The Characteristics Of The Coalbed Methane Accumulation And Evaluation In Yilan Mining Area

Coalbed methane is a new kind of highly efficient clean unconventional energy,attracting the attention of more and more people in recent years.Heilongjiang province,as a big province of coal resources,the coalbed methane exploration and development degree is low,and the study on correlation of coalbed methane is relatively weak.Yilan mining area is located in the middle of heilongjiang province,which is a large comprehensive coal mine.It is still in the primary stage of coalbed methane exploration.In order to solve the problem of increasingly nervous energy and reduce accidents in coal mining at the same time,more and more people begin to study the coalbed methane deeply.Thesis mainly adopts the coalbed methane well test and laboratory analysis of coal samples to study the coalbed methane characteristics of reservoir and gas-bearing in yilan mining area.Experimental results show that the reservoir pore fracture system is relatively good,permeability is low and adsorption is medium.In general,the reservoir in yilan mining area is suitable for coalbed methane accumulation.According to the experimental results of laboratory desorption of coal sample,coalbed methane content is an average of 7~8 m~3/t,and the gas composition is given priority to with methane.The formation of the resevoir is divided into two parts:the accumulation mechanism and mode.The accumulation mechanism can be further divided into accumulation conditions and accumulation process.Study the accumulation conditions mainly from the following three points:(1)coal bed methane generated gas source conditions,including basin sedimentary environment,spatial distribution of main coal seam and the distribution of coalbed methane content;(2)coal reservoir adsorption capacity;(3)the preservation conditions of coalbed methane,including the main cap rock and surrounding rock,tectonic geological condition of coal seam and hydrodynamic conditions of three parts.The analysis results show that the accumulation conditions of yilan mining area is suitable for coalbed methane rich integration.Accumulation process is divided into the coalbed methane tectonic evolution,sedimentary burial history and evolution of coalbed methane.The process of the coalbed methane is summarized as centralization of angry,short-term late phase and stable phase these three dissipation process.Combining yilan area regional geology characteristics,establish the fault-hydraulic joint closed accumulation mode of coalbed methane.Yilan mining area is located in the northeast of yilan coalfield in the southern depression.According to its structural characteristics,the coalfield can be divided into nine sections.Combining coal field geological data in the study area,got coalbed methane resources of the whole yilan coalfield.Use five index method to evaluate coalbed methane resources,and then use the multi-level fuzzy evaluation method to optimize the target area for coalbed methane exploration and development.Shahe region is important potential area,southwest tun area with emphasis on the exploration and development zone.In general,the accumulation condition of yilan mining area is suitable for coalbed methane,fault patterns-hydraulic seal is good for coalbed methane enrichment,and the southwest tun area is the target area for coalbed methane exploration.