Research On Remaining Oil Distribution Of The Middle Es₃ Member In Block Fan 29 Of Daluhu Oilfield, Dongying Sag

Fan 29 block of Daluhu Oilfield is a deep structural-lithologic reservoir with low permeability,the 4 sand group of Sha-3 middle sub-member is the main oil layer in this area,and it's also taken as the target interval.The geological research degree is low in the study area.The sedimentary times of single sand body and sedimentary microfacies distribution is not clear,sedimentary facies model remains to be implemented and the reservoir research for inhomogeneous is little.All of this lead to poor development effect of water injection in some wells of the study area,and remaining oil distribution in the study area is complicated.Aiming at these problems,by comprehensively utilizing seismic,logging and production dynamic data,fine stratigraphic division and comparison to target layer Sha-3 middle sub-member 4 sand group set are conducted,and the isochronous stratigraphic framework of layers is established;and 10 phases single sand bodies are identified in the 4 small layers of Sha-3 middle sub-member 4 sand group.Following the division and comparison,the sedimentary microfacies are studied,and the middle fan and outer fan subfacies of sublacustrine fan are mainly developed.The middle fan subfacies was further divided into braided channel,inter channel,lobe and sheet sand microfacies,and braided channel and lobe microfacies are more developed.Further clarified the distribution characteristics of various sedimentary facies and established sedimentary facies models of sublacustrine fan in the study area.The characteristics of the reservoir in the study area were briefly illustrated in this paper,it is concluded that the reservoir of studied area has medium porosity and low permeability,meanwhile,the distribution of reservoir and its physical properties is controlled by sedimentary facies zone.Through quantitatively striking reservoir heterogeneity parameters and intercalations research,in small layer unit,inner-layer,inter-layer and plane heterogeneity of reservoir are studied,it is concluded heterogeneity of 43 and 45 small layers of 4 sand group in the study area is weak,which of 42 and 44 small layers is stronger.Fine geological reservoir models are made based on single sand body,which include structural framework model,fine single sand body model,sedimentary microfacies model under the restriction of single sand body and reservoir attribute model.In the model validation aspect,the model is verified through comparison between the geological model and the concept model and the probablity of consistency test,the results show that the geological model is of high reliability.Combined with the numerical simulation results,distribution of remaining oil and the controlling factors are studied.It is considered that geological factors such as sedimentary microfacies,reservoir heterogeneity,the micro structure and fault,the reservoir pore structure and fluid properties and the development factors such as injection-production well network and perforation,both of them affect the distribution of remaining oil.Overall,remaining oil is enriched in the 42 and 43 small layers of 4 sand groups,relatively concentrated in 44 small layer and 45 small layer.Aiming at the problems of the study area,some counter corresponding measures are put forward to improve the development level of the oilfield,which including well pattern optimization and improving injection-production well pattern,dividing layer series of development,perforations adding and other measures.