The recent development of wireline standoffs (WLSOs) has effectively eliminated cable sticking during deepwater logging operations, offering a viable alternative to pipe-conveyed logging, and saving considerable rig time and risk in the process. On eight high overbalance wells in the Gulf of Mexico, multiple arrays of wireline standoffs (WLSOs) have been successfully deployed to facilitate deep formation sampling without any incidence of cable sticking. This success should be viewed in the context of the fact that the cable force modeling for WLSO deployment indicated that several fishing operations were averted.The oil and gas industry has been using standoffs for years in order to prevent sticking of everything from logging tools to casing. Applying standoff technology to logging cable was a natural progression, although there were many technical challenges that needed to be overcome in order to make the effective use of WLSOs a reality. To begin, the wireline standoffs could not be allowed to damage the logging cable. Yet, these standoffs had to provide a grip sufficient to avoid slippage under high tensions. In addition, the WLSOs needed to be capable of both maximum cable lift and minimal formation contact, while allowing a 3-3/8" fishing grapple to smoothly pass over them. Finally, WLSO modeling had to be able to identify their optimal placement on the cable, taking into account such factors as logging objectives, wellbore trajectory, and applied cable forces (including cable sag between WLSOs in deviated holes). This paper discusses the origins of WLSO design, job planning, and operating procedures. Recommendations for future research into the issue of cable sticking are also included.

Wireline cable sticking is most frequently experienced during formation fluid sampling. In this situation, if the cable cannot be freed, strip-over fishing is the only remedy; this is a cost and risk-intensive activity which may extend the logging job by several days and result in further inefficiencies such as wiper trips or pipe-conveyed logging to fully satisfy the formation evaluation objectives. In this paper, the authors outline a proven engineering approach that permits the systematic identification of high-risk wells for cable sticking, where the deployment of wireline standoffs (WLSOs) may facilitate safe and efficient sampling on wireline. The precursor of all cable sticking is slot cutting into mud-cake or formation. The slot is generated by sustained lateral pressure from the moving (tensioned) logging cable, referred to hereafter as "cable thrusts". A sophisticated 3D cable force model evaluates the cable contact zones and thrusts along the open hole section under analysis. For differential sticking, a cable contact and sticking limit in mud-cake is computed, having adjusted the pore pressures to offset data. For keyseating, the well is benchmarked against wells with similar trajectories, gained from a global study on cable sticking. Sticking-linkage is also assessed, whereby overpulls from tool sticking may induce cable sticking, via amplified cable thrusts against mud-cake or formation. To reduce cable sticking risks to an acceptably low level an array of WLSOs may be deployed, combined with optimised logging procedures and winch techniques. Operators are now employing this approach on a regular basis as an important risk management tool, from the well planning stage through to completion. WLSOs have been successfully deployed for 40 sampling runs on 25 wells, in fields with a history of severe cable sticking or fishing. Prior signs of sticking have largely been eliminated, resulting in significantly reduced well costs, whilst avoiding pipe-conveyed logging or LWD, and without consideration to the value of lost data or samples. Well Engineering may now use this approach to design and optimize ambitious well trajectories, potentially saving a hole section, in the full knowledge that future wireline fluid sampling can be performed within the bounds of acceptable risk. Real-time risk assessments have proven invaluable, to track the risk trend as the well is drilled, leading to a final decision on the requirement for WLSOs, with additional optimisation of the sampling procedures if needed. Operational best practices and lessons learned are summarized, as well as an outline for future R&D to understand and reduce wireline conveyance risks even further.

During open-hole wireline operations, at least 95% of cable sticking events are known to be predictable and avoidable. Approximately 40% of these cable sticking events escalate to fishing operations, adding substantial costs to the AFE. Sub-optimal well design, from a wireline acquisition perspective, is known to contribute to such sticking. This paper offers practical guidance for drilling engineers on how their well designs may impact wireline conveyance and sticking risks and what measures they can take at both the design and execution stages to ensure a safe and efficient wireline logging job.