Role of fracture in controlling the reservoir stratum in the carboniferous bioclastic Limestone member in Hetian river gas field,Tarim basin

Hetian river gas field is a large-scale carbonate gas pool found and proved in Tarim basin.Carboniferous bioclastic limestone member accounts for 53% of the total gas reserves and is an important producing formation in Hetian river gas field.The buried solution taken place around fractures produced solution pores,possibly by sulphuric acid,which provide more than 47%～61% of the total porosity.The primary karstification includes interlayer karst and buried krast.Fracture styles are consisted mostly of structural fracture,which not only make up the principal permeability contributor,but also control porosity distribution in the vertical and planar section.The matrix porosity has good correlation with the fracture's development in the Carboniferous bioclastic limestone member.High porosity zones are commonly found in fracture well developed parts such as structure axes,low porosity zones in less fracture structure nek.