This IDEAS 12 1?4” MDi716 PDC bit successfully met all directional and drilling performance objectives while being run on a steerable PDM and both a point-the-bit and push-the-bit RSS in the North Sea. (Image courtesy of Smith International Inc.)

Bit selection and optimization have always been a focus for the drilling engineer, but with the growing complexity in well geometry and increasing use of rotary steerable systems (RSS), this issue has become critical to achieving drilling objectives. Thus a significant challenge has been to understand the behavior of the drill bit and its influence on the overall drilling system.

To address this issue, Smith International developed IDEAS (Integrated Dynamic Engineering Analysis System), a comprehensive 4-D modeling tool that accurately predicts a drilling system’s performance and behavior. The IDEAS model delivers a projection of a bit’s performance considering the drive system, bottomhole assembly, formation characteristics, and operating parameters.

A crucial first step in this process is to understand the rock. Rigorous laboratory studies are designed to characterize the rock/cutter interface across a full range of rocks and cutter types. With this data the modeling program performs an analysis in a fully dynamic simulation that accurately represents conditions encountered in the real drilling environment. Using IDEAS, the design engineer can then evaluate and manipulate design characteristics that achieve dynamically stable design solutions on multiple drive systems. All this is achieved while ensuring the rate of penetration (ROP), durability, and directional control objectives are not compromised. With improved stability comes reduced levels of vibration that result in longer life for sensitive RSS/measurement-while-drilling/logging-while-drilling electronics and increased ROP/total footage. IDEAS provides an understanding of interaction of the rock, drill bit, and drive system. In a project in the North Sea, IDEAS was used to design the resultant bit MDi716. The bit demonstrated stability and steerability on multiple drive systems giving minimal vibration and excellent directional control. Thus, using IDEAS it has been capable to develop a PDC bit design solution that can be successfully deployed on multiple drive systems, without compromising performance.

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