The invention provides a downhole borehole traction apparatus (10) and method of use. The apparatus comprises a body comprising a borehole engaging section wherein the borehole engaging section comprises an outer surface comprising at least one thread. The at least one thread comprises a crest surface (32), a leading surface (30), and a trailing surface (28) having a curvilinear shape. The at least one thread has a low pressure generation means comprising one or more formations.

Bottom hole assemblies with a combined roller-underreamer assembly can include: a body configured to be attached to a drill pipe; an uphole ring attached to the body; a downhole ring attached to the body between the uphole ring and the downhole end of the body; a sliding ring mounted around the body between the uphole ring and the downhole ring; a set tube slidably mounted around the body between the uphole ring and the sliding ring; a reamer assembly with at least one first articulated arm with extending between the uphole ring and the downhole end of the set tube; and a roller assembly with: at least one second articulated arm extending between the uphole end of the set tube and the sliding ring; and a rolling positioned at a joint of each second articulated arm.

A reamer for use in underground drilling back-reaming operations. The reamer comprises a body comprising a plurality of pockets. The pockets are configured such that an arm, a rolling cutter, and a retainer may fit within each of the pockets. Each of the rolling cutters is connected to each of the arms via a spindle. The rolling cutters are held on the spindle and connected to each of the pockets via a retainer. Each of the arms is secured to each of the pockets via a plurality of fasteners. A mechanical lock is used to secure at least one of the fasteners in place. Each of the arms comprises a grease passage and a pressure compensation system. The rolling cutters are replaceable with rolling cutters of like size or rolling cutters of different sizes and shapes.

A reamer for use in underground drilling back-reaming operations. The reamer comprises a body comprising a plurality of pockets. The pockets are configured such that an arm, a rolling cutter, and a retainer may fit within each of the pockets. Each of the rolling cutters is connected to each of the arms via a spindle. The rolling cutters are held on the spindle and connected to each of the pockets via a retainer. Each of the arms is secured to each of the pockets via a plurality of fasteners. A mechanical lock is used to secure at least one of the fasteners in place. Each of the arms comprises a grease passage and a pressure compensation system. The rolling cutters are replaceable with rolling cutters of like size or rolling cutters of different sizes and shapes.

A system that includes a drillstring with a bottomhole assembly (BHA). The system also includes at least one stabilizer or reamer integrated with the BHA, wherein each of the at least one stabilizer or reamer includes a position adjustment assembly. The system also includes a processing unit that provides control signals to each position adjustment assembly, wherein the control signals are based on a cost function.

A system that includes a drillstring with a bottomhole assembly (BHA). The system also includes at least one stabilizer or reamer integrated with the BHA, wherein each of the at least one stabilizer or reamer includes a position adjustment assembly. The system also includes a processing unit that provides control signals to each position adjustment assembly, wherein the control signals are based on a cost function.

A debris removal system includes: a drill pipe disposed within a borehole including a threaded portion disposed longitudinally above a bottom hole assembly (BHA). The threaded portion includes at least one spiral notch that wraps around the drill pipe. An outer diameter of the threaded portion of the drill pipe remains constant throughout a longitudinal length of the threaded portion.

A debris removal system includes: a drill pipe disposed within a borehole including a threaded portion disposed longitudinally above a bottom hole assembly (BHA). The threaded portion includes at least one spiral notch that wraps around the drill pipe. An outer diameter of the threaded portion of the drill pipe remains constant throughout a longitudinal length of the threaded portion.

A wellbore roller-reamer comprises a mandrel rotatable about a mandrel axis, and a first roller mounted around the mandrel and having an outer reaming surface for engaging a wall of a wellbore. The first roller is rotatable relative to the mandrel about a first roller axis which is offset from the mandrel axis such that, during use, rotation of the mandrel with the outer reaming surface engaged with a wall of the wellbore causes the first roller to be driven to rotate relative to the mandrel and ream the wall of the wellbore.

A wellbore roller-reamer comprises a mandrel rotatable about a mandrel axis, and a first roller mounted around the mandrel and having an outer reaming surface for engaging a wall of a wellbore. The first roller is rotatable relative to the mandrel about a first roller axis which is offset from the mandrel axis such that, during use, rotation of the mandrel with the outer reaming surface engaged with a wall of the wellbore causes the first roller to be driven to rotate relative to the mandrel and ream the wall of the wellbore.