Published: 10/05/2012
Published: 10/05/2012
Drilling 8 3/4-in lateral sections in the Eagle Ford shale of Karnes County, Texas, an operator was experiencing the difficulties commonly associated with shale play applications: Drilling is generally conducted using low-power rigs and mud weights of 10.0 to 12.6 ppg. These factors produce a poor hydraulic environment with low flow rates. Adding to this, is a hydraulic horsepower (HSI) of 0.02 to 1.71 at the bit, which impairs cuttings evacuation, and results in poor toolface control, and low ROP.
To increase the operator's drilling efficiency in shale formations, Smith Bits recommended the next-generation Spear bit. It is based on the first-generation Spear bit—characterized by its distinctive bullet-shaped steel body—which significantly reduced bit balling and cuttings packing around that afflicted matrix PDC bits.
The new generation of Spear PDC bits, developed using IDEAS integrated drillbit design platform, features increased capabilities through design enhancements: Taller blades resulting in an increased junk-slot area, promotes cuttings migration from the bit face. A shale evacuation channel around nozzle ports and an improved hydraulic configuration directs cuttings evacuation to inhibit nozzle plugging. In addition, a reduced bit body profile improves cuttings evacuation into the annulus.
The next-generation Spear bit design drilled the 4,308-ft 8 3/4-in curve and lateral section at an average rate of 79 ft/h while demonstrating good toolface control. Compared with the offset well median ROP of 64.7 ft/h, the new Spear PDC bit increased ROP 22%. Upon reaching TD, it was pulled in excellent dull condition: 0-1 with no wear on the cutting structure. Compared with the offset well median ROP of 64.7 ft/h, the new Spear PDC bit's ROP represents an increase of 22%.
Challenge: Drill an 8 3/4-in curve and lateral section, of at least 4,000 ft in a problematic shale formation—with maximum efficiency and toolface control—in a single run.
Solution: Run 8 3/4-in, SDi516MHPX, five-blade, next-generation Spear shale-optimized steel-body PDC drill bit, which has enhanced cuttings removal from the bit face, delivering improved directional control.
Results: Drilled curve and lateral section at an average rate of 79 ft/h while maintaining good toolface control and increasing ROP over nearest offsets by 22%.
