Taking CO2 Enhanced Oil Recovery to the Offshore Gulf of Mexico

Abstract

Abstract This paper evaluates the recoverable crude oil resource associated with applying carbon dioxide enhanced oil recovery (CO2 EOR) to reservoirs in the offshore Gulf of Mexico (GOM). Using data maintained by the Bureau of Ocean Energy Management (BOEM), a database containing 531 oil fields with a total original oil in-place (OOIP) of 69 billion barrels was used for the study. A total of 391 fields, representing 35% of the OOIP, were screened out at as not amenable to CO2 EOR based on size, residual oil saturation, and/or well-spacing. For the remaining 140 oil fields (containing 696 reservoirs), the data elements required to model a CO2 EOR flood, such as sweep efficiency and heterogeneity, were derived using a variety of methods. Crude oil production and CO2 demand profiles were produced from stream-tube finite-difference simulations for each oil-bearing reservoir. The study assumes that groups of proximate fields will be served by an anchor CO2 supply pipeline (one billion scf per year CO2) at a levelized transportation cost of $1.06/MscfCO2 (equivalently 20$/mtCO2). The economic determinations are based on a crude oil price of $90/bbl, CO2 price of $1.59/Mscf (30 $/MtCO2) at the capture facility plant gate, 18.75% royalty, and a 20% rate of return before taxes. BOEM projects that 182 billion barrels of OOIP remain undiscovered, two and a half times the discovered resource. Data from the analysis of discovered oil fields was used to estimate the expected CO2 EOR oil recovery from the undiscovered oil fields. Under the current CO2 EOR Technology scenario, the economically recoverable resources (ERR) is 0.8 billion barrels, a small fraction of the technically recoverable resource (TRR) of 23.5 billion barrels. The average efficiency of CO2 use in the ERR oil fields is estimated to be 7.2 Mscf/bbl and the associated demand for CO2 supply is 5.8 TCF. Under a scenario with Next Generation CO2 EOR performance, the ERR increases significantly to 14.9 billion barrels and 74 TCF of CO2 demand, consistent with an improved use efficiency of 5.0 MscfCO2/bbl.