Geological Risk Analysis And Quantitative Evaluation Of Shanxi Formation Shale Gas In Ordos Basin

Based on the full investigation of the geological risk theory at home and abroad,the domestic geological anomaly theory and shale gas research findings,by means of comprehensive utilization of field outcrop observation,drilling data and sample testing data,as well as in-depth analysis of oil and gas exploration information and shale gas reservoir geological characteristics in study area,the modern shale gas geological theory and geological risk theory and the geological anomaly theory are organically combined with the qualitative and quantitative analysis methods being well used,it's also successfully explored the application of geological risk theory in shale gas accumulation condition analysis of Shanxi group in Erdos Basin,the application of Monte Carlo method in quantitative calculation of shale gas resources and the application of geologic anomaly theory in the different shale beds of shale gas favorable area prediction.Good resources evaluation and necessary empirical data are acquired subsequently.The shale of Shanxi group in Erdos Basin belongs to continental faces deposition.According to moderate buried depth,the embedded depth of the shale is about 1000m-2500m in the main part of the basin.Shale rocks distributed widely in the basin,the vertical accumulative shale thickness is up to 120m in max.The Shanxi group shale has high organic matter contents,of which TOC is generally between 1.5%and 4.0%,and the southwest of the basin in plane presents lower content of organic matters,while the northeast of the basin in plane shows higher contents of that.The maturity of organic matter is relatively high,and Ro is generally between 1.0%-2.0%with a trend of higher values in the southwest of the basin and lower values in the northeast of the basin.Organic matters are mainly in type ?,partly in type ?1 and type ?2.High brittle mineral contents of the shale usually range from 30%to 50%.The tectonic stability of the main basin's been conductive to the shale gas preservation.Shale gas resources in Shanxi group shows great potential,it is one of the major targets for shale gas exploration in Erdos basin.The risk geological analysis of shale gas reservoir accumulation in different shale rocks shows that the shale gas geological risk of each layer in Shanxi group is moderate,that is much suitable for the exploration and development of shale gas resources.Resources calculation results show that the Shanxi group also has great potential in the future.Shale gas resource potential of each layer is in great difference,of which the prospective resources of layer ? and layer ? accounts for about 60%of the volume of Shanxi group resources.By the way of the shale gas favorable quantitative evaluation,favorable areas of shale gas are chosen from each layer of the delineation,of that layer ? and layer ? are more development.There're obvious differences in the distributions of each favorable layer,the West of Tianhuan depression and the east of northern North-Shaanxi slope is the major favorable belts of shale gas distribution.