Research On The Resources Potential Of Biogenic Gas In The North Of Song Liao Basin

The exploration potential of biogenic gas in China is very considerable,and there are some problems needed to be studied about it.Therefore,doing some research on the forming process,distribution,and the resources potential of biogenic gas and then predict its favorable area are very meaningful to the exploration and development of biogenic gas resources.Based on the study of a large amount of domestic and foreign literature about the exploration and development of biogenic gas,the geological and physicochemical conditions which are required for the formation of biogenic gas are summarized,and the relevant conditions of the study area were analyzed.It's clear that both advantageous and disadvantageous factors exist in Song Liao basin.Elements equilibrium model and isotopic equilibrium model used to appraise biogenic gas generation period and generation amount are established in this issue,and the parameters in these models are determined.Finally,the two models are applied in the Song Liao basin to evaluate the gas production of shallow biogenic gas in different periods.The current total quantities of generated gas which are evaluated by the two models are 285.10×10¹²m³ and402.89×10¹²m³.The results are different,but the two models have their own theoretical basis and disadvantages.It's estimated that the current total quantities of generated gas of Song Liao basin is?285⁴03?×10¹²m³.A method to calculate natural gas diffusion amount of multi-source rocks is established,and it's also applied to Song Liao basin.Combined with the elements equilibrium model and isotopic equilibrium model,the loss amount of biogenic gas of Song Liao basin is calculated,which ranges from 77.87×10¹²m³ to 99.23×10¹²m³.Using the dynamic accumulation method to calculate resource amount,the resource amount calculated by isotopic equilibrium model is more than that calculated by elements equilibrium model,and the value is ranging from 1.33×10¹²m³ to 2.60×10¹²m³.The displacement amount calculated by material balance method ranges from 179.81×10¹²m³ to276.34×10¹²m³.Based on the resource appraisement,the advantageous areas are predicted.A partition scheme is given,two types of source-reservoir-cap combination are given in vertical.The lower combination contains K₂n² stratum which is cap rock and K₂qn^1K₂n² stratum which are source rock and reservoir.The upper combination contains K₂m¹ stratum which is cap rock,K₂n³ stratum which is source rock and K₂n^3K₂m¹ stratum which are reservoirs.The desserts of lower combination are east and south Sanzhao sag,Heiyupao sag,Erzhan^Alaxin region and Honggang oil field are the desserts of both two combinations.