Research On Diagenesis And Key Controlling Factors Of Huangliu Formation In Dongfang Area Of Yinggehai Basin

Yinggehai Basin is one of important oil and gas bearing basin on the offshore ofSouth China S, with abundance oil and gas resource, having extensive foreground ofpetroleum exploration. After dozens of years exploration, a few of gas field werediscovered, Huangliu Formation in deep strata of middle diaper in Yinggehai Basingained little breakthrough, the main reason was that the little breakthrough of theforecast of high quality reservoir distribution, the sandstone reservoir was affected bythe setting of high temperature and overpressure, the developmental mechanism andthe distribution of high quality reservoir were complex, which were the importantfoundation for the next step of exploration.With the theory of reservoir sedimentology and reservoir geochemistry, on thebasis of rock core, well logging data and log data, this paper studied the petrology andreservoir physical property, divided the lithofacies. With the SEM, thin sectionanalysis, electron microprobe and X diffraction, this thesis studied the pore category,diagenesis and diagenetic facies, summed up the key controlling factors of thereservoir, then forecasted the high quality reservoir distribution, the main researchoutcome as follows:⑴The petrology and reservoir physical property in Dongfang district have thefeature of regionality, Dongfang13-1district mainly developed lithic quartz sandstone,which was mesoporosity and medium permeability reservoir, Dongfang13-2districtmainly developed feldspathic lithic sandstone, which was mesoporosity and lowpermeable sublayer-extremely low permeable sublayer. With the pore texture andphysical property, the reservoir of reseach district were divided into4types: I、II、III、IV reservoir.⑵The diagenesis of the research location were affected by high temperature,and overpressure, the compaction was influenced by overpressure, the compactionwere inhibited at a certain extent, cementation was weaker with the overpressure, thecorrosion was stronger because of the multiple phase hot fluid, the clay mineral wasaccelerated by high temperature. Based on the development degree of3types of diagenesis, there were8types of diagenetic facies, different diagenetic faciescorresponded with correlated pore assemble and deposition microfacies.⑶The reservoir of the research district were controlled by sedimentary,diagenesis, overpressure and hot fluid, sedimentary facies influenced the material baseof the reservoir development, the appearance moment of overpressure controlled thedevelopment extent of the primary porosity. The hot fluid affected the intensity of thedissolution, diagenesis controlled the evolution of porosity.⑷Based the classification criteria of reservoir, the high quality reservoir weredivided into two types: I and II high quality reservoir. I high quality reservoir of the Igas group of Huangliu Formation developed in the well HD13-2-2, the distributionarea is smaller, and the valid thickness is lesser. The II high quality reservoir of I gasgroup of Huangliu Formation developed in well HD13-1-2and HD13-1-7, thedistribution area is bigger, and the valid thickness is bigger. Besides, well HD13-1-4developed I-II high quality reservoir, well HD13-1-6developed I type high qualityreservoir, and the relation between porosity and permeability is good, the other areadeveloped II type high quality reservoir. The I type reservoir in II gas group ofHuangliu Formation distributed in the well HD13-2-8d, which permeability is higherrelatively, and distribution area is bigger than I gas group. The II type reservoir in IIgas group of Huangliu Formation distributed in well HD13-1-2, which permeability islower relatively, and distribution area is smaller than I gas group.The research outcome had essential reference meaning for the research ofdevelopment mechanism to the sandstone in the setting of overpressure and hightemperature, which also helped the forecast of the high quality reservoir. The idea willinspire the forecast of the high quality reservoir in the deep strata of Yinggehai Basin,and promote the reservoir geology and petroleum geology in the deep strata on theoffshore.