The concept of Mechanical Specific Energy (MSE) has been used effectively in lab environments to evaluate the drilling efficiency of bits. MSE analysis has also been used in a limited manner to investigate specific inefficiencies in field operations.3,4 In early 2004, the operator initiated a pilot to determine whether the concept might be used more broadly by rig-site personnel as a real-time tool to maximize the rate of penetration. The results have exceeded expectations. The average ROP on the six rigs selected for the three-month pilot was increased by 133% and new field records were established on 10 of 11 wells.
The MSE surveillance process provides the ability to detect changes in the efficiency of the drilling system, more or less continuously. This has improved performance by 1) allowing the optimum operating parameters to be identified easily, and 2) providing the quantitative data needed to cost-justify design changes to extend the current limits of the system. MSE analysis has resulted in redesign in areas as diverse as well control practices, bit selection, BHA design, makeup torque, directional target sizing and motor differential ratings. The use of MSE surveillance is a key feature in a family of well planning and operational practices that are referred to as the ExxonMobil Fast Drill Process (FDP). These are now being introduced in other operating areas throughout the global organization.