Research On The Diagenesis And Pore Structure Of Chang6₁Reservoir In ZJW Oil Region, Eastern Ordons Basin

The thesis mainly focuses on the research of diagenesis and pore structure characteristics in chang61ZJW oil region of eastern Ordos basin, for the purpose of finding out their effects on oil productivity in that region. Through practical rock samples, collection of basic material and production material in the oil region, a series of testing and analyzing methods, I did research on the diagenesis and pore structure characteristics carefully, and then some conclusions are draw as follows:Ⅰ.According to triangle graphic method, the primary rocks in chang61ZJW oil region are mainly feldspar sandstone and few feldspathic lithic sandstones. And the general distributed rocks are quartzose, calcite, feldspathic, laumontite and some cement. Granularity gives priority to fine grain. Roundness of particles is mainly sub-angular. Level is medium. The connection between particles is mainly line contact and scattered concave-convex contact and point-line contact. Cementation types of reservoir rock in Chang61are pore cementation, mosaic cementation and diaphragm cementation.Ⅱ.The main effects on the Chang61are compaction and pressolution, cementation, denudation. Among these factors the preceding two factors have destructive effects on reservoir properties while the latter two have constructive significance to it. According to the standardized digenetic stage, I made it be in the A digenetic stage.Ⅲ.The diagenetic facies in study area is divided into five types:compaction and pressure solution sandstone phase, weakly compacted sandstone--chlorite cementation facies, chlorite cementation sandstone--feldspar dissolution facies, carbonate cementation Sandstone facies, lomontite cementation dissolution facies--Feldspar dissolution facies.Ⅳ.Reservoir space of Chang61in study area is divided into residual intergranular pore, miscellaneous grains within the pore micro pore solution, corrosion intragranular pore, corrosion intergranular pore, the mould pore, authigenic mineral intercrystalline pore and Fracture porosity. They constitute two types of pore assembly, including intergranular pore and intergranular pore-dissolving pore. According to pore structure, pores are divided into A-pore and B-pore for the purpose of distinguishing high-quality reservoir space.V.Because chlorite cementation sandstone—feldspar dissolution facies and lomontite cementation dissolution facies--Feldspar dissolution facies have better pore throat structure, they has become the dominant enrichment zone of oil and gas in the study area.