The Research Of Gas Reservoir-forming Conditions In Huoshiling Formation Of Yushu Depression

In terms of source rocks, by using the experimental data of source rock respectivelymapped the TOC, chloroform bitumen "A", rock pyrolysis parameters S1+S2and the plot ofS1+S2and TOC maps, etc. Yuxi depression is final evaluation results show that theabundance of organic matter, on the whole, for the medium level, Yudong depression for pooroverall abundance of organic matter levels; at the same time using themaceral of kerogen,biological identification of compound, the plot of Pr/NC17and Ph/nC18and hydrogen indexand Tmax judgment Yushu depression type organic matter type is Ⅱ~Ⅲ, give priority towith Ⅲ type; According to the Ro evaluation results it is concluded that Yushu depressionsource rocks in the mature and high mature near boundaries, has reached the stage of a largenumber of generated gas. But Yudong depression with relatively low abundance of organicmatter, the formation of natural gas industrial value of the possibility is very small, so thisarticle only evaluates the Yuxi depression other accumulation conditions. According to thedark mudstone accumulative thickness and source rock geochemical parameters, this iscalculated Huoshiling Formation of Yushu depression of source rocks and exhaust strength,shows high exhaust strength distributions of source rocks in the east of Yushu Depression.Based on Huoshiling Formation of Yushu depression volcanic lithology and lithofaciesstudy shows volcanic lithology is given priority to with the andesite lava, lithofacies is givenpriority to with eruption facies, lower subfacies of the highest proportion; analysis ofHuoshiling Formation of Yushu depression reservoir space characteristics known Huoshilingformation of Yushu depression complex reservoir space types, fault in the main reservoirspace for the primary porosity in the primary pore, mainly occurs for basic lava lithology,secondary pore in the dissolution pores are also important reservoir space；According to the drawing of the Huoshiling formation of Yushu depression mudstonecumulative thickness figure, the thickness of the largest single figure and mud than mapshows Yushu depression cap rock as a whole the eastshould be better than that of the west inthe east. According to the displacement pressure distribution obtained Huoshiling formationcaprock displacement pressure of high value area are mainly distributed in the northeast andsouthwest, up to more than7MPA.Using the hydrocarbon expulsion intensity, volcanic rock facies reservoir performanceand comprehensive evaluation of caprock index to hydrocarbon source rock, volcanic rockreservoir and cap rock isdivided into three or four grades respectively. Using the dividedgrade evaluation of Yuxi depression, in source-reservoir-sea accumulation conditions, and onthis basis, the accumulation level forecast，the best area is located in the northeast gasaccumulation conditions. At present, the Middle East has not seen industrial drilling oil andgas reservoirs, so only Yuxi depression of the northeast may be beneficial for the gas storagearea.