Influence of tectonic activities on CBM enrichment and accumulation in Junnan Coalfield
In order to find out the control rules of tectonic activities and types on coalbed methane(CBM)enrichment and accumulation in the Junnan Coalfield,the tectonic activities and types since the coal-forming period were described and sorted out.The results showed that tectonic activities have three major effects on CBM reservoirs:transformation,gas content control and gas reservoir genetic type adjustment.Based on the geological understanding of CBM exploration and development and the tectonic division of high/low gas-bearing areas in south China,the relationships between c CBM enrichment and accumulation,tectonic activities,and tectonic types were established.It is concluded that the tectonic activities controlling the CBM accumulation in south China are mainly Yanshan and Himalayan tectonic activities,which have both destructive and reshaping effects.The tectonic types are divided into folds and faults,in which two wings,the axis and middle plane of synclinal folds are dominated by the compressive stress,which are high-pressure area and conducive to CBM enrichment.Parts below the axis and middle planes of synclinal folds and upper parts of the anticlinal folds are dominated by the tension stress and fractures are more open,which are not conducive to CBM accumulation.The faults are divided into tensile and compressive ones.The tensile faults produce fractures in the cap formation of CBM reservoir,which is not conducive to CBM storage but may be used as a channel for CBM migration and accumulation.Compressive faults are the key factor of the reservoir trap,which is conducive to CBM storage.An accurate understanding of tectonic control provides a basis for the evaluation,selection,and engineering layout of CBM in Junnan Coalfield.
Junnan CoalfieldCBMtectonic activitystructural typeenrichment and accumulation
万方数据
维普
