the idea with VAPEX is to create a gas
chamber, using gravity to achieve
production.
“As you inject across that interface, you’re “We see a huge resource here in Western
putting in a chamber that is created and Canada. A lot of that resource is being
then depleted. It’s along the length of the produced with very small recovery
horizontal well that you are creating that factors.”
At the Winter pilot, Nexen is using a face,” Thomas says. “You’re always
three-well pattern to test the efficiency of recharging the solvent.”
He says that when companies are looking
at recovery rates as low as 10 per cent,
the potential to increase that to even 20
per cent is significant.
VAPEX. There are two horizontal injection
wells near the top of the reservoir and At the Plover pilot, the approach is
one horizontal production well offset somewhat different as there is no
between the injectors near the bottom of underlying water leg. There is, however,
the reservoir. The injector wells are part of the challenge of managing a series of “All that you have to do is increase
the original infrastructure used for wormholes in the reservoir caused during recovery rates by 10 per cent and you
primary depletion, while the producer primary production, when a significant have a huge resource.”
was added for the pilot development. The amount of sand was produced along with
ability to use downhole and surface the oil. Thomas says these wormholes EnCana Corporation is also pursuing the
equipment that was already there adds could actually help the VAPEX process. potential promise of VAPEX with a pilot at
to the appeal of the technology, Thomas The idea is still to create a gas chamber, the company’s Foster Creek site in the
explains. but the well configuration is different Cold Lake oil sands. Foster Creek was the
than at Winter. first commercial-scale SAGD project in
the world, and now EnCana hopes to
successfully prove the value of VAPEX.
The technology may be in the very early
stages of development, but it is an
example of the continuing commitment
of heavy oil and oil sands producers, as
well as government agencies.
“That’s the beauty of VAPEX. It has
minimal impact on your existing “We’re trying to establish a chamber
infrastructure. Really it’s a fairly using a combination of vertical and
low-capital-cost [technology] with a high horizontal wells,” Thomas explains.
potential reward.”
Nexen plans to develop both of these
At Winter, where there is an underlying pilots into commercial demonstration
water leg, the process begins with projects in the near future. Thomas says
injecting solvent and displacement gas the company has latched on to the VAPEX “If you don’t make steps along the way,
into all three wells to link them and technology because it has the potential you will never get there,” Nexen’s Thomas
create the chamber. The bottom well then to unlock a substantial amount of heavy explains. “We continue to be encouraged
becomes the producer. oil that is not currently being produced. [by VAPEX].” ■
