Three-dimensional Geological Model Of Tide-dominant Estuary

On the whole,the formation of estuaries is made up of a complex set of subenvironments,whose sedimentary characteristics are always difficult for geologists because of their complex and changeable characteristics.Estuaries are often found in modern transgressive coasts.Because of the complex sedimentary sequence of estuaries,the stratigraphic records of estuarine facies models are very rare.It is difficult to compare ancient estuary sediments with modern estuaries because estuaries straddle shoreline and shallow sea environment.Taking the Asabasca area of Mc Murray area as an example,this paper studies the three-dimensional Geological modeling of the reservoir in the tide-dominant estuary.Firstly,based on Google Earth analysis of 107 tidal sandbars in 52 tidal estuaries in the region,a similar relationship between tidal control range and estuarine width in tidal controlled estuaries with different curvature is obtained.The shape development of tidal estuary is controlled by the curvature of BLC section.The smaller the curvature is,the easier it is to produce tidal estuary with good shape.There are universal correlations between the length and width of tidal-control sand dams in different regions.And the length of the linear sand bars is at least 3 times its width,and the length of the U-shaped and composite sand bars is at most 5 times its width.A reservoir geological knowledge base in tide-dominant estuary was established.Secondly,with the sedimentary characteristics and reservoir characteristics of well logging,core data,complete the division of stratigraphic frame,divides the Mackay river area Mike Murray group objective layer into 5 layers.Through core analysis,it is determined that the tidal controlled estuarine facies are mainly developed in the study area,and the main sedimentary microfacies are tidal bar deposition,sand flat deposit,mixed flat deposit,mud flat deposit,point dam deposit,salt marsh deposit,etc.The source direction is mainly southeast.Finally,a sequential modeling method was used to conduct 3D geological modeling of the study area.Through well data,different micro-phase variograms in the study area were calculated,combined with the geological analysis and the knowledge base established by modern deposition,the characteristic parameters of the variograms of different microfacies were determined.Establishment of sedimentary microfacies distribution model in the study area.The comparison of the cross sections of the wells shows that the model better reflects the spatial distribution characteristics of the sedimentary facies and has higher accuracy.Subsequently,a three-dimensional model of porosity and permeability was established using sequential phase modeling techniques using sequential Gaussian simulations.It laid the foundation for subsequent geological and reservoir engineering research.