The Characteristics Of Ordovician Karst Reservoirs In Xinken-Rewapu Block,Halahatang Oilfield

At present,Halahatang is the main area for production in the Tarim Oilfield,and the Xinken-Rewapu block is the main block for the construction of the second stage of the Halahatang Oilfield.The Ordovician karst reservoirs in Halahatang Oilfield are highly heterogeneous and have poor lateral continuity.The main controlling factors of different reservoirs are complex.Therefore,it is of great significance to fully understand the reservoir characteristics.In this paper,the Ordovician karst reservoir in the Xinken-Rewapu block is the main research object,and the multidisciplinary theories and methods of stratigraphy,sedimentology,carbonate reservoir geology,and paleogeomorphology are fully used.The Ordovician carbonate reservoirs are described in many aspects such as stratum,sedimentary,tectonic,karst,and paleogeomorphology.On this basis,by summarizing the development characteristics and distribution rules of the four karst zone reservoirs and identifying the main controlling factors for the development of the four karst zone reservoirs,the reservoir development geological models of the four zones were obtained.By summarizing the reservoir characteristics of the four karst areas in the study area,the commonalities and differences were found.Affected by the karst layer formation,the reservoir develops mainly in the Yijianfang formation,and the upper part of the Yingshan Formation also develops slightly,while the Buried hill karst area is more developed due to the uplift of the Yingshan Formation.In the marginal marginal zone,the Lianglitage Formation also developed reservoirs.The main controlling factors for reservoir development in the four karst regions are summarized: the karst layer formation and the karst period are the basis for the development of the reservoir;the underground river pipelines control the distribution of the reservoirs in strips;the north and south differences in paleo-geomorphology Buried hill karst area and interlayer karst area,and control of the development of ancient water system;fracture is the main channel of karst groundwater seepage,runoff,karstification,is the main control factor for the formation of karst fractures and caverns.In short,the development characteristics and scale of karst are jointly controlled by the ancient karst geomorphology,ancient water system and fault structure.Finally,based on the reservoir characteristics and distribution rules,the reservoir development patterns in the four karst regions are summarized.