Study On The Distribution Characteristics Of Source Rocks And Evaluation Of Gas Generation Potential In Block 53 Of Sulige Gas Field

Sulige gas field is the largest natural gas field found in China at this stage,belongs to dense sandstone gas reservoir,Su 53 block natural gas reservoir has low hole,low seepage characteristics,geological reserves are difficult to use,strengthening the hydrocarbon source rock distribution characteristics and gas reservoir abundance law research is of great significance to enhance exploration efficiency.Through the experimental analysis of natural gas samples and source rock samples,it is clear that natural gas in the study area is a near-source source,there is horizontal transport adjustment,Shanxi Group,Taiyuan Group,Benxi Group of coal,carbon peatstone,dark mudstone is the hydrocarbon source rock in this area.In the natural gas composition of block Su53,the value of?¹³C₁is-31.86 to-29.21,and the value of?¹³C₂is in-25.13 to-22.35,the value of?¹³C₃in-26.7 to-22.23,judged to be rotting coal into gas,and the upper paleo-life coal system hydrocarbon source rock type consistent.Using CH4 isotopes to calculate Ro is significantly lower than the measured Ro value of the source rock,which indicates that the natural gas in the early stage is preserved and can also reflect that the natural gas in this area is likely to be the result of different phase gas mixing.The ethane content in natural gas is generally 5%-8%,the propane content is 1%-2%,the iso butane/positive butane value is generally about 1%,and the above parameters are not significantly different in the vertical,and the methane carbon isotopes and source rock maturity overlap shows a relatively high area,natural gas is dry,methane carbon isotopes are heavy,all show the characteristics of near-source aggregation.The isotope values of?¹³C₁,?¹³C₂,?¹³C₃,and?¹³C₄have not changed much overall,and the whole has the characteristics of near-source tibetan.The fractionation of isotopes in some samples indicates that there is lateral movement adjustment after the gas is close to tibet.The distribution characteristics of hydrocarbon source rock in Su 53 block are clarified by means of seismic interpretation and reservoir introducing.Dark mudstones are relatively developed in the southern part of Shanxi,with a thickness of up to 20m,while carbon peatstones are generally scattered,with incomplete development of different layers and relatively small thicknesses,with a maximum thickness of no more than 6m.As the main hydrocarbon source rock coal seam,in this stream group 1 is the most developed,thickness is usually more than 5m,the thickest up to 10m,in the region have development.This study,the"six small layers",divided into"three rocks"respectively,the intensity ofanger and the amount of anger calculation,by the analysis of the results can be seen:from the group level to see the largest amount of anger in this group,is the most important source of gas rock formations,followed by Taiyuan group and Shanxi group;This paragraph 1 and Taiyuan 1 have a large amount of anger,accounting for 46%and 23%of the total amount of anger,respectively,is the main force of the study area of the angry layer segment.