| Huanghua Depression is a rift basin, which have developed since Paleogene. The shore area of Dagang lies in the Middle-north of Huang Hua Depression, which is west to Cangxian apophysis, east to boundary of diggings, south to South Dagang-East Qikou fault and north to Xingang fault. The samples were derived from Es32 Formation in the shore area of Dagang. The objective of this research is to describe the characteristics of petrology of reservoir sandstone, reveals its characteristics of diagenesis, analyse the characteristics of properties. and confirm the reservoir-forming period of sand rock from Es32 in the shore area.Acquisition of such objective, the techniques applied in this study include thin-section observing, stained-thin section identification, Scanning Electro Microscope (SEM) observation, cathodoluminescence analysis, alizarin red-S coloration, X-ray diffraction analysis, fluorescence and of fluid inclusion, heating-cooling experiment and etc.Through thin-section observing, to confirm rock types developed in the shore area are mostly feldspathic Iitharenitc sandstone and calcium lithic feldspathic sandstone wirh every granularity. Combination of rock scraps is:rhyolite,andesite,firestone,micrite,metamorphic rock, also with granite and siltstone, which has good coherence with lithology combination of western Cangxian apophysis. Interstitial material composition is mainly carbonate cementation and silicon cementation, silicon cementation. The former includes two types:calcite and dolomite.The use of thin-section observing, SEM observation, cathodoluminescence analysis, alizarin red-S coloration, X-ray diffraction analysis and etc, main types of diagenesis of Es32 formation reservoir sandstone include mechanically compaction, alteration, solution, cementation, metasomatism, corrosion etal. Diagenetic facies can be devideed into carbonate mineral cement metasomatism, kaolinite filling phase, authigenic mineral microlite and compaction dissolution. According to vitrinite reflectance, lay mineral assemblages and Eamonn in the mixed-layer smectite ratio and so on, diagenesis is determined in the phase A for a view.Through measures of stained-thin section identification,Hg-pressding curve analysis,image analysis, to define porosity types of Es32 Formation reservoir sandstone include original intergranular pore,enlarged intergranular pore,intragranular dissolved pore,intergranular dissolved pore,mold pore,intragranular tiny pore,crack. Category of pore structure is based on medium (about 44.1%), followed by good-grade pore structure (about 29.4%), poor-grade pore structure (about 26.5%). As a whole, reservoir properties belong to the category of medium porosity and extralow to superlow permeability, face-hole rate focuses on 7%-9%, average breadth of hole throat is mainly between 5 to 6μm, which belongs to the medium category. Reservoir sandstone of good properties distributes on depth of 3000～3350m and 3750m.Based on the study of diagenesis characteristics, fluorescence of fluid inclusion, and heating-cooling experiment were conducted to identify the temperature and maturity of fluid inclusion, and the time of hydrocarbon emplacement. On the basis of fluid inclusion study, the emplacement of petroleum in this area is interpreted as occurring in two main phases. The first one took place for the first time of quartz overgrowth, and the oil inclusions were found in cemented cracks of detrital quartz grain un-crossing quartz overgrowths at the stage of mid-late lower Nm, with the period 9-5Ma. The second is during the second time of quartz overgrowth and later calcite vein deposition at the stage of upper Nm to mid Quaternary, with the period 5-0.5Ma. At the second phases, the source rock begains entering oil-generating peak, so the scale of oil migration and accumulation is larger. The activity of the main faults is strong and controls the vertical migration of oil, with the result of the large scale of oil and gas.
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