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.