Optimization Study On Drainage And Production Of Cbm Wells In Liulin Block,Shanxi Province

Coalbed methane is a high quality,clean and efficient energy and chemical material.The development of coalbed methane,a new type of clean energy,is not only conducive to protecting human living environment and solving safety problems in coal mining,but also conducive to adjusting the energy structure of sustainable development strategies.The research on rational drainage system in the development of coalbed methane has important practical significance for the efficient development of coalbed methane.Targeting the scientific and technical issues in the production of coalbed methane well,this thesis focused on the studies on the selecting and optimization of drainage equipment,the disclosing the drainage law and gas production processes,and the optimization of the design of drainage system in the Liulin block,eastern Ordos basin.The Liulin block in Shanxi Province is located in the middle of the Hedong coalfield.The whole block is inclined to the southwest with a monoclinic structure;the dip angle of the stratum is about 5°,with scarce of the fault.There are many layers of coal seam development in the area.The average buried depths of No.3+4,No.5,and No.8+9 are621.75m;642.29m;and 716.13 m,respectively.The buried depth of coal seam increases gradually from northeast to southwest.The Liulin block currently has 15 sets of multi-branch horizontal wells and 183 vertical wells,133/192 layers of fracturing,14 sets of horizontal wells,and 13 vertical wells.This thesis analyzed the geological conditions of the Liulin block,including the geographical location,the stratum and structure,the characteristics of the coal measures and coal seams,and as well as the drainage system of the coalbed methane wells in the Liulin block.The tube pump mechanism is used as a model for the pump.Perform kinematics and mechanics analysis.Based on the production data of exploration wells and production wells,it is summarized that the production capacity of gas wells in the study area has low output,large difference in productivity between different regions,and large difference in productivity between adjacent wells in the same area.The main controlling factors affecting the production capacity of the area are the reservoir heterogeneity characteristics,the success rate of fracturing transformation,the development method and the rationality of drainage engineering.The production of coalbed methane wells in the Liulin block,has typical characteristics including the long drainage cycle of single well,,the slow gas production rises,the fluctuate of gas production curve,and the short stable production time.The thesis analysed the main reasons for these characteristics are the frequent shut-in and well repairs,and furthermore provided detailed methods to choose appropriate drainage equipment and stable drainage technique.TIt was also found that the multi-branch horizontal well drainage work system deployed in the northern part of the Liulin block is not perfect.This thesis provided a proper drainage system i to realize the fine management of the production of coalbed methane wells.