CASE STUDY: Extended Depth High Deviation Well Surveys by Slick-Line

GARD U-line™ Roller system enables record breaking lower cost slick-line survey in highly deviated well using its novel next generation conveyance technology.

Country: Nigeria

Year: 2020

Technology: GARD U-line™ Roller WR02 Series

The Challenge

A Nigerian operator client needed to carry out a series of well surveys in a highly deviated well using several BHA tools.

Initially an electric tractor was considered to be the only feasible means to carry out these survey operations but the costs were prohibitive and an alternative viable solution was needed to reach a Target Depth (TD) of approximately 11,000ft at 79°deviation.

This gas well in the Niger Delta had hitherto only been accessed by tractor technology but the G A R&D team in collaboration with Future Oilfield Services of Nigeria team were confident they could reach TD and carry out the survey operations much more cost effectively by slick-line using their novel GARD U-line™ Roller conveyance system with its unique modular wheel retention and its top running performance characteristics modelled on the automotive industry.

The Solution


To achieve TD efficiently with slick-line the BHA required to be conveyed by a set of three GARD U-line™ Rollers dressed with a 2.750” wheel kit. The selected wheel kit allowed safe passage through all the well diametrical restrictions whilst sustaining low rolling friction and maximising debris clearance. This solution optimised travelling time whilst providing well integrity and optimum clearance between the BHA tools and the well bore. The BHA was deployed at a relatively high speed of 9ft/s (c165m/min) with capability of faster trips which would further reduce operational run time and achieve greater TD. For this case study the operator had approved the rollers to run at this speed which is far in excess of the capability of any tractor and consequently saving considerable rig time. The rollers are capable of speeds in excess of 16ft/s (c300m/min) and are these are being planned for some future runs.


Multiple operations were carried out successfully with a well site rig-up of 3 GARD U-line™ Rollers used in each different BHA tool-string survey.

All rollers were inspected and re-deployed between runs in a much tighter timescale than otherwise normal. Maximum agreed deployment speed was recorded and TD was reached in 15 mins with retrieval of the tool in similar timescale for all runs for all BHP, CCL and other operations.

Some of the surveys required travel to different zones whilst pausing for collection of data. This normally significantly further slows run time but much less so with the GARD U-line™ rollers which because of the patented interlock wheel retention system and modular wheel sets allows much higher speeds to be achieved without damage to well integrity.

The operator highlighted the much better operational efficiency and cost savings achieved in using the rollers and that that the GARD U-line™ roller system had surpassed their expectations. The simpler, safer, greener, more easily serviced and better performing modular design of the rollers helped them achieve TD at a fraction of the cost and time of a tractor solution without detriment to well integrity.

The results of those runs has proven the performance claims of the GARD U-line™ Roller system and of their being a highly cost effective solution for all the wells with similar or less challenging characteristics in the region. In summary:


· Extended TD to 80° deviation with Slick-Line

· Saved ½ Day in Rig Time

· Easier and 70% Faster Servicing

· 90% Less Cost than Tractor Solution

· Zero Failure Risk (no screws)

· Improved Well Integrity – no scouring

· Optimised Flow & Debris Resistance

· Most Effective Conveyance Cost Solution

Video Clip


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