American Oil and Gas Reporter - June 2014 - 111

SpecialReport: Artificial Lift Technology
space for surface equipment, and no electricity source in the vicinity.
Other typical well conditions include
formation depths between 4,000 and 8,000
feet measured depth, water cuts of less
than 5 percent, fluid rates up to 700
barrels a day, 24 API degree gravity, low
sand production (less than 0.1 percent),
and low viscosity.
The field was equipped initially with
progressing cavity pumping systems, but
the high GOR created challenges for the
elastomers in the pump, such as swelling
and high torque variation during operation.
Subsequently, the pumps would have run
lives of less than 30 days prior to elastomer
failure, causing a lengthy waiting period
for workover rigs and an unfavorable
amount of downtime.
The operator looked at electrical submersible pumping systems as an alternative
to PCPs. While the ESPs satisfied the
surface-space limitations and worked
well, their initial high investment costs
and energy requirements to overcome efficiency limitations made their widespread
expansion across the field impractical.

Rod Lift Solution
A field analysis indicated a reciprocating rod lift system was the best alternative solution, based on the space limitations and experiences with previous artificial lift systems. The entire RRL system
consisted of a variable-speed hydraulic
unit and gas-pusher pump as the main
components, thanks to their ability to
adapt to continuously changing well conditions and to work effectively in a high
GOR environment without serious detriment to system efficiency.
The system also included rod pump
controllers-which provided continuous
monitoring of well conditions-and continuous rods to reduce the wear associated
with well deviation. Rounding out the
RRL system were gas separators to improve the handling of free gas at the
intake of the pump.
Installing the RRL system with continuous rods eliminated most of the failures
encountered with the previous artificial
lift equipment. The system has been running
in the field for more than 800 days with
no significant downtime or maintenance

issues. The operator recouped his investment
in a relatively short time, which enabled
continued development of the field.
Successes such as these are spurring
greater interest in continuous rod lift systems for horizontal wells in U.S. unconventional resource plays. The technology
has been deployed in some 100 oil shale
wells in the Permian Basin already, and
industry demand continues to grow in
horizontal plays in both the United States
and Canada.
❒
RYAN ORR is global product line
manager for COROD™ continuous
rod lift technology at Weatherford in
Edmonton, Alberta. Previously, he
served for eight years as a global
progressing cavity pump application
specialist at Weatherford, and before
that was a cased-hole wireline completions specialist at Baker Hughes.
Orr holds degrees in petroleum engineering technology and project management from Northern Alberta Institute of Technology.

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American Oil and Gas Reporter - June 2014

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