Chicontepec field is located in the northern portion of the state of Veracruz, Mexico. The typical well drilled in the field has a directional "S" shape profile (up to 4°/30m DLS) with three casing points. The main challenge is constructing the 6-3/4" section generally between 500m to 2000m including Tantoyuca (500-700m), Guayabal (700-1200m), and Chicontepec Formations (1200-2000m). The Tantoyuca formation is a shaley sandstone with an average UCS of 8,000psi. The Guayabal is deep-water shale with an average UCS of 3,000psi. Finally, the Chicontepec paleochannel is composed of sandstone and shale with an average UCS of 10,000psi with maximum values reaching 25,000 psi.

A detailed analysis of the application was performed to optimize the BHA (motor/PDC bit) to improve performance and drill the section in one fast run. As a result of the study, the operator elected to implement a two-staged performance improvement strategy including a more powerful mud motor (5:6 greater torque) in combination with a 5-bladed PDC with 13mm cutters.

The new bit design selected has an innovative depth-of-cut control technology designed to eliminate the reactive torque problem while sliding. The bit also has a new, highly abrasive resistant PDC cutter for increased durability. This new technology was coupled with a revised set of operating parameters and drilling recommendations to optimize performance and meet the operator's ROP requirements.

The authors will document how the implementation of best practices and the correct combination of the motor/PDC BHA contributed to drill 30% of all 6-3/4" production sections in 2005 at over 33m/hr average ROP. This resulted in an average reduction of three days to finish the wells, saving the operator $1.5 Million USD while setting a new field benchmark.

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