Links between hydraulic fracturing (fracking) and earthquakes, and predicting and preventing the tremors, remain riddles requiring far more scientific study, according to a report commissioned by the British Columbia (BC) government.
Only 0.3% of fracking and 1% of waste disposal by western Canadian wells since 1985 shook the ground — and explanations for the cases remain elusive, said the report, “Scientific Review of Hydraulic Fracturing in British Columbia.”
“AIS [anomalous induced seismicity] is observed in clusters and not scattered across a region with active fluid-injection operations,” according to an inquiry panel of three experts from technical specialties involved in natural gas, liquid byproducts and oil extraction.
“Differentiating why certain areas are more susceptible to AIS, understanding the variability within susceptible areas and accurately forecasting whether a fluid-injection operation is susceptible to AIS are key challenges.”
Improved measurements of subterranean rock, water and forces are needed to close fracking knowledge gaps.
“Forecasting whether a specific operation will induce anomalous seismicity requires physics-based modeling with accurate hydro-geomechanical parameters.”
Detection of earth tremors with suspected industry causes has multiplied since 2013, when BC quadrupled to eight the number of its seismic activity observation stations in northern shale drilling regions. Sensitive instruments register even tiny tremors.
BC has linked 129 subterranean tremors to drilling in its richest shale target, the Montney formation. Of four tremors that were strong enough to be felt on the ground surface as earthquakes, two are attributed to fracking injections, one to fluid disposal and one to both types of industry operations.
A single Montney well was associated with two earthquakes last fall and prompted the BC Oil & Gas Commission (BCOGC) to suspend all fracking in the region for a one-month review and improvement of drilling plans.
The inquiry recommends strengthening BCOGC earthquake prevention by requiring assessments of naturally vulnerable underground rock faults for all fracking wells and following an Alberta example of mapping sensitive spots in geological formations.
The fracking report’s account of earthquake knowledge gaps is part of a 236-page recital of technical uncertainties that also covers pollution emissions, health, and water quantity, quality and use issues.
“The very rapid development of shale gas in northeastern B.C. has made it difficult to assure that risks are being adequately managed at every step. Furthermore, the panel could not quantify risk because there are too few data to assess risk.”
But the report adds, “Nevertheless, it is the view of the panel that the current regulations under many acts appear to be robust.”
No fracking ban is recommended. No plans to halt drilling have emerged in the B.C. government, which has granted supportive tax breaks to a CDN$40-billion (US$30-billion) liquefied natural gas export terminal, pipeline and shale supply development now under construction.
An energy ministry statement says a “phased approach” will be adopted to respond to 97 technical recommendations by the fracking report. The ministry says, “Over the last 18 months, government has implemented a number of changes to strengthen the regulatory framework for the oil and gas industry. Much of this work addresses concerns raised by the scientific panel.”
As a textbook on fracking methods, knowledge gaps and uncertainties, the inquiry report became instant ammunition for a environmental protest caravan seeking a B.C. counterpart to bans enacted by Quebec, Nova Scotia and New Brunswick.
Free public forums reciting fracking risks are being held in B.C. centers including the provincial capital, Victoria, by the Canadian Centre for Policy Alternatives, David Suzuki Foundation, Force of Nature, My Sea to Sky, Sierra Club B.C., Quest University and Watershed Sentinel. Star speakers include Canadian Green Party leader Elizabeth May.
© 2020 Natural Gas Intelligence. All rights reserved.
ISSN © 2577-9877 | ISSN © 2158-8023 |