Application of New Impregnated Diamond Bit Technology Saves Operator $2 Million Drilling Southern Oklahoma Well

Abstract

Abstract Economic development of deep gas wells, such wells in the Carter-Knox field in Stephens and Grady Counties, Oklahoma, depends on the effectiveness and efficiency of the drilling program. Many costly challenges are encountered while drilling the deep, high compressive strength, abrasive sandstone and interbedded shale in this geologically complex area with high-angle beds, faults, fractures, and depleted formation pressures. Improvements in bit technology have expanded the variety of formations that can be drilled with impregnated bits at penetration rates equivalent to roller cone bits. This technology has helped reduce the risk in drilling operations while improving well economics. A recent well in the Carter-Knox field utilized three new impregnated bits to drill the interval from the third Bromide sandstone (15,000 ft) through the Arbuckle limestone and dolomite (18,700 ft) in 51 days improving well construction time by 35% over the best offset. Previous offset wells required 18 to 20 roller cone, natural diamond and traditional impregnated bits to drill the same interval in 78 to 155 days. The operator reached total depth 21 days ahead of the AFE and $2.07 million under budget. Reducing the dry hole cost more than 30% has positively impacted the development plans for the Carter-Knox field. The operator and a bit manufacturer cooperatively applied new bit technology to an optimized well program to reduce drilling costs. Attention focused on using recently developed impregnated bits that drill shale at penetration rates equivalent to rollercone bits without loss of performance in the hard abrasive sandstone formations. This technology combined with changes in drilling practices has increased the overall average penetration rate, kept the bit drilling on bottom, and replacing multiple bits. The longer bit runs also reduced the number of bit trips limiting potential problems associated with tripping operations through depleted and sensitive formations.