Research On Deposition Characteristics And Sedimentary Facies Of Upper Ordovician Reef-beech Complex In TaZhong 24-82 Well Areas

Guided by the advanced theories of carbonate petrology,sedimentology, sequence stratigraphy etc, stratigraphic division,characteristic of rocks ,depositional environment,depositional model and characteristic of sedimentary facies of Upper Ordovician reef-beech complex in TaZhong 24-82 well areas have been studied extensively ,with the multiple method of field and indoor, macroanalysis and microanalysis being used.According to elaborate observation of drill cores of 20 wells in the research region, combining with characteristic of rocks,sedimentary cycle,response characteristic of bore log and analyse of depositional setting information, we divided LiangLiTaGe Formation into trangressive systems tract (TST) and highstand systems tract (HST), 3～4 parasequence sets , 8 parasequences and 11 members. In the base of characteristic of carbonate petrology ,analyse of environment,subfacies distribution characteristic in vertical and horizontal, we subdivided marginal facies of braiding continental shelf into 4 subfacies such as reef of shelf edge,beach of grain,lime-mud mound of shelf edge,sea in beach and 12 microfacies. And this paper has explained the development scale and facies combination change of reef-beach complex of every period, established pattern of reef-beach complex development and transfer, blocked out advantaged facies distribution scale of reef-beach complex in shelf edge and summarized evolvement and distribution rule of depositional facies. Contrasted it with domestic example, this article has demonstrated that Late Ordovician gioherm of TaZhong areas belongs to large-scale...