万口井数据透视煤层气和煤岩气开发特征、关键技术及前景OA

To improve the development technology of coalbed methane(CBM)and coal-rock gas under complex geological conditions,this study integrated the dynamic production data of 8204 CBM wells and 639 coal-rock gas wells from the Total-soph unconventional oil&gas platform(UOG).The resource endowment,development status and key technologies of these two types of gas reservoirs were systematically reviewed using comparative analysis and machine learning methods.The differ-ences in development indicators were quantified,and the challenges and prospects were analyzed.The results show that the total geological resources of CBM and coal-rock gas in China is of 71.5×1012 m3 with technically recoverable resources of 22.5×1012 m3.Two major industrial gas production bases have been constructed in Qinshui Basin and the eastern margin of Ordos Basin.The breakthrough of coal-rock gas in Ordos Basin in 2019 marked the industry's entry into a new stage of coor-dinated shallow and deep gas development.A full-process technical system has been established,covering exploration and e-valuation,drilling and completion,reservoir stimulation,drainage and production,enhanced recovery and digital intelli-gence.CBM horizontal wells exhibit the characteristics of"slow peak arrival and gentle decline",with main intervals of sin-gle-phase water drainage period of 4-120 d,gas breakthrough pressure of 0.07-1.02 MPa,first-year average daily produc-tion of 2120-7592 m3,first-year production decline rate of-31%to 21%,and single-well estimated ultimate recovery(EUR)of(963-2714)×104 m3.Coal-rock gas horizontal wells show a production feature of"gas breakthrough rapidly after well startup",with"fast peak arrival and high peak production"having gas breakthrough pressure of 5.4-8.7 MPa,first-year average daily production of 44 077-62 288 m3,first-year decline rate of 27%-56%,and single-well EUR of(4 547-6 232)×104 m3.The two types of gas reservoirs are highly complementary and can be synergistically build into a production capacity model combining"rapid response and stable supply".The industry currently faces many challenges,such as strong reservoir heterogeneity,immature development technology of deep reservoirs,economic dependence on subsidies,insufficient digital intelligence integration and environmental constraints.However,the development models of"integrated coal mining and gas extraction"and"carbon sequestration with resource development"have broad prospects driven by the dual carbon goals,policy coordination and technological iteration.