Intelligent Straddle Deepens Gas Lift, Significantly Boosting Production

A major operator in the Gulf of Mexico was experiencing reduced production due to a suboptimal gas lift design, where the gas injection points were too shallow within the well completion. Unable to remove the existing completion, the operator sought Interwell’s expertise for a wireline intervention to improve production. The challenge was complicated by multiple restrictions in the original completion and the presence of an incompatible fluid in the annulus between the production packer and the deepest gas lift mandrel. These factors created additional hurdles for optimising the gas lift while safeguarding the reservoir.

Interwell deployed its 363-450 Multi-Run Anchored Production Straddle (APS). The lower module was equipped with an Intelligent Barrier Valve (IBV), and the upper module included a Go-Lift retrofit Gas Lift Valve. 

To optimise gas injection, Interwell performed a gas lift design study to determine the ideal depth for deepening the injection points. Following this, all existing gas lift mandrels were replaced with dummies. The APS lower module was installed, suspending the IBV. Initially, the IBV was left open to allow fluid bypass through the tight restrictions and automatically closed 8 hours after surface activation. With the valve closed, the tubing could be pressure-tested against the set lower module and the sealed IBV. 

Mid-operation, an unplanned evacuation occurred due to a hurricane threat, requiring the well to be suspended. Fortunately, the well was left in a secure state with a gas-tight barrier in place for four days.

Upon returning to the facility, a drilling tool was used to create tubingto-annulus communication by drilling holes above the lower module. This allowed fluid from the annulus to enter the tubing, and diesel circulation was performed to replace the incompatible fluid with diesel in both strings. During circulation, a pressure command was sent to the IBV, which triggered it to open 56 hours later. Once the circulation was complete, the upper module and Go-Lift sub were installed, and the IBV successfully opened.

The intervention met all objectives. The straddle system’s design allowed the entire system to be tested after installation, which is not typically possible with conventional straddle systems. This gave the operator confidence in the tubing-to-annulus integrity. The reservoir remained protected throughout the operation, ensuring optimal well conditions for re-entry into production. As a result, production increased by over 200%, significantly enhancing the wells output.