Abstract: Methods, systems and products for evaluating a downhole component condition for a drilling assembly in a borehole. Methods include estimating a bending moment on the component at a selected depth along the borehole; estimating a number of rotations of the component at the selected depth; and estimating the condition of the component using the estimated bending moment and the estimated number of rotations at the selected depth. Estimated bending moment may be derived from a borehole model using an estimated deviation on a selected length of the borehole about the selected depth. The condition may be accumulated fatigue or estimated remaining useful life. Estimating the condition may include tracking a total estimated number of rotations wherein the component is subjected to bending moment values in a corresponding moment window, which may be greater than a predetermined threshold bending moment. Weight factors may be associated with at least one moment window.

Abstract: An apparatus for drilling a borehole into an earth formation includes: a drill bit configured to be rotated to drill into the formation; a drill tubular coupled to the drill bit and configured to rotate the drill bit; a steering device coupled to the drill string and configured to impart a force on the drill string to control a direction of drilling; and a controller configured to communicate a control signal to the steering device. The control signal includes information for directing actuation of the steering device for steering the drill bit in an intended drilling direction. The controller is further configured to direct the steering device to provide a compensating force on the drill string that prevents or reduces an azimuthal deviation from the intended drilling direction due to drill bit walking.

Abstract: Methods, systems and products for evaluating a downhole component condition for a drilling assembly in a borehole. Methods include estimating a bending moment on the component at a selected depth along the borehole; estimating a number of rotations of the component at the selected depth; and estimating the condition of the component using the estimated bending moment and the estimated number of rotations at the selected depth. Estimated bending moment may be derived from a borehole model using an estimated deviation on a selected length of the borehole about the selected depth. The condition may be accumulated fatigue or estimated remaining useful life. Estimating the condition may include tracking a total estimated number of rotations wherein the component is subjected to bending moment values in a corresponding moment window, which may be greater than a predetermined threshold bending moment. Weight factors may be associated with at least one moment window.

Abstract: An apparatus for drilling a borehole into an earth formation includes: a drill bit configured to be rotated to drill into the formation; a drill tubular coupled to the drill bit and configured to rotate the drill bit; a steering device coupled to the drill string and configured to impart a force on the drill string to control a direction of drilling; and a controller configured to communicate a control signal to the steering device. The control signal includes information for directing actuation of the steering device for steering the drill bit in an intended drilling direction. The controller is further configured to direct the steering device to provide a compensating force on the drill string that prevents or reduces an azimuthal deviation from the intended drilling direction due to drill bit walking.