Carbon sequestration – or long-term storage, of anthropogenic carbon dioxide in subsurface geologic formations – has long been on the radar screen of scientists, politicians and others as a potentially viable means to reduce greenhouse gas emissions into the atmosphere.
In the United States, consideration of this type storage ordinarily is associated with onshore regions.
The first study in the United States to investigate the potential for permanent underground storage of CO2 in offshore geologic formations has been launched by the University of Texas at Austin via its Bureau of Economic Geology (BEG).
The three-year project is being funded by $6 million in grants from the U.S. Department of Energy (DOE) via the National Energy Technology Laboratory and the Texas General Land Office. It’s designated to identify state-owned areas underlying the Gulf where CO2 can be stored safely and economically.
Dubbed Gulf of Mexico Miocene CO2 Site Characterization Mega Transect, the effort is focused specifically on the geologic potential of Miocene age rocks of Texas State Submerged Lands to store CO2 for geologically significant periods of time.
The effort is designed to help meet the DOE goal of characterizing geologically representative formations that may be used to economically store anthropogenic CO2 emissions.
Program principal investigators are AAPG members Timothy “Tip” Meckel and Ramon Treviño, research associates at the BEG.
“This is a dramatic shift in thinking about carbon storage in the United States,” Meckel said. “Until the funding of this proposal, most people thought of carbon storage as an onshore exercise.
“Owing to decades of oil and gas exploration, the Texas state lands of the northern Gulf of Mexico make up one of the most geologically studied areas in the world,” Meckel said. “That makes us very comfortable with the idea of starting new activities in this area.
“Preliminary estimates of carbon storage capacity suggest many billions of metric tons of carbon dioxide could be stored in offshore geologic formations in Texas,” he said, “making offshore storage an extremely promising resource for mitigating greenhouse gas emissions for Texas as well as other parts of the U.S. with more limited storage potential.”
Treviño noted an array of advantages that Texas brings to the table for this type project:
♦ State lands ownership extends 12 nautical miles offshore, compared to three miles for all other states except Florida.
♦ Available sources of carbon dioxide from industry and power generation.
♦ Existing infrastructure from the decades-old oil and gas activity.
♦ Reduced environmental risks to underground sources of drinking water compared to sequestration beneath land onshore.
Scott Tinker, director of the BEG and a past AAPG president, originally proposed the idea to the Texas House of Representatives Carbon Dioxide Caucus in 2008.
“Because Texas produces copious quantities of energy and industrial products for the U.S., which in turn results in large output of carbon dioxide, Texas has a strong interest in developing effective CO2 management options,” Tinker emphasized.
Meckel summarized the objectives of the project:
♦ Assess and analyze the existing data from historical hydrocarbon industry activities in a regional transect of the Texas Gulf Coast.
♦ Verify the ability of the Miocene age rocks of the region to safely and permanently store large amounts of anthropogenic CO2 .
♦ Identify at least one specific site that can accept at least 30 million tons of CO2 from future commercial carbon capture and storage operations.
Among the many efforts planned to help meet the objectives, the study participants will investigate reservoir and seal quality of the target units and generate datasets of geologic information needed to assess geologic storage viability.
Additionally the study will evaluate the possible risks involved with geologic carbon storage. To help with the objective of defining risks, the Environmental Defense Fund, Los Alamos National Laboratory and Sandia Technologies are partners in the project.
Various methodologies will be utilized by the project team to achieve the project objectives. These include geophysical interpretation of seismic data (commercially available and perhaps acquired specifically for the study).
In fact, ION contributed its GulfSPAN seismic data library to the investigation, according to Bob Peebler, CEO at ION. Additionally, a 3-D seismic survey was provided by Formosa Plastics and its subsidiary, Neumin Production Co.
“The results of this study should provide the next step in making geo-storage of CO2 a commercial reality,” Meckel said, “and may provide the impetus for the future creation of a geo-repository State of Texas Submerged Lands.”
Contributing to the enthusiasm is the fact that sub-seafloor CO2 storage has the potential to generate significant capital for public education in Texas.
The Texas General Land Office has a longstanding requirement to direct revenues generated from resource utilization on state lands into the Texas Permanent School Fund, Meckel said.
Texas Land Commissioner Jerry Patterson has said oil and gas exploration in the Gulf alone has brought more than $6 billion to the fund. He emphasized that oil and gas are finite resources, noting that CO2 storage may replace some of the revenue lost as those resources deplete.
“It’s a new way to think about sequestration in terms of managing long-term liability while distributing benefits,” Meckel noted.