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Reservoir Sedimentary Characteristics And Tight Sandstone Gas Reservoirs Forming Rules Of Badaowan Group In The Baka Area, Tuha Oilfield

Posted on:2014-01-11Degree:DoctorType:Dissertation
Country:ChinaCandidate:J H WuFull Text:PDF
GTID:1220330398480883Subject:Oil and gas field development project
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The study object of this article is the gas pool in Ba-DaoWan formation,Bakablock,we use ways of sedimentology,reservoir geology and mineral petrology toanalyse the depositional system,petrology characteristics,diagenesis type,reservoirphysical property and so on.So that we can understand that how the factors ofsedimentary environment, diagenesis and reservoir physical property affect the gaspool in the tight sand; we analyse the source rock, transforming system, trapcharacteristics, time-space relationship,gas and oil distribution method and gas and oilformation mode, so that we can sum up formation characteristic and explorationpotentiality of gas pool in tight sand in this block.According to core, logs, well logging and seismic data, we systematically studiedthe sedimentary facies type, distribution characteristic and evolutionary process inBaka, Badaowan formation. Conformed that Badaowan formation, in study area, mainfacies is braid river delta plain, it can subdivide to braided channel, abandonedchannel, flood plain and flood plain swamp,4microfacies. Base on the conclusion,we established sedimentary facies mood of this area.We use ways of rock slice, cast slice,SEM and infrared ray diffraction, combinewith mercury penetration data to study petrology characteristic of gas pool, diagenesisand pore structure characteristic.Both textural maturity and composition maturity ofrocks in study area are low.The rocks are mainly composed of lithic sandstone andfeldspathic lithic sands.Diagenetic phase can be divided into A2subperiod and Bphase of the middle catagenesis.We identified compaction,cementation,metasomasisand dissolution,4types of diagenesis.There are several kinds of porosity types in thereservoir,the main types are secondary corrosion intergranular pore and corrosionintraparticle pore;pore throat composition is mainly micro pore-throat;pore structureparameters and reservoir physical property correlation is not good, but both presentregularity.According to nuclear magnetic resonance (NMR) technology and reservoirphysical properties analysis, reservoir’s T2spectrum is continuous bimodal structureand near low T2area. Movable fluid saturation and movable fluid porosity have goodpositive correlations with reservoir physical properties; Reservoir overall showultra-low porosity, super permeability or no permeability, but porosity andpermeability have good correlation, reservoir physical properties are stronglyanisotropic in in plane, vertical and inner layers.According to sedimentary system distribution pattern and reservoir physicalproperties, we make comprehensive research of area tectonic style,source-reservoir-seal assemblages and oil-gas migration characteristics, thensummarize the accumulation and distribution rules of oil and gas reservoir incompacted sandstone formation, predict advantaged districts of different reservoirs,provide basis for exploration.
Keywords/Search Tags:Baka area, sedimentary system, diagenesis, reservoir heterogeneity, reservoir control factors
PDF Full Text Request
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