The unique 3D geometry of the Stinger* conical diamond element has proven to increase bit performance across a wide range of formations and operating parameters.
Positioning Stinger elements across the bit face delivers a step change in drilling performance and rock failure.
StingBlade* conical diamond element bits provide multiple advantages over conventional PDC bits.
- Significantly improved footage and ROP;
- Higher build rates with better toolface control;
- Enhanced bit stability for BHA shock and vibration mitigation;
- Larger cuttings for better surface formation evaluation at the rig site.
Stinger elements apply a significantly higher concentrated point load on the rock, and the elements’ thicker diamond table enhances impact strength and wear resistance. This combination enables StingBlade bits to significantly improve footage and ROP in challenging drilling applications—including hard, interbedded, conglomerate, and chert- and pyrite-inclusive formations—that can cause impact damage to conventional drill bits.
During field tests of more than 250 runs in 14 countries, StingBlade bits averaged a 55% increase in footage with a corresponding 30% increase in ROP compared with bits used in offset wells.
Efficient rock destruction
Smith Bits engineers optimized the Stinger element’s 3D conical geometry using finite-element analysis (FEA) to model the precise point at which the element’s tip contacts the formation. The result is an ultrahigh-concentrated force that fractures high-compressive-strength rock more efficiently.
Impact strength
Stinger elements have a thicker diamond table compared with PDC cutters, yielding significantly improved impact strength. When impacted onto hardened steel at more than 18,000 lbf to simulate drilling into a high-compressive-strength carbonate at 60 ft/h, a conventional PDC cutter experienced a catastrophic failure on the first impact while the Stinger element survived more than 100 impacts with no damage.
Wear resistance
Composed of a state-of-the-art blend of polycrystalline diamond materials and built into a unique conical shape, Stinger elements dissipate heat more efficiently than conventional PDC cutters for improved wear resistance. When a Stinger element and a PDC cutter were tested by drilling a 30,000-psi granite formation, the Stinger element drilled 30% farther than the PDC cutter without losing its cutting edge.
Case Study1
An operator planned to drill a 12.-in vertical section in the Browse basin offshore Australia through the challenging Dampier, Heywood, Baudin Marl, and Wollaston Formations. These formations are composed of interbedded hard limestones and chert with high compressive strengths, which induce heavy damage to conventional PDC bits. Such damage slows ROP and requires the operator to pull bits prematurely, requiring more time to drill the section.
To improve bit durability and ROP, Smith Bits, a Schlumberger company, recommended using StingBlade bits. Engineers used the IDEAS* integrated drillbit design platform to determine the optimal placement of Stinger elements across the bit face. The Stinger elements’ 3D conical shape is designed to fail high-compressivestrength rock with a concentrated point load. The elements also have a thicker diamond layer for maximum strength and durability. This enables StingBlade bits to drill farther through formations that typically cause impact damage to PDC bits.
The first StingBlade bit drilled 1,516 m at 11 m/h, equaling 97% more footage than the best run in the same section of the offset well. ROP also improved by 57% in this run. The second StingBlade bit drilled the remaining section to TD at an average ROP of 16 m/h. Altogether, the two StingBlade bits helped the operator save more than 5 days of drilling time.
Case Study2
GMT Exploration planned to drill three horizontal wells in the Bone Spring Formation, located in the Delaware basin section of the Permian basin. These wells have challenging 77?8-in intermediate intervals composed of interbedded shales, limestones, and sandstones, which typically require multiple PDC bits because of slow ROPs caused by impact damage to the PDC cutting structure.
Smith Bits recommended StingBlade bits. Engineers used the IDEAS platform to determine the optimal placement of the Stinger elements for the specific application. The Stinger elements’ 3D conical shape is designed to fail high-compressive-strength rock with a concentrated point load while maximizing strength and durability with a thicker diamond layer. This enables StingBlade bits to drill farther through formations that typically cause impact damage to PDC bits.
One StingBlade bit drilled 4,030 ft at 57 ft/h, which increased footage by 77% and ROP by 29% when compared with the average performance of bits used in offset wells. On the following two consecutive wells, StingBlade bits repeated the performance improvements over the average offsets; the second run had 73% greater footage and 26% greater ROP, and the third run had 44% improved footage and 10% higher ROP. Between the three wells, GMT Exploration saved 2.5 drilling days.
Case Study3
Operators and directional drillers continue to face issues with steerability and toolface control of conventional PDC bits when drilling curve sections in unconventional wells. Bits containing rolling cones can suffer from reliability issues and low rates of penetration, resulting in operating hour limitations and the ever-present chance of losing cones downhole.
A controlled field test was carried out comparing the directional response of a StingBlade bit and a PDC bit in an unconventional curve section. Both bits were run in adjacent boreholes less than 50 ft apart, kicking off at identical depths and using the same rig, steerable motor, BHA, and directional drillers.
The StingBlade bit yielded 23% higher build rates and had less overall torque and toolface-angle fluctuations, making it easier for the directional drillers to stay on the planned curve trajectory.
One of the directional drillers who ran the test bits said, “I was surprised to find how easy the StingBlade bit was to steer. It had very little reactive torque; all it took was a little tweak to the right or left to maintain toolface.”
Case Study4
During operations in Kazakhstan’s Chinarevskoe field, Zhaikmunai LLP, a member of the Nostrum Oil & Gas Group, sought to increase ROP and identify lithology types and properties of a hard carbonate formation with high chert concentration. Diamondimpregnated drill bits were the standard approach due to high durability, but ROP was low and cuttings were small, limiting surface logging formation evaluation. Furthermore, the small cuttings made it difficult to separate them from the drilling fluid, which created a gradual increase in mud weight throughout the interval.
Smith Bits engineers suggested using a StingBlade bit along with the PowerV* vertical drilling RSS. Stinger elements interact with the formation through a unique rock-destruction mechanism that creates larger cuttings at optimal drilling speeds.
The integrated BHA drilled the entire planned interval with a 166% increase in ROP compared with offset wells. This improved drilling efficiency saved Zhaikmunai 6 days of drilling time and approximately USD 180,000. Additionally, the larger cuttings produced by the StingBlade bit enabled wellsite geologists to readily identify lithology types and properties. The cuttings were also easier to separate from the drilling fluid, reducing costly mud replacements.
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