Crisman Annual Report 2009 - Harold Vance Department of ...

Sustainable Carbon Sequestration
Introduction
Concerns that CO 2
emissions from the combustion
of fossil fuel are causing global climate change have
led to research that focuses on various ways in
which CO 2
can be captured, sequestered and stored
permanently in deep saline aquifers. The majority
of CO 2
produced in the US comes from coal-fired
power plants which account for about 50% of the
electricity generation. At the rate in which CO 2
is
produced from a typical power plant, it will require
multiple injection wells, and each well will have a
finite injection well area.
Objectives
Bulk CO 2
injection in a finite volume increases the
pressure of the aquifer. To avoid breeching the
aquifer seal, the injection well pressure must not
exceed the formation fracture pressure. The result
is a need for many wells and a prohibitively large
aquifer area. Alternatively, it may be possible to
avoid pressurizing the aquifer area and increase CO 2
storage efficiency by producing the same volume
of brine as is injected as CO 2
. This transforms the
problem from CO 2
storage to water handling.
brine displacement with and without saturated brine
injection. Finally, insights gained from the conceptual
modeling phase will be used to develop optimization
methods for improving CO 2
sweep efficiency.
Significance
The significance of this approach lies in its potential
advantages over processes currently envisioned.
Aquifer pressurization that may lead to breaching
the integrity of the reservoir seal is avoided, and the
CO 2
storage efficiency is increased compared to bulk
CO 2
injection.
V z
This study will investigate options for CO 2
storage
management, including evaluating the feasibility of
desalinating produced brine.
Approach
Previous studies have addressed issues related
to sequestration of CO 2
in closed aquifers and the
risk associated with aquifer pressurization. In this
study, we will produce brine to relieve the pressure
in the aquifer. First, we begin by extending known
(waterflooding) conceptual models to apply to the
CO 2
/brine displacement process. This will help in
the determination of well completion geometries,
spacing, and flow rates that optimize CO 2
storage
efficiency. Next, we will extend the work of Anchliya,
2009, such that the brine injector will inject saturated
brine from the desalination process. Anchliya
intended that injected brine would help curtail CO 2
breakthrough while increasing CO 2
trapping, as seen
in Fig. 1. The conceptual models will be calibrated
using rigorous numerical models. For this work,
it will also be the mechanism to handle saturated
brine from the desalination process.
We will evaluate the economic feasibility of CO 2
/
Fig. 1. Conceptual case of a horizontal CO2 and a brine injector and two
horizontal brine producers (Anchliya, 2009).
CRISMAN INSTITUTE
Project Information
4.1.7 Sustainable Carbon Sequestration
Related Publications
Anchliya, A., and Ehlig-Economides, C.A. Aquifer
Management to Accelerate CO 2
Dissolution and Trapping.
Paper SPE 126688, presented at the 2009 International
Conference on CO 2
Capture, Storage, and Utilization, San
Diego, California, 2-4 November.
Contacts
Christine Ehlig-Economides
979.458.0797
c.economides@pe.tamu.edu
Oyewande Akinnikawe
Crisman Annual Report 2009
81