Comprehensive Evaluation And Regionalization Of Shale Gas Resources In Tarim Basin

With the economic development and increasing energy demand, the conventional oil andgas reservoirs has been unable to meet their requirements, and then unconventional oil andgas reservoirs has played an increasingly important role. Shale gas as an important part of theunconventional reservoirs becomes the focus of the present-day society. China’s shale gasresearch is still in its infancy, the geological conditions of shale gas production has the featureof complexity and specificity, and we are lack of systematic recognizing for the explorationand development of domestic gas shale, therefore, to carry out a comprehensive evaluationand regional planning of the shale gas resources of Tarim Basin is significant to theexploration of shale gas resources in China.Tarim Basin mainly developed Cambrian-Ordovician marine facies hydrocarbon sourcerocks and Triassic-Jurassic transitional facies coal measures source rocks. The layer has hugethickness of Shale which generally can reach more than100m, high organic carbon content,Cambrian-Ordovician is about0.3~14%, Triassic-Jurassic can even reach more than20%. Thetype of organic matter mainly contains I-II, thermal evolution is high, which generally staysin the mature-over-mature stage. Hydrocarbon source rock strata buried generally deeper,Triassic-Jurassic layer of northern Tarim buried deep in2500to4000m, Cambrian-Ordoviciansource rocks with its stratigraphic depth which can reach in6000to10000m widelydeveloped in the basin, part of the strata even buried below10000m. The Tarim Basin mainlydeveloped three sets of main shale source rocks including the Seoul Tuol group,Black Femalegroup, Saar stem group, Triassic and Jurassic.The thesis most uses volume method, statistical method and geologic analogue toevaluate exploration target segment of Tarim Basin shale gas. The statistical method is basedon a certain ratio relationship between the shale gas resources and gas resources, gets aconservative value of0.8to0.9, the Tarim Basin shale gas resources reaches in9.072×1012m3. Volumetric method’s computing resources is to multiply shale volume by the free gas contentper unit volume in corresponding burial conditions, in this way, the Tarim Basin shale gasresources reaches in101.27×1012m3. geologic analogue using the similarity of geologicalconditions between standard area and evaluation area, estimate the evaluation area’s resourceabundance depending on the known standard area, thereby further calculate oil and gasresources of the area to be evaluated, then evaluation result becomes （39.485-88.235）×1012m3.The influencing factors in shale gas comprehensive evaluation can be summarized intotwo aspects, which are geological factors and technical factors. The geological factors includeshale thickness, TOC, organic matter type and Ro, the technical factors include depth,topography condition and infrastructure construction. According to contrast of these factors indifferent area of Tarim Basin, the paper drawn the following conclusions: Weili area innorthern of Tarim basin, Tadong1well area in eastern of Tarim basin, Hadson area in middleof Tarim basin and parts of southwestern of Tarim basin can be the favorable explorationtarget of Tarim Basin shale gas exploration, Tazhong area, Manjiaer Sag and others areasshould be the secondary exploration target, Kuche Depression in in northern of Tarim basin,Awati Sag and others areas should be the last exploration target, which provided support forthe further shale gas exploration in Tarim Basin.