AAPG/SPE Africa Energy and Technology Conference

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A Case Study of the Successful Deployment of Tractor Conveyed Perforation in Highly Inclined Well

Abstract

Well A is one of the only two wells on the XY reservoir structure providing the optimum drainage point on that reservoir. However, Well X had been shut in due to high sand production and had been flagged as ‘non-integral’ with regards to SPDC Well Integrity Management (WIM) policy due to its faulty Tubing Retrievable Surface Controlled Subsurface Safety Valve (TRSCSSSV). The well was thus scheduled for repairs. The objective of the workover operation as with most others done in SPDC was to restore integrity of the well, remediate sand control and improve production across the XY reservoir. On re-entry into the well, a mechanical restriction was met in the high angle section of the well thus impeding access to drain hole. A review of the situation, showed a possible collapse of the lower completions (sand screen) possibly due to high sand production. An attempt at sand clean-up was futile. This paper describes the unconventional but successful deployment of wireline conveyed perforation gun on tractor in SPDC to perforate this highly deviated well, thus, providing drainage access and recovering 2.14 MMstb of oil and 0.79 BScf of associated gas. Amongst several options including the use of coiled tubing or wireline as means of perforation, the tractor conveyed guns stood out for a highly inclined well such as Well A. The Well Tractor functions with an electric over hydraulic power relationship and uses its wheel section to push the passenger tool downhole as cable is fed off the electric line unit. The make-up of the tractor conveyed system makes it suitable for high angle wells while providing a cost savings over other systems.