Research On Constraint Of Geological Factors Of Multi-layer Production In Guanzhai Minefield

In the area of multiple coal seams,multi-layer production is an important means to reduce the development cost and increase capacity,however,in the process of multi-layer production,the existence of interlayer interference restricts the drainage effect of coalbed methane well.There are many layers,thin thickness and clumped distribution in Guanzhai minefield,where is included within the key development block in 13th Five-Year plans of CBM,it is of great significance to study on constraint of geological factors of multi-layer production.This paper is relied on the 13th Five-Year National Science and technology major project(2016ZX05045-002),based on a large number of research on influence factors of CBM productivity and interlayer interference at home and abroad,we analyzed geological sensitivity affecting multi-layer production,it includes reservoir pressure system,critical desorption pressure,permeability and hydrogeological conditions;combined with geological features of Guanzhai minefield,we identified the main controlling factors of Guanzhai minefield multi-layer production,that are reservoir pressure difference,critical desorption pressure difference and permeability ratio;on this basis,we used numerical simulation method,the range of different factors is adjusted and the constraint range of each factor under different coal seam combination conditions is put forward.By multivariate analysis,we combined with the research results of the constraint range in three main controlling factors,multi factor combination scheme is selected,that is suitable for multi-layer production in Guanzhai minefield,coal group 1 and coal group 2 are in the the range of physical property difference of geological condition in Guanzhai minefield,which is suitable for multi-layer production;in coal group 2 and coal group 3,when the reservoir pressure difference is less than or equal to 0.3MPa,the critical desorption pressure difference is within the range of-0.3～0.5MPa,permeability ratio is in the range of geological conditions difference in Guanzhai minefield,which is suitable for multi-layer production;in coal group 1 and coal group 3,when the reservoir pressure difference is less than or equal to 0.6MPa,the critical desorption pressure difference is in the range of geological conditions difference in Guanzhai minefield,permeability ratio is in the range of 2:1～4:1,which is suitable for multi-layer production;the key factors affecting multi-layer production of different coal seam combination are discussed,which has laid a theoretical foundation for the following multi-layer production.We analyzed CBM geological conditions of GZ-01 well,selected the best combination of GZ-01 well,combined with the drainage effect of the well,verified the correctness and practicability of the research results,that lays a theoretical foundation for optimizing the combination of multi-layer production in Guanzhai minefield.