The industry continues to demand drill bits that are more application-specific and that extend the performance envelope in terms of rate of penetration (ROP), bit life, (particularly in harder, more abrasive formations), bit stability and vibration mitigation and directional predictability and responsiveness.

In addition to improved performance, the industry has been demanding objective, quantitative analysis tools for identifying the specific bit that will perform best in a given application. As bits become more application-specific, a more precise analytical approach to bit selection is essential.

To achieve a less risky, faster method of developing better bits and to provide a more

When comparing the bottomhole pattern of the conventional M813 (right) to the IDEAS Mi813 (left) bit design, the significant stability improvement of the IDEAS design is readily apparent. (Image courtesy of Smith Technologies)
quantitative and accurate method of bit selection, Smith Bits has developed its IDEAS (Integrated Dynamic Engineering Analysis System) design platform, and the advanced engineering modeling system has been applied successfully to both roller cone and PDC bit designs.

The highly sophisticated drilling models that underlie the IDEAS design platform are based on exhaustive laboratory studies of the precise mechanics of the rock/cutter interface for an extensive range of cutter types across a broad range of formation types. By incorporating this quantitative understanding of rock chip generation and removal for each individual cutter into a dynamic model of the total drill string including each individual element of the bottomhole assembly (BHA) all the way up to the surface drive mechanism, the company can accurately predict the performance of a new bit design before the first prototype bit has been run downhole. The result is the ability to produce improved bit designs faster, with greater predictability, and without exposing the operator to a high degree of risk and uncertainty.

The elements of IDEAS

There are six basic elements to the IDEAS certification:
Comprehensive drilling system analysis. The IDEAS process does not develop the bit design in isolation from the other elements of the total drilling system. IDEAS recognizes the significant impact of the drill string and the individual BHA components on bit performance, and it takes into account the specific operating parameters and the interaction of the individual elements of the entire drilling assembly.

Holistic design process. With proper insight, virtually every cone or cutter layout and configuration can be designed to be stable. Specific features previously thought to be essential to manage stability independently may or may not be effective depending how they are deployed. IDEAS bits are therefore not feature-specific, but are holistically designed for optimized performance in the targeted application.

Application-specific performance enhancement. IDEAS bits have consistently outperformed previous designs when measured against their key design objectives, whether the need is for improved ROP, durability, or specific behavior for today’s complex rotary steerable tools. As a result of the total design understanding, operators often see increased footage and faster ROP resulting from the improved dynamic stability of the designs.

Synergistic integration with the total drilling system. IDEAS bits are dynamically stable within the parameter envelopes for which they are designed. The benefit of this stability is that optimized parameters can be maintained for faster, longer runs with less stress on the BHA and rig equipment, and with the added benefit of improved bit durability.

Rapid solutions, reliable results. IDEAS bits can go from concept to successful deployment much faster than conventional design regimens. Since the process uses a simulation model that predicts the real world behavior of the bit extremely accurately, testing of the new design is done in a virtual environment instead of the time consuming multiple field trial iterations associated with conventional drill bit design.

Optimized integration of advanced materials. IDEAS gives the ability to use advanced cutter materials to do more than just correct for weak, high-wear areas in non-optimized bit designs. The combination of advanced cutter materials with IDEAS analysis helps get the most benefit out of advanced, more abrasion and impact resistant cutters.

Design certification

The IDEAS process can be used for both the certification of new bit designs and to compare the performance of two or more bit designs to help determine the best bit for an application. The process begins with the collection of data from the operator and the Smith Drilling Records system. This information includes:
• Bit performance and dull bit analysis from offset wells;
• Lithology of the target well; and
• Make up of the drill string and the individual components of the BHA, including precise dimensions of each component.

Once the actual rock/cutter data is obtained, it is integrated into a full bit design model to determine the characteristics of the bit in actual drilling conditions. Not only does this model allow examination of the bit in a confined mode for initial design development, but it also delivers an accurate projection of a bit’s performance considering the actual BHA under the actual well characteristics, (geometry, parameters and lithology variations), in a fully dynamic simulation mode where the influences on the bit are virtually identical to those encountered in the real drilling environment. Outputs from these simulations enable the designer to “tune” the desired performance objectives of the bit with the highest degree of dynamic stability engineered into the bit.

From these parameters, actual laboratory rock/cutter tests are devised and carried out. The laboratory data from IDEAS quantifies actual cutter forces and rock removal rates that are then used for the design analysis in lithologies that compare to the particular field application, rather than estimated rock/cutter behaviors generated by other design tools.

IDEAS analysis customer package

The company provides the operator with a specific recommendation of either a roller cone or PDC drill bit that has been designed and certified by the IDEAS simulation process to be the best solution for the target application. The customer receives a comprehensive package that contains detailed analysis of the bits evaluated. This covers the particulars of the bit, a detailed description of the drill string and its components, the proposed operating parameters and the formations to be drilled. The data provided also includes graphs of:
• The specific BHA configuration modeled for the well;
• Bit bottomhole pattern;
• Bit center trajectory demonstrating the relative stability of each design;
• Torque/torsional vibration;
• weight on bit/axial vibration;
• Lateral force; and
• Lateral acceleration.

Quantitative results of the comparative bit analysis provide the operator with a sound basis for implementing the recommendations of the IDEAS analysis. When multiple bit designs are being considered for an interval, three or more performance simulations may be provided to the customer for use as a bit selection tool.