Unversity of Calgary researchers believe vents under the seafloor may allow gas to escape through thick shale
BY ANTHONY STADNYK
The development of science is often characterized by changes in what is perceived as obscure and what is perceived as mainstream.
In the science of chemistry, for example, it was once widely believed that combustion was caused by the liberating of a mysterious, undetectable material called phlogiston. Indeed phlogiston theory worked very well for early chemists — not only could the theory explain the process of combustion, but it also explained the development of rust and the workings of biologic metabolism.
The development of chemistry went through leaps and bounds after Mikhail Lomonosov’s obscure research into the weights of metals before and after combustion became mainstream.
And despite its youth, the science of geology has also seen a number of these paradigm shifts. Consider the theory of continental drift, for example. Or radiometric age dating.
In Febuary of this year, a paper published by four local scientists recently brought forth another one of these big paradigm shifts within the geologic community.
By studying 70 million year old tubeworm traces in the Pierre Shale of Colorado, Dr. Federico Krause, P.Geol., of the University of Calgary and his colleagues ended up shedding new light on methane hydrate venting — one of the most poorly understood processes in the ocean. The research was co-authored by Dr. Selim Sayegh, P.Eng., Dr. Renee Perez and Jesse Clark.
A DIFFERENT SORT OF TUBEWORM
Beyond impacting the academic community, their research may also prove to have a material impact on the energy industry as it moves into the next generations of technologies involving CO2 sequestration and CH4 hydrate extraction.
Using an electron microprobe at the university’s Laboratory for Microbeam Analysis, Dr. Krause and his colleagues were able to uncover the mineralogical and chemical composition of the layers within the Pierre Shale’s tubeworm-like conduits. This rather sophisticated technique allowed them to see the traces in a detail far beyond what can be seen by simple visual observation.
“What our research shows,” says Dr. Krause ,“is that it turns out that these tubes were not actually tubeworms. Basically they are fossilized conduits through which bubbles escaped — and everything about them suggests an origin related to the venting of methane beneath the seafloor.
“The microstructures and diameters of the conduits are indicative of bubble sizes that we would expect under these conditions — and our isotope ratios are indicative of flowing CH4 gas. Of course, cavities don’t just hold themselves open. In this case they were propped open by moving fluids and stabilized by calcium carbonate and silt-sized clastic particles.”
OK. But is it a big deal?
Yes, says Dr. Krause. The observations made by him and his colleagues add up to the first-ever discovery of an ancient, natural geologic conduit system where gas, water and solids were vented simultaneously.
“What it implies is that we now have geologic evidence that gas present under the seafloor can escape through a thick layer of shale,” says Dr. Krause. “So people planning to sequester CO2 need to study the seals of the geologic intervals that are being considered for sequestration to identify structural features that developed at the time that the rocks accumulated.
“For example, they can acquire 3D seismic data and make sure that they understand the potential failure planes that have existed from the time of deposition. Under certain circumstances it may be possible to imagine scenarios where fluids injected into the sequestration beds could seep out, as happened in the Pierre Shale 70 million years ago.”
He continues: “What it also implies is that we need a lot of further research before we go forward with establishing gas hydrate production and containment facilities on the seafloor. If hydrates were to be inadvertently destabilized and released, methane bubbles would also bring up large quantities of microparticles into the ocean and cloud it with silt and clay. The added turbidity could lead to the suffocation of surrounding sealife.”
Gas hydrates are a crystalline form of water that contains a molecule of gas (usually methane or carbon dioxide) within its crystal structures. In modern oceans, gas hydrates are found buried under seafloor sediments.
Recent estimates by Alexei Milkov of BP America suggest that there may be between 15×1015 m3 and 5×1015 m3 of methane trapped in gas hydrates. This is between two and 10 times the currently known world reserves of natural gas. Estimates by the United States Geological Survey state that gas hydrates may contain twice the amount of carbon held in all fossil fuels on Earth.
A big deal indeed.
Inaugural Energy Summit Earns Support
University of Calgary students organizing their first-ever international student energy conference in Calgary have received $240,000 from the Alberta Government and global energy company Nexen Inc.
The International Student Energy Summit aims to attract about 500 post-secondary students from around the world to Calgary this June 11 to 13, for an interactive forum on sustainable resource management and the future of energy.
Alberta Energy has contributed $125,000 towards ISES, and Alberta’s Energy Resources Conservation Board has provided $65,000.
“Energy has underwritten the story of our province and it will continue to do so in the future. That’s what makes Alberta the perfect place to host this summit,” says Energy Minister Mel Knight. “The Government of Alberta is proud to support this initiative, which will bring together the next generation of energy experts around their common goal of securing a sustainable energy future.”
“This summit is important because our energy future will soon be in the hands of our students,” says ERCB Chairman Dan McFadyen, P.Eng.
ISES will feature internationally recognized energy experts speaking on three main themes: finance, regulation and sustainability; global energy cooperation; and technology and innovation. Student leaders will dialogue with the experts and submit outcomes from the forum in a report to government and industry leaders, to help advance sustainable energy development.
Calgary-based Nexen has committed $50,000 to the summit.
“Attracting and retaining young people is one of the key challenges facing the petroleum industry. ISES represents an excellent opportunity for enhanced dialogue with the youth of today,” says Randy Gossen, vice-president of global business relations at Nexen and the current president of the World Petroleum Council, which has also endorsed ISES.
“The ISES team is thrilled to have the support of the Alberta Government and Nexen, in helping us to deliver this exciting event,” says U of C student Kali Taylor, the event’s chair. “We are seeking additional sponsorship and support from the energy industry. We want to ensure we can bring a large number of international students to Calgary by offering them scholarships to attend the conference.”
The U of C’s Institute for Sustainable Energy, Environment and Economy is administering the summit and providing staff support to the student organizing committee.