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Research On Reservoir Characterization And Key Controlling Factors Of Cambrian Reservoir In Bachu Region Of Tarim Basin

Posted on:2014-02-27Degree:MasterType:Thesis
Country:ChinaCandidate:W HeFull Text:PDF
GTID:2230330398994385Subject:Mineral prospecting and exploration
Abstract/Summary:PDF Full Text Request
Good gas shows have be found during drilling in Bachu region of Tarim Basin,The Comprehensive Evaluation of the Cambrian reservoir development and has goodpotential for oil and gas exploration. In this paper, the research based on the drillingcore data, logging data, comprehensive utilization of the means of thin sections,cathodoluminescence, X-diffraction, scanning electron microscopy, and oxygenstrontium isotope testing, the characteristics of petrology, the characteristics ofsedimentary facies, the characteristics of reservoir space, the combination of reservoirspace, physical characteristics were analyzed, discussed and summarized. Study theorigin of dolomite and diagenesis, and finally analyze the key controlling factors ofthe reservoir.As the theoretical basis is carbonate sedimentology and petrology, the use ofdrilling data and on the basis of previous research, this area in addition to LowerCambrian system for shore shelf facies, the main types of sedimentary facies areshallow water platform facies, which are divided into the restricted platform, openplatform and evaporation platform facies. The open platform is only developed in theShayilike formation in He4wells and Fang1wells. Generally speaking, Cambriansedimentary facies are mainly restricted platform and evaporation platform inalternating evolution in the region.The use of core observation, thin section analysis and scanning electronmicroscopy, the area have four types of dolomite, which are grain dolomite, crystaldolomite, mud dolomicrite and transitional dolomite. Summed up several reservoirspace, which are intergranular pores and intergranular dissolved pores, intercrystalpores and intercrystal dissolved pore, mold pore, dissolved pores and cracks. Goodreservoir intervals are mainly in medium-coarse crystal dolomite, as well as somefine-grained dolomite, dissolved pores and cracks is the most important reservoirspace.With the analysis of conventional logging data, imaging logging data and drillingdata, Cambrian reservoir is divided into the type of dissolved holes, cracks andcomposite, and accordingly analyze the combined reservoir space features of the wells in Bachu region which drilled into Cambrian reservoir, and finally drawn thedistribution of combinate characteristics of reservoir space in different regions on aflat surface.Through the analysis of degree of order, carbon and oxygen isotopes, strontiumisotope and cathodoluminescence, combined with the previous comprehensive studyof reservoir characteristics, explore the causes of dolomite of Cambrian reservoir inBachu region. In this article the dolomitization is divided into:(quasi-) syngeneticdolomitization, burial dolomitization and hydrothermal dolomitization. UpperCambrian is mainly burial dolomitization, Middle-Lower Cambrian is mainly(prospective) syngenetic dolomitization, and the distribution of hydrothermaldolomitization is related with fracture.The dolomite reservoir of Cambrian in Bachu region is controlled by manyfactors. The sedimentary facies is the foundation, the diagenesis is the key to theformation of the reservoir, dolomitization and dissolution is the most important. Thedissolution of the area include the (quasi-) syngenetic dissolution, epigenetic karst andburial dissolution, in which the most important to the reervior is buried hydrothermaldissolution, mainly developed in Xiaqiulitage formation, followed by Xiaoerbulakeformation, significantly along the fault development. The active tectonic movement inthe area caused a large crack development, cracks have two-fold effect on thereservoir. One can exist as a reservoir space and another one can be used as themigration channels for the dissolutive fluid.
Keywords/Search Tags:Sedimentary facies, Characteristics of reservoir, Hydrothermal dissolution, Cambrian, Tarim Basin
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