After identifying losses at 6,985 m while drilling an 8½-in reservoir section in an offshore ultradeepwater environment, the operator wanted to cure the losses using conventional lost circulation material (LCM) pills to preserve the reservoir and stabilize equivalent mud weight to 1.23 sg to run wireline logs. Eighteen conventional LCM pills comprising a variety of materials were deployed, but they were unsuccessful in curing losses, resulting in more than 2,491 m3 of drilling fluid lost to the formation. The mud circulation evaluation at 1.21 sg showed more than 48 m3/h of losses. Drilling operations stalled for more than 12 days, creating significant NPT.
SLB recommended Losseal Max lost circulation control treatment to reduce fluid loss and save a significant amount of NPT. The treatment is a blend of fine particulates and reinforcing fibers able to bridge large fractures up to 10 mm to reduce fluids lost to the formation. It is applicable to lost circulation scenarios for moderate to severe or total losses in land and offshore environments. Losseal Max treatment was pumped with a cement unit and squeezed into the formation for 1 h. The treatment was chased with FLOPRO NT™ water-based reservoir drill-in fluid.
One hour after squeezing the treatment into the formation, the operator verified that the losses had been completely cured. The equivalent mud weight reached 1.23 sg, enabling successful completion of openhole wireline logging. The desired reservoir samples were retrieved with no damage resulting from tool activity. The success of Losseal Max treatment made it possible to acquire the reservoir information in that section instead of switching to PMCD mode at this stage. Losseal Max treatment worked quickly and effectively to enable information, preventing additional NPT.
