Architecture And Modeling Of Braided River Reservoir In The Upper Guantao Formation,Block 6 Of Gudong Oilfield

At present,there are several problems faced by this oilfield including extra-high water cut,high distribution of remaining oil,difficulties in stable production.Therefore,in order to achieve the goals of enhanced oil recovery and stable productivity,the meticulous portrayal of reservoir architecture has become an entry point for solving problems.According to the previous studies and the analysis of the core,well logging,seismic and dynamic data in the study area,it is believed that braided river deposits are formed in the upper layer of 5⁴?6⁸ in the upper section of the sixth block of Gudong Oilfield.In this paper,the types and characteristics of sedimentary microfacies are analyzed and identified by the identification and division of sedimentary facies.The microfacies can be divided into four types,including braid channel,braid bar,floodplain and overbank sand.On the basis of sedimentary microfacies control,the sedimentary microfacies model is established by deterministic modeling.On the basis of the high-resolution sequence stratigraphy reservoir reservoir architecture theory,the internal architecture of the braided river reservoir is finely dissected.Based on the well correction in dense pattern,the quantitative characterization of the scale of the reproduction body in the braid bar of the braided-river reservoir was realized.The range of parameters for 4^th-order architecture was determined.Among them,width is 100-350 m,length is 400-500 m,thickness is 4-12 m of the braid bar.The length of the braided bar has positive correlation with the width of the braid bar,and the width of the braid has almost positive correlation with the thickness of the braid bar.The range of parameters for 3^rd-order architecture of the off-silt and accretion body was determined.The average dip of the off-silt at the head of bar is 0.93°and that at the end is0.53°and that at two wings is 1.47°,and the length of single accretion body in the braid bar at direction of long axis is from 280 to 800 meters,and its width is from 165 to 400 meters.The width of the the off-silt may be from 250 to 700 meters and its length may be from 150 to350 meters.In the framework of reservoir architecture,the distribution characteristics of interface in different architecture orders are analyzed,and the 3^rd-order and 4^th-order architecture surfaces are identified.The top and bottom constraints are applied to different levels of architecture units.Based on the constraints of sedimentary microfacies,using the robust sequential Gauss simulation method,to establish a three-dimensional model that can truly reflect the distribution characteristics of underground reservoirs architecture.The architectural model can be used to simulate the 3^rd-order and 4^th-order architecture surfaces.This architectural model improves the accuracy of heterogeneity of reservoir model,clarifies the structural characteristics of different scales,and clarifies the relationship between the types of interlayers and the superimposition of sand bodies.On the basis of architectural model constraints and fine characterization of architectural units,a set of physical parameter models such as porosity and permeability model are established.The research results can provide a model basis for reservoir numerical simulation,remaining oil tapping and development program adjustment.