Study on the composition and inter-layer correlation of coalbed methane system of Xishanyao Formation under sedimentary control, Southern Junggar Basin, NW

<p>In order to investigate the controlling of the sedimentation environment evolution on the coalbed methane system in Xishanyao Formation on the southern margin of Junggar Basin&#65292;using drilling wells&#65292;logging wells&#65292;outcrops and other data with the assistance of fine analysis methods&#65292;such as scanning electron microscope and image granularity&#65292;the coalbed methane system was divided&#65292;and its sedimentation evolution process was researched&#65294; The research results show that sand body of five types of sedimentation microfacies&#65292;whose water and air blocking capacity is sorted as &#8220;diversion channel&#65308;crevasse splay and beach dam&#65308;natural levee and shore&#65293;shallow lake&#8221;&#65292;can be identified in the research area&#65292;and single&#65293;well vertical coalbed methane system was divided; during the SQ1&#8212;SQ2 period&#65292;the rise of lake level led to the expansion of the development area of lacustrine facies&#65292;as well as the weakening of the coal&#65293;accumulating process which was mainly concentrated in the TST and LST stages of SQ1&#65292;and the east&#65293;west characteristic difference regarding the coalbed development and gas content appeared and was in accordance with the plane distribution of sedimentary facies; during exploitation&#65292;the coalbed methane system should be defined according to the blocking capability of surrounding rock&#65292;appropriate exploitation methods should be selected according to the characteristics of each system&#65292;and the avoidance of vertically joint&#65293;developing sandstone aquifer and combined layer series of development should be paid attention to&#65294;</p>