dummy valve, Oil & Gas Glossary

A dummy valve is a solid, ported-but-plugged or wholly blank gas-lift valve insert that is run into a side-pocket mandrel (SPM) on the production tubing string to mechanically isolate the tubing bore from the casing annulus at the mandrel depth. In a conventional gas-lift completion, each SPM carries a working gas-lift valve that admits injection gas from the annulus into the tubing on a calibrated opening pressure, lightening the produced fluid column so the well can flow at a target rate. When the well must be intervened (tubing inspection, wireline plug setting, pump installation, well kill, or tubing repair), those producing valves are pulled with a wireline or slickline kick-over tool and replaced with dummy valves, which prevent any communication between the high-pressure injection gas in the annulus and the tubing. This is critical because annulus gas pressures in WCSB gas-lift wells routinely run 6,900 to 13,800 kPa (1,000 to 2,000 psi), and any communication during intervention could blow the well in unexpectedly, jeopardize crew safety, or contaminate well-kill fluids with gas. Dummies are short steel cylindrical mandrels (typically 25.4 mm or 38.1 mm outside diameter, matching the 1.0 in or 1.5 in SPM dummy pocket) with the same external geometry as a working gas-lift valve so they latch and seal in the mandrel pocket using the same set of upper and lower elastomeric packing elements. The internal flow path is plugged solid with no check valve, no orifice, and no flow ports, so there is no possibility of gas transfer in either direction. Major manufacturers include Schlumberger Camco (formerly Camco/Otis), Halliburton (formerly WellDynamics), and Weatherford, each producing dummies in the standard 1.0 in OD R, RMO, and BK series sizes and the 1.5 in OD K, KBM, and KBMG series sizes that dominate WCSB gas-lift completions. A dummy valve unit costs CAD 200 to CAD 450 depending on metallurgy (carbon steel, 316 stainless, or Inconel for sour service), while the slickline trip to install a full string of dummies on a typical Cardium oil well with six SPMs runs CAD 8,000 to CAD 15,000 including the slickline crew, lubricator, BOP rental, and supervision. Sour-service applications in the Foothills or southern Alberta require NACE MR0175/ISO 15156 compliance, with Inconel 718 or 925 dummies replacing standard carbon-steel units to resist sulfide stress cracking. Dummies are also used in newly commissioned gas-lift wells to isolate planned mandrels until the well is unloaded enough for the kickoff (top) valve to be replaced with a working valve, and in artificially lifted wells transitioning from gas lift to electric submersible pump (ESP) or progressing cavity pump (PCP), where every SPM is filled with a dummy to convert the tubing string to a sealed conduit for the new lift method.

Key Takeaways

Mechanical Annulus Isolation: A dummy valve is a blank insert in a gas-lift side-pocket mandrel that mechanically blocks all flow between casing annulus and tubing at that depth. It has no check valve, no orifice, and no flow ports. Annulus pressures in WCSB gas-lift wells of 6,900 to 13,800 kPa (1,000 to 2,000 psi) cannot communicate to tubing while dummies are seated, which is essential for safe wireline and pump intervention.
Slickline Installation by Kick-Over Tool: Dummies are installed and retrieved using a slickline kick-over tool that latches onto the valve fishing neck, tilts it out of (or into) the pocket, and seats it on the upper and lower packing. WCSB slickline contractors such as Pure Slickline and STEP Energy Services charge CAD 8,000 to CAD 15,000 for a complete dummy installation trip on a six-mandrel Cardium gas-lift well, including crew, lubricator, BOP rental, and supervision.
Common Sizes and Standards: Dummies are produced in 1.0 in OD and 1.5 in OD series matching Schlumberger Camco R, RMO, BK, K, KBM, and KBMG mandrel pockets, plus equivalent Halliburton (WellDynamics) and Weatherford lines. Sour service in the Foothills and southern Alberta requires Inconel 718 or 925 metallurgy compliant with NACE MR0175/ISO 15156. Standard carbon steel dummies cost CAD 200 to CAD 350; Inconel sour-service units run CAD 600 to CAD 1,100.
Intervention and Workover Use: Producing gas-lift valves are pulled and replaced with dummies before any tubing pressure test, wireline plug setting, pump installation, or tubing repair operation. The dummy string allows safe well kill, fluid circulation, and pressure isolation. Once intervention is complete and well-kill fluids are reversed out, dummies are pulled and working valves reinstalled, with the production string restored to gas-lift operation.
Conversion to Other Artificial Lift: When a WCSB well transitions from gas lift to electric submersible pump (ESP), progressing cavity pump (PCP), or rod pump, every SPM in the original gas-lift completion is converted to a dummy. This converts the tubing into a sealed conduit so the new lift method operates without bypass through old SPMs. Cenovus and CNRL routinely convert mature Cardium gas-lift wells to PCP using full dummy strings.

