After analyzing client data from offset wells, the Baker Hughes drill bit team in Egypt developed a case for a trial run of the Hughes Christensen Quantec™ PDC bit technology, which resulted in savings of $152,000 on two wells. After using both PDC and Tricone bits in demanding deep-drilling applications, the multinational oil company that operates as a joint venture with the Egyptian Government Petroleum Company, had found the Tricone bits delivered only slow rates of penetration (ROP).
After studying the formation characteristics, Tricone selection and failure of other PDC bits that had been used, Baker Hughes experts realized that they needed to increase durability without sacrificing ROP. “Working with the client to analyze offset data, Baker Hughes committed to trial bits to help the client reduce overall costs with bit selection to increase ROP and to realize longer bit runs,” says Mohamed Zanaty, technical marketing representative.
In the first well chosen for the test, the interbedded Alam El Bueib formation was drilled with an 8 ½-in. Quantec bit, replacing two tungsten carbide insert (TCI) bits from direct offsets. “The Quantec frame is stable, and the premium cutters are both durable and impact resistant, resulting in longer, faster runs,” says Darren Eckstrom, senior application engineer for Baker Hughes drill bits for Egypt, Syria and Jordan.
The heterogeneous Alam El Bueib formation is highly interbedded with abrasive intervals that go from hard to soft and vice versa, posing great challenges for PDC bits, Eckstrom adds. “There are often negative drill breaks and a very high probability of the onset of drilling dysfunctions such as stick-slip or whirl, which are destructive to PDC bits. Six-bladed, 16-mm cutter bits were tried, but they came up short because of durability and cutter breakage and were pulled for slow ROP.”
With a high percentage of torque management, the Quantec bit drilled smoothly, handling the interbedded formations without bringing on drilling dysfunctions. The results were 73% higher ROP and 35 percent lower cost per meter compared with recent offset wells, delivering cost savings of $71,000. Another opportunity for Baker Hughes came after a competitor’s bit had been tripped out of the hole after delivering a ROP of only 1 m (3.2 ft) per hour.
“The client elected the Q506FHX bit, which delivered 278 m (912 ft) at 7.7 m (25 ft) per hour, an ROP improvement of more than 185 percent at 47 percent lower cost per meter when compared with the average competitor performance in this section,” Zanaty says. “This was a savings of $81,000, bringing the total savings for two wells to $152,000.”