Tight Sandstone Reservoir Characteristics Of Shanxi Formation In Su 59 Well Block, Sulige Gas Field

Sulige Gas Field is is located in the northwest of Yishan slope. Exploration area is about 4×104km2. The main production formation is Xia Shihezi Formation and Shanxi Formation Su 59 Wellblock is on the west of gas field.The average porosity and permeability of Shanxi Formation is 7.37% and 0.17 mD.It is the density of the typical reservoir. Due to the thickness of source rocks is relatively thin, production of natural gas intensity is weak, has the characteristic of low-efficient accumulation. So the poor physical property of reservoir often difficult to accumulate effectively. So high quality reservoir control factors and distribution of research is the basis of favorable regional prediction.The purpose of this thesis research is Shan 1 Section of Shanxi Formation, this formation has 3 layers.Based on the knowledge of Petroleum geology, Sedimentary petrology and Petromineralogy, comprehensive application of geophysical log and subsurface geology, and combined with core observation,scanning electron microscopy and X-ray diffraction analysis studied the characteristics of petrology,type and structure of pore, reservoir physical properties,relationships among lithology,poroperm characteristics, electric properties and oil-bearing properties and diagenesis of Shan 1 Formation in Su 59 Well block. The results show that:(1)Shan 1 Formation in the study area has delta plain sedimentary facies, belong to the meandering river delta subfacies. Lithofacies and electrical characteristics of corresponding relation is obvious, lithofacies have a certain control on types and physical characteristics in the study area.(2)Research result suggest that the lithotypes are debris-quartz and debris sandstone, which have the characteristics of low compositional maturity and high texture maturity. The most of clastic particles possess coarse grain structure, filling with clay, quartz and calcite cement. Pore types are secondary intergranular dissolved pore, intragranular dissolved pore, kaolinite intergranular pore and microcrack.(3)On physical characteristics:The average reservoir porosity is 7.37%,permeability is 0.17 mD,porosity to permeability is positive correlation trend.Lithologically, clastic particles are coarser, the reservoir properties are better.According to mercury injection experiment, the pore structure can be divided into three categories, which, small pore and fine throat primarily. The relationships among lithology, poroperm characteristics, electric properties and oil-bearing properties is closed.(4)On diagenesis:Volcanic material corrosion, kaolinite dissolution,andcarbonate karst erosion are the main constructive diagenesis on the region, carbonate mineral cementation and siliceous cementation are the main destructive diagenesis on the region. Overall, Shan 1 belong to typical low porosity and low permeability reservoir. Reservoir quality jointly controlled by sedimentary and diagensis together,with a strong heterogeneity.(5)According to the above analysis and understanding, we evaluated the reservoir of Shan 1 with multi factors. There are three types of reservoir formation in Su 59 Well block. Type?and ?are the favorable reservoir stratum, which porosity are more than 8% and between 4%-8% permeability are more than 0.1mD and between 0.01-0.1mD, type ? is the low effective reservoirs, which. porosity is less than 4%, permeability is less than 0.01 mD.