Multi-aggressiveness cutting face on PDC cutters and method of drilling subterranean formations

A method of drilling subterranean formations of varying hardness with a rotary drill bit including a plurality of cutting elements having a multi-aggressiveness cutting profile and disposed at preselected cutting element backrake angles thereon comprising:

• providing the rotary drill bit with a plurality of superabrasive cutting elements having a multi-aggressiveness cutting profile, each superabrasive cutting element comprising a plurality of cutting surfaces preselectively angled with respect to a reference line positioned adjacent an outer periphery of each of the plurality of cutting elements and extending parallel to a longitudinal axis of each of the plurality of cutting elements, and each of the plurality of cutting surfaces respectively positioned at a preselected radial distance from the longitudinal axis of each of the plurality of superabrasive cutting elements;
• drilling a borehole with the rotary drill bit at a preselected weight-on-bit,
• generally maintaining the preselected weight-on-bit within a preselected tolerance;
• drilling a relatively hard formation by engaging at least one of the cutting surfaces of the plurality positioned more radially outward with respect to the longitudinal axis with the relatively hard formation at a first depth-of-cut;
• and
• drilling a relatively less hard formation by additionally engaging at least one of the cutting surfaces of the plurality positioned more radially inward with respect to the longitudinal axis with the relatively less hard formation at a second depth-of-cut greater than the first depth-of-cut.

A method of drilling subterranean formations with a rotary drill bit comprising:

• providing a rotary drill bit including at least one cutting element thereon, the at least one cutting element including a longitudinal axis, a radially outermost sidewall, and a superabrasive multi-aggressiveness cutting face extending in two dimensions generally transverse to the longitudinal axis, the cutting face of the at least one cutting element including a first cutting surface oriented at a first angle with respect to a reference line positioned adjacent the radially outermost sidewall and extending parallel to the longitudinal axis, a second cutting surface positioned radially inward of the first cutting surface and oriented at a second angle with respect to the reference line extending parallel to the longitudinal axis, a third cutting surface positioned radially inwardly of the second cutting surface and oriented at a third angle with respect to the reference line extending parallel to the longitudinal axis, and a fourth cutting surface positioned radially inward of the third cutting surface and oriented at a fourth angle with respect to the reference line extending parallel to the longitudinal axis;
• drilling a relatively hard formation with the rotary drill bit by engaging at least a portion of the first cutting surface of the cutting face of the at least one cutting element with the relatively hard formation at a first depth of cut;
• and
• drilling a relatively soft formation with the rotary drill bit by engaging at least a portion of at least one of the second cutting surface, the third cutting surface, and the fourth cutting surface of the superabrasive cutting face of the at least one cutting element with the relatively soft formation at a second depth-of-cut in addition to engaging at least a portion of the relatively soft formation with at least a portion of the first cutting surface of the superabrasive cutting face.