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Title: The use of tracers to assess leakage from the sequestration of CO2 in a depleted oil reservoir, New Mexico, USA

Abstract

Geological sequestration of CO2 in depleted oil reservoirs is a potentially useful strategy for greenhouse gas management and can be combined with enhanced oil recovery. Development of methods to estimate CO2 leakage rates is essential to assure that storage objectives are being met at sequestration facilities. Perfluorocarbon tracers (PFTs) were added as three 12 h slugs at about one week intervals during the injection of 2090 tons of CO2 into the West Pearl Queen (WPQ) depleted oil formation, sequestration pilot study site located in SE New Mexico. The CO2 was injected into the Permian Queen Formation. Leakage was monitored in soil–gas using a matrix of 40 capillary adsorbent tubes (CATs) left in the soil for periods ranging from days to months. The tracers, perfluoro-1,2-dimethylcyclohexane (PDCH), perfluorotrimethylcyclohexane (PTCH) and perfluorodimethylcyclobutane (PDCB), were analyzed using thermal desorption, and gas chromatography with electron capture detection. Monitoring was designed to look for immediate leakage, such as at the injection well bore and at nearby wells, and to develop the technology to estimate overall CO2 leak rates based on the use of PFTs. Tracers were detected in soil–gas at the monitoring sites 50 m from the injection well within days of injection. Tracers continued tomore » escape over the following years. Leakage appears to have emanated from the vicinity of the injection well in a radial pattern to about 100 m and in directional patterns to 300 m. Leakage rates were estimated for the 3 tracers from each of the 4 sets of CATs in place following the start of CO2 injection. Leakage was fairly uniform during this period. As a first approximation, the CO2 leak rate was estimated at about 0.0085% of the total CO2 sequestered per annum.« less

Authors:
; ; ; ;  [1];  [2]
  1. (West Virginia University, Morgantown, WV)
  2. (Parsons Corp., South Park, PA)
Publication Date:
Research Org.:
National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV
Sponsoring Org.:
USDOE - Office of Fossil Energy (FE)
OSTI Identifier:
913405
Report Number(s):
DOE/NETL-IR-2007-131
Journal ID: ISSN 0883-2927; TRN: US200802%%808
DOE Contract Number:
None cited
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Geochemistry; Journal Volume: 22; Journal Issue: 5
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; ADSORBENTS; DESORPTION; DETECTION; ELECTRON CAPTURE; GAS CHROMATOGRAPHY; GREENHOUSE GASES; INJECTION WELLS; MANAGEMENT; MONITORING; SOILS; STORAGE

