ABSTRACT: Reduction of "greenhouse gas" emissions through underground CO2 sequestration in Texas oil and gas reservoirs

Holtz, Mark H.¹, David L. Carr², and Peter K. Nance¹
(1) Teknecon Energy Risk Advisors LLC, Austin, TX 
(2) Geoscience Consultant, Austin, TX 

A promising method for reducing CO₂ emissions -- and thus reducing potential human impacts on global climate -- is through sequestration of CO₂ in subsurface reservoirs. The greatest concerns regarding the feasibility of subsurface CO₂ sequestration are the economics and the long-term trapping capability of a given reservoir over geologic time. Using CO₂ emissions in enhanced oil recovery (EOR) operations may provide a solution that addresses both concerns. Oil reservoirs are ideal candidates for CO₂ sequestration because they are proven geologic traps. Structural analysis, caprock evaluation, and pressure monitoring similar to the methods widely used by operators of underground gas-storage reservoirs can be applied to oil reservoirs to determine their viability for CO₂ sequestration. The economic benefit from increased oil production resulting from EOR by CO₂-injection would partly, or in some cases, fully offset the costs of power-plant CO₂ capture, pipelines, and transportation. CO₂ EOR can produce oil that would otherwise not be recovered, at an incremental cost of $6 to $12 per stock tank barrel (STB; 1992 U.S. dollars). More than 1,700 oil reservoirs are possible candidates for CO₂ EOR in Texas. These reservoirs represent 80 billion STB of original oil in place, of which 31 billion STB is residual oil, the target for CO₂ EOR. Eight (8) billion STB of this resource is within a 90 mile radius of candidate coal or lignite fired plants in Texas. In addition, between twelve (12) and twenty (20) years of CO₂ production from nineteen (19) lignite or coal fired boilers could be sequestered.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia