging data.Secondly,given is the relationship between horizontal major stress and pore pressure that takes the cross dipole sonic logging interpretation data as relative standard,which makes the horizontal major stress calculated through conventional logging data come true as well as gives a technique guarantee for oil-water well formation stress calculation.Tests from 5 well's cross dipole sonic logging data show that the average relative error is 5%,and the maximum absolute error is 1.1 MPa which can meet the basic requirements of exploration.