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Research For Sediment System, Reservoir Character And Oil-reservoir Formation Of Yanchang Formation, Triassic,Ordos Basin

Posted on:2006-02-16Degree:DoctorType:Dissertation
Country:ChinaCandidate:W T DouFull Text:PDF
GTID:1100360155458557Subject:Paleontology and stratigraphy
Abstract/Summary:PDF Full Text Request
This paper investigates the Yanchang formation in Triassic system of Ordos basin, using theories as sedimentology, petroleum geology, geophysics, et al. based on abundant outcrop sections, well drilling and seismic data. This paper synthesis a lot of welling and petroleum geology. This paper also systemic analyse the characteristics of deposition systems in Ordos basin and sequence stratigraphic, go down to research sedimentary microfacies of the leading pay formations, sand bodies and its distributions, reservoir characteristics and control factor, adopting the technique methods of academic research combined with practice research and macroexaminations combined with microexaminations. This paper detailed discuss the formation condition and controlling factor of reservoir, building the model of forming reservoir. This paper take out main results and realizations as follows:1. Through detailed research the identification of Sediment System ,The deposition systems of the Yanchang formation in Triassic system of Ordos basin compose of alluvial fan, fluvial deposition, fan delta, braid delta, meandering river delta, lake. This paper detailed discuss every the characteristics of deposition systems, alluvial fan, braid delta, turbidite fan mainly lies in the west of basin, and meandering river delta mainly development the north, east and southeast of basin, sedimentary models are founded.2. On the basis of systemic discuss the characteristics of every oil layer's deposit facies zone and the distributions of sand body. The distributions of the sand bodies are controlled by deposition system. The distributions of the sand bodies are controlled by deposition system. Southeast deposition system's sand bodies' configuration that have low component and textural maturity presents a band shape of east-west and northeast-southwest trend from Huanxian to Zhengning. Northeast deposition system's sand bodies which have a good continuity presents a northeast-southwest trend in the plane and a general trendof progradation to the south in the cross section in the strata from member 8 to member 2 of Yanchang formation.3. The interstices in the majority reservoir sand includes intergranular porosity, feldspar interstice, lithic fragment solution hole, laumonite solution hole(which does not appear in braid river delta in the southwest) and intercrystal porosity that is the main accumulating space. Sedimentary enviroment is the main geological basis which affects the reservior's storability by analyzing the contribution factor of reservoir, Mineral component and grain size of the sandstone are important conditions which affect the reservior's storability. Component, content, and diagenesis of the matrix are the dominant factors which affect the reservior's storability. Microfissuring can greatly reform the reservoir permeability.4. The formation mechanics of petroleum deposit in the Yanchang formation in Triassic system of Ordos basin is gone deep into analyse. The type of petroleum deposit is the rock character petroleum deposit that mainly controlled by deposition system. According to the formation controlling factor of petroleum deposit, the Yanchang formation in Triassic system of Ordos basin is further divided into consists four species, i.e. lithologic oil pool, structural lithologic reservoirs, stratum lithologic reservoirs, contrast erosion petroleum deposit. Petroleum deposit found in ch3's oil layer and upper stratum usually belongs to structural lithologic reservoirs, its struture formation is bound up with compaction of action. Petroleum deposit found in ch6-8 oil layer mainly belong to lithologic oil pool, a few rate of structural lithologic reservoirs, principally distribute the west of fault brand area and the south of Weibei area.5. Analysed the controlling factor of petroleum deposit are pointed to: the distribution of petroleum deposit(especially ch6-8 petroleum deposit)is clearly controlled by the thickness of oil source rock, the intensity of generation hydrocarbon, the intensity of expulsion hydrocarbon. Ch7 is the main oil source rock in the basin. Its character is that Have the thickness big, distribut range wide, organic quality plentifulness, organic type kind, maturity high. The upper of ch7's oil source rock is ch6's standrock of Northeast delta, covered the lower side of ch7's oil source rock that southwest braid of ch8's sand rock belong to the beneficial layer that is in favor of accumulating oil and gas. The advantage sedimentation facies zone is the basic geology condition of delta oil pool, the...
Keywords/Search Tags:Ordos Basin, Triassic, Yanchang Formation, Sediment System, Reservoir, Reservoir-formed Condition, Reservoir-forming Model
PDF Full Text Request
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