Abstract

Successful stimulation fluid placement in extended reach wells (ERW's) through coiled tubing (CT) is primarily dependent on the depth reached for maximum reservoir contact. Well configurations of minimum bypass (2.4 in.) and openhole sections (6 1/8 in.) are the main challenges for CT reach in these ERW's. Implementation of a CT slim tractor along with fiber-optic enabled cable were applied to overcome the challenges and set a new record for CT reach.

CT lockup is the phenomenon that occurs due to friction forces and helical buckling, which limits the CT reach. To tackle these challenges, an accurate simulated lockup depth is estimated using historical data to identify the required pull force. The CT slim tractor (2 1/8-in.) was chosen as the optimum tool to provide the required pull force, as well as pass through the minimum ID restriction of the well. Specially designed tapered CT with fiber-optic enabled cable acquired real-time data from the downhole tension-compression (TC) sub to confirm both the activation and lockup depth of the tractor.

The expansion ratio of the tractor from 2 1/8-in. to 6 1/8-in. OH section opens a new era for CT reach in restricted ERW's. The world slimmest tractor passed the 2.44-in. minimum ID restriction and provided more than a 3,000 lbf pulling force, allowing the CT to cover the entire openhole section. Along the way, two new records were recorded for the longest section tractored by a slim CT tractor and the furthest distance travelled in a producer well reaching a TD of 24,706 ft. Increased reservoir contact during stimulation through engineered solutions has set a new standard enabling the implementation of a full stimulation campaign.

These engineered solutions demonstrate the potential for CT interventions in extended-reach horizontal wells with completion restrictions, where the main challenge is to maximize the reach for optimum stimulation. As a direct result of several innovative solutions applied simultaneously, a new record for CT reach was set, surpassing the previous record by nearly 5,000 ft.

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