New Generation PDC Bits Set New Benchmarks in Carbonate Drilling, Resulting in Significant Performance Improvements and Cost Savings for the Operator
Authors: Al Hinaai Ahmed , Geraud Marcel , Cruz Marco , Butt Imran , Evans Nicholas 
Published: January 2013

Intensive application engineering analysis, extensive technology research and proven field tests have delivered a new generation of PDC technology for drilling carbonates. This new technology will be a step improvement and benchmark for flawless drilling performances and cost saving well economics.

Different carbonate applications in Oman require PDC bits that deliver extended lengths of intervals drilled, high speed, exceptional steering capability in case of deviated wells and low cost per foot runs. In-depth engineering analysis for each application with different customers culminated in the right choice of bit for every operation.

The latest state of the art PDC bits, with significant enhancements to the bit features, are delivering outstanding performance for drilling carbonates in the Sultanate of Oman.

The first trial of this technology was conducted in field A. This application utilized a steerable motor in a typically fast ROP environment to drill through a carbonate section up to KOP and then drill the nudge section of 25-35 degrees at a 2-4 deg/100’ build up rate. The accumulated length drilled with the new PDC bit technology amounted to approximately 5500 ft. The bit also managed to improve penetration rate up to 46% as compared to the previous record and 37% (1.5 days) savings in time were achieved when compared to the best composite time for this field.

The success of the first new technology PDC run was an encouragement to proceed with a trial in a more challenging application. Different designs of the new PDC bit were tested for Field B in Deep Gas exploration wells. The application in Field B was vertical drilling through +2000m interval of interbedded carbonate with a stringer of shale. The new PDC, in combination with a Rotary Steerable system and low speed motor, drilled the section achieving 28% faster ROP than the best fastest drilled record interval for the field. At the same time it also delivered 55.5% (3.98 days) savings in time as compared to the best composite time record for this field.

Another accomplishment of the new technology was in Field C, which utilized the same bit design as was run in Field B. The application was vertical motor drilling through long intervals of interbedded carbonate, shale and hard as well as abrasive sandstone. The new technology PDC managed to set a new field record in the first run, drilling the longest, deepest, and fastest run in the field. The bit was 11% faster than best previous run, and came out in an excellent dull condition. The new technology has delivered a step change in drilling performance, improved ROP, extended run lengths, better steerability, and lower cost per foot.

The authors will describe the technologies included in the new generation of PDC bits. The target applications and objectives will be discussed and several cases studies will be provided to show the exceptional performance and major cost saving benefits of the new technology.