Geostatistic Modelling and Flow Simulation of a Mixed-Influenced Deltaic Reservoir

摘要

Compared with deltaic stratigraphic and sedimentary architecture,diagenetic influences on fluid flow are less commonly modeled.Precipitation of extensive cement during diagenesis modifies depositional permeability and affects production behavior.Carbonate cement may have a strong influence on fluid flow.Heterogeneity may trap a significant portion of mobile oil in analogous deltaic reservoirs.This article examines a delta lobe in the Wall Creek Member Cretaceous (Turonian) Frontier Formation,Powder River Basin,Wyoming using digitized outcrop images,3D ground penetrating radar surveys for 3D reservoir characterization and flow modeling.Geostatistical models reproduce the size,orientation,and shape of the calcite concretions using GPR,well,and outcrop data including variograms and trend models for concretion occurrence.Relationships among GPR attributes,well data,and outcrop data are used to generate soft data for modeling calcite concretion occurrence.Sequential Gaussian Bayesian Simulation and Tau-Model are used to predict 3D concretion distributions.Flow Simulation indicates that calcite concretion can significantly affect the flow responses.Fail to model the concretion vertical trend will overestimate the recovery and uncderestimate reservoir heterogeneity.The proposed concretion models can guide data acquisition,improve performance prediction,and help upscale models of analogous deltaic reservoirs.