Optimization of Drilling Performance in Argentina through a New PDC Bit Generation

The lithology of the North West of Argentina presents two major portions where PDC bits have not succeeded in the past. The first portion was mainly made up of alternating sands and shales with spot zones of conglomerates erratically encountered. The second portion was made of dense shales and cemented sandstone stringers, with altemances of limestones. In spite of acceptable performance on the top portion. conventional PDC bits faced premature failures when the compacted sandstones and limestones were faced. Rock bit performances were usually in the range of ± 6 to 7 m/h and the footage around 360 m. The section was drilled with five to six bits for a total drilling time of 220 hours. The introduction of a new generation of PDC bits allowed to triple the ROP and increase by five times the potential footage. This paper describes the methodology and shows the efficiency of a good partnership between the operator and the service company; a good level of communication, a knowledge of mutual skills and expectations, as well as a prompt reaction from both sides led to the definition of a reliable product using the latest developments of the PDC bit technology: . the ability to control the quality of the PDC cutters, . the use of an advanced cutter lay out defined by 3-D software, . the use of CFD code for optimized cleaning and cooling, . the mastering of vibration reducing features, including spiralled blades etc. Savings in the range of 200,000$ per well were recorded at the first trial of a drilling program. Fine tuning of the technology and parameters now allow savings beyond 350,000$ per well.