Citation Formats

Wells, A.W., Diehl, J.R., Bromhal, G.S., Strazisar, B.R., Wilson, T.H., and White, C.M. The use of tracers to assess leakage from the sequestration of CO2 in a depleted oil reservoir, New Mexico, USA. United States: N. p., 2007. Web. doi:10.1016/j.apgeochem.2007.01.002.
Wells, A.W., Diehl, J.R., Bromhal, G.S., Strazisar, B.R., Wilson, T.H., & White, C.M. The use of tracers to assess leakage from the sequestration of CO2 in a depleted oil reservoir, New Mexico, USA. United States. doi:10.1016/j.apgeochem.2007.01.002.
Wells, A.W., Diehl, J.R., Bromhal, G.S., Strazisar, B.R., Wilson, T.H., and White, C.M. Tue . "The use of tracers to assess leakage from the sequestration of CO2 in a depleted oil reservoir, New Mexico, USA". United States. doi:10.1016/j.apgeochem.2007.01.002.
@article{osti_913405,
title = {The use of tracers to assess leakage from the sequestration of CO2 in a depleted oil reservoir, New Mexico, USA},
author = {Wells, A.W. and Diehl, J.R. and Bromhal, G.S. and Strazisar, B.R. and Wilson, T.H. and White, C.M.},
abstractNote = {Geological sequestration of CO2 in depleted oil reservoirs is a potentially useful strategy for greenhouse gas management and can be combined with enhanced oil recovery. Development of methods to estimate CO2 leakage rates is essential to assure that storage objectives are being met at sequestration facilities. Perfluorocarbon tracers (PFTs) were added as three 12 h slugs at about one week intervals during the injection of 2090 tons of CO2 into the West Pearl Queen (WPQ) depleted oil formation, sequestration pilot study site located in SE New Mexico. The CO2 was injected into the Permian Queen Formation. Leakage was monitored in soil–gas using a matrix of 40 capillary adsorbent tubes (CATs) left in the soil for periods ranging from days to months. The tracers, perfluoro-1,2-dimethylcyclohexane (PDCH), perfluorotrimethylcyclohexane (PTCH) and perfluorodimethylcyclobutane (PDCB), were analyzed using thermal desorption, and gas chromatography with electron capture detection. Monitoring was designed to look for immediate leakage, such as at the injection well bore and at nearby wells, and to develop the technology to estimate overall CO2 leak rates based on the use of PFTs. Tracers were detected in soil–gas at the monitoring sites 50 m from the injection well within days of injection. Tracers continued to escape over the following years. Leakage appears to have emanated from the vicinity of the injection well in a radial pattern to about 100 m and in directional patterns to 300 m. Leakage rates were estimated for the 3 tracers from each of the 4 sets of CATs in place following the start of CO2 injection. Leakage was fairly uniform during this period. As a first approximation, the CO2 leak rate was estimated at about 0.0085% of the total CO2 sequestered per annum.},
doi = {10.1016/j.apgeochem.2007.01.002},
journal = {Applied Geochemistry},
number = 5,
volume = 22,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}
  • Reduction of anthropogenic carbon dioxide (CO2) release to the environment is a pressing challenge that should be addressed to avert the potential devastating effects of global warming. Within the United States, the most abundant sources of CO2 emissions are those generate from coal- or gas-fired power plants; one method to control CO2 emissions is to sequester it in deep underground geological formations. From integrated assessment models the overall leakage rates from these storage locations must be less than 0.1% of stored volume per year for long-term control. The ability to detect and characterize nascent leaks, in conjunction with subsequent remediationmore » efforts, will significantly decrease the amount of CO2 released back into the environment. Because potential leakage pathways are not necessarily known a priori, onsite monitoring must be performed; the monitoring region in the vicinity of a CO2 injection well may be as large as 100 km2, which represents the estimated size of a supercritical CO2 bubble that would form under typical injection scenarios. By spiking the injected CO2 with a radiological or stable isotope tracer, it will be possible to detect ground leaks from the sequestered CO2 using fewer sampling stations, with greater accuracy than would be possible using simple CO2 sensors. The relative merits of various sorbent materials, radiological and stable isotope tracers, detection methods and potential interferences will be discussed.« less
  • In recent years depleted oil reservoirs have received special interest as carbon storage reservoirs because of their potential to offset costs through collaboration with enhanced oil recovery projects. Modeling is currently being conducted to evaluate potential risks to groundwater associated with leakage of fluids from depleted oil reservoirs used for storage of CO2. Modeling results reported here focused on understanding how toxic organic compounds found in oil will distribute between the various phases within a storage reservoir after introduction of CO2, understanding the migration potential of these compounds, and assessing potential groundwater impacts should leakage occur. Two model scenarios weremore » conducted to evaluate how organic components in oil will distribute among the phases of interest (oil, CO2, and brine). The first case consisted of 50 wt.% oil and 50 wt.% water; the second case was 90 wt.% CO2 and 10 wt.