This case study explains an innovative technique used to mechanically exercise and to lock open the surface controlled subsurface safety valve (SCSSV) in a well. The repair consisted of locking open the valve prior to installing a wireline insert in order to return the well to production. The conventional slickline method of locking open the SCSSV was not possible due to the position of the stuck flow tube.

As an alternate to a costly workover of retrieving the tubing and the SCSSV, a novel wireline technique was deployed providing a solution to exercise the flow tube and then lock open the valve.

This technique helped diagnose the cause of the failure, mechanically shift the stuck flow tube, and then lock out the flow tube in a single run. It can be used subsequently on any safety valve without mobilizing a custom mechanical lockout tool. The instrumentation provided real-time quality control of the process, reducing the risk for subsequent runs through the valve.

The solution consists of a wireline tool composed of two anchors with a linear actuator in between. The top anchor provides a fixed point in the tubing and the linear actuator extends and retracts to exercise the flow tube and measure the displacement and applied forces. At the bottom, a second anchor grips the flow tube and transmits the axial force of the linear actuator. The second anchor can also be used as a dimpling tool to deform the flow tube and lock it out by increasing the force of the lower anchors.

By measuring the amount of force and the opening diameter of the second anchor, the operator can choose either to exercise or to deform the flow tube at a suitable location without pulling out of hole. The final opened diameter of the lower anchor the tool can further confirm if the deformation range has been reached for locking open, providing additional quality control capabilities.

Moreover, the instrumentation generates a signature for each exercising stroke, highlighting the impact of this process. Eventually, the tool can confirm the final flow tube position showing if full movement is possible prior to dimpling.

The tool was deployed in a gas well to first exercise the flow tube, stroking up and down five times and recovering its functionality. This step was followed by leaving the flow tube in the closed position and performing a successful inflow test of the flapper. However, recovering hydraulic functionality of opening and closing via surface control line pressure cycles was not successful.

Eventually, the tool was run to mechanically shift the flow tube in the required position for dimpling in the open position. A subsequent drift run through the valve proved the effectiveness of the lockout.

The successful intervention proved that this advanced solution can exercise and dimple a SCSSV. Additionally, it can also be used on other flow control equipment, such as ball valves and sliding side doors.