Abstract: A drilling tool including at least two cutting elements (e.g., redundant or upon a selected profile region) sized, positioned, and configured thereon so as to contact or encounter a change in at least one drilling characteristic of subterranean formation along an anticipated drilling path prior to other cutting elements thereon encountering same is disclosed. Methods of designing a drilling tool are also disclosed including placing such cutting elements upon the cutting element profile in relation to a predicted boundary surface along an anticipated drilling path. Methods of operating a drilling tool so as to initially contact a boundary surface between two differing regions of a subterranean formation drilled with at least two cutting elements is disclosed. The cutting elements configured on drilling tools and methods of the present invention may be designed for limiting lateral force or generating a lateral force having a desired direction during drilling associated therewith.

Abstract: A casing bit, which may comprise a composite structure, for drilling a casing section into a subterranean formation, and which may include a portion configured to be drilled therethrough, is disclosed. Cutting elements and methods of use are disclosed. Adhesive, solder, electrically disbonding material, and braze affixation of a cutting element are disclosed. Differing abrasive material amount, characteristics, and size of cutting elements are disclosed. Telescoping casing sections and bits are disclosed. Aspects and embodiments are disclosed including: at least one gage section extending from the nose portion, at least one rotationally trailing groove formed in at least one of the plurality of blades, a movable blade, a leading face comprising superabrasive material, at least one of a drilling fluid nozzle and a sleeve, grooves for preferential failure, at least one rolling cone affixed to the nose portion, at least one sensor, discrete cutting element retention structures, and percussion inserts.