NIKIFORUK: Next Oilsands Threat: Caprock Integrity

NIKIFORUK: Next Oilsands Threat: Caprock Integrity

Postby Oscar » Mon Oct 07, 2013 10:18 am

Next Oil Sands Threat: Caprock Integrity

[ ... ds-Threat/ ]

Risks of steam-assisted bitumen recovery are too little discussed, experts say.

By Andrew Nikiforuk, Today,

October 7, 2013

A recent blow-out at Canadian Natural Resources Ltd.'s Primrose facility in northern Alberta sheds light on a serious but little discussed topic in the oil sands industry: caprock integrity.

The blow-out allowed more than 10,000 barrels of steamed bitumen to seep into the boreal forest through ground fissures as long as 159 metres, putting groundwater at risk.

While highly technical, the issue is a critical one, with high stakes for investors and the province alike.

Approximately 80 per cent of Alberta's bitumen deposits lie deeper than 75 metres and cannot be mined. As a consequence, these deep deposits, all capped by rock, are currently being heated to as high as 300 degrees Celsius with highly pressurized steam.

Industry uses either a steaming tool called steam-assisted gravity drainage or cyclic steam stimulation to melt a resource as hard as a hockey puck.

The overlaying caprock acts as a primary but not always impermeable seal that keeps steamed bitumen from seeping into aquifers, neighbouring industry wellbores and other geological formations, as well as the forest floor and lakes.

In general, industry tries to keep the pressure significantly low enough to ensure the caprock does not break -- but high enough to push the melted bitumen out.

It is a very fine line. In 2006, French multinational company Total blew a 300-metre crater in the forest while trying to steam up a shallow formation of bitumen.

Although regulatory reports on the event weren't published until four years later, the "catastrophic event" put caprock integrity on the agenda and forced Total to abandon its project.

Ever since then, all steam-based bitumen operations, the industry's most energy-intensive facilities, report yearly on caprock integrity. The Society of Petroleum Engineers devoted a sold-out workshop on the subject last spring in Banff.

Given that there are more than 100 steam plant facilities poking thousands of holes into irregular layers of bitumen, there is "a need to improve the collective capabilities of operators, service providers and regulatory bodies in the area of caprock integrity management," noted the event's organizers.

This heightened interest explains why Environment Canada is now investigating Canadian Natural Resources Ltd.'s blow-out, which involved four different well locations.

Regulator denies public review

The event, not the first of its kind as a Tyee investigation reveals,
[ ... n-Alberta/ ] killed wildlife, polluted a small lake and seeped nearly 20 barrels of bitumen a day into muskeg over the last five months.

The company suggests that the cause of the bitumen seepage may be due to "mechanical failures of wellbores in the vicinity of the controlled areas." But others say it's possible the company broke the caprock or connected with existing fractures in the rock.

The blow-out also explains why 23 different groups asked for a public review of safety regulations for steam plant operations last August.
[ ... n-blowouts ]

The Alberta Energy Regulator denied the request, saying that "[cyclic steam stimulation] and high pressure cyclic steam stimulation have been successfully used as bitumen recovery techniques in Alberta for many years" and that a public inquiry would "not provide any new information that may be able to support or guide regulatory change."
[ ... our-months ] Steam-assisted gravity drainage has a 13-year commercial history in Alberta.

Yet the same regulator created a special Oilsands Caprock Integrity Project (OCRIP) five years ago.
[ ] OCRIP's website specifically warns that "uncontrolled releases of steam, oil or formation water caused by in situ oil production (e.g. cyclic steam stimulation and steam-assisted gravity drainage) create concerns for resource and environmental conservation."

OCRIP has yet to publicly release a promised analysis of "human-induced geological hazards" in the region, as well as an incident review database of steam operations that have broken the caprock.

Echos of fracking

Recent studies by petroleum scientists as well as annual industry progress reports to the Alberta Energy Regulator show that the technologies used to steam deep bitumen deposits have created the same sort of problems now plaguing the hydraulic fracturing of unconventional oil and gas resources across North America.

Both technologies inject highly-pressurized fluids into formations where the resulting pressure can crack or fracture overlying rock and well casings in unpredictable ways. These fractures can bring fluids or gases to the surface, contaminate groundwater or connect with other existing wells.

The end result for both technologies are the same: hydrocarbons go where regulators don't want them or industry can't control them.


[ ... ds-Threat/ ]
Site Admin
Posts: 9176
Joined: Wed May 03, 2006 3:23 pm

Return to Next Tarsands Threat: Caprock Integrity

Who is online

Users browsing this forum: No registered users and 1 guest