Research Of The Depositional Systems Of Neopaleozoic In Tabamiao Area

According to the deposit mained lithologic trap, lithologic-structure complex trap, the sedimentary system research is the base of reservoir assessment and prognosis. The gas concentration of shanxi group and xiashihezi group of Permain system in Tabamiao area was mainly constrolled by sedimentary facies belt. Therefore, it is an important content in this geological research area that study sedimentary systems character of object layers, research combined character of subfacies and microfacies ,and its regular between vertical evolution and reservoir sand bodies.Under the guidance of theories of sedimentology, petroleum geology and sequence stratigraphy , and through the comprehensive analysis of outcropsrock , cores, well logs and testing outcomes of rock gas, this paper studies the depositional systems of Neopaleozoic and the character of aeration zone in Tabamiao area of Ordos basin .The result indicates that the object layers are divided into two depositional systems, the barrier seacoast depositional systems are recognized on upper Carboniferous taiyuan phase with tidal flat, lagoon and barrier bar sedimentary deposit . Lake delta depositional systems appear from lower Permian shanxi to middle Permian xiashihezi phase, braided river delta in shanxi phase with delta plain subfacies sedimentary deposit, and so early xiashihezi , meandered river delta plain subfacies in later xiashihezi group. Facies association, lithologic composition, deposition sequence, sectional structure, sedimentary structure and grain size probability are analysed in detail.Being or the base of depositional systems, eight pieces of sequence paleogeographic map have been drawned up on condition of long-term cycle sequence as drawing unit, then discussing the distribution of depositional systems on different phases, paleogeographic spread and evolution have been disclosed. On studying of them .using the testing outcomes of gas fully, lithologic characters .strata sequence, sand body shape, sequence sectional structure in aeration zone and main channels migrating pattern on different phases have been analysed . For futher reservoir, cap, source rock and oil gas expiortion...