% oil. Several key organic compounds were selected for special attention in this study based upon their occurrence in oil at significant concentrations, relative toxicity, or because they can serve as surrogate compounds for other more highly toxic compounds for which required input data are not available. The organic contaminants of interest (COI) selected for this study were benzene, toluene, naphthalene, phenanthrene, and anthracene. Partitioning of organic compounds between crude oil and supercritical CO2 was modeled using the Peng-Robinson equation of state over temperature and pressure conditions that represent the entire subsurface system (from those relevant to deep geologic carbon storage environments to near surface conditions). Results indicate that for a typical set of oil reservoir conditions (75°C, and 21,520 kPa) negligible amounts of the COI dissolve into the aqueous phase. When CO2 is introduced into the reservoir such that the final composition of the reservoir is 90 wt.% CO2 and 10 wt.% oil, a significant fraction of the oil dissolves into the vapor phase. As the vapor phase moves up through the stratigraphic column, pressures and temperatures decrease, resulting in significant condensation of oil components. The heaviest organic components condense early in this process (at higher pressures and temperatures), while the lighter components tend to remain in the vapor phase until much lower pressures and temperatures are reached. Based on the model assumptions, the final concentrations of COI to reach an aquifer at 1,520 kPa and 25°C were quite significant for benzene and toluene, whereas the concentrations of polynuclear aromatic hydrocarbons that reach the aquifer were very small. This work demonstrates a methodology that can provide COI source term concentrations in CO2 leaking from a reservoir and entering an overlying aquifer for use in risk assessments.« less
  • To study potential ecological impacts of CO{sub 2} leakage to shallow groundwater and soil/sediments from geologic CO{sub 2} sequestration (GCS) sites, this work investigated the viability and metal reduction of Shewanella oneidensis MR-1 under CO{sub 2} stress. While MR-1 could grow under high-pressure nitrogen gas (500 psi), the mix of 1% CO{sub 2} with N{sub 2 at total pressures of 15 or 150 psi significantly suppressed the growth of MR-1, compared to the N{sub 2} control. When CO{sub 2} partial pressures were over 15 psi, the growth of MR-1 stopped. The reduced bacterial viability was consistent with the pH decreasemore » and cellular membrane damage under high pressure CO{sub 2}. After exposure to 150 psi CO{sub 2} for 5 h, no viable cells survived, the cellular contents were released, and microscopy images confirmed significant cell structure deformation. However, after a relatively short exposure (25 min) to 150 psi CO{sub 2}, MR-1 could fully recover their growth within 24 h after the stress was removed, and the reduction of MnO{sub 2} by MR-1 was observed right after the stress was removed. Furthermore, MR-1 survived better if the cells were aggregated rather than suspended, or if pH buffering minerals, such as calcite, were present. To predict the cell viability under different CO{sub 2} pressures and exposure times, a two-parameter mathematical model was developed.« less
  • Mathematical tools are needed to screen out sites where Joule-Thomson cooling is a prohibitive factor for CO{sub 2} geo-sequestration and to design approaches to mitigate the effect. In this paper, a simple analytical solution is developed by invoking steady-state flow and constant thermophysical properties. The analytical solution allows fast evaluation of spatiotemporal temperature fields, resulting from constant-rate CO{sub 2} injection. The applicability of the analytical solution is demonstrated by comparison with non-isothermal simulation results from the reservoir simulator TOUGH2. Analysis confirms that for an injection rate of 3 kg s{sup -1} (0.1 MT yr{sup -1}) into moderately warm (>40 C)more » and permeable formations (>10{sup -14} m{sup 2} (10 mD)), JTC is unlikely to be a problem for initial reservoir pressures as low as 2 MPa (290 psi).« less
  • Near-surface monitoring and subsurface characterization activities were undertaken in collaboration with the Southwest Regional Carbon Sequestration Partnership on their San Juan Basin coal-bed methane pilot test site near Navajo City, New Mexico. Nearly 18,407 short tons (1.670 × 107 kg) of CO{sub 2} were injected into 3 seams of the Fruitland coal between July 2008 and April 2009. Between September 18 and October 30, 2008, two additions of approximately 20 L each of perfluorocarbon (PFC) tracers were mixed with the CO{sub 2} at the injection wellhead. PFC tracers in soil-gas and in the atmosphere were monitored over a period ofmore » 2 years using a rectangular array of permanent installations. Additional monitors were placed near existing well bores and at other locations of potential leakage identified during the pre-injection site survey. Monitoring was conducted using sorbent containing tubes to collect any released PFC tracer from soil-gas or the atmosphere. Near-surface monitoring activities also included CO{sub 2} surface flux and carbon isotopes, soil-gas hydrocarbon levels, and electrical conductivity in the soil. The value of the PFC tracers was demonstrated when a significant leakage event was detected near an offset production well. Subsurface characterization activities, including 3D seismic interpretation and attribute analysis, were conducted to evaluate reservoir integrity and the potential that leakage of injected CO{sub 2} might occur. Leakage from the injection reservoir was not detected. PFC tracers made breakthroughs at 2 of 3 offset wells which were not otherwise directly observable in produced gases containing 20–30% CO{sub 2}. These results have aided reservoir geophysical and simulation investigations to track the underground movement of CO{sub 2}. 3D seismic analysis provided a possible interpretation for the order of appearance of tracers at production wells.« less