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The Analysis Of Sedimentary Facies And Research On Reservoir Of South Dagang Oilfield Of The Upper Paleozoic

Posted on:2016-10-07Degree:MasterType:Thesis
Country:ChinaCandidate:F C WangFull Text:PDF
GTID:2180330464461959Subject:Mineral prospecting and exploration
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Dagang oilfield has been discovered more than 40 years, Huanghua Depression has entered the middle and late stages of exploration, exploration is becoming more and more difficult, Dagang exploration area seeks second pioneering exploration work because of the increasing complexity of oil and gas accumulation. The late 1990s, Paleozoic coal-bearing strata of the hill with the oil and gas sources was found, which indicates that Upper Paleozoic reservoirs have great exploration potential. According to the study of core, well logging data, scanning electron microscopy, ordinary sheet, casting thin sections, the mercury method and X-diffraction, the sedimentary facies analysis and reservoir studies of the Huanghua Depression provide a scientific basis for the later exploration deployment.Huanghua Depression during Carboniferous-Permian time was divided into Benxi Formation, Taiyuan Formation, Shanxi Formation, Lower Shihezi Formation, upper Shihezi Formation and Shiqianfeng Formation from the bottom to top. Huanghua Depression Carboniferous-Permian strata major sedimentary facies types:fluvial sand body is commonly developed in Upper Shihezi Formation, Lower Shihezi Formation and Shiqianfeng Formation; delta sand body is commonly developed in Shanxi Formation; tidal flat-lagoon sand and lagoon-barrier island sand bodies are commonly developed in Benxi Formation and Taiyuan Formation. From the analyzes of sedimentary facies, Huanghua Depression most favorable reservoir sand bodies are fluvial sands Xiashihezi and Shihezi group, followed by the Shanxi delta plain distributary channel sand bodies and Taiyuan Formation sandstone barrier island. The character of Huanghua depresssion reservoir during Caboniferous-Permian time shows that he favorable sandstone body composed of fluvial and delta sand bodies.The result indicated that the main sandstone reservoir rocks of Upper Paleozoic on the Huanghua depression consist of feldspathic sandstone and lithic feldspathic sandstone. Generalized quartz sandstone (including lithic quartz sandstone and feldspathic quartz sandstone) Basically are distributed in Lower Shihezi Formation and Upper Shihezi Formation. The content of quartz in the reservoir showed significant increasing trend, while the content of the cuttings decreased from bottom to top. The maturity of component and texture of the sandstone reservoir are gradually decline. Overall, porosity and permeability of the Lower Shihezi Formation is better than Taiyuan Formation and Upper Formation, the Lower Shihezi Formation is the key exploration areas in the future. Porosity and permeability of the Shanxi Formation is poor.The influence was caused by Diagenesis of the sandstone reservoir is very obvious, compaction basically decide the quality of the sandstone reservoir, compaction have an negative effect on the sandstone reservoir, compaction is to reduce the original porosity of sandstone. In the latter part of the depth of sand, cementation gradually replaced compaction become the main factor that have an negative effect on sandstone reservoir. Claystone cement (mainly kaolinite), carbonate cement (calcite, dolomite and siderite), siliceous cement are to make the sandstone porosity and permeability decline. Dissolution (acid dissolution and alkaline dissolution) is an important method to improve storage physical properties of sandstone, dissolution is beneficial to improve the reservoir quality.The pore of sandstone reservoir of Huanghua depression reservoir during Carboniferous-Permian time are mainly intergranular pore, intragranular pore and casting hole. Fracture only developed in Shanxi Formation. Secondary solution pores is beneficial to improve the reservoir quality. Overall,the expulsion pressure of Upper Shihezi Formation is low, throat sorting coefficient is low, the expulsion pressure of Lower Shihezi Formation and Taiyuan Formation are middle, throat sorting coefficient is low, the expulsion pressure of Shanxi Formation is high, throat sorting coefficient is high. Connectivity pore throat of Upper Shihezi Formation is the best.The sandstone reservoir show the characteristics and pore structure features in-depth study of the study area under the sandstone reservoir for low porosity and ultra-low permeability. The study indicates that the reservoir is controlled and influenced by various factors, sedimentary environment and sedimentary facies conditions determined the initial conditions of sandstone reservoir, and the reservoir is mainly influenced by diagenesis (compaction, cementation and dissolution). The most favorable reservoir sand bodies are Upper Shihezi Formation and Lower Shihezi Formation. Upper Paleozoic fluvial body is the most promising reservoirs.
Keywords/Search Tags:Huanghua Depression, Sedimentary Facies, Reservoir physical Property, Diagenesis, Pore Throat Structure
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