Infill drilling targeting the highly depleted reservoir sections in the North Sea has been severely impeded with mechanical instability, induced differential sticking and induced losses. Throughout this mature field, equivalent circulating densities (ECD) are always close to leak-off test (LOT) results, typically resulting in borehole breakout and the inability to run liners to target depth, often requiring re-drills to access production targets. In this formation, fracture sizes were larger than 500 micron (μm), requiring a broader wellbore shielding technology to avoid lost circulation.
In previous wells, Impact’s FLC 2000® wellbore stabilizer, the fluid technology which deposits a thin and impermeable filter cake that effectively seals fractures up to 250 microns allowed the operator to mitigate drilling problems in the interbedded and heavily depleted formation. In this well, FLC SUPREME was used in conjunction with FLC 2000 to stabilize the wellbore and limit lost circulation in large fractures.
Mud losses were non-existent with the combination of FLC 2000 and FLC SUPREME. The operator drilled one sidetrack, 2,849 MD with zero mud losses. The operator drilled to TD and ran a liner to bottom and cemented the well with no fluid related problems. Both FLC 2000 and FLC SUPREME will continue to be used by the operator in this challenging region.