Shale gas accumulation condition and evaluation system

In order to make a better exploration and development on shale gas,perfect the shale gas evaluation in each link,it is necessary to make a study on shale gas accumulation condition and evaluation system.Based on existing shale gas exploration and development,combined with foreign development technical data,through the contrast analysis between each evaluation index and shale gas accumulation features,the accumulation regularity and quantitative size of evaluation indexes have been made clear.The results indicate the shale gas accumulation should have conditions of mud/shale formation,single-layer thickness of 30m or higher,shale content of 10% or higher,TOC≥0.3%,Ro≥0.4% and etc.and the geological condition for shale gas target area is more demanding.At present,the volume method is the main method to calculate shale gas resource.There are many factors influencing shale gas reservoir evaluation.By using comprehensive evaluation method,to establish evaluation model,to determine the weights of factors on the reservoir quality,and to divide the reservoir hierarchies.Among them,the structural equation model and analytic hierarchy process(AHP)has been applied,and the evaluation results are of high accuracy.In south China,there exists great potential in shale gas exploration and development.The evaluation system mentioned above can be applied there,which can provide quantitative indicators for policy makers and be helpful for shale gas exploration and development.