Replacing damaged or blocked control lines that operate downhole equipment is costly and time-consuming. Doing without control features that help operators optimize production can be aggravating. But when the equipment is a surface-controlled subsurface safety valve (SCSSV), the repair urgency takes on an entirely new perspective. Between the proverbial rock and a hard place, operators sought a technique to repair damaged control lines without performing costly interventions, estimated at more than US $10 million in some situations.

Weatherford’s Renaissance WDCL safety shut-in system can replace a damaged control line and SCSSV in a simple retrofit procedure without a workover. Run on wireline and set in either the valve landing nipple or an existing tubing-mounted safety valve, the WDCL valve contains an internal pod that routes control line fluid to operate the new safety valve. Once the valve is in place, a Renaissance capillary hanger is run down the center of the tubing string. The bottom end wet-mates with the pod, and the upper end provides a pressure-tight conduit through the hanger/tree assembly. Surface-controlled subsurface shut-in capability is immediately restored. The wet-mate capillary can be removed at any time for necessary interventions, and when it is in place it maintains tubing flow capacity at 95% of currently available subsurface-controlled valves.

The Renaissance System comprises a family of components, each uniquely engineered to perform reliably specific tasks in the completion.

• Capillary Hanger — supporting the weight of the capillary string, the capillary hanger provides a conduit for control line fluid through the hanger/tree assembly into the capillary string and ultimately to the safety valve.

• Control Line — running down the center of the tubing to a pod on the WDCL valve, the control line supplies hydraulic fluid via the pod to a rod-and-piston mechanism that activates the safety valve.

• Stinger — containing the female end of a unique Weatherford wet-connect, the stinger joins the capillary to a mating connection on the pod. The wet-connect allows the stinger to be mated and unmated so the capillary can be removed if necessary without loss of fluid. When the capillary is pressured up, the wet-connect is locked and cannot be removed.

• Pod — containing the male end of the wet-connect, the pod reroutes the flow of hydraulic fluid from the centered capillary string to the outer perimeter of the valve.

• WDCL SSSV — engineered to land in the valve landing nipple from a previous wireline safety valve or existing tubing-mounted safety valve, the WDCL SSSV combines with the rod-piston activated flapper valve to maintain 95% of the flow area provided by conventional wireline retrievable valves.

Recently, the trouble-free installation of a Renaissance WDCL system allowed a North Sea operator to regain surface control of its SCSSV and increase production by 3.5 MMcf/d of gas, significantly increasing production revenue while avoiding a costly workover. The original control line had become blocked, and the well was being operated using a storm choke with high back-pressure. This technique resulted in reduced production. Weatherford installed a 3.81-in. Renaissance WDCL system consisting of a new safety valve

Renaissance WDCL damaged control line system. (Image courtesy of Weatherford)

, a stinger to transport the control line to the surface, and a control line hanger used for new well penetration. The valve was set at 1,855 ft (566 m), and flowing tubing pressure was lowered, reducing back-pressure. The entire job was performed on slickline without pulling the tubing.

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