Study On Petroleum System Based Upon Framework Of Sequence Stratigraphy In Chagan Fault-depressed Lacustrine Basin

Guided by the theory of sequence stratigraphy and petroleum system using cores, lithologic log or well-logging, biostratigraphic and seismic data, adopting seismic inversion constrained to well data, digital analysis technology, basin modeling, test method and so on, and adopting an integrated study technology, aiming at lower exploration in Chagan Depression, this work put forward a new research thoughtfulness, technic flow and method system that is an integrated study by "looked upon sequence stratigraphy as a base, looked upon petroleum system as a integer ,combing with each other closely" and tie in qualitative analysis and quantitative analysis and applied synthetically new theory, new technology and new method. The method has triumphantly applied in sag evaluation in Chagan Depression, and enhanced the forecast of exploration targets, and achieved favorable effect, and auspicated a new way of exploration for similar lower exploration mid-small basins.After have systematically studied sequence stratigraphy of Chagan Depression, a analysis method of high precision sequence stratigraphic framework in fault-depressed lacustrine basin. The core of the establishing framework is exploration-significant identify of sequence, division of 2,3,4,5 grades sequence and analysis of base-level based on lithologic log or well-logging, high-resolution seismic inversion constrained to well data. Then using the results of 2D seismic data, and interpret sequence to enhance the precision of interpretation. The sediment stratum in Chagan Depression is devised into tree supersedences. Among them, Lower Cretaceous can be devised into eight sequences and twenty-two system tracts which have been studied in characteristics of sedimentary cycle, distribution and genetic analysis. After this study, formed mechanism, distribution model and evolvement of sequence have been put forward.Depend on the contents and aims of petroleum system this paper put forward the study thought fulness and method of petroleum system based on the framework of sequence stratigraphy. The qualitative study and quantitative simulation has resolved the " seven analysis" that are qualitative analysis (characteristic analysis of static geologic elements), boundary analysis ( of oil and gas distribution ), time analysis (of pool -forming),direction analysis (of migration of oil and gas), quantitative analysis ( of migration and accumulation scale of oil and gas),location analysis ( of petroleum province ), and zone analysis ( of oil and gas accumulation). Qualitative study is about qualitative and boundary analysis .The basic analysis thought and method is to study the distribution and characteristics of source rock and caprock by analyzing the classification and characteristics of the condensed sections, and to research the distribution and characteristics of reservoir by analyzing the characteristics and distribution of the sedimentary systems and system tracts. Quantitative simulation is analyzing time, direction, quantitative and location which are belong to the study contents of dynamic geologic processes. The analysis is using basin modeling analysis to rebuildthe 5 histories of a petroleum system, such as geological, thermal, hydrocarbon generation, expulsion, and accumulation histories, and to calculate hydrocarbon generation potential and resources ,and to point out favorable region of oil and gas accumulation. Establishment of 4D the relationship between the static geologic elements and dynamic geologic processes is a zone analysis in which we establish 3D prediction models, synthetically evaluate the petroleum system, and finally select favorable zones to explore.In the condensed sections analysis, the concept of water-bearing lacustrine basin condensed sections and non-water-bearing basin condensed sections are firstly put forward, and have been described their features of lithology, mineral and geophysics, and have been predicted their distribution. Meantime, this paper has studied the geochemical characters of source rocks, and contras...