Increase ROP through hard, interbedded section of 38 wells
Block 61 of the East Basin in Ecuador features the Tiyuyacu Formation. This formation is made up of interbedded claystone, sandstone, and conglomerates with chert cobbles and pebbles. This formation is well known to cause extensive damage to cutting structures in the shoulder area of the bit, and in this location, has an unconfined compressive strength (UCS) of 10,000 to 15,000 psi. Damage caused by this formation leads to multiple bit runs per section—which means more rig time and money.
The operator needed a new type of durable bit to drill each section of 38 wells in this block, avoiding pulling out of hole for bit changes.
Use the StingBlade bit to mitigate impact damage
To meet the operator’s requirement for bit durability in this section, Schlumberger proposed using StingBlade bit to drill through the harsh formation. The shape of the Stinger conical diamond element is designed to withstand high impacts, preventing damage to the other cutting elements and resulting in greater durability in these kinds of formations. Higher durability in this formation meant that the operator could drill longer runs and at a high, sustained ROP.
Based on information gathered from previous runs, Schlumberger used the IDEAS integrated dynamic design and analysis platform to maximize bit aggressiveness, durability, and drilling dynamics. Schlumberger designed the bit to have Stinger elements across the bit shoulder area and optimized hydraulics to improve cutter cooling. The design also implemented three blades in the venter with Lo-Vibe depth of cut control inserts to mitigate torsional vibrations, and adjustments to the back-rake angle of the cutting elements.
Saved 64 drilling days and USD 7,000,000
The addition of the Stinger element in the shoulder area of the bit mitigated the cutting damage, confirming that the new bit design was effective.
Throughout the 38 runs, the StingBlade bits increased the average ROP by 33% and saved the operator 64 rig days—and an estimated USD 7,000,000 in rig time. The operator was able to get to production early, enabling it to drill more wells in a given period than anticipated. The overall performance of the StingBlade bit outperformed the operator’s expectations and the average performance of offset wells in Block 61 of the East Basin in Ecuador.