Relative Permeability: A Critical Parameter in Numerical Simulations of Multiphase Flow in Porous Media

Nathan Moodie,Wei Jia,Brian Mcpherson,William Ampomah

doi:10.3390/en14092370

Abstract

Effective multiphase flow and transport simulations are a critical tool for screening, selection, and operation of geological CO2 storage sites. The relative permeability curve assumed for these simulations can introduce a large source of uncertainty. It significantly impacts forecasts of all aspects of the reservoir simulation, from CO2 trapping efficiency and phase behavior to volumes of oil, water, and gas produced. Careful consideration must be given to this relationship, so a primary goal of this study is to evaluate the impacts on CO2-EOR model forecasts of a wide range of relevant relative permeability curves, from near linear to highly curved. The Farnsworth Unit (FWU) is an active CO2-EOR operation in the Texas Panhandle and the location of our study site. The Morrow ‘B’ Sandstone, a clastic formation composed of medium to coarse sands, is the target storage formation. Results indicate that uncertainty in the relative permeability curve can impart a significant impact on model predictions. Therefore, selecting an appropriate relative permeability curve for the reservoir of interest is critical for CO2-EOR model design. If measured laboratory relative permeability data are not available, it must be considered as a significant source of uncertainty.

Highlights

With the prospects of climate change looming and an ever-increasing demand for power generation and heavy industry, reducing greenhouse gas emissions from large point-source emitters, such as coal and natural gas power plants or fertilizer operations, has become paramount
Careful consideration must be given to this relationship, so a primary goal of this study is to evaluate the impacts on CO2Enhanced Oil Recovery (CO2-EOR) model forecasts of a wide range of relevant relative permeability curves, from near linear to highly curved
We utilized an empirical formula for relative permeability developed by Corey [10] to described oil and gas flow in porous media

Summary

Introduction

With the prospects of climate change looming and an ever-increasing demand for power generation and heavy industry, reducing greenhouse gas emissions from large point-source emitters, such as coal and natural gas power plants or fertilizer operations, has become paramount. Laboratory measurements have historically been focused on measuring two- and threephase relative permeability curves for oil and gas (CH4) reservoirs [7,8,9] From these data, empirical models have been developed which promise broad applicability, including use in GCS numerical simulations [7,8,9,10,11,12,13,14]. Other numerical simulators, such as the Eclipse® numerical simulator used in this study, leverage table data in the form of two-phase saturation versus relative permeability tabular data coupled with linear interpolation between data points [20] These methods use a combination model to calculate the three-phase relative permeability. A primary goal of this study is to evaluate how uncertainty in the relative permeability curves impacts CO2-EOR model forecasts

Study Site

Well Operations Schedule and Model Fit

Discussion

Oil Production

Findings

Pressure