Slickline Procedure for Installing a Dummy String

On a Cardium gas-lift oil well with six side-pocket mandrels at depths between 1,250 m and 2,100 m, the slickline crew rigs up a 2,000 m unit with a 4.76 mm (3/16 in) slickline and a kick-over tool with valve-pulling and valve-running prongs sized for the SPM series. The crew runs in hole, finds each mandrel with a casing collar locator (CCL) correlation, pulls the working valve to surface, and runs back in with the dummy. Each mandrel cycle takes 35 to 50 minutes including correlation, pull, surface swap, and run-in. A full six-mandrel trip averages 5 to 7 hours on bottom and adds 2 hours of rig-up and rig-out. Total cost for the slickline trip plus six dummies typically runs CAD 12,500 to CAD 18,000 per well in 2025 prices.

Dummy Valves During Conversion From Gas Lift to PCP

Mature WCSB Cardium and Pembina oil wells often see gas-lift performance degrade as reservoir pressure declines below approximately 4,000 kPa (580 psi), at which point progressing cavity pump (PCP) systems become economically superior. Conversion involves a workover rig pulling the gas-lift tubing string, but operators frequently leave the original SPMs in the new PCP string to avoid recutting tubing, instead filling every pocket with a dummy. A typical Cenovus conversion in the Westerose area replaces six working gas-lift valves with six Inconel 925 dummies (sour service), at total dummy cost of CAD 4,800 plus CAD 22,000 in slickline labor, then runs the PCP rod string above the now-isolated mandrels.

Fast Facts

The original side-pocket mandrel was patented by Camco Inc. of Houston, Texas, in 1955, with the dummy valve concept introduced in 1958 as part of the same kick-over tool family. Camco was acquired by Schlumberger in 1998 and the Camco brand remains the dominant gas-lift hardware standard in the WCSB seven decades after the original patent. By volume of dummies installed, Western Canada is one of the world's largest end markets, with an estimated 18,000 to 22,000 active gas-lift wells in Alberta alone as of 2024 carrying typical strings of three to seven mandrels each.

Dummy valves connect directly to several adjacent glossary entries. Gas-Lift Valve is the working component that dummies temporarily replace during intervention. Side-Pocket Mandrel is the tubing accessory that houses both working valves and dummies in offset pockets accessible from inside the tubing. Kick-Over Tool is the slickline assembly that latches, tilts, and seats valves and dummies in and out of mandrel pockets. Artificial Lift is the broader category encompassing gas lift, ESP, PCP, and rod pumping, with dummies playing a role in conversions between methods.

Real-World WCSB Scenario: CNRL Pembina Cardium Well, October 2025

A Canadian Natural Resources Limited (CNRL) Cardium gas-lift oil well at Pembina, Alberta, completed in 2008 with five Schlumberger Camco K-series side-pocket mandrels between 1,180 m and 1,985 m measured depth, was scheduled for a tubing inspection and pressure test in October 2025. Pure Slickline mobilized a unit to the location, pulled the five working K-series gas-lift valves to surface, and replaced them with five standard carbon-steel K-series dummies (CAD 285 each, total CAD 1,425). The slickline rig-up, dummy installation, and rig-out completed in 8.5 hours at CAD 1,650 per hour, for an invoiced slickline cost of CAD 14,025.

With the dummies isolating the annulus, CNRL pressure-tested the tubing to 10,500 kPa for 30 minutes, identified a small leak at 1,640 m via temperature log, and repaired the joint with a wireline-set patch. After repair, the dummies were retrieved and the original working valves reinstalled. The well returned to production at 28 m3/day oil plus 4.2 e3m3/day gas-lift gas, validating both the isolation function of the dummies and the integrity of the patched tubing joint.