The Analysis Of Tectonic Evolution And Preservation Condition Of Oil And Gas In Guizhong Depression

Guizhong depression is a residual basin which filled from Paleozoic to Triassic. It deposited early and has been strongly renconstructed, also the study of guizhong depression is low level. This thesis base on field investigation,gravity and regional survey and lithofacies palaeogeography basic information. Using of plate tectonics theory, the basin structural analysis, marine carbonate deposition theory , balanced cross-section technology and other methods and means. Study the tectonic pattern, tectonic evolution and hydrocarbon storage conditions of Guizhong Depression. It can be used to guide the oil and gas exploration of Guizhong Depression.Based on the study of field investigation,regional survey and gravity, I consider that Guizhong depression has epimetamorphic Epiproterozoic and folding lower Palaeozoic two kinds of basement, develops NNE-NE, NW, near EW and NS four groups of discordogenic fault system , has NNE-NS, NW, EW three major tectonic belts. These compose the tectonic pattern of Guizhong depression which is NNE-NS tectonic belt is the main belt, the central-north and southern be cut and limited by EW tectonic belt; the western be limited by NW tectonic belt.Based on the study of regional data, the prototype tectonic lithofacies palaeogeography, field investigation, depression undergo Caledonian,Hercynian, Indo-China movement, Yanshan movement, Himalayan movement during its'formation and evolution. The basin evolution of depression can be divided into Eopaleozoic folding base form, Devonian- Middle Triassic passive continental margin basins, Late Triassic-Early Jurassic foreland basin and Middle Jurassic- nowadays reconstruction four types of phases.Based on the study of structural characteristics and classic ancient reservoir of depression, Summarize that depression hydrocarbon accumulation started from the Hercynian. Most ancient reservoir distribute along fault, The uplift and erosion of formation and the activity of fault caused the reservoir destruction.At the basis of the above-mentioned study, integrate with regional survey, make the quantitative research of the formation dip, fold intensity, fault development, strata uplift denudation. After that I can make comprehensive evaluation of oil and gas preservation conditions of Guizhong depression. The Midwest of Guizhong depression formation deformation is weaker, is better oil and gas preservation district.