Three-dimensional Geological Modeling Of Sandy Conglomerate Reservoir In The Fourth Member Of Shahejie Formation,Yong559,Dongying Sag

The Yong559 area of Dongying Sag is located in the southeastern part of the Jiyang Depression.It is an asymmetrical dustpan-like basin with a steep slope in the north and a gentle slope in the south.The sandy conglomerate reservoir has complex rock mass distribution and strong heterogeneity.The porosity and permeability are relatively low.The distribution of oil and gas is obviously controlled by sedimentary facies,and the physical properties of reservoirs in different facies zones are quite different.Moreover,the study area lacks more refined three-dimensional geological models.In this paper,using the core,logging,earthquake and pre-human geological research in this area,based on the principle of cyclic contrast and hierarchical control,the stratigraphic comparison of the VIII oil layer of the fourth member of the Shahejie Formation is divided into six layers of three sand groups.Under the premise of systematic analysis of paleogeography and regional tectonic setting,the core facies and logging facies are integrated,the sedimentary facies marks are identified,and the single well,plane and profile facies are identified and divided.It is considered that the sedimentary facies developed in this area are nearshore underwater fan,further divided into six microfacies: main channel,space between main channel,braided channel,space between braided channel,fan-middle frontal edge and fan-end mud,and the spatial distribution relationship of the sedimentary microfacies is analyzed.According to the core interpretation data,the reservoir is characterized by low porosity and low permeability.Using Petrel software,the tectonic model is established by the stratigraphic correlation results and the topographic tectonic map.Based on the study of sedimentary microfacies,the deterministic assignment modeling method and the sequential indication simulation modeling method are compared and analyzed,and the deterministic assignment method is chosen to establish the phase model.Then,the sequential gaussian simulation method is used to establish the attribute model under the constraint of sedimentary microfacies model.Through the reliability analysis of the model,it is concluded that the model has higher precision and predictability.Finally,based on the results of the modeling,the reserves of the study area are estimated,and the oil geological reserves of the VIII oil layer of the fourth member of the Shahejie Formation are determined to be 1.974 million tons.