By focusing on the specific well objectives, application and drilling system used, Direction by Design software can quantify how changing bit features and dimensions will affect steerability, bit walk and bit face control for any given well trajectory and BHA. (Image courtesy of Halliburton)

In an effort to advance the science of bit design engineering, Direction by Design software from Security DBS, a product service line of Halliburton, incorporates a new kinematics model that allows drill bit designers to quantify the impact of changes to a bit’s design on its ability to drill a deviated well.


Objective

The industry needs more advanced tools and technology due to the growing complexity of directional wells.

Meeting this challenge is the objective of Direction by Design software technology. The new software compares bits according to their downhole directional tendencies to supply customers with the most compatible bit for their desired results. Steerability, bit walk, and bit face control are directional aspects that are integral to a drill bit’s success.
 
Evaluating bit directional behaviors depends greatly on understanding the steer device mechanism and bit/formation interaction. Previous models represented bit motion by axial penetration rate, rotational speed, and lateral penetration rate without giving thought to the different steer mechanisms of various bottomhole assembly (BHA) systems.

Direction by Design software combines bit geometry, including cutting structures, gauge pads and sleeve pads, and hole geometry, including transition layers into 3-D spherical coordinate systems. Bit motion is represented by rotation speed, axial penetration, dogleg severity and dimensions specific to the BHA configuration.

For given bit and drilling conditions, the software predicts the side force required, walk force created, walk rate and direction, and bit torque variance during directional drilling, accounting for different bit behaviors during kickoff, build/drop, and hold drilling. Integrated into the bit design package, the software is used for design modification and/or application specific bit selection.

Impact on industry

Capable of predicting bit walk more accurately, Direction by Design software advances bit design for directional drilling to a new level, so that what previously has been intuitive can now be measured. The new model facilitates intelligent design decisions without negatively impacting other deliverables, demonstrating significant benefits in solving problems in the field.

In a multi-well development field in Alaska, where rotary steerable drilling is used to achieve complex multilateral 3-D well designs, bit trajectory control began to suffer in the soft formations of the critical production interval, requiring frequent well corrections to hit the expected target.

With drilling costs increasing to the point where the viability of continuing the project was threatened, Direction by Design software was used to determine why the polycrystalline diamond compact bits would not steer and had a strong tendency toward right hand walk. By analyzing the 3-D bit geometry and translating the forces acting on the bit, outputs of the new model accurately calculated bit walk force, bit walk direction, and bit walk rate, providing insight that made it possible to devise bit/BHA design recommendations that solved the problem.

Inspiration

Supplying a tool the industry has been lacking, Direction by Design software transitions design technology from vertical drilling to directional drilling, putting the focus on optimizing bit selection and parameters in real time to meet the customer’s need to drill smooth, deviated hole with minimum effort from the tool, without losing energy in walk tendencies or vibrations.

Providing the means to optimize matched bit design and system performance for fast, responsive rotary steerable drilling, Direction by Design software is enabling operators to pursue even the most ambitious drilling programs.