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Technical Paper: Maximizing BHA Durability/Reliability: Turbodrill/Impregnated Bit Significantly Reduces Drilling Time in Granite Wash Laterals

Society: SPE
Paper Number: 163408
Presentation Date: 2013
 Download: Maximizing BHA Durability/Reliability: Turbodrill/Impregnated Bit Significantly Reduces Drilling Time in Granite Wash Laterals (0.80 MB PDF) Login | Register

 

Abstract

Inconsistent roller cone/PDC bit performance drilling horizontally through the hard/abrasive Granite Wash reservoir in western Oklahoma has resulted in low ROP, increased operating days, and escalating drilling costs. The difficult Marmaton age wash formation is encountered at 11,000-13,000 ft TVD and has unconfined compressive strength (UCS) in excess of 30,000 psi. The typical well requires drilling a curve to horizontal, then 4,000 ft of 6-1/8-in lateral borehole. Offsets analysis revealed that one to four RC/PDC bits are required to drill the curve, in addition to one to 13 bits to finish the lateral. The operator required a technological solution to minimize bit consumption/trips to lower well construction costs while achieving directional requirements.

An analysis of the most troublesome wells was conducted and a mathematical-based predictive analysis software identified the changes required to efficiently deliver the directional objectives. The study indicated that using a 4 3/4-in high-power steerable turbodrill, with two bends and a specific stabilization setup coupled with an application-specific 6 1/8-in diamond impregnated bit would significantly increase BHA performance and enhance section economics. The operator’s drilling team studied the recommendation and concluded the BHA had the potential to increase reliability and reduce operating costs drilling the difficult Marmaton Wash.

This new turbodrill/impregnated bit BHA was run in several Washita and Beckham County wells with outstanding results. In one well the BHA drilled 4,040 ft of 6 1/8-in lateral hole section in a single-run saving the operator eight drilling days and  USD 348,000 versus plan. The assembly required steering only 17% of the time. The borehole was completed in 589 hrs at an average ROP of 6.9 ft/hr. This performance set several new world drilling records. The authors will present case histories that illustrate performance achievements in the horizontal section and provide details that contributed to the success of the unique BHA.

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