The operator’s concerns

The operator wanted to drill an 8 3/4-in vertical as fast as possible in a formation consisting of hard limestones intermixed with anhydrites and sand. The formation strength required a durable bit capable of increasing ROP in the section.

What was tried first

A third-party 8 3/4-in bit used in a baseline run achieved an on-bottom ROP of 147 ft/h.

What Schlumberger recommended

Customizing a Smith Bits AxeBlade bit with Axe SR elements was recommended for outstanding durability and cutting efficiency. Axe ridged diamond elements in the cone of the bit enable higher ROP.

What was achieved

The shape of the Axe SR elements in the cone of the 8 3/4-in bit enabled a higher depth of cut with the same parameter set. The point-loading shape in the cone efficiently broke away the hard formation in the lower vertical section while increasing ROP. Compared with the baseline run, the AxeBlade bits incorporating Axe SR elements increased average ROP by more than 10%, achieving on-bottom ROPs of 159 ft/h, 168 ft/h, and 175 ft/h in three runs.