Due to adverse hole conditions, Operators in the Nam Con Son Basin have had difficulties carrying out their wireline logging programs. Unplanned wiper trips and pipe conveyed logging have often been necessary to acquire log data. These remedies are expensive and time consuming and lead to substantial inefficiencies during execution. In search for operational efficiency, a revolutionary conveyance technology was used with the wireline logging tools.
The conveyance system consists of wheeled carriages which are secured to the exterior of the logging tool housings and aligned at regularly spaced intervals. The carriages have large diameter wheels with an active bearing lubrication system and carry the tool-string over and above wellbore cuttings. The wheels significantly reduce tool drag, facilitating conventional logging in very high angle wells. The carriwages orientate the logging tool sensors to enhance sample recovery and data quality. The holefinder consists of an upturned nose cone, analogous to a ski tip, which effortlessly slides over ledges without stopping.
The intermediate logging operation continued over 5 days, during which 5 runs were made with up to nine carriages and a hole-finder on each tool string. All tool-strings ran seamlessly to TD and logged out smoothly without issues, facilitating excellent data acquisition. Following success in the intermediate hole section, the conveyance system was deployed on all wireline runs in both the main wellbore and sidetrack with similar results. The conveyance devices allowed the drilling and exploration team to achieve all of the pre-drill objectives while eliminating the unplanned costs experienced with previous logging programs. The conveyance system provides a cost effective method for managing high deviation wellbores while enhancing the operator's data acquisition needs for exploration evaluation. By avoiding pipe conveyed logging and wiper trips, 11 days of rig time was saved on a floating rig, with associated cost savings of USD 9.4M.
Together, these complimentary devices form a complete conveyance system that uniquely resolve all the challenges that have plagued wireline logging for over 50 years while enhancing data quality. The technology also has applications in well intervention operations.