Study On Coalbed Methane Development Unit-Bottom Hole Flowing Pressure Cooperative Drainage In Fanzhuang Block

Because of the strong sensitivity of coal reservoir,the influence of drainage system and measures on the high-efficiency development of coalbed methane is very significant,and the key way to construct the high-efficiency drainage system of coalbed methane is to coordinate the geological conditions of the reservoir to realize the dynamic regulation of the bottom hole flow pressure.In this study,the high rank coal in Fanzhuang block of Qinshui Basin is taken as the research object.Through the systematic arrangement and analysis of the production rules of different types of coalbed methane wells in Fanzhuang block,the bottom hole flow pressure control model of coalbed methane wells under different types of geological conditions is established,the intelligent stable monitoring and dynamic regulation technology is optimized,and the development efficiency and benefit of coalbed methane are improved.The main achievements are as follows:(1)based on the analysis of the geological characteristics of coalbed methane in Fanzhuang block,it is pointed out that the structure of the area is relatively complex,the reservoir heterogeneity is very strong,the distribution of coalbed gas content is different,the enrichment rule well interval is very different,and the technical system of drainage and mining needs to be adapted to local conditions;(2)the geological conditions of coke accumulation and the transformation effect are two major factors,and the basis and principle of development unit division are established The development units of the research area are divided,and it is pointed out that the vertical well type I units are mainly distributed in the areas with well-developed fractures in the south,the type II units are distributed in the areas with overall underdeveloped fractures in the middle,and the type III development units are located in the areas with overdeveloped or underdeveloped fractures in the north,which provides reliable basis and technical support for the formulation of coal-bed methane drainage system and stimulation measures;(3)according to the division of development units Results:according to the study of the mechanism of drainage and production,the first type development unit insists on continuous drainage and production,does not pursue short-term high-yield,keeps the bottom hole flow pressure steady and slow decline,gas volume rising gradually,and maintains high-yield and stable production;the second type development unit strives to control its pressure drop range,ensure its drainage and production continuity,and ensure stable production;the third type development unit has poor fracturing and reconstruction,small single well pressure drop range,and its management On the low geological productivity;(4)the high-efficiency development is realized by adopting the mode of bottom hole flow pressure collaborative drainage,taking the formation pressure as the benchmark value,setting the rate of bottom hole flow pressure drop,continuously adjusting the deviation between the actualdecline range and the original set value through closed-loop feedback control,until the bottom hole flow pressure meets the requirements,so as to achieve a continuous,slow and stable drainage system and realize the high level of coal-bed gas wells Effective development.