| On the basis of fully collecting the previous data and absorbing the predecessors' research results,this paper,combined with the actual geological conditions of the study area,guided by the geology of sedimentary geology,tectonic geology and coalbed methane,sedimentary facies,tectonic evolution and Coal law as the main line,according to the observation of the drill core and outcrop section observation,log presentation,,coal industry analysis identified maceral other technical means,wherein the phase of the study area Jurassic Jurassic Yan'an deposition of structural features,coal bed methane enrichment law and the law has been studied systematically,finally gives a more reasonable evaluation of the coal-seam methane resource potential of the region.According to mining development in Yan'an Formation Jurassic,especially a few signs of a more stable layer,combined with previous studies,the Yan'an Formation of the study area is divided into the first,second and third segments of Yan'an Formation from the bottom to top,and the fourth and fifth segments are missing.It is considered that the first and second segments of Yan'an Formation in the study area are the main coal seam development horizons.Among them,the first segments of Yan'an Formation has developed coal seam of NO.3 and the second segments of Yan'an Formation is coal seam of NO.2In the Jurassic Yan'an Formation,the lacustrine facies and the fluvial facies are mainly developed in the study area.the first phase of the Yan'an Formation is mainly developed lake facies,and mainly to the lake subfacies.the second and third sections mainly develop the river facies,the river facies is the meandering river facies,and the riverbed subfacies are developed.Based on the weak folding of Indo-China movement in the end of the Late Triassic,and the Extrusion of Yanshan Movement,and stretching and depression in the period of Himalayan Movement.Combined with the characteristics of coal seam and the exposed characteristics of rock formation,the tectonic evolution characteristics in the study area are briefly analyzed,It is concluded that the formation of many folds in the study area is taken from the north-south direction of the Yanshan movement,and the later North-South-east stress is roughly shaped,the final shape of the mountain movement.this paper analyzes the reasons why the coal seam floor height difference in the east and west of Hanjiayi field in eastern Yonglong mining area is analyzed.The main development of the No.3 coal seam in the mining area is the peat swamp of the lake facies,and the coal seam development area is mostly thick and thick coal seam,and the distribution area is larger.No.2 coal seam is mainly developed in the river marsh of the meandering river facies.The coal seam is thinner than that of No.3 coal seam,and the distribution area is shrinking significantly.The development of the whole Yan'an coal seam is affected by the characteristics of the early geomorphology,and it is affected by the later tectonic uplift and scouring.Based on the research results of coalbed methane enrichment in the study area,combined with the results of coalbed methane estimation(the coalbed methane resources of No.2 and No.3 coal seam of several coal fields are estimated at 19.38 × 108m3,among which the total amount of coalbed methane resources in the coal field of Hanjia is 8.31 × 108m3,accounting for 44% of the total resources).With reference to the collection of coalbed methane samples,it is believed that the coal field of Hanjia in Yonglong mining area can be used as a favorable area for coalbed methane exploration or development. |
PDF Full Text Request