As computing power has become more affordable and E&P industry understands of down hole drilling dynamics has improved, sophisticated simulation software has been developed to optimize drilling. Most drilling engineering analysis software has been based on using static analysis assuming steady-state conditions. Although useful, the end result was little more than a snapshot of anticipated forces. Advanced sensors in Bottom Hole Assembly (BHA) and improved surface sensors now provide digital measurements of Weight on Bit (WOB), Rate of Penetration (ROP), torque, and vibration as a function of time. As a result, it is possible to develop and validate more-complex and -accurate drilling models. Drilling simulation can now provide access to any one of the thousands of nodes presented by means of mesh software rather than by means of static analysis. The i-DRILL drilling simulation from Smith Technologies is an example of this functionality.
Within the virtual environment, the bit type/style, the individual BHA elements and their relative placement, the drill string, the operating parameters, and the drive and/or steering mechanism (e.g., positive-displacement motor, rotary-steerable tool, and turbo drill) can be varied to identify the optimum combination. Bits and BHAs are methodically tested and retested through the virtual simulation regime, eliminating the poorer performers until the best match and highest normalized score are found. Once these elements are identified, the targets are quantified and weighted according to the economic and strategic (reservoir) project drivers. Once the “best” system is selected from all the options analyzed, dynamic simulations are prepared to visually compare the best vs. worst performance across a variety of drilling dynamics including torque, contact forces, and bending moments. Typically, the driller on tower and the office-based engineering supervisor are briefed during the prespud planning meetings so that the ranges of parameters are clearly understood. A series of video clips are generated so that engineers can see the system in action and to confirm the choices made.