Research On Diagenesis And Reservoir Characteristics Of Yanchang Formation In Yichuan-Xunyi Area In The Southeast Of Ordos Basin

Yichuan-Xunyi area is low in exploration,nobody has studied on the sedimentary facies, diagenesis and reservoir characteristics systematically in this area. This article eyes on the problems existing in this area, under the guidance of sedimentology and oil geology theories,we researched the sedimentary facies, diagenesis and reservoir characteristics deeply by means of many tests and analyses.this is very important for the next oil and gas exploration and helpful to play down the cost of exploration.Firstly, by means of outcrop drilling core,slice, cathodoluminescence, SEM and vitrinite reflectance ,reservoir Lithological Features and diagenesis is stuied in detail.in this area, the componential and textural maturities is lower and the Lithological types are mostly Arkoses, lithic arkoses and feldspar litharenite. Diagenesis types: mainly compaction, cementation , Silty filling ,dissolution and Metasomatism. The former two functions are the main reasons of decreasing reservoir quality. the dianenetic sequence being as fol lows: mechanic compaction→authigenie chlorite clay rim→the dissolve of felspar→quartz overgrowths→latter calcite cementation→calcite Metasomatism→felspar overgrowths→Hydrocarbon Emplacement.Nowadays it is a period of time A, terminal diagenesis for Yanchang formation.Secondly, with the former two research,based on the test of porosity and permeability ,some research has been done on the characteristic of hole and petrophysical property ,the reservoir of this area can be divided into three types according to the appropriate scheme,there areⅡ,Ⅲ,Ⅲ--Ⅱ. Further exploration targets are predicted to be Yicuan--Xiangsimiao area and Xunyi--Huangling area.