Abstract

In order to sustain the current production capacity of conventional oil in Western Canada, enhanced oil recovery (EOR) technologies must be increasingly applied. Among these, carbon dioxide (CO2) flooding is a highly attractive possibility A large amount of CO2 is being produced by coal-fired power plants in this region. The CO2 is currently discharged into the atmosphere and could be a major contributor to the so-called greenhouse effect, which would lead t0 global warming. 'Thus, the concept of capturing CO2 and utilizing it as a flooding agent in EOR processes is currently generating much interest among oil, utility and coal companies.

This paper demonstrates how cogeneration concepts, together with process optimization strategies, help to reduce the CO2 production cost by utilizing low-pressure steam and waste heal from various sections of the power generation process. Based on these concepts and strategies, results from this study show that the recovery cost of CO2 from a coal-fired power plant can range between ﹩O.50-2.00/mscf. Therefore cost is approximately S1.25/mscf, the production cost of a barrel of incremental oil would be less than ﹩18. Therefore, even at today's modest oil prices, there is room for profit to be made operating a CO2 flood with flue gas extracted (,OJ. The technical and economical feasibility of the concepts are evaluated and the practical implications for the Saskatchewan resources are discussed.

Introduction

The concept of capturing carbon dioxide from coal-fired power plants and utilizing it as a flooding agent for enhanced oil recovery (EOR) processes is currently drawing much interest from oil, utility and coal companies in Western Canada. Implementation of such a scheme would provide two important benefits:

  • the captured CO2, could be marketed as a flooding agent which would generate revenues and

  • CO2 emissions to the atmosphere would be reduced.

Since CO2 emissions arc considered to be the main contributor to the possible serious environmental problem of global warming, the proposed scheme could become an important instrument to reduce such emissions at minimal incremental cost to the environment.

In the past few years a few pilot test projects on CO2 extraction from the Canadian coal-fired power plants (such as the Sundance and Boundary Dam projects) were organized by consortia of oil companies in collaboration with government organizations and utility companies these projects were primarily aimed at using the recovered CO2 for EOR applications. A variety of process technologies available from gas processing including chemical gas absorption, cryogenic separation, dry bed adsorption, and membrane separation processes were screened. The lc1ection process resulted in the chemical gas absorption process being chosen as it had better overall economical advantages and a proven operability record over other processes l,2. However the pilot plant results demonstrated that eyen though this process technology was technically feasible chemical gas absorption capital and operating costs were too high for EOR applications in the current crude petroleum market. The primary reason for the high cost of CO2 extraction was that a substantial amount of energy was required for the process.

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