In Algeria, workover operations are almost exclusively carried out with a rig or coiled tubing unit. Some tractors had been rented and deployed in the past but with very limited success. So when Welltec® proposed using the Well Tractor for a routine workover, the operator was skeptical. However, based upon our extensive track record of 20 years of operations around the globe with this technology, they decided to reevaluate this approach.
The candidate well was for a workover to recomplete an old well, originally drilled and completed back in 1999. The initial, 7” cased hole completion had been sidetracked and extended with a horizontal drain some years later and completed with a 4 ½” liner. Now, the lateral was experiencing a high water cut, and the operator wished to isolate the watered out section of the well and add new perforations.
A rig was already on location but it was estimated using e-line to set the bridge plug and convey the perforating guns would save substantial time. In addition the client worried that in case of problems, non-productive time (NPT) would be measured in days, whereas a Welltec solution, run on e-line, is measured in hours.
Because of the potential increase in efficiency and the high deviation of the setting depth, 87.5°, the client decided to apply Welltec’s solution, using a Well Tractor® 318 run on e-line cable.
The first run was done to ensure that producing well was clear and in gauge down to the setting depth. A drift run with a junk catcher was rigged up on the Well Tractor and run in hole prior to the bridge plug (BP) run. Unfortunately, the toolstring encountered difficulties while navigating from the 7” casing into the 4-1/2” liner.
Subsequently, the toolstring was quickly pulled out of the hole, modified, and run back in the hole. At the junction, the Well Tractor was powered up to improve centralization. This time, the drift run was successfully conveyed down to the planned setting depth of the BP.
For the 2nd run, the e-line toolstring consisting of a Well Tractor 318, a 3rd party setting tool and the BP were run in hole. By applying the same centralization techniques as on the 1st run, the BP was successfully conveyed to depth and set in place.
Following the e-line runs, the rig spotted a cement plug on top of the BP platform to complete the water shut-off. Days later, the Well Tractor was called out again and successfully conveyed four, perforating gun runs, efficiently adding new production for the operator.
From rig-up to rig-down the drift run and BP setting operations were performed in only 12 hours, ~ six times faster than conveying it on pipe. Also, by applying an e-line solution, the BP was placed on depth with a much higher degree of accuracy.
But more importantly, the successful utilization of the Well Tractor in Algeria has demonstrated to the operator that this technology is reliable and adds value.
WELL TYPE: OIL PRODUCER
MAX. TEMPERATURE: 108⁰ CELSIUS
MAX. PRESSURE: 3900 PSI
From rig-up to rig-down the drift run and BP setting operations were performed in only 12 hours, ~ six times faster than conveying it on pipe.