单层复合盐层地应力研究新方法

在单层复合盐岩地层的地应力研究中,单层复合盐岩地层的水平地应力不能简单地认为均匀分布,且等于上覆岩层压力值。文中采用测井资料计算得到研究区块复合盐层上、下砂泥岩地层的岩石力学参数及地应力值,并把上、下砂泥岩地层的参数作为地应力分析的边界条件,建立复合盐层及上、下砂泥岩层地应力计算的分析模型,通过有限元计算得到中间盐层的地应力场。采用该方法对某区域复合盐层的地应力场进行研究,结果表明,单层复合盐层的水平地应力大于其上、下砂泥岩层的水平地应力,对单层复合盐层钻井施工中的钻井液密度设计提供了理论依据。

A New Method Research on Compound Saltbed Earth Stress

During design of drilling engineering for compound salt bed,it is usually assumed that overburden pressure equals to horizontal stress.Field data indicates that the casing designed by above means can't satisfy collapse resistance frequently.Rock mechanics parameters and earth stress of sand-shale strata and compound salt bed were calculated in researched area,based on logging data.Taking the above parameters as boundary condition for earth stress analysis,a finite element model was established to invert earth stress field of compound salt bed.By analysis of the earth stress field of compound salt-rock in Tarim basin,it was indicated that the horizontal stress of compound salt bed was greater than that of sand-shale strata.The conclusions in this paper provided foundation for designs of borehole stability and casing safety in Tarim region.