Accumulation Geological Condition And Resource Potential Evaluation Of Coalbed Methane Of Hunchun Formation,paleogene,hunchun Basin

With China's overall strength of the continuous improvement of economic growth and environmental protection has become equally important.As a clean energy,the coalbed methane has received more attention.China has many coalbed methane resources,which coalbed methane geological reserves of 102.3 billion cubic meters have been identified.But because of the complex geological conditions,the development and utilization is in a low level.Meanwhile,due to China's frequent gas accidents,people's production and life have a huge threat.Therefore,the study of Hunchun coalbed methane is urgent.Hunchun Basin is located in the eastern part of Jilin Province,which is the richest coal reserves in the region.It also has very rich coal-bed methane resources.But the formation and enrichment of coalbed methane in Hunchun Basin is very low,which has affected the exploration and development of CBM.Based on the previous studies,this paper using sedimentology,gas geology,coal geology and other theories,Carrying out field outcrop observation,drilling,logging data analysis,laboratory samples related test analysis to study on Geological Characteristics of Coalbed Methane Accumulation in Hunchun Formation of Paleogene in Hunchun Basin.This study not only provides scientific basis for coalbed methane gas control and exploitation in Hunchun Basin,but also can provide reference and reference for the national coalbed methane exploitation.Hunchun basin is a Paleogene critical rift basin with less fold and more fault.Anomaly of gravity shows that the whole basin forms the structural pattern of two depressions and one upheaval.Experienced early upheaval,downfaulted development and downfaulted atrophy three development period.The magmatic activity and volcanic eruption in the basin are very intense,and in the Hercynian period there are large-scale granite body intrusion,which affects the tectonic pattern of this area.Through the field profile observation,combined with drilling,logging and other information derived,the Hunchun Basin is mainly developed with conglomerate,sandstone,siltstone,mudstone and coal.four sedimentary facies of alluvial fan,fan delta,lake facies and river facies Basin are identified and divided in Hunchun basin.Among them,the main sedimentary facies in the lower part of the Hunchun Formation are alluvial fan,fan delta,swamp and river facies sediments;the middle is mainly marsh-lake facies sediments;the upper part is lake,lake,delta sedimentary,The lacustrine facies are the main causes environment of coal in the Hunchun Basin.The coal seam in the western part of the Hunchun basin is more developed than the eastern part.In the west,the number of coal layers is deep,the depth is deep and the accumulated thickness is large.In the east,the number of coal layers is small,the depth is deep and the accumulated thickness is large From the composition of coal and rock,Ban Shi,Ba Liancheng and Ying'an lied in the basin of the western is mainly bright coal-based,and Wu Jiazi,Luo Tuohezi lied in the basin of the eastern is mainly dark coal-based.Tthe microscopic components are mainly vitrinite.In addition to WujiaZi coal mine for the quality of lignite,the Ban Shi,Ba Liancheng Ying'an and Luo Tuohezi coals are long flame coal.From west to east,coal ash and volatile yield increased gradually.It can be seen that gas source rock develops and the ability to generate gas is strong in Hunchun Basin.Coal reservoir characteristics show that the pores and fissures of coal seam in Hunchun basin are more developed.Cracks and cuttings become the main reservoir space for coalbed methane The faults in the Hunchun basin are mainly composed of extensional fault,with low structural stress.The preservation of coalbed methane will cause adverse effects.However,the surrounding rock is dominated by mudstone and siltstone,and the coalbed methane is highly closed and the distribution is relatively stable,which provides favorable conditions for the preservation of coalbed methane.With effective groundwater aquifers,coal-bed methane is not easy to move with the groundwater,so the destruction of coal-bed methane is not strong.Overall it benefit the coalbed methane preservation.In this paper,the volume method is used to evaluate the CBM resources in the area of Banshi coal mine,Ba Liancheng coal mine,Ying'an coal mine,Wujiazi coal mine and Luo Tuohezi coal mine in Hunchun Basin.The total amount of coalbed methane in Hunchun Basin is 3039.590Mm3.According to the geological conditions of the Hunchun Basin,the corresponding index system of coalbed methane favorable area is established,and selected Ba Liancheng coal mine and Ban Shi district one coal mine for coal-bed methane favorable area.