Economic Model of Mobility Control Methods for CO2 Flooding
Authors: Pande P.K. , Heller J.P. 
Published: December 2007

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A levelized cost procedure is used to determine the profitability of carbon dioxide flooding in profitability of carbon dioxide flooding in non-waterflooded fields, and of the use of thickening agents for mobility control. The effects on production of changing the mobility of the injected CO2 are estimated by use of a correlation developed by Claridge [11 from his analysis of the literature on developed five-spot patterns. The procedure shows that mobility control can be applied procedure shows that mobility control can be applied profitably to carbon dioxide floods. Greater profitably to carbon dioxide floods. Greater profits result from operating at lower mobility profits result from operating at lower mobility ratios. The effect of varying critical operation and financial parameters on the profitability of carbon dioxide floods is investigated. The profitability of the project is highly dependent on profitability of the project is highly dependent on the cost of carbon dioxide. The oil price, oil price escalation rate, carbon dioxide cost price escalation rate, carbon dioxide cost escalation rate, and discount rate for discounting future cost and revenue stream affect the profitability of the project by an order of profitability of the project by an order of magnitude less than the cost of carbon dioxide. However, for conventional carbon dioxide floods, carbon dioxide recycling is important and the recycling affects profits more than the parameters just mentioned previously. The cost, concentration, and escalation rates of mobility control agents are also important factors which affect the profitability of mobility controlled carbon dioxide profitability of mobility controlled carbon dioxide floods. The fixed charge rate for capital and the operation and maintenance cost escalation rate affect the profitability of the flood but these parameters play a far less significant role than any parameters play a far less significant role than any of the other factors described above.

Introduction

Economic considerations are important for determining whether or not enhanced oil recovery processes will be applied to petroleum reservoirs. The objective of this work is to provide a means by which to consider the costs and benefits of ability control for carbon dioxide flooding. The mobility control alternatives investigated include use of conventional carbon dioxide flooding, and thickening the injected CO2 by mans of an additive such as foams or polymers for mobility control.

A levelized cost procedure is used to evaluate the different mobility control alternatives under consideration. By definition, levelized costs are a stream of constant annual payments over the life of the investment, with the same discounted present value as the actual stream of payments. When capital as well as continuing yearly operation and maintenance costs are involved, the levelized cost is the sum of the appropriate fixed charge rate times the capital outlay plus the levelized stream, of annual costs. The use of levelized costs provides a means of comparing different investment provides a means of comparing different investment strategies; in this case, a commitment to a particular mobility control alternative with different particular mobility control alternative with different capital outlays and annual cost streams

In this analysis, a Fortran IV computer program with approximately 50 input variables is used to perform the engineering and economic analysis. These input parameters relate to operating characteristics parameters relate to operating characteristics (mobility ratio, amount of CO2 injected, flood type - conventional, foam, or polymer CO2 flood), field characteristics, and financial parameters. These parameters are initially set at base case values and then altered to investigate the effect of changes in the parameter on profit.

The program incorporates subroutines to calculate the oil recovery which occurs as a function of time, capital investment costs, operation and maintenance costs, and crude oil revenue over time. The windfall profits tax, royalties, and state and local oil and gas severance taxes are taken into account. The program finally levelizes cost stream and provides program finally levelizes cost stream and provides levelized (annualized) profit which can be used to compare the different investment alternatives. The annualized profit does not account for overhead expenses or the corporate income tax.

The oil recovery model incorporated into the program is based on the work of Claridge. It is assumed that the rate at which CO2 is injected and the mobility ratio remain invariant with time. The oil recovery model is applied to a non-waterflooded field.

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