Progress，potential and prospects of CBM development in Guizhou Province

The Longtan Formation of Late Permian in western Guizhou is rich in coalbed methane(CBM)resources，ac⁃ counting for about 10% of the national CBM geological resources. In the national energy strategic plan，this area is an important backup base after the successfully developed Qinshui Basin and eastern margin of the Ordos Basin which are the CBM industrialization base. This paper aims to refine the characteristics of the special geological resources of CBM in Guizhou Province，China，comment on the development history of more than 30 years，summarize the develop⁃ ment progress of CBM in Guizhou Province，theoretical and technological breakthroughs，and analyze the future development potential and prospects. The CBM geological resource in Guizhou Province have five major features of “many but thin coal seams，high CBM content，complex coal body structure，main large gas fields，and deep resources account⁃ ing for a large proportion”. The development process can be divided into three stages:the CBM resource investigation and development technology reference stage ( 1989 - 2010 ) ， the independent technology exploration stage ( 2011 - 2015)，and the independent technological breakthrough stage(2016-Present). The current rapid development benefits from the breakthroughs in multi⁃coal seams CBM theories and development technologies. The breakthroughs in geolog⁃ ical theories include the superimposed CBM system theory，the production layer optimization combination theory， and the joint⁃mining development unit optimization theory. Development technological breakthroughs include the popu⁃ larization of cluster wells，U⁃shaped wells and L⁃shaped wells，and the increase of fracturing scale and fracturing effect. For the future，the development potential is huge and the large⁃scale development prospects can be expected. It is nec⁃ essary to focus on promoting the geology⁃engineering high⁃yield models of “Wenjiaba” and “Yangmeishu” in small but rich blocks throughout the province. The development should move from a single⁃well single⁃layer group develop⁃ ment to a layered sequential development，increase the production capacity of a single well at all layers and extend the life of CBM wells. To speed up the exploration and development of deep coal⁃measure gas is an important approach to large⁃scale development. At the same time，it is necessary to pay attention to new layers and new areas of the Xiang⁃ bai marine coal measure gas development potential from Upper Carboniferous.