Study Of Sequence Stratigraphy And Its Application For Oil And Gas Exploration And Development In Late Mesozoic And Cenozoic Of Jiangsu And Anhui Area

On the stratigraphic regionalization, the region of Jiangsu and Anhui area is belongto Yangtze Stratigraphic Region, Huanan Stratigraphic Super Region. It can be dividedinto two parts by the boundary of line of Shitai—Xuancheng—Changzhou which arenorth Lower Yangtze Stratigraphy Area and south Jiangnan Stratigraphy Area. Takingthe sequence stratigraphic standpoint as the theories guides and technique means,making usefulness of outcrop, drilling cores, logging and seismic data, the authorproceeded a comprehensive study of the characteristics of sequence stratigraphy, thelithofacies paleogeography characters and evolution of tectonic-sequence and otheraspects of the continental stages from Upper Triassicis to Neogene in the region ofJiangsu and Anhui area.(1) Systematically reorganized the Late Mesozoic and Cenozoic continentalstages of research area, determined the relationship between lithostratigraphy andchronostratigraphy, further studied on the correlation of the whole research area.(2) On the comprehensive analysis of outcrop, drilling cores, logging and otherdata, the author considered there are seven kinds of depositional system in thesedimentary basin of research area, which are alluvial fan, fan delta, nearshoresubaqueous fan, fluvial facies, lake delta, lacustrine, and sublacustrine fan. It can begeneralized to three kinds of sedimentary model which regarded the sedimentary systemof fan as principle, the first sedimentary model is simple-stage fan which is constitutedby nearshore subaqueous fan only, the second is two-stage fan which is the combinationof fan delta and sublacustrine fan, the third is triple-stage fan which is the combinationof alluvial fan, delta and sublacustrine fan.(3) Taking the sequence stratigraphic theory as the guiding thought, regarding thetectonic sequence and sedimentary sequence as objects, the author divided the LateMesozoic and Cenozoic continental stages of research area into twelve tectonicsequence and twenty-eight sedimentary sequence, further studied the characteristics ofall tectonic sequence. On the base of these research findings, regarded the tectonic sequence as frame, regarded the sequence boundary and maximum-flooding surface oftectonic sequence as the marker of chronostratigraphic correlation, regarded thesedimentary sequence as units of chronostratigraphic correlation, establishedtime-sequence stratigraphic framework of cross sections which cross the Cretaceous andAncient Near Discipline stratum, studied the details of the characteristics of the tabulatedistribution of the tectonic sequence.(4) Regarded the sequence boundary and maximum-flooding surface of tectonicsequence as the boundary, regarded the lake basin expansion systems tract and lakebasin contraction systems tract as the map-making units to establish lithofacies andpaleogeography maps of the tectonic- sequence, represent the lithofacies andpaleogeography feature of lake basin expansion and contraction. Emphasis on studiedthe development status of sedimentary basin, evolution characteristics and exhibition ofspace-time of lithofacies and paleogeography.(5) Pass to make analysis of the collecting samples and associative them with theanalytic data and research findings which have been acquired, on the base of sequencedividing and establishing the sequence-stratigraphic framework, analysed theregularities distribution and the characteristics of combination of hydrocarbon sourcerock, reservoir and cap rock, on the base of these studies, the author further studied thecharacteristics of the petroleum system of continental stages of research area fromUpper Triassicis to Neogene.(6) Regarded Majiazui-Lianmenzhuang area of Gaoyou Subbasin in Subei Basinas major block, regarded Dainan Formation as major layer, made a detailed analysis ofseismic stratigraphy and high-resolution sequence stratigraphy, on the base of thesestudies, associative them with research findings which have been acquired to analyzethe favourable exploration targets and supply the reliable sedimentary and sequencestratigraphic evidence to proceed exploration and development of oil and gas.