Resource Potential Evaluation And Favorable Exploration Areas Prediction Of The Taiyuan Formation Shale Gas In Qinshui Basin

By reviewing and studying the shale gas both at home and abroad,in this study,we analyzed the key geological problems,collect and collate the characteristics of tectonic evolution in this area,the characteristics of shale development,organic geochemical characteristics,reservoir characteristics and so on.And we also analysis the shale gas formation and geological conditions.By getting the key parameters of the source rock,such as the area?thickness and gas content of the hydrocarbon,we use qualitative and quantitative analysis methods to calculate the resources and forecast the favorable exploration area.Qin shui Basin is a relatively stable basin,it is a large compound syncline.The transgression direction changed from the northwest to the southeast in Taiyuan group.it belongs to transitional faces deposition,in the north it is delta depositional system,in the centre,it is lagoon system,in the south it is platform facies.The formation is mainly mudstone,sandstone,coal and limestone.The shale has many layers,but the single layer thickness is relatively small,In addition to part of the region,the average effective of shale thickness is less than 20m,With moderate buried depth,the embedded depth of the shale is more than 1000m in the north and central part of the basin.The depth of buried depth increases gradually from the edge of the basin to the center.The identification and analysis of the micro components of the kerogen showed that the type of organic matter in the shale is mainly in type 2.Experimental analysis method shows that the Taiyuan group shale has high organic matter contents,of which TOC is generally between0.9%and7.2%,but the logging curve analysis shows the TOC is between 0.36%~3.94%.The shale also has high maturity of organic matter,and Ro is generally between0.34%and 3.96%,shows higher maturity of organic matter.The data of X-ray diffraction analysis indicates that the shale has high brittle mineral contents,which usually rang from 38%to 44%,that is conducive to the late fracturing.By scanning electron microscope and argon force sub polishing,we can see kinds of pore structure characteristics.By nuclear magnetic resonance,we find the pore is 2nm~50nm;By using Isothermal adsorption experiment,the mudstone Adsorbed gas is between 1.38 m~3/t and 2.83m~3/t.Reservoir comprehensive evaluation indicates that the mudstone reservoir is mainly type I and type II,and the reservoir performance is betterBased on the evaluation method of shale gas resource which is establishment by the Ministry of Land and Resources,the shale gas resources potential in Taiyuan group calculated by analogy and volumetric methods is great.The calculation results show that the Taiyuan formation has some potential.According to evaluation criteria,we can prefer three favorable areas;the more favorable areas are mainly concentrated in the northeast and central part of the basin.The first favorable areas is in the north of the basin,which resource quantity is about 2332×10~8m~3,the second favorable areas is about 480×10~8m~3,and the third favorable areas is about 408×10~8m~3.