Ordos Basin Long Seven Tight Reservoir Facies And Diagenetic Logging Identification

Currently, the difficulties of petroleum exploration and development increase a lot and petroleum productivity slows down its increasing steps and the petroleum exploration interest is put forward on the deep reservoirs and lithologic reservoirs which are harder than before. Meanwhile, tight oil of continental petroliferous basin has large potential exploration interest, among which the Chang7formation of Ordos basin has4.2×109t of petroleum reserve. The diagenesis faces control the reservoir characteristics and represent intuitively stratum characteristics and types. Therefore, accurate and objective understanding diagenesis faces characteristics will be meaningful guiding the petroleum exploration and development.This paper takes Chang7formation of southeast Ordos basin as the object. Based on the previous research findings, detailed core observation and description of Chang7formation and outside geological profile are completed on the vertical variation particle size and laminated rhythm. Based on the study of diagenesis by various analysis method diagenesis faces types are classified and analyzed respectively, which lays foundation for the building of representative profile and diagenesis faces space distribution and geometrical model of core intervals which are all about Chang7formation of Ordos basin. Then the discerning of various diagenesis faces by logging method is studied and statistically acquiring variation range of logging parameters corresponding to various diagenesis faces is the base of the choose of sensitive logging parameters and then cross-plot modeling. The following conclusions are about the distribution characteristics of favorable diagenesis faces.The study area mainly develops compaction, cementation, dissolution and pressure solution and five kinds of diagenesis faces are chlorite film residual intergranular pore faces, unstable component dissolution faces, poor solution micro pore faces, illite cemented tight faces and carbonate cemented tight faces which are mainly subject to diagenesis, reservoir property and particle components. As a whole the former two faces are favorable in reservoir property and the third faces is secondary in reservoir property.Logging parameters analysis of five diagenetic faces points out that they have various different parameter ranges. Comparing neutron and density parameters can distinguish from five diagenesis faces and then two kinds of cross-plot model of neutron-density porosity difference and neutron and density logging are built which finally result in effective recognition of various diagenesis faces. Based on the recognition methods, the systematic interpretation of diagenesis faces in the study area is made, the result of which is validated by the thin section data. The planar distribution of diagenesis faces is drawn from the logging explanation results, which indicates the favorable target.