Datong Lake Area Biogenic Gas Geochemical Exploration And Resource Prospect Forecast

Dongting basin belongs to the Mesozoic and Cenozoic inland rift basins,and the Mesozoic and Cenozoic sedimentary siltstone rocks in the basin have the geological conditions for forming a certain scale biological gas reservoir.China University of Geosciences(Beijing)in 2013 ? 2015,for the Dongting Basin biogas resources to carry out a systematic geochemical surface hydrocarbon survey survey sweep work,infer the Yuanjiang depression north slope of the Datong Lake Green Tree-River town abnormal area The most favorable target area for biogas.From 2015 to 2016,geochemical detailed investigation was carried out in the target area.The aim of this study was to investigate the geochemical phenomena of surface sediments by means of encrypted point design,and to find out more about the composition and properties of biogas in this area.Characteristics,the source of abnormal biogas,and the relationship between the upper exposed and the lower reservoirs to solve specific problems such as biogas expulsion,leakage area and resource potential in the Datong Lake area.For the Dongting Basin biogas resources Exploration and development to provide the basis.The results show that there are four significant head air methane anomalous blocks and three significant acid hydrolysis hydrocarbon anomalies in the Chase Lake area.The exposed area of ? ? the top air anomaly block in the Datong Lake area is34.82km2,and the exposed area of ? ? the acid block is 5.69km2.It is assumed that the average value of the top air anomalous area is 28950.17 ppm and the average value of the acid hydrolysis zone is 14150.05 ppm.The top air anomaly block: the new village abnormal block features the top air is high,evenly distributed,the background is high;five division Yifeng village abnormal block features the top air high value of the most concentrated,the largest range of the largest and most important high background,The most abundant subsurface gas is the most abundant low sediment thickness anomaly block;the new Rituca anomaly block is characterized by the Quaternary thicker,with the five sub-plant Yifeng village abnormal block as a hidden whole;green tree mouth-four village abnormal The band has significant geochemical anomalies.Acidification hydrocarbon anomaly block: green tree mouth-Simei village abnormal block and head air methane abnormal part of the overlap;Laohe village abnormal block acid hydrolysis hydrocarbon amplitude fluctuation;three wealth embankment abnormal block acid hydrolysis Amplitude and area are significant.Through the verification of the results of the wide area electromagnetic field in the study area,there is a fault in the lower geological structure of the anomalous block of the new village and the abnormal block of the Sancai embankment.The depositional thickness is larger and the biogas formation conditions are ideal as the next exploration prospect Area.