The Potential Of Shale Gas Resouces Of Xujiahe Formation In Lianhuashan-Guankou Area, Southwest Sichuan Basin

With the limitations of conventional energy and the increasingly prominent en-vironment problem,environmental protection and renewable energy attract more and more attentions from various countries.Shale gas has been generally recognized as a clean energy and exploration and development of shale gas has entered a new stage.Take the shale of the Xujiahe formation of Lianhuashan-Guankou area in Sichuan Ba-sin.Forecaste the shale gas resources from the shale hydrocarbon generation and res-ervoir.On the basis of summarizing the shale gas exploration and development data from home and abroad,taking full advantage of the analysis data of the study area,the ge-ochemical characteristics are discussed.Investigating the gas content in the study area by combining the raw data of the drilling and logging in study area;Research the characteristics of shale reservoir by the identification of cores and cuttings flakes,the ordinary SEM,Argon ion polishing SEM etc.,combining with shale Mineral sheers X-ray diffraction analysis and the data of the porosity and permeability.According to comprehensive logging and logging data of the single well and some outcrop data,and Combining with the regional sedimentary background,the depth,thickness and area distribution of high GM shale formation in Xujiahe formation are completed statistics and determined.Besides,the longitudinal and transverse distribution characteristics of organic-rich shale are researched.On the basis of the previous research,shale gas re-source of section I,III and V of Xujiahe formation in Lianhuashan-guankou district are estimated,and shale gas resource potential areevaluated comprehensively.By the means of core observation and well logging data analysis,the Xujiahe Formation in Lianhuashan-guankou district are mainly continental sedimentary and it has a large set of dark grey,grey black mudstone,carbonaceous mudstone clip a thin layer of argillaceous siltstone further in Southwest Sichuan Basin.The deeper shale buried,thelarger thickness effective shale has,and themore stable distribution is,it is helpful for the preservation of shale gas.Investigating the gas content in the study area by combining the raw data of the drilling and logging in study area,gas display type is given priority to with gas logging abnormal,followed by gas cut and lost circulation,the gas are found more frequently in mud shale section of Xujiahe,the possibility of existing shale gas is relatively larger in the section V of the Xujiahe group in Lianhuashan-guankou district.According to statistics data about the residual organic carbon from 150 shale cores and debris samples of 16 wells in upper-Triassic in Lianhuashan-guankou district.We found the average content of the organic carbon is 2.0%,Based on the examination under the microscope and C isotopic composition,kerogen is given priority to with?type and individual samples is?₂ type,shale thermal evolution of organic matteris in high-over mature stage?the average of Ro is 1.32%?which has great potential for hydrocarbon generation.The content of brittlemineral such as Siliceous shale is high in 48%⁵4%,the average is 50%.So it has a good brittleness.The majority of clay mineralis illite and chlorite,a small amount of pyrite and sideriteexistedin some part wells,the brittleness of shale is good.The content of kaolinite and i/s is very low,whichit is not easy to plug cracks.Horizontalseam,oblique joints and microcracks are extensively distributed in Xujiahe formation of Lianhuashan-guankou district.There are many different pore types in shale reservoir,corrosion holes and construction joint in the inorganic mineral exist generally.The organic pore is less by comparison.The range of the porosity be-tween 0.5%³%,The range of the permeability between 0.001×10^-30.01×10^-3?m²,Porosity and permeability are very small,the correlation between porosity and per-meability is worse,it may be have relationships with microcracks existed in some in-dividual samples.Use the perameters of TOC,R_o,siliceous content,depth,thickness,the strength of gas productionand other parameters,we evaluate the resource potential of shale gas,and obtain that section V of the Xujiahe formation is favorable mining segment,section I of the Xujiahe formation is good mining segment,section III of the Xujiahe formation is relatively unfavorable mining segment.Finally,integrating various geological parameters,we can estimate the total geo-logical reserves of shale gas in the section V of Xujiahe formation is 60840×10⁸¹82520×10⁸m³,the resource abundance is 13×10⁸³9×10⁸m³/km²,by using the genetic assessment method,combined the analogous method.Section III of Xujiahe formation is 3588×10⁸¹0764×10⁸m³,the resource abundance is 1.04×10⁸³.12×10⁸m³/km²,section I of Xujiahe formation is 7030.4×10⁸²1091.2×10⁸m³,the resource abundance is 1.69×10⁸⁵.07×10⁸m³/km².In summary,the section V of Xujiahe formation in Lianhuashan-guankou district has a good resource potential.