FLC 2000® Plays Key Role in Landing Sidetrack in Problematic Section in Saudi Arabia

While drilling in the offshore Hasbah field, a polymer mud with conventional lost circulation material was used to drill the 16-in. hole section on the HSBH-49. The initial mud weight was 9.6 lb/gal and increased to 10.2 lb/gal while drilling to 8,760-ft. (Lower Fadhili formation). The circulation rate was 900-925 gal/min with an average rate of penetration (ROP) of 60 ft/hr. The transition zone to the Dhruma shale (at 9,160-ft.) consists of interbedded layers of dolomite and limestone, with possible fractures. While drilling through this section, lost circulation was encountered and the rig was unable to regain circulation. The decision was made to drill ahead with the mud cap, with no returns to the surface. Stuck pipe was encountered at 9,031-ft. Fishing operations were unsuccessful and the BHA could not be retrieved. The decision was made to sidetrack the well.

The polymer mud formulated for the sidetrack and included an addition of 5 lb/bbl of FLC 2000 wellbore stabilizer. The mud weight was maintained at 9.6 lb/gal and drilling rate was controlled at 30-40 ft/hr with a circulation rate of about 800 gal/min. The mud system was later converted to an enhanced water-based mud (WBM) system with the addition of shale inhibitors added from +/- 9,000-ft. before entering Dhruma shale. The change in drilling parameters and mud formulation resulted in no drilling fluid related issues while drilling to 9,268-ft. (16-in. hole) as well as the 83⁄8-in. pilot hole to a depth of 9,873-ft.