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March/April 2006 issue	In this issue Table of Contents Feature: Titanic ice In-depth: On ice Feature: Dance of the dunlins Feature: Off the rails Feature: Being caribou The Inside Story Editor’s Notebook Reverberations Explorer À la carte Mosaic

Every last drop
With petroleum prices soaring, oil producers are taking a virtual look underground to squeeze the most out of their reserves
By Jodi Di Menna and Steven Fick

RESERVOIR FOG Steam laced with a hexane solvent is wafted into a well (vertical orange line) that has been tapped into a rock formation holding a reservoir of deeply buried oil sands. The vapour (in yellow, red and blue) seeps into the formation, rising where the rock is permeable and forming horizontal streaks under impenetrable sheets of shale. This sequence of 3-D images reveals the steam penetrating more thoroughly into the reservoir over a 10-year period, dissolving the thick oil and allowing it to flow and be pumped to the surface. The images were created by combining seismic crosssections with data including the porosity of the rock and the density and viscosity of the oil.

Click images to enlarge

Year one

Year two

Year six

Year ten

For every barrel of conventional oil that is pumped from the ground in Alberta using standard techniques, as many as three barrels remain economically unavailable. With oil prices hovering around $65 (U.S.)/barrel, producers now have the incentive and the cash flow to chase even those hard-to-reach leftovers — as much as eight billion barrels in Western Canada.

Powerful imaging software is increasingly used to test creative retrieval methods, which include lighting fires in underground reservoirs or injecting solvent-laden steam to coax the thick bitumen to flow.

The industry is abuzz with the prospects of what is called enhanced recovery, but renewed activity around old wells also means more environmental impact.

"Areas that perhaps were beginning to be reclaimed back into wilderness will again be subject to that disturbance," says Dan Woynillowicz of the Pembina Institute, an environmental-policy organization based in Drayton Valley, Alta. One particular concern are steam-injection methods, which drain aquifers, lakes and streams of considerable amounts of water, endangering fish populations and wetlands.

It’s a win-win situation for oil firms. "Companies are saying, ‘We’ve already got a number of wells in the ground, and here’s an opportunity for us to go back and get more oil out of what’s already been drilled,’" says Greg Stringham, vice-president of the Canadian Association of Petroleum Producers. "Enhanced recovery is becoming a prime factor in the continuation and maturation of the oil reservoirs in Western Canada."

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