Improved drilling performance and cost reduction through straight-hole-motor drilling in the Fort Worth basin

This paper discusses Mitchell Energy Corp.`s attempt to improve performance and to reduce drilling cost through routine drilling with downhole mud motors. The potential to increase rate of penetrating (ROP) and to reduce drillstring attrition was the primary driver for developing a practical straight-hole-motor (SHM) operation. An economic criterion based on ROP increase compared with that in conventional rotary-drilled offset wells was established to monitor performance to justify motor expense. During the trial and learning phases, problems were encountered and the ROP-based economic criterion was barely met; however, additional benefits emerged. Hole enlargement was significantly reduced, which led to mud and cement savings, and less hole rugosity improved general log quality. These early results prompted the persistence needed for problems resolution. Thus, drilling contractor, operator, and service company personnel worked together as a team and developed a SHM operation beneficial to all.