Dynamic Behavior of CO2 in a Wellbore and Storage Formation: Wellbore-Coupled and Salt-Precipitation Processes during Geologic CO2 Sequestration

Jize Piao,Kue-Young Kim,Weon Shik Han,Sungwook Choung

doi:10.1155/2018/1789278

Abstract

For investigating the wellbore flow process in CO2 injection scenarios, coupled wellbore-reservoir (WR) and conventional equivalent porous media (EPM) models were compared with each other. In WR model, during the injection, conditions for the wellbore including pressure and temperature were dynamically changed from the initial pressure (7.45–8.33 MPa) and temperature (52.0–55.9°C) of the storage formation. After 3.35 days, the wellbore flow reached the steady state with adiabatic condition; temperature linearly increased from the well-head (35°C) to the well-bottom (52°C). In contrast, the EPM model neglecting the wellbore process revealed that CO2 temperature was consistently 35°C at the screen interval. Differences in temperature from WR and EPM models resulted in density contrast of CO2 that entered the storage formation (~200 and ~600 kg/m3, resp.). Subsequently, the WR model causing greater density difference between CO2 and brine revealed more vertical CO2 migration and counterflow of brine and also developed the localized salt-precipitation. Finally, a series of sensitivity analyses for the WR model was conducted to assess how the injection conditions influenced interplay between flow system and the localized salt-precipitation in the storage formation.

Highlights

As an approach for decreasing CO2 emissions into the atmosphere, geologic carbon storage (GCS) is one of considerable solutions for relieving global climate change [1]
Several pilot-scale projects were successfully completed CO2 injection at a rate of 10,000 metric tons per year; these projects included Frio, Texas [6], Nagaoka, Japan [7], Ketzin, and Germany [8] as well as Regional Carbon Sequestration Partnership’s (RCSP) Phase II program implemented by the US Department of Energy [9, 10]
The numerical studies varying multiple CO2 injection scenarios were conducted to elaborate the relationship between the wellbore process and associated changes occurred within the storage formation

Summary

Introduction

As an approach for decreasing CO2 emissions into the atmosphere, geologic carbon storage (GCS) is one of considerable solutions for relieving global climate change [1]. While operating GCS projects, CO2, directly captured during industrial processes at fossil-fuel power plants, was injected through the wellbore and stored within the specific geologic formation covered by low-permeability caprock [2,3,4]. Several pilot-scale projects were successfully completed CO2 injection at a rate of 10,000 metric tons per year; these projects included Frio, Texas [6], Nagaoka, Japan [7], Ketzin, and Germany [8] as well as Regional Carbon Sequestration Partnership’s (RCSP) Phase II program implemented by the US Department of Energy [9, 10]. During the demonstration of such pilot- or commercialscale GCS projects, transported CO2 from the sources (e.g., coal-based power plants) must be injected through the wellbore, which is the pathway connecting the ground surface to the targeted subsurface formation [15].

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