Diagenesis of Chang-2 reservoir and its influence on physical properties in Jiyuan oilfield

By using scanning electron microscopy(SEM),casting thin sections identification,mercury injection and X-ray diffraction and based on qualitative identification,the diagenesis and its influence on physical properties in the study area were studied,and then the quantitative calculation was used to show the characterization of pore evolution after all kinds of diagenesis.Research results indicate the original porosity through calculation restoration is 37.65%,among which the impact of compaction is greatest and its loss-rate of porosity is 49.17%,and the loss-rate of porosity of cementation is 25.83%.In the study area,the feldspar dissolution was well developed,a large number of secondary porosity was produced and the dissolution of the reservoir sandstone improved porosity about 4%.The quantitative results and the laboratory test results are basically consistent.