Multiphase CO2 flow, transport and sequestration in the Powder River Basin, Wyoming, USA

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Abstract

Sequestration of anthropogenic “greenhouse gases” such as CO2 is proposed as a means of reducing global warming. We tested the possibility of sequestering CO2 in regional-scale aquifers in sedimentary basins, including residence time in possible aquifer storage sites and migration rates away from such sites. The example basin studied is the Powder River Basin, Wyoming. We calibrated regional scale rock properties in the Powder River Basin using surface heat flow observations. We determined advection by a regional-scale groundwater flow system in the basin can explain anomalously high surface heat flow not explained by conduction alone. Our study suggests that regional scale sedimentary basin aquifers are viable candidates for CO2 sequestration for time-scales of 103 years.

Introduction

Anthropogenic greenhouse gases, such as carbon dioxide, are considered a major contributor to global warming. Sequestration of power plant generated CO2 by injection into groundwater aquifers and (petroleum and gas) reservoirs has been proposed as a possible alternative for the reduction of excessive greenhouse gases in the atmosphere. Ideally, injected CO2 will migrate through an aquifer from injection wells to remote storage sites, and remain isolated from the atmosphere for a considerable period of time.

CO2 has been used for enhanced oil recovery (EOR) purposes since the 1950s. Research concerning terrestrial sequestration of CO2 for environmental purposes began only during the last 10 years or so.

Engineering and economics require CO2 storage sites as close as possible to sources such as fossil-fuel power plants. Subsurface groundwater aquifers are suggested, and this idea may be refined to groundwater aquifer systems and petroleum reservoir aquifers such as those found in sedimentary basins. These aquifer systems are large in size, possibly permitting storage of large quantities of CO2.

In a sedimentary basin, the capability of an aquifer to transmit and store CO2 is controlled by the fundamental geology: depositional environment, structure, stratigraphy, and pressure/temperature conditions. We investigated processes of CO2 sequestration in specific aquifers in a typical intracontinental sedimentary basin, the Powder River Basin in Wyoming, USA, using conceptual and numerical modeling.

Section snippets

Fundamental processes: aspects of transport

CO2 may be transported through aquifers in three different forms: (1) in solution in groundwater, (2) as a separate gas phase, and (3) as a separate supercritical phase, which exhibits properties of both gases and liquids. CO2 in solution may coexist with either gaseous or supercritical CO2, which occur as separate phases that depend on pressure and temperature conditions. The three different forms of CO2 respond to pressure and temperature in different ways. CO2 in solution behaves much like

Fundamental processes: aspects of storage

When CO2 moves into the intended storage area or reservoir, the same transport processes discussed above are applicable. As CO2 migrates through an aquifer, whether in the intended storage area or in the flowpath to that area, various trapping mechanisms may occur, as summarized below.

Petroleum migration research provides the best body of literature to describe trapping mechanisms—most principles that apply to petroleum migration and accumulation are directly applicable to CO2 trapping. In this

Study area: Powder River Basin, Wyoming, USA

In general, intracontinental basins possess a range of clastic to carbonate type aquifers. Clastic aquifers consist of sandstones and siltstones, typically interlayered with shales or mudstones. Such aquifers are found in most sedimentary basins, albeit some are better examples than others. For instance, dolomitic aquifers are found in the Uinta, Williston and Permian basins, while a range of clastic to limestone aquifers are found in the San Juan Basin, among many others. The Powder River

Numerical modeling analyses

We used numerical modeling analyses to evaluate flow, transport and storage of groundwater and CO2 in candidate aquifers of the Powder River Basin. Our primary goal was to characterize which types of aquifers and depositional environments are promising CO2 transport and storage sites.

Numerical modeling of basin scale groundwater flow and transport processes involves solving the appropriate mass and energy conservation equations (Bredehoeft and Norton, 1990, Garven, 1995, McPherson and Garven,

CO2 flow and transport: equation-of-state

Hydrologic properties such as fluid density and viscosity are often assumed to be constant in space and through time. For many applications, this is perfectly acceptable and appropriate. However, CO2 is subject to extreme and highly nonlinear changes in these properties as pressures and temperatures change. Weir et al. (1996) developed an extended Redlich-Kwong equation based on the work of Kerrick and Jacobs (1981) to describe the transport and thermodynamic properties of CO2 mixtures as a

Groundwater flow, heat flow and permeability in the Powder River Basin

McPherson and Chapman (1996) studied the thermal regime of the Powder River Basin, analyzing temperature and geologic data from over 3000 oil and gas wells within a 180×30 km transect; the cross-section shown in Fig. 1 cuts the center of that transect. McPherson and Chapman (1996) discussed anomalously high heat flow (>200 mW m−2) over the Salt Creek anticline on the southwestern side of the transect (Fig. 1), but did not provide a conclusive explanation.

The anomalous thermal regime observed in

CO2 transport and residence time: model simulation results

In our numerical model simulations of the Powder River Basin, we injected separate phase CO2 into the Fox Hills Sandstone, an Upper Cretaceous formation, at ∼1800 m depth (location∼solid circle on Fig. 1). The unit above the Fox Hills is the Lance Formation, a Paleocene sandy shale unit. Groundwater flow in this area of the Fox Hills formation is relatively slow, inasmuch as the hydraulic head gradient is weak. Migration of separate phase CO2 is towards the area of lowest surface elevation

References (8)

  • Bredehoeft, J.D., Norton, D.L. 1990. Mass and energy transport in deforming Earth's crust. In: The Role of Fluids in...
  • G. Garven

    Continental-scale groundwater flow and geologic processes

    Ann. Rev. Earth Planet. Sci.

    (1995)
  • D.M. Kerrick et al.

    A modified Redlich–Kwong equation for H2O CO2, and H2O–CO2 mixtures at elevated pressures and temperatures

    Am. J. Sci.

    (1981)
  • B.J.O.L. McPherson et al.

    Thermal analysis of the southern Powder River Basin, Wyoming

    Geophysics

    (1996)
There are more references available in the full text version of this article.

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