|
Worldwide, marine strata is a very important hydrocarbon reservoirs of Health, the world's recoverable reserves of 61% are produced in marine strata. In contrast, China's marine strata sedimentary area of ??the mainland accounted for 40%, while in the oil and gas discoveries in marine strata are relatively small. Therefore, the Chinese marine carbonate strata should have considerable exploration potential. Previous studies have confirmed that China Southern Permian important marine source rocks. In this thesis, Yangtze Permian three typical profiles of anatomical objects to carbonate rocks outcrop sequence stratigraphy of theoretical guidance, the use of trace elements, carbon and oxygen isotope geochemistry test and analysis, combined with the actual field test and indoor observation sheets, system to carry out the typical profile of Permian sedimentary facies and sequence stratigraphy studies and discusses the basic characteristics of sequence stratigraphy. In previous sequence stratigraphic analysis and habitat type on the region on the basis of research, combined with residual organic carbon tests to explore the Permian organic matter accumulation in the Yangtze region, and then sentenced to identify typical profile high quality source rocks rich keep horizons and to explore a marine source rocks of the Earth biology sentenced identification methods, concludes the study area grade hydrocarbon source rocks mode. Major knowledge and achievements: 1, according to records describing and interior flakes field observation of typical profiles Permian sedimentary facies were divided, summed up the geochemistry of sedimentary facies. Co, Ba, V, Rb and other elements with a defined relative significance, sedimentary facies closer to deep water environments, Co, Ba, V, Rb greater average abundance, and Sr / Ba value from the platform facies to basinal facies tended to decrease overall . From the terrace in front of Guizhou Luodian profile continental shelf slope facies → → → slope facies basin facies, REE value increases. Section of the sedimentary facies Guizhou Luodian REE patterns obvious Ce anomaly. Summarizes Guangyuan area, Huaying regions and regions of Guizhou Luodian carbonate depositional model. Guangyuan regions and regional Huaying reef carbonate platform margin is not developed, platform slope facies bad before, between the shallow shelf slope and basin are not developed. Guizhou Luodian sedimentary carbonate rocks are mainly located in the slope facies, platform front slope facies and slope facies development is good. 2, through the study area outcrop examined, carbon and oxygen isotopes and trace element testing, in-depth study on the basis of sequence features in Guangyuan Permian identified the nine three sequences, Chongqing Huaying next two sections Permian identified the six three sequences, Guizhou Luodian section identified the seven three sequences. Detailed discussion of each sequence and systems tract constituent features: Based on lithological characteristics summed eight kinds Parasequence basic fabric types; discussed the carbonate platform, slope deposits, sedimentary basin three kinds of background lower sequence constitutes The geochemical characteristics and system elements within distribution. From the transgressive systems tract to the HST, REE and REE (ΣREE) decreased; transgressive systems tract (La / Yb) N is greater than HST, indicating transgressive systems Domain LREE enrichment of greater than HST. Carried out on the basis of sequence stratigraphy contrast, the establishment of the Lower Permian isochronous sequence stratigraphic framework; discussed the study area the main controlling sequence development factors include: sea-level change, tectonic subsidence, climate, sediment supply and so on. Including sea-level change and climate as the main controlling factor. 3, through the study of organic enrichment characteristics typical profiles drawn: enriched with organic matter is closely related to lithology, thin chert and siliceous shale or laminated layers of limestone and shale is the most organic matter enriched lithology, where limestone bedding thickness increases with organic matter significantly lower laminae and thin limestone highest TOC; Permian residual organic matter distribution and habitat types are closely related, high-quality source rocks most favorable habitat type type Ⅳ 2 and habitat type Ⅴ 2 , again Habitat type Ⅲ; developmental sequence enrichment of organic matter influence, TST obvious organic matter enrichment of organic matter than the HST is higher. Guangyuan section on the Temple could become a quality source rocks are mainly three layers: the lower part of Qixia, Maokou top and Dalong Central; Huaying section may become effective hydrocarbon source rock layers have two layers, Maokou are located in central and lower Chihsian, Guizhou Luodian Permian strata there is no valid source rocks below. 4, we use TOC <0.3% for non-hydrocarbon source rocks, TOC> 1.5% for high-quality source rocks three discriminant program, discover known source rocks with various biological indicators of the earth following relationship exists between: ① from productivity associated with old age biogenic elements and associated with the burial environment geochemical indicators, Cr, Ni, Cu, Zn, Ba, Mo, U and other elements as well as indicate the average content of redox conditions Ni / Co, V / Cr, V / (V Ni) and other non-hydrocarbon source rocks from (TOC <0.396) to the general source rocks (0.3% 1.5%) showed regular changes , in addition to V / (V Ni) ratio did not change significantly, the other elements and ratios were significantly increased, which high-quality source rocks of the element content and element ratios increased significantly. ② compare different lithologies (limestone, chert and shale) content in the various elements found on high-quality source rocks, the mud shale Ni, Cu, Cr, Ba, Mo, U element content significantly higher than the limestone and chert, and Ni / Co and V / Cr ratios are relatively close; limestone Ni, Cu, Cr, Ba element content and siliceous rocks are similar, but Mo, U significantly less than the silicon element content rocks. For non-hydrocarbon source rocks (TOC <0.3%) and general source rocks (0.3% |