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BP-led research project investigates gas hydrate production for North Slope DOE funding supports analysis and commercial assessment of ANS hydrates; resources estimated to be 590 trillion cubic feet of methane Patricia Jones PNA Contributing Writer
Researchers are gearing up for the first of a possible three-phase project that will characterize, quantify and assess the feasibility of commercial production from gas hydrates found beneath existing North Slope infrastructure.
BP Exploration (Alaska) Inc. is leading the collaborative research project, which the U.S. Department of Energy is partially funding with a $13.2 million grant. Industry and academic partners will kick in a remaining amount, primarily in-kind data information and personnel time, up to a total project cost of $18 million.
“We will assess the long term commercial viability of the gas hydrate unconventional resource,” said Robert Hunter, BP Exploration’s gas hydrate project manager. “Industry will provide the data and potentially the infrastructure … our project is designed to solve the technological challenges and assess the economic issues.”
Hunter detailed the collaborative research project, which involves University of Alaska Fairbanks and University of Arizona researchers and the U.S. Geological Survey, during an energy workshop held at the UAF in early April.
“This is the right time and the right place for government and industry to support a project of this type,” he said. “This is the first time in 30 years of Alaskan North Slope production that we see an alignment of diverse interests of government, industry and academia to accomplish the collaboration that gas hydrate research needed for this project.”
Such an alignment came about for a variety of reasons. First, known gas hydrate resources lie beneath existing gas production infrastructure, Hunter said. That aids in access for the initial research effort, and, should the project show gas hydrates to be an economically viable energy source, provide an extraction and transportation system.
Secondly, development of conventional gas supplies has become a higher priority among Alaska’s North Slope oil producers, possibly opening the door for gas transportation off Arctic coast to markets in the Lower 48.
“This is not something that industry would undertake on its own. It is an unconventional resource,” Hunter said. “We cannot at this time bring conventional gas resources economically to the marketplace.” Size of resource motivates researchers Industry and government alike are extremely interested in gas hydrate resources because of the potential size of the resource.
It’s an energy source that, if technology offers an economical way to tap the frozen methane, could provide up to 200,000 trillion cubic feet of methane in the United States alone, according to the U.S. Geological Survey.
In Alaska, the size is also staggering. USGS research conducted in the 1980s and 1990s on the North Slope put a resource number on the region’s gas hydrates at 590 trillion cubic feet, Hunter said.
“The prize, once again, is very large,” he said. “The Eileen trend alone contains nearly twice the in-place gas resources of the conventional Prudhoe Bay gas cap.”
First tapped in 1972 by oil exploration teams, the Eileen gas hydrate zone is a shallow layer of the vast methane energy source. Small amounts of methane gas are contained or trapped by an ice cage, a structure called clathrate.
Naturally occurring clathrates are attractive as a non-conventional gas resource because of their “very large gas storage capacity,” Hunter said.
The Eileen trend is believed to be from 2,000 to 4,000 feet below the surface, just under the permafrost layer.
“There is an undetermined amount of free gas associated with it,” Hunter said. “That is important as it may help define what role the depressurization would take in bringing the gas hydrates to an economic resource.”
Currently, researchers believe the Eileen trend, which stretches between parts of Prudhoe Bay, Kuparuk and Milne Point, contains 44 trillion cubic feet of gas hydrates, Hunter said.
A possibly even larger gas hydrate zone is called the Tarn trend, believed to contain up to 60 trillion cubic feet of the frozen methane gas. The Tarn zone, located southwest of Kuparuk, has no known associated free gas, Hunter said, and it lies within and below the permafrost layer, from 500 feet down to 2,400 feet.
“The Tarn trend is more problematic — a lot of the gas hydrates actually occur within the permafrost,” he said.
Research planned in phases, starts later this year DOE funding for the Alaska gas hydrate project led by BP was awarded in September 2001. The project’s scope involves three phases that could stretch out over a four-year period. Each phase includes a conclusive evaluation that requires participants to decide whether to advance to the next stage of the project, Hunter said.
The first phase is essentially “a desktop exercise,” he told PNA following his presentation at UAF. Researchers will verify existing resources, which includes characterizing the reservoir and fluids and potential compartmentalization.
“We will also study drilling completion and production methodology during this time to prepare for field operations,” Hunter said.
The second phase involves fieldwork, as the group will select the best areas for data acquisitions and short-term testing of the gas hydrate accumulation. Crews will drill and possibly complete a production test gas hydrate well.
“If results from phase two are successful, we will continue our studies, probably a long-term production testing operation,” Hunter said. “Innovation will be necessary to develop this potential gas resource ... the primary unknown variable out here is recovery — how do we unlock the gas hydrate from clathrate structure?”
Drilling techniques to access gas hydrates include multi-lateral wells and other types of completions used in viscous oil recovery, he added.
“Gas hydrates have the resource potential to close the gap created by the decline of fossil fuels by the year 2020. This is a very real possibility,” he said. “In certain areas, particularly in Alaska’s North Slope, given sufficient economic motivation — and that’s the key — we could see gas hydrate production in five years, so that could help us accelerate the 2020 timeframe.
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