| Zhenzhuchong member of Ziliujing formation of the Jurassic of is one of the significant of shallow gas reservoir in the northwestern sichuan basin region. The characteristics about Zhenzhuchong member of reservoir and the reservoir forming mechanism of in-depth study is of important guiding significance to promote further naturalgas exploration and development in this region. In this paper, Zhenzhuchong memberof Ziliujing formation of Jiulong mountain and Jiange area as the research object, on thebasis of summarizing predecessors’ research achieveme nts, the sedimentology andpetroleum geology theories as the instruction of this paper. Through the description ofthe various drilling cores in the research area, the observations of a large number ofregular and casting thin sections, the data analysis of scanning electron microscopy(sem), X-ray diffraction. And combined with the reservoir physical property testing andlogging data. Made a systematic research of the zhenzhuchong member of reservoircharacteristics and diagenesis function and the following understandings:(1)The reservoir rock types in Zhenzhuchong member of Jiulong mountain are asfollows: conglomerate, glutenite and sandstone. The reservoir rock types isconglomerate in Jiange area. The differences of reservoir rock types are caused b yphase transformation. The Jiulong Mountain region is mainly formed with deltadeposit, Sediment has experienced a certain handling modification, sorting androunding are medium, maturity structure is medium. Jiange area is mainly formedwith fan delta deposits, due to rapid proximal sediment accumulation, sorting androunding are medium, maturity structure is low.(2)Zhenzhuchong member of reservoir space types are mainly intergranularpores,and secondly holes and cracks in intergranular pore, gravel. The Jiulongmountain and Jiange area of the reservoir property have significant differences inreservoir property: The maximum porosity of zhenzhuchong member is5.69%and theminimum porosity0.08%and the average porosity1.63%in Jiulong mountain region.maximum porosity is7.8%and minimum as0.1%and mean is3.63%in Jiange area. Reservoir physical properties are different is because of the different degree ofdiagenesis modification.(3) mainly including compaction pressure, solution, cementation, metasomatism,alteration, dissolution, fracture and infilling of the caves and cracks in Zhenzhuchongmember of Ziliujing formation of Jiulong Mountain and Jiange area. According to theresults of clay mineral X-ray diffraction, S%(I/S) is0.1, shows that the evolution hasreached into rock-late diagenetic stage B period in zhenzhuchong member.(4)Diagenesis has significant difference in different areas, embodied in thefollowing aspects: The Jiulong mountain region cement is mainly with siliceous-calcium ceme nt, while that in J ia nge Area was clay infilling into the crack;metasomatism in Jiulong mountain was developed, but that in Jiange Area was leastdeveloped; Dissolution overall performance in the aluminum silicate material such asfeldspar, clay rock cuttings dissolved, Jiange area dissolution characteristics is moreobvious than the J iulong mounta in re gion.Filling in the for m o f d ickite andkaolinite-calcite these three authigenic mineral in the Jiulong mountain region,Jiangea r e a is c ha r a c te r ize d b y tw o a uth ige n ic mine r a l： q ua r tz-d o lo mite.(5)Diagenesis is the main controlling factors of the reservoir in Zhenzhuchongmember of Jiulong mountain and Jiange area. According to the statistical results showthat the cement porosity, Sediment after compactio n,37.6%of the pore isdestroyed.Compaction is the main reason of the reservoir density. Acidic fluid on clay,clay rock cuttings and feldspar dissolution increased by2-4%of the pore thatdissolution is the key to improve the reservoir property. Formed by the tectonic fracture,to a certain extent, improved the reservoir of reservoir performance. |
PDF Full Text Request