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Tabei(塔北) uplift is an area with the highest hydrocarbon enrichment in Tarim basin,and large oilfields have been found on Akekule(阿克库勒) arch at the middle section of Tabei uplift,with Ordovician carbonate reservoirs.Storage space of the Ordovician carbonate reservoirs in the Akekule arch are mainly caves,pores and fractures resulted from dissolution and/or karstification.The Ordovician carbonate reservoirs are affected and modified by the diagenetic process in penecontemporaneous,epigenetic and burial periods and the multi-stage karstification related with deep hydrothermal activities,among which the most significant effect is from the meteoric water karstification related to the tectonic uplift from the end of Middle Ordovician to the end of Late Ordovician(end of O 2-end of O 3) and at the end of Middle Devonian(end of D 2).Varied palaeogeologic settings and tectonic features at different geologic periods lead to different fluid flowing patterns,karstification mechanisms and transformation features in different regions,which further influence the reservoir distribution.The paleo-uplifts at different periods,such as end of O 2-end of O 3 and end of D 2,control the dominant development zones of karstification;the paleogeomorphology and faults resulted from tectonic uplift control the flowing depth of the karst fluid;and the lithology controls the position and extent of karst development.
Tabei (塔北) uplift is an area with the highest hydrocarbon enrichment in Tarim basin, and large oilfields have been found on Akekule arch at the middle section of Tabei uplift, with Ordovician carbonate reservoirs. Storage space of the Ordovician carbonate reservoirs in the Akekule arch are mainly caves, pores and fractures resulted from dissolution and / or karstification. Ordovician carbonate reservoirs are affected and modified by the diagenetic process in penecontemporaneous, epigenetic and burial periods and the multi-stage karstification related with deep hydrothermal activities, among which the most significant effect is from the meteoric water karstification related to the tectonic uplift from the end of Middle Ordovician to the end of Late Ordovician (end of O 2-end of O 3) and at the end of Middle Devonian (end of D2). Vary palaeogeologic settings and tectonic features at different geologic periods lead to different fluid flowing patterns, karstification mechanisms and transformation features in different regions, which further influence the reservoir distribution. The paleo-uplifts at different periods, such as end of O 2-end of O 3 and end of D 2, control the dominant development zones of karstification; the paleogeomorphology and faults derived from tectonic uplift control the flowing depth of the karst fluid; and the lithology controls the position and extent of karst development.