Research On The Reservoir Characteristicin Chang2in Dongrengou Area,Dingbian Oil Filed, Ordos Basin

Dingbian Oil Field locates in the center of North Shaanxi Slope in Ordos Basin, its main purposed formation of exploration is Chang2oil layer of the Upper Triassic YangChang Reservoir.In order to master the geology and acumulation characteristic of shuanghe area, this study used sedimentology, reservoir geology,natural gas geology,petroleum entrapment geology and logging geology ete.theory as the instruction.by analysis of geological, logging, production test and measurement test, test oil and production dynamic data as the foundation, combined with various testing methods and analysis tools,studied deeply and systematically on the formation,structure,sedimentary microfacies types and distribution characteristics, reservoir characteristics.Identiied the targeted strata (each small layer or subgroups within Chang2) developed delta front subfacies depositional model. Further divided into underwater distributary channel, distributary bay, mouth bar, far sand dam, four kinds of microfacies. Among them, underwater distributary channel microfacies is the skeleton sand bodies of reservoir.On the basic of observation drilling core, laboratory test datum, Studies have shown that Chang2reservoir belongs to low-especially low porosity, low permeability reservoir. Property become better from Chang23to Chang21gradually. Considering the reservoir rock types, sedimentary facies, reservoir physical property (mainly for porosity and permeability), sand body thickness, the microcosmic pore structure characteristic, the reservoir in this area are classified as:Ⅲa～Ⅳb type, in which Ⅲa, Ⅲb type are good reservoir of Chang2in the research district,IIIb type is better reservoir Ⅳa type is medium reservoir, IVb type is poor reservoir.Comprehensive analysis think that Chang2reservoir in this research district is condoled by structure and lithology.oil layers mostly distributed in the underwater distributary channel, or in the underwater distributary channel flank area, oil layers’ distribution direction and the main channel distribution direction is consistent. The sand body continuity of Chang21-1is the best, but the property is most poor. The characteristic of Chang21-1reservoir is that low amplitude structure is the main type of reservoir trap.