Diagenesis and diagenetic facies of deep and ultra deep tight sandstone in Turpan-Hami Basin:a case study of the second Member of Sangonghe Formation in the J7 well area,Qiudong Subsag
The tight sandstone reservoir of the second Member of Sangonghe Formation,which is the main target of oil and gas exploration in Turpan-Hami Basin,lacks quantitative evaluation of diagenesis and diagenetic facies.Diagenetic facies division was carried out based on the data of rock thin section,physical property analysis,grading analysis,X-ray diffraction and scanning electron microscopy,and on the basis of the calculation of related parameters such as apparent compaction rate,apparent cementation rate,porosity increased by dissolution,porosity increased by fracture and diagenetic comprehensive coefficient.At the same time,grey correlation analysis was used to establish the logging calculation model of diagenetic comprehensive coefficient,which realizes the quantitative evaluation of diagenesis and diagenetic facies.The results show that the lithology of the second Member of Sangonghe Formation in Qiudong subsag,Turpan-Hami Basin is mainly lithic sandstone and feldspar lithic sandstone,with poor structural maturities and compositional maturities,porosity less than 6.0％and permeability less than 1.0×10-3 μm2,which is a typical ultra-low porosity and ultra-low permeability reservoir.In geological history,the reservoir has undergone diagenetic transformation such as compaction,dissolution,cementation and fracturing.There are six kinds of diagenetic facies in tight sandstone reservoirs of the second Member of Sangonghe Formation,and the strong compaction-dissolution facies and the strong compaction-dissolution microfracture facies are important constructive diagenetic facies in the study area.There are some differences in the distribution of diagenetic facies among different sand groups of the target layer in the study area,but the general rule is basically the same,and it is affected by sedimentation under certain conditions.This study not only clarified the characteristics of the transverse and horizontal distribution of diagenetic facies in the second Member of Sangonghe Formation in the study area,but also provided methods and technical support for the quantitative evaluation and prediction of diagenesis.
NETL
NSTL
万方数据
