Basin Analyses And Simulation Of Up-Paleozoic In Ordos Basin

After systematically introducing the technology of Basin analysis and simulation, this paper analysis the developing actuality on geology model, mathematical model, software exploiture and so forth, on the basic study of last development of modern petrology .In order to bring forward a proper Basin analyses and simulation method and thoughtway, congruent to the large scale lithologic deposit of Up-Paleozoic in Ordos Basin, the investigation focus on the study of dynamic system of petroleum accumulation, including the modeling of geohistory, hydrocarbon generation history, expulsion history and migration-accumulation history.According to the history simulation of tectonic subsidence, the tectonic development in Ordos Basin can be divided into five phases since Up-Paleozoic. Combining with the character of tectonic subsidence in different regions, four fundamental tectonic subsidence models are summarized, such as steady subsidence, multi-lifting, late-lifting and strong-late-lifting.As a result of the abnormal high geothermal field of Ordos Basin in the late Jurassic-early Cretaceous, the hydrocarbon generation evolution, which was nearly keep stagnation after Cretaceous, was dominated by hypometamorphism before the Jurassic, and was controlled by hypometamorphism and regional thermal metamorphism synchronously during the late Jurassic and early Cretaceous. The properly collocated geologic condition, such as diagensis dominated lithologic and stratigraphic trap, late gas-generation-peak, wide-covered resource distribution give birth to the large and extensive distributed up-Paleozoic natural-gas pool.Up-Paleozoic gas field is kind of a large-scale low-permeability sand-reservoir formed on a gently west-tilt slope. One of the important characters is that part of natural gas leaks out upside during the forming procedure. Due to low permeability, the exchange of formation water could be quite slowly. Gas-leak brings on the losing of energy and pressure, and could induce low abnormal fluid pressures. As a result, gas-leak is slow and gas pools could be preserved.The Up-Paleozoic exploration region is divided into four classes, according to the 5-histories study and resource potential evaluation, together with the extensive analyses of reservoir accumulation condition, collocation way and resource enrichment as well. It is the basis to the favorite district evaluation in further exploration.