Published: 06/13/2017
Published: 06/13/2017
Oil and Natural Gas Corporation Limited (ONGC) in India needed to drill 300 m [984 ft] through a very hard and abrasive intertrappean basalt formation to complete a 2,000-m [6,562-ft] section of a well in the Kutch-Saurashtra block in Western Offshore, Mumbai High. The compressive strength of the formation ranged from 18,000 – 42,000 psi [124.1 – 289.7 MPa]. In two offset wells, the operator required 15 roller cone bits to drill through the same section. The average meterage achieved with roller cone bits was 100 m [328 ft] at an average ROP of 1.1 m/h [3.6 ft/h]. This poor ROP resulted in a high cost per meter.
Based on simulations using the IDEAS integrated dynamic design and analysis platform, Schlumberger suggested deploying a 12 1/4-in Z813 StingBlade bit with RockStorm technology. This type of bit has proven performance in hard-to-drill applications, such as in chert and pyrite, which are typically abusive to conventional or standard PDC bits.
In Run 4, the StingBlade bit drilled through 229 m [751 ft] of basalt with an average ROP of 2.2 m/h [7.2 ft/h], which is an increase of more than 70% from the offset average. This run set the field's highest ROP and lowest cost per meter while drilling basalt. In addition, it doubled the footage drilled, compared with the offset wells. It was also the first run of a StingBlade bit in the basalt formation worldwide.
Challenge: Drill through hard, abrasive basalt with one PDC bit to reduce the number of roller cone bit runs.
Solution: Use a 12 1/4-in Z813 StingBlade conical diamond element bit with RockStorm wear-resistant high-impact PDC cutter technology.
Results:
