As Canadian producers line up to export liquefied natural gas (LNG), an effort has formed to answer safety questions about hydraulic fracturing (fracking), which is built into industry plans to make British Columbia (BC) shale deposits the prime supply source for LNG exports.
In a first look into one of the environmental fears aroused by the technology — earthquakes — the BC Oil and Gas Commission (BCOGC) has collected evidence that the side-effect exists, but not on a harmful scale.
Sensitive instruments have detected 272 subterranean shocks associated with more than 8,000 uses of high-pressure fluid fracking on northern BC’s deeply buried shale gas to date, about one occurrence for every 29 wells. But only one of the subterranean movements was strong enough to be felt above ground, BCOGC said in a report titled “Investigation of Observed Seismicity in the Horn River Basin.”
The lone notable vibration fell well short of an earth-shattering scare, said an account of the moment on May 19, 2011, which was logged by scientists in Canada’s Department of Natural Resources (NRCan) and unearthed by the BCOGC inquiry.
“Only one event studied within this investigation was reported felt at surface,” the BC commission said. “NRCan’s report indicates that the event was ‘felt by workers in the bush.’ No injuries or damage to surface structures were reported for this or any of the events studied within this investigation.”
In more than half a century of oil and gas activity, BC has only one fully documented case of earthquakes induced by industry operations. A series of shocks were recorded over a 10-year period.
But the events happened in 1984-94, or about 15 years before fracking reached BC. The site was a conventional oil field near the regional industry capital of Fort St. John, about 400 kilometers (240 miles) south of the Horn River Shale drilling area near BC’s northern border with the Yukon and Northwest Territories.
“High-pressure fluid injection for secondary oil recovery was identified as a possible cause.” Like UK and U.S. inquiries into industry-induced earthquakes, the BC examination points to changes in pressure and liquids along natural geological fault lines as the most likely driver of the seismic events.
In response to the shaking at Fort St. John, BC authorities ordered a reduction of the pressure used by the oil field operation. “Since that time, reservoir waterflood and injection pressures within British Columbia are required to be maintained below levels capable of re-opening pre-existing fractures or faults,” said BCOGC.
The Canadian Association of Petroleum Producers (CAPP) supported the inquiry and encouraged all concerned to press ahead with the scientific work. Further investigations are planned, including increased use of the most sensitive seismic instruments available for portable arrays of detectors capable of reaching mobile fracking operations in the remote BC shale gas region.
The industry and BCOGC took their cue from the National Energy Board (NEB).
In a 2010 decision to grant the first in an unfolding series of 20-year LNG export licenses, the NEB made it plain that federal authorities expect provincial regulation and industry practice to establish environmentally acceptable shale supply development practices. The Conservative government in Ottawa this year sent the same message with a regulatory reform package that abolished environmental reviews for export license applications and created an option for assessments of supply development schemes to be delegated to provincial agencies when their rules are up to national standards.
The favorable export ruling said, “The board is satisfied that there is a comprehensive regulatory and environmental assessment scheme that will consider environmental and socio-economic effects related to the development of the Horn River Basin.”
The first three long LNG export schemes that have gone before the NEB to date call for total overseas tanker shipments of 45 Tcf of liquefied gas. The volume equals 65% of the combined currently established gas reserves of BC and Alberta. Industry plans call for much of the gas for the LNG to be developed by tapping BC’s Horn River and smaller northern shale deposits at an accelerating rate with increasingly intense use of fracking. The northern BC industry is forecast to expand steadily as trade grows with gas distributors and users in China, Japan and South Korea that have bought investment shares in production programs as well as terminal and pipeline projects.
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