3-D Modelling and Experimental Comparison of Reactive Flow in Carbonates under Radial Flow Conditions

Piyang Liu,Gary Douglas Couples,Jingsheng Ma,Jun Yao,Oleg Iliev

doi:10.1038/s41598-017-18095-2

Abstract

We use a two-scale continuum model to simulate reactive flow and wormhole formation in carbonate rocks under 3-D radial flow conditions. More specifically, we present a new structure-property relationship based on the fractal geometry theory, to describe the evolution of local permeability, pore radius, and specific area with porosity variation. In the numerical calculation, to improve the convergence rate, the heterogeneous medium in question is extended by adding a thin layer of homogeneous porous medium to its inlet. We compare the simulation results with the available experimental observations and find that they are qualitatively consistent with each other. Additionally, sensitivity analysis of the dissolution process with respect to acid injection rate and rock heterogeneity, including heterogeneity magnitude and correlation length, is presented.

Highlights

In Walle and Papamichos’ experiment, 15% HCl was injected radially into the Mons chalk core through the central borehole at a constant injection rate of 25 mL/min, which is the optimum injection rate leading to wormhole formation
The simulation result from the present model is in good agreement with the available experimental results
By analysing the effect of injection rate, heterogeneity magnitude, and correlation length, on the dissolution process, the following conclusions are made: (1) The dissolution patterns observed in experiments are obtained from simulation under the 3-D radial flow condition

Summary

Introduction

These extensions include simulating the wormhole formation under the radial flow condition[44,57], using various types of injected acids[50,51,53,58,59], for various reservoir characteristics such as the presence of fractures[20,55] and vugs[46], different completion methods[47], and various reservoir temperatures[45,48] All these studies bring important insights about the dissolution process, there are some issues that still remain to be further investigated. A sensitivity analysis of the dissolution process with respect to acid injection rate and rock heterogeneity, including heterogeneity magnitude and correlation length, is presented

Methods

Results

Conclusion