The Investigation On Logging Response And Geochemical Characteristics Of Tight Oil In Lucaogou Group, Jimsar Depression

The Lucaogou group of Permian series in Jimsar depression in Junggar Basin is an important area of tight oil exploration currently.The thesis is based on using the experiment measures of rock-eval,gas chromatograph and mass spectrometer,researchs that the tight oil ‘s oiliness and its influences on logging response characteristics and geochemical characteristics,and the properties of crude oil and the tight oil ‘s reservoir.In this investigation,author describe the Rock-Eval ‘s parameters characteristics of tight oil reservoir in details for the first,and expressed the organic matter abundance,types and maturity of organic matter.Also Applicated the logging oil level corresponding relationship with Rock-Eval ‘s parameters,and establish the effective parameter to indicate the oiliness of tight oil in Lucaogou group like TOC,S1,chloroform bitumen ‘A' and PG.And we found that the reservoir of Lucaogou group,it has the high organic matter abundance and good potential of hydrocarbon generation,and its source rocks are in the mature stage.The Lucaogou group 's source rock ‘s organic matter type is the I and II,and these type can have a very good potential of oil generation.The up and down sweet spot has the different maturity level and the different type of stones also has the different maturity level.The maceral is given priority to with sapropel group,and it's also the type that can generate a large number of crude oil.The crude oil fo Lucaogou group ‘s group composition is mainly composed by saturated hydrocarbon,the aromatic hydrocarbon,non-hydrocarbon and asphaltene only less contented.The oil' s density spread over 0.8 to 0.9,thus the quality of oil is between middle oil and heavy oil.The oil' s biomarker' s characteristics show that its main peak carbon number is among C23 to C25,its Pr/Ph spread over 0.8 to 2.5,and the CPI and OEP both are above 1,and the whole carbon chain don't has obvious advantages of parity.The TIC shows the ?-Carrot alkanes and gammacerane‘s content is relatively high,this proves that the crude oil in Lucaogou group generated in a salt water and highly reduced environment.Judging from the oil-sourcecorrelation,the tight oil of Lucaogou group is always the proximal accumulation.Because the the geochemical characteristics of source rock and oil are quite similar.And then,on the section of the biomarker parameters,we can get that part of the biomarker fingerprint parameters can be used as identification of oil content standard.From the perspective of the result of logging evaluation,the crude oil and the extract of rocks' logging curve and pyrolysis parameters have a good fitting relationship,the fitting degree achieved about 50%.And we can also know that the rock with good oil bearing properties always have logging characteristics which shows tow high and a low parameters.Logging lithology shows that the lithologic of Lucaogou group combination of shale and dolomite,limestone interbedding.And from the physical properties of rocks,the porosity and permeability of this tight oil reservoirs is good,it's a nice preservation condition of storing the tight oil.