Continuous
Sucker
T he unique design characteristics of the COROD® continuous sucker rod offer distinct production
enhancement and cost saving advantages to rod string applications. Unlike conventional sucker
rods that are coupled every 25 or 30 feet (7.6 or 9.1 meters), continuous sucker rods require couplings
only at the top and bottom of the rod string - regardless of well depth. With fewer joints, this solid length of
Rod steel is lighter and enhances tubing life due to a more uniform contact between the tubing and sucker rod. It
also addresses many premature tubing wear challenges, especially in directional and horizontal wells.
Corod continuous sucker rods are manufactured in multiple round and semi-elliptical sizes for high system
Technical efficiency in various downhole environments.
Excellence Minimal Pin and Coupling stay on production for longer periods threaded rods. The load-bearing con-
by Design Failures and costs associated with retrieval, tact area of the COROD string on the
With only two threaded connections — repair and replacement of rod string tubing wall is 100 to 150 times less for
one at the polished rod and one at the components are minimized. semi-elliptical rod and 50 to 75 times
pump, pin and coupling failures that less for round rod compared with other
Extended Tubing Life
commonly occur in conventional rod systems. The consequent redistrib-
The protruding diameter of threaded
threaded rod strings are dramatically ution of the load-bearing area minimizes
couplings often become a bearing or
reduced. Fewer failures mean wells can wear and potential failure, especially in
concentrated point on the tubing ID
directional or slant wells.
that can eventually erode the tubing
wall, especially in deviated wells. Minimal Torque and Power
Because COROD systems do not Requirement
point-load the ID of the tubing with COROD strings lower torque and
couplings, the uniformly distributed power requirements of primary drivers
side load of a continuous sucker rod by eliminating the restrictions or flow
means reduced tubing wear rates and losses associated with couplings,
prolonged tubing life. centralizers and rod guides. COROD
systems are subject to reduced loads
Minimal Rod and
and run more efficiently for extended
Tubing Wear
periods in rotary (PCP) applications.
In tubing less than 3-inch (7.7-cen-
Continuous sucker rod strings also
timeter) ID, the semi-elliptical cross-
lower stress since they can be made
section rod designs contact the tubing
in larger sizes than conventional rod
wall at two points rather than one
strings for the same tubing size.
point observed with conventional
sucker rods. For every 25 feet (7.6 Enhanced Pump Efficiency
meters) of tubing, there is 50 feet COROD continuous sucker rods elim-
(15.2 meters) of line contact versus inate the rod-coupling piston effect,
the 4 to 4 ½ inch (10.2 to 11.4 cen- resulting in longer net plunger travel
timeters) of coupling OD contact of and higher pump efficiency.
Designed and manufactured for opti- where chlorides and carbon dioxide
mum performance, COROD continuous may be present or in more corrosive
sucker rod combines industry-leading environments where a corrosion
innovative design with quality materials inhibitor is present. ENDURA material
and manufacturing excellence. Every is also used in high-strength contin-
rod is manufactured to exacting specifi- uous rod strings for high loading
cations under the highest degree of applications.
quality control. Rigid manufacturing
Available in three round and seven
processes, plus skilled operators and
semi-elliptical configurations, rod
specially designed equipment, monitor
sizes range from 12/16 in. to 18/16
each phase to ensure the integrity of
in. (19 to 28.5 mm.) tapered to any
every design and finished product.
length. Both type configurations are
COROD sucker rods are manufactured ideally suited for reciprocating rod-
from API Grade D carbon steel, pumping applications. The round
chrome-moly, and special-service rod configurations have also proven
alloys. COROD systems made of extremely effective in rotary-type rod
ENDURA™ material are used in wells pumping methods.
D, DE and SE
COROD products are
successfully used in
H2 S Environments
when the wells are
effectively inhibited.
Continuous
Sucker
Rod
Technical
Excellence
by Design
SIMPLE, QUICK INSTALLATION AND FIELD SERVICE
By nature of its unique design, COROD continuous sucker rod is transported and installed at the wellsite by our custom-built
service rig and welder. Stored on an 18-ft. (5.4-m.) diameter reel, the rod is deployed into the well at rates of 90 to 100
ft/min (27 to 30 m/min) by a variable-speed, hydraulically driven gripper mechanism. With the rod installed directly off
the reel and through the gripper system, damage often associated with make-
up equipment and human handling is minimized.
Installation is simple, fast and conducted by highly trained rig crews. Since
COROD strings only require top and bottom connections, the top connection
can be welded onsite during installation. This welding procedure produces top-
quality, long-lasting joints on the string. These techniques can also be used to per-
form field repairs, if necessary, or to transfer a continuous rod string from one well
to another.
THE RIGHT SOLUTION FOR MULTIPLE APPLICATIONS
COROD continuous rod is ideally suited Rotary Rod Pumping
to both reciprocating and rotary pumping Round cross-section COROD sys-
applications. Backed by a wealth of tems function efficiently in rotating
experience and technical expertise in rod-pump applications. In a rotating
each of these applications, Weatherford (PCP) system, COROD strings can
Specialists help operators select the reduce the torque placed on motors
right solution for optimum performance and pumps, decrease the power
and production enhancement. requirements, and in turn, decrease
the required size of the progressing
cavity pump. The reduced load and
Reciprocating Rod Pumping
stresses on system components can
Both semi-elliptical and round cross-
result in operational cost savings
section COROD systems work effectively
through fewer tubing leaks, lower flow
in reciprocating rod lift applications.
losses, and higher system efficiency.
Properly selecting the applicable cross-
section can reduce internal tensile, Special Applications
compressive, and bending stresses in Special applications such as highly
the rod, minimize the load imposed on deviated wells and heavy, high-vis-
the pump and enhance pump efficiency. cosity oil production are prime
All the advantages translate to increased opportunities for the high-strength,
cost savings and enhanced production high-torque capabilities of the
from the well. COROD systems.
A recent case history published by Stocker Resources, Inc. in California reported that the performance of the COROD system saved approximately $350,000 (US)
through reduced operational costs and improved overall system efficiency.
When selecting a sucker-rod system for your
artificial lift application, whether for ease of
installation, longer run life or operating cost
®
reduction, choose Weatherford COROD
continuous sucker rod.
COROD continuous sucker rod is an
integral part of Weatherford's comprehensive
portfolio of artificial lift systems, products
and services for optimum performance and
production enhancement. Its unique design
characteristics reflect Weatherford's ongoing
commitment to providing customers more
efficient and cost-effective solutions to
reservoir production problems.
Contact your Weatherford Artificial Lift representative
for an in-depth analysis of your rod string applications.
US & International Canada
713-693-4000 403-571-2424
Weatherford products and services are subject to Weatherford’s standard terms and conditions. For
more information concerning the full line of Weatherford products and services, please contact your
515 Post Oak Blvd. S Houston, Texas 77027 authorized Weatherford representative.
www.weatherford.com Unless noted otherwise, trademarks and service names noted herein are the property of Weatherford.
© Copyright 1999 Weatherford • All rights reserved • ALS7500 • 0699/7000 • Printed in U.S.A.
