Analysis Of The Key Factors Affecting The Management And Control Strategy Of The High-rank Coalbed Methane Drainage

Coalbed methane is considered an ‘unconventional' gas resource that occurs in coal reservoirs.High-rank coal in the Q inshui Basin is the major target in C hina.Although some national demonstration areas have been built and several high-yield coalbed methane wells have been discovered in the 3# coal reservoir,coalbed methane in these areas has not been fully commercialized because the enrichme nt degree of coalbed methane varies greatly in different settings.Taking Fanzhuang Zhengzhuang block in Q inshui Basin as the target study area,this paper investigates and analyzes the geological conditions of 3# coal reservoir(high-grade coal)in the study area.According to the occurrence characteristics of the target layer and the dynamic change law of permeability,combined with the key factors affecting the production of high rank coalbed methane,the accurate relationship between the extraction parameters of high rank coalbed methane have been established.In addition,we discussed further the law of high-rank coal-bed methane gas production in combination with reservoir sensitivity characteristics.Combined with the laws and on-site management characteristics,the gas well drainage control rules are obtained,and these requirements are put forward for the drainage control equipment of the coalbed methane wells.Finally,a set of drainage rules and production scenarios are proposed to meet the actual production of high-rank coalbed methane.According to analysis,there are seven factors that mainly restrict the gas production of high-rank coal-bed methane.It is found that "pressure sensitivity" plays the most important role in high-rank coalbed methane production in the southern Q inshui Basin(laboratory conditions).The sensitivity intensity of coal reservoir in Fanzhuang area in the south of Q inshui Basin is "pressure sensitive",followed by "12% HC l + 3% HF acid sensitive" and "alkali sensitive",and "water sensitive" and "speed sensitive" are the weakest.The dynamic change of permeability runs through the entire single well drainage management and control process.The drainage management and control process is the process of efficiently correlating dynamic permeability and gas and water production.In fact,the use of horizontal well groups,vertical well fracturing and vertical well cavitation and other transformation methods require a certain low-yield stage.Finally,a high-rank coalbed methane reservoir drainage gas recovery technology was formulated from the perspective of gas reservoir engineering.