Schlumberger

Case Study: WELL COMMANDER Tool Provides Effective LCM Contingency for Coring Operations

Challenge: An operator offshore Qatar had to make multiple coring runs from a 9 5/8 in. side track into an 8 1/2 in. hole.

Solution: M-I SWACO Specialized Tools recommended the operator employ the WELL COMMANDER multi-ball-activated drilling valve that would allow the LCM to be placed while bypassing the sensitive coring assembly tools.

Result: A field test was first performed to determine whether the WELL COMMANDER valve would provide an effective bypass of the core barrel.

During the field test, the first pill was pumped at 65 spm/690 psi, followed by 1530 strokes of active mud at 50 spm/590 psi. When near the core barrel, the pump was slowed to 20 spm and once the pill hit the core barrel the pressure spiked to 400 psi and went through coring assembly.

The second 30 bbl (4.7 m3) pill was pumped at 50 spm/500 psi, followed by 950 strokes of active mud. When near the core barrel, the pump rate was slowed again to 20 spm and when the pill hit the core barrel the pressure spiked to 550 psi and barely went through coring assembly. Consequently, with the pressure spiking up and down, the pump rate was reduced to allow the pill to get through the core barrel.

The third pill was pumped at 55 spm/570 psi, followed by 950 strokes of active mud. Upon approaching the core barrel, the pump rate was slowed to 20 spm and when the pill hit the core barrel the pressure spiked to 1600 psi and plugged off the core barrel. At that point, the Well Commander ball was dropped and the tool opened, effectively allowing for circulating out the sweep.

For the coring operation, the Well Commander was placed two stands above the core barrel. The 1 1/4 in. core barrel activation ball passed through the Well Commander tool and Bypass Ball Catcher sub without activating the valve or being stopped by the ball catcher, but activated the core barrel each time.

The operator was so impressed with the functionality of the Well Commander tool that it has since been included as part of the standard 8 ½ in. reservoir drilling BHA to treat losses as and when required.


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