Abstract

The thermal EOR steam generation projects in Gulf oilfields are on such a large scale that they affect an entire country's economic position. As such, the policies related to oilfield steam generation should be decided at the national level using the cost of the marginal fuel. This paper calculates the steam cost for three methods: 1) once-through steam generator (OTSG) 2) once-through heat recovery steam generator (OT-HRSG) and 3) solar steam generator (SSG).

We have created detailed performance and economic models of the steam generation methods and used them to calculate the levelized cost of energy and the Fuel Break Even (FBE). We explore the environmental and economic burdens on the cost of steam generation. The effect of fuel price on the cost of steam is also analyzed with a focus on the marginal fuel price.

The analysis shows that the fully burdened steam costs using $6/MMBTU fuel, for OTSG, OT-HRSG, and SSG are $27/ton, $20/ton, and $17/ton, respectively. The FBE for SSG vs. OTSG is $4.95/MMBTU when the OTSG is unburdened and decreases to $2.25/MMBTU when the environmental burden of Carbon Cost is added. The FBE for SSG vs. OT-HRSG is $7.70/MMBTU when burdened with Power Opportunity Cost and $4.50/MMBTU when the additional burdens of Carbon Cost and Water Opportunity Cost are accounted for.

Finally, we analyze the limitations of OT-HRSG in an isolated oilfield where the electric:thermal demand necessitiates electricity-matched cogeneration. This limitation along with the steam cost at the marginal fuel price provides the decisionmaker with a steam supply curve.

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