Methods of forming an earth-boring tool may involve attaching one or more cutting elements to a replaceable cutting structure and positioning the replaceable cutting structure proximate a region of a body of an earth-boring tool that is susceptible to at least one of localized wear and localized impact damage. The replaceable cutting structure may be to the body. Methods of repairing an earth-boring tool may involve bringing a replaceable cutting structure proximate at least one portion of a body of an earth-boring tool exhibiting at least one of localized wear and localized impact damage. The replaceable cutting structure may be attached to the earth-boring tool at the at least one portion.

Methods of forming an earth-boring tool may involve attaching one or more cutting elements to a replaceable cutting structure and positioning the replaceable cutting structure proximate a region of a body of an earth-boring tool that is susceptible to at least one of localized wear and localized impact damage. The replaceable cutting structure may be to the body. Methods of repairing an earth-boring tool may involve bringing a replaceable cutting structure proximate at least one portion of a body of an earth-boring tool exhibiting at least one of localized wear and localized impact damage. The replaceable cutting structure may be attached to the earth-boring tool at the at least one portion.

Earth-boring tools may include a body and a passively adjustable, aggressiveness-modifying member secured to the body. The passively adjustable, aggressiveness-modifying member may be movable between a first position in which the earth-boring tool exhibits a first aggressiveness and a second position in which the earth-boring tool exhibits a second, different aggressiveness responsive to forces acting on the passively adjustable, aggressiveness-modifying member.

A cutting element includes a sleeve, a rotatable cutting element, and at least one retaining ring. The sleeve has a first inner diameter and a second inner diameter, wherein the second inner diameter is larger than the first inner diameter and located at a lower axial position than the first inner diameter. The rotatable cutting element has an axis of rotation extending therethrough, a cutting face, a body extending axially downward from the cutting face, wherein the body has a shaft that is disposed within the sleeve, and a circumferential groove formed around an outer surface of the shaft. The at least one retaining ring is disposed in the circumferential groove and extends at least around the entire circumference of the shaft, wherein the at least one retaining ring protrudes from the circumferential groove, thereby retaining the rotatable cutting element within the sleeve.

A cutting element includes a sleeve, a rotatable cutting element, and at least one retaining ring. The sleeve has a first inner diameter and a second inner diameter, wherein the second inner diameter is larger than the first inner diameter and located at a lower axial position than the first inner diameter. The rotatable cutting element has an axis of rotation extending therethrough, a cutting face, a body extending axially downward from the cutting face, wherein the body has a shaft that is disposed within the sleeve, and a circumferential groove formed around an outer surface of the shaft. The at least one retaining ring is disposed in the circumferential groove and extends at least around the entire circumference of the shaft, wherein the at least one retaining ring protrudes from the circumferential groove, thereby retaining the rotatable cutting element within the sleeve.

A drill bit for drilling a borehole in earth formations may include a bit body having a bit axis and a bit face; a plurality of blades extending radially along the bit face; and a plurality of cutting elements disposed on the plurality of blades, the plurality of cutting elements comprising: at least one cutter comprising a substrate and a diamond table having a substantially planar cutting face; and at least two non-planar cutting elements comprising a substrate and a diamond layer having a non-planar cutting end, wherein in a rotated view of the plurality of cutting elements into a single plane, the at least one cutter is located a radial position from the bit axis that is intermediate the radial positions of the at least two non-planar cutting elements.

A downhole-milling-tool method for milling through hard substances, such as barite, found in underground wells, providing a stepped increase of diameters and positioning of carbide cutters and appropriate positioning of fluid ports and channels, to provide removal of cuttings and cooling and lubricating of the cutting head, in turn providing more efficiency and a better rate of penetration (ROP).

An actively controlled self-adjusting earth-boring tool includes a body carrying cutting elements and an actuation device disposed at least partially within the body. The actuation device may include a first fluid chamber, a second fluid chamber, and a reciprocating member dividing the first fluid chamber from the second fluid chamber. A connection member may be attached to the reciprocating member and may have a drilling or bearing element connected thereto. A first fluid flow path may extend from the second fluid chamber to the first fluid chamber. A second fluid flow path may extend from the first fluid chamber to the second fluid chamber. A rate controller may control a flowrate of a hydraulic fluid through the first and second fluid flow paths. The rate controller may include an electromagnet, and the flowrates of the hydraulic fluid may be adjusted by adjusting fluid properties of the hydraulic fluid.

An expandable tool includes an expandable block set having a plurality of segments longitudinally arranged. Each segment of the plurality of segments has a segment configuration. The segment configurations of the expandable block are customized for a particular application, based on the anticipated formation type. During operation, the downhole segment wears or breaks away, exposing the uphole segment, which takes over as the primary segment.

An expandable tool includes an expandable block set having a plurality of segments longitudinally arranged. Each segment of the plurality of segments has a segment configuration. The segment configurations of the expandable block are customized for a particular application, based on the anticipated formation type. During operation, the downhole segment wears or breaks away, exposing the uphole segment, which takes over as the primary segment.