Floater drills with casing off Indonesia

April 21, 2003
Santos Madura Offshore Pty. Ltd. completed the industry's first well drilled with casing from a floating rig, according to Weatherford International Ltd.

Santos Madura Offshore Pty. Ltd. completed the industry's first well drilled with casing from a floating rig, according to Weatherford International Ltd.

The Transocean Sedco 601 semisubmersible drilled the well in the Madura Straits, off East Java, Indonesia, an area prone to shallow gas kicks and blowouts. In an announcement, Weatherford said the drilling included surface blowout preventers (BOPs). With drilling with casing technology, Santos eliminated a 30-in. casing string and was able to substitute a 133/8-in. casing string for the usual 20-in. casing string run in the area.

The casing used was 133/8-in., 72 lb/ft buttress with a P-110 NSCC riser pipe. The drill shoe had a 171/2-in. OD.

The 133/8 casing was drilled to 869 ft in 5 hr at a 132-fph penetration rate, according to Weatherford. It said the procedure saved 21/2 days of rig time, reduced more than 80% in the overall running time, and enhanced safety by reducing the number of people on the rig floor during casing running operations.

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Fig. 1 compares the time for drilling this section of the well with casing vs. time with conventional drilling in an offset well.

Weatherford further said that the use of its easily drillable DrillShoe technology, which includes a drillable drill bit with thermally stable synthetic diamonds (TSP) and tungsten carbide cutting structure, eliminated the time-intensive process of retrieving casing bit bottomhole assemblies required by other methods of casing drilling.

Cementing operations, therefore, began almost immediately after drilling reached casing's setting depth. The casing was set and cemented in 21.5 hr, according to Weatherford.

Drilling parameters included 5,000 lb weight on bit, 50-55 rpm, 0-3,000 ft-lb torque, 575-gpm circulation rate, 0.78-in. total flow area, 560-psi pressure developed, and 1.0 hp/sq in.