A Gate-to-Gate Life Cycle Assessment for the CO2-EOR Operations at Farnsworth Unit (FWU)

Abstract

Greenhouse gas (GHG) emissions related to the Farnsworth Unit’s (FWU) carbon dioxide enhanced oil recovery (CO2-EOR) operations were accounted for through a gate-to-gate life cycle assessment (LCA) for a period of about 10 years, since start of injection to 2020, and predictions of 18 additional years of the CO2-EOR operation were made. The CO2 source for the FWU project has been 100% anthropogenically derived from the exhaust of an ethanol plant and a fertilizer plant. A cumulative amount of 5.25 × 106 tonnes of oil has been recovered through the injection of 1.64 × 106 tonnes of purchased CO2, of which 92% was stored during the 10-year period. An LCA analysis conducted on the various unit emissions of the FWU process yielded a net negative (positive storage) of 1.31 × 106 tonnes of CO2 equivalent, representing 79% of purchased CO2. An optimized 18-year forecasted analysis estimated 86% storage of the forecasted 3.21 × 106 tonnes of purchased CO2 with an equivalent 2.90 × 106 tonnes of crude oil produced by 2038. Major contributors to emissions were flaring/venting and energy usage for equipment. Improvements on the energy efficiency of equipment would reduce emissions further but this could be challenging. Improvement of injection capacity and elimination of venting/flaring or fugitive gas are methods more likely to be utilized for reducing net emissions and are the cases used for the optimized scenario in this work. This LCA illustrated the potential for the CO2-EOR operations in the FWU to store more CO2 with minimal emissions.

Probabilistic Assessment and Uncertainty Analysis of CO2 Storage Capacity of the Morrow B Sandstone—Farnsworth Field Unit

“…The PDF equation for a random variable X represented by normal distribution is shown in Equation (1). The mean, median, and mode are generally equal for normal distributions due to their symmetrical nature.…”

“…Energies 2021, 14, x FOR PEER REVIEW 8 of 19 Ampomah et al [26] presented an improved geological model that modeled the field permeability distribution by developing correlations that separated the east and west sides of the field, which appear to have different behaviors. Detailed geological descriptions for FWU have been presented in several publications [1,[25][26][27][28][29][30][31][32]. Ross-Coss et al [33] presented an updated geological model for the SWP project, which significantly improved the site characterization efforts at FWU.…”

“…In recent decades, global warming as a result of the greenhouse gas effect has become the forefront of every discussion worldwide [1][2][3][4], and it signifies how much this unabated issue is of concern to the inhabitants of the world. To address this issue, this study focuses on the ways in which the greenhouse gas effect can be reduced by capturing, utilizing, and storing anthropogenic CO 2 gas in geologic formations.…”

Analysis of Geologic CO2 Migration Pathways in Farnsworth Field, NW Anadarko Basin

“…In Farnsworth Field, northern TX (Figures 1 and 2), CO 2 was injected into an existing porous petroleum reservoir (the Morrow B sandstone, at a depth of about 8000 feet) as part of an enhanced oil recovery operation in which the CO 2 displaces and mobilizes oil. A portion of the CO 2 is extracted; the remainder is stored in the subsurface [4]. To protect future generations from environmental impacts, the storage time of the sequestered CO 2 needs to be of a timescale of 100-1000s of years or longer [2].…”

“…The first oil well was drilled in 1955 and completed in the Morrow B sandstone [15], at a depth of ~7965 feet. Secondary oil recovery began in 1964 by waterflooding, and tertiary recovery is currently underway through CO 2 injection [4]. In Farnsworth Field, leakage through abandoned or aged wellbores is monitored by the Southwest Regional Partnership (SWP) through CO 2 atmosphere monitoring and soil gas measurements.…”