Source-Reservoir-Cap Rock Association within Sequence Framework and Its Exploration Significance

Key words: 
• petroleum exploration /
• sequence stratigraphy /
• You jiang Basin

Abstract: Based on the sequence stratigraphy, in conjunction with the res ult of petroleum exploration, the correlation model of sequence stratigraphic framewor k and oil & gas source-reservoir-cap rock association has been established. Em phasi zed on Nanpanjiang depression and Shiwandashan basin, this paper deals with the genetic type and distribution pattern of source-reservoir-cap rock strata with in different hierarchies of sequence stratigraphic frameworks in the Youjiang Basin, and then discusses on their genesis and development model. Various sequence frameworks in different genetic basins contain different hydr ocarbon prospects. In general, transgressive system tracts (TST), condensed sec t ion (CS), highstand system tracts (HST) and lowstand system tracts (LST) of inte rplatform basin, deep-water basin are generally impo rtant source rocks and significant cap rocks, and coal-bearing carbonate formations of hi ghstand system tract in cratonic basin and carbonate platform. Highstand system tracts and lowstand system tracts in cratonic basin and carbon ate platform are important reservoins,and karst reservoir is developped along s equence boundary.Reservoirs maimly include all kinds of favoura ble sandbodies within different system tracts:①basin floor and slope fans, del ta front, alluvial fan, channel sandbodies, progradation complex, shoal-bioher m -reef complex, calcareous and mixed clastic turbidites within lowstand system tract; ②sandbodies of barrier beach, shoal, estuary, tide-controlled delta, fandelt a, turbidity fan, lag sediment, bioherm-reef complex, pyroclast turbidite withi n transgressiue system tract; ③river and wave dominated deltatic sandbodies, a lluvial-fan-channel sandbodies, fandelta, turbidity fan, terrigenous and car bonate shales, bioherm-reef complex, calcareous-clastic beach-bioherm-reef complex, calcareous clastic turbidite and dolostone within highstand system tra ct; and ④paleokarst reservoir dominated by sequence boundary.