Abstract
Manipulation of downhole completion components such as formation isolation valves, inflow control valves and sliding sleeves has become a regular phase of both new well initiation and existing well production optimisation scope. This often occurs in deviated and extended reach well trajectories frequently involving mono-bore completions. Although primarily done by pressure activation, electric line deployment of linear actuators that engage with associated shifting profiles of such valves and sleeves offers a secondary means of manipulation, one that is often relied upon. Deployment of these devices through smaller ID restrictions located higher up in the completion string necessitates in-situ activated high expansion anchoring and shifting capabilities.
The electric line powered tractor-stroker-shifting device toolstrings capable of high deviation conveyance coupled with precise and real-time controlled completion component manipulation are desired, providing visibility throughout the operation. Furthermore, sufficient force to cover not only the shifting specification of the valve or sleeve design but also to overcome sleeve seizing commonly encountered downhole from scale or debris infringement is necessary to maximise the certainty of these operations. The technology platform presented in this paper has been designed to provide conveyance, positioning, anchoring, and high bi-directional force and stroke generation in a slim tool architecture offering high expansion shifting capability. Its downhole logic for optimised electric and hydraulic power distribution and a high degree of instrumentation and sensors has brought reliable target search, device engagement and real-time operational visibility and control to completion manipulation operations.
Extensive system integration tests done on replica valve sleeves using the full tractor-stroker-shifting device toolstring to confirm the functionality and effectiveness will be described in the paper. This has been done within a reconstructed horizontal completion configuration to confirm successful string conveyance, shifting dog engagement and stroker shifting action, collaborating toolstring sensor measurements with those incorporated in the test jig configuration. A single run multi-sleeve shifting operation carried out in the North Sea will also be described, with real-time surface readout information which allowed the engineer to better understand the in-situ situation and take immediate and controlled corrective actions, circumventing a false shift scenario due to sleeve seizing and delivering an efficient operation.
The seamless integration and interaction between the tractor, stroker and shifting device that make up the full manipulation toolstring assembly presented in this paper are transformative. Tractor wheels are kept in an extended mode whilst setting the stroker anchors, aiding optimal centralisation of the toolstring throughout the stroker anchoring and manipulation sequence. This reduces the risk of the shifting dogs unlatching from the profile of the completion component being manipulated as is often the case with a sequential tool operation scenario—the intervention technology platform providing a true convey-position-inspect-act-verify ethos.
