Innovative Impregnated Drill Bit Design With Enhanced Durability Improves Performance in Challenging Application in Colombia


Vertical wells are drilled in the Colombian foothills with various types of drill bits, including polycrystalline diamond compact bits (PDC), tungsten carbide insert bits (TCI), and impregnated (impreg) drill bits. With an operator’s support a new 14¾-in. impreg bit was designed using an innovative new cutting structure to complete a challenging interval. This bit was paired with a low-speed power section and a high-speed power section in the bottomhole assembly (BHA) for two runs in the same well. Both runs did well, but the operator found the low-speed BHA to be a better match for the automated drilling system tool that was also in the BHA.

The multi-layered 14¾-in. section consists of hard and abrasive sandstone, interbedded claystone, and siltstone formations. The majority of drill bits suffer short runs due to severe wear in the outer region (shoulder) of the bit. The new impreg design was developed to increase run length and avoid unnecessary trips in the challenging formations.

The impreg bit uses diamond impregnated segments imbedded in blades comprised of diamond grit matrix material to create a cutting structure with variable wear along the bit face. This particular combination of diamond and matrix specifically corresponded to the application and improved overall aggressiveness and durability in the shoulder.   

To drill efficiently, impregs are typically paired with high-speed motors or turbines (500-1200 rpm) due to the low depth of cut. This new impreg design, however, successfully drilled on two different BHAs. The first was with a high-speed power section (0.93 rev/gal) and drilled 108 ft at 4.9 ft/hr. The bit did not show signs of wear and was used on a second BHA with a low-speed power section (0.15 rev/gal) that drilled another 665 ft at 3.9 ft/hr. The impreg’s overall performance was 773 ft drilled at 4.0 ft/hr. The bit showed only minor wear when compared to offset wells (15% vs. 80 to 100% cutting structure wear).

The addition of the impregnated segments and mixed grit combination improved the cutting structure durability. This success provides an opportunity to further develop the grit, matrix, and impregnated segment combination to increase the aggressiveness of the bit to drill faster and lower the overall drilling cost of a well.

This article will explain the benefits of the new technology and discuss how impregs effectively drilled hard and abrasive formations in a low-revolution application.  

IRev Impregnated Diamond Drill Bits

IRev™ impregnated diamond bits offer a more aggressive rate of rock removal for improved drilling performance, ROP, and reduced NPT in abrasive environments.

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