The Glutenite Bodies Depositional Stage Fine Division Of The Upper Fourth Member Of The Sha He Jie Sand Formation In Yan Jia-Yong An Zone

Along the age-old broken and denuded level of Chen Nan major fault, the glutenite reservoir of the upper fourth member of the Sha he jie sand formation in Yan jia-Yong an zone grows in front of the Yan16 and Yan18 paleo-gully, and distributes in the shape of skirt belt. Under the condition of high hill, steep slope, deep water, the glutenite bodies rapidly and abundantly deposits, thus it leads to the complex depositional system, and causes the absence of fossil organisms and stable mudstone barrier which can help to validly track and contrast the stratums in the zone. So the stratum division method combining the traditional fossil organism and rock electricity relation is difficult to adapt for the job of the glutenite bodies depositional stage fine division and contrast in the zone. But it can't further meet the request of the upper fourth member of the Sha he jie sand formation reservoir development and reserve estimation owing to the glutenite body's depositional stage coarse division only divided to the middle period depositional cycle by the predecessors and the huge formation thickness of the development block. Whilst the study's extent of the glutenite reservoir depositional model and sedimentary facies(microfacies) is very low. Thereby one of the bottle necks restricting the glutenite reservoir exploratory development in the zone is the glutenite depositional stage fine division, contrast and sedimental feature research.On the basis of sufficient absorption and digestion of the predecessors'study outcome, with the help of comprehensive application of the theory about geology of petroleum, high resolution sequence stratigraphy, and reservoir bed sedimentology, by utilization of well drilling, rock core, FMI, general log and the relative test analysis information, the following jobs subsequently are accomplished: Contrasts and fine divides the glutenite depositional stage of the upper fourth member of Sha he jie sand formation; Builds high resolution sequence stratum framework; Further probe into the character of the sandbody distribution and sedimentary facies(microfacies); And finally founds the unique depositional model of region of interest. This paper can provides not only the theory solving the issues about the huge thickness glutenite bodies depositional stage division and sedimentary facies(microfacies) distribution feature, but also the reliable geological criterion of the glutenite reservoir exploratory development and calculation of proven reserves.According to the glutenite reservoir bed geological character and high resolution FMI logs information which was contrasted and analyzed, the correlation between FMI model and rock core is built. Both the FMI answering feature about various glutenite reservoir beds and the identification signs of sedimentary sequence such as various bedding, Bouma sequence, turbidite deposit sequence etc. are summarized.According to the glutenite reservoir bed's fine division criterion, the blocks of Yan22 and Yong920 are subdivided into three middle period depositional cycles, eleven / ten short period depositional cycles respectively. These middle period cycles whose upper semi-cycle is transgression phase are folded together and compose the whole long period depositional cycle whose upper semi-cycle also is transgression phase in the upper fourth member of the Sha he jie sand formation, which reflects sediment retrogradation process, along with the water body gradually deepens, the lake basin continuously enlarges, and the lake capacity gradually increases during the upper fourth member of the Sha he jie sand formation deposition stage.By means of the individual well phase analysis of the core wells and the research result about sedimentary facies(microfacies) feature and sand body spread rule, the conclusion can be reached that during the upper fourth member of the Sha he jie sand formation deposition stage, large numbers of detrital materials coming from the north material source named Chen Jia Zhuang bulge are carried into the lake through the Yan16 and Yan18 paleo-gully in the flood period. Result from steep slope and deep water, the detrital materials merely deposit on the lower fault step and the downward slopes, and respectively form the Yan22,Yong920 coastal subsea apron glutenite depositional system. While the subsea apron body is depositing, part of sediments in the Yan22 coastal subsea apron slumps caused by abundant sediments action of gravity on the slope, and then speedily carries toward the deeper southeast trough fault, in the end this forms Yan 222 block gravity flow waterway depositional system.There exists the close correlation between Yan22, Yong920 coastal subsea aprons distribution and Yan16, Yan18 paleo-gully. During the upper fourth member of the Sha he jie sand formation deposition stage, with the lake basin expansion, the main part of the subsea apron takes on the recession sequence along upward steep slope, and forms the finite recession type depositional model of the coastal subsea apron. While under the controlling of the coastal subsea apron depositional system, the Yan222 gravity flow waterway deposition distributes the front or flank of the subsea apron located deep water area, and finally forms the gravity flow waterway depositional model.