At many oil installations around The key to current CHOPS operations is the
Lloydminster and Cold Lake, Alberta, instead progressing cavity pump (PCP). With the
of hearing the slow up-and-down creak of capability to manage material comprised of
conventional pumpjacks, one hears the soft more than 50 per cent sand, it is no wonder
whir of progressing cavity pumps bringing the PCP has made its mark on the Canadian
to the surface a coveted mixture of heavy market. The roots of the PCP go all the way
oil and sand. back to the 1920s, when a French aerospace
engineer named Rene Moineau envisioned
Managing sand effectively is key to the a screw compressor designed to increase
success of Alberta’s heavy oil producers and engine power. As the story goes, in the
has been for decades. In some reservoirs, 1970s and 1980s, the oil and gas industry
producing sand is the last thing operators took the concept and, by increasing its
want, but in others, sand is what makes length, was able to deploy it deep into a In 2004, according
production economic. In 2004, according to wellbore, stimulating production.
the Alberta Energy and Utilities Board, to the Alberta
about 210,000 barrels of heavy oil were “That’s when it became a viable product for
produced in Canada using this method, Canadian heavy oil,” says Mike Findley, Energy and Utilities
called Cold Heavy Oil Production with Sand manager of Canadian PCP systems with
(CHOPS). That represents about 22 per cent Baker Hughes Centrilift. of the country’s daily production, and Board, about
technology continues to evolve to make the Basically, the PCP can provide a solution process ever more efficient and productive. anywhere oil and gas producers are dealing 210,000 barrels of
with abrasive and/or viscous fluids. Different “[CHOPS] involves the encouragement and PCP suppliers have different takes on the heavy oil were
sustaining of sand influx because of the technology, but the central concept is the dramatic improvement in production rates same. Basically, what it looks like is a produced in Canada
that it brings,” says Dr. Maurice Dusseault, carefully and consistently twisted steel pipe renowned heavy oil specialist and professor inside a cylinder, attached to a motor. using this method,
of geological engineering at the University Material enters through the bottom, and Waterloo in Ontario. “If sand is kept out of when the cylinder is filled, the bottom called Cold Heavy
these wells by using a filter screen, the closes. The material then travels up the production would be two to 20 barrels per twisted steel as it turns and moves to the Oil Production with
day. However, if sand influx is unimpeded in surface.
any way, the production rates are 20 to 300 Sand (CHOPS). That
barrels per day as a result.” The Lloydminster Oilfield Technical Society
(OTS) has a more technical description of represents about 22
The idea is to create what are often called the device. The group says it is a stator
“wormholes,” or channels, within the secured inside a pump barrel, which per cent of the
reservoir. The wormholes provide a conduit attaches to tubing to enter the producing
for the heavy oil to flow into the reservoir. A helical rotor is turned within the production well. stator, and at the suction end, an open country’s daily
cavity fills with product. As the rotor turns, this cavity is sealed off, and the full cavity production, and
then progresses along the axis of the pump to the discharge end. technology
“It looks sort of like an ant colony,” says
John Festival, president of heavy oil
producer BlackRock Ventures. “You form
little sand wormholes out from the
wellbore.”
“As the pump moves, cavities are continually continues to evolve
made and transferred, producing a relatively CHOPS is certainly not new to the Canadian constant flow,” the OTS explains. “The rpm of to make the process
industry, but the technique has gained the rotor can be adjusted to suit the flow interest since the early 1990s thanks to nature of the well.” ever more efficient
improved pumping equipment that can handle sand production, says Canadian The OTS says heavy oil in the Lloydminster and productive
Natural Resources Limited. CNRL is the area is ideally suited to PCP use because
biggest heavy oil producer in Canada and wells are shallow and at lower
uses CHOPS at all its producing fields in the temperatures. There are a number of factors
Lloydminster/Bonnyville area. that make a reservoir suitable for CHOPS,
explains Dusseault, including conditions like
depth and the presence of water and gas.
“Fifteen years ago, sand cuts of roughly 10
per cent could be handled by pumping
equipment of the day,” the company says.
“Today, wells typically produce at 30 to 50
per cent sand cut for the first number of
months before decreasing to values less
than 10 per cent.”
The reservoir must be unconsolidated sand
where the grains are not cemented
together by mineral matter, most likely
high-porosity sandstone. Gas must be
present in the oil, meaning it must be a
“virgin” reservoir that has not been depleted
