A downhole tool, comprising: a mandrel having first and second opposing ends and an outer mounting surface, the first end comprising a male threaded portion; a tool component mountable on the mounting surface by sliding said tool component onto the mounting surface from the first end of the mandrel; and a load sleeve defining a torque shoulder, wherein the load sleeve is mountable on the mandrel and securable adjacent the male threaded portion of the first end of the mandrel such that the torque shoulder and the male threaded portion define a pin connector to facilitate connection with a box connector of a separate component.

A simple centralizer, comprising a mandrel extending between box couplings, a rotor receiving surface between the box couplings, a shoulder on the mandrel defining a first end of the rotor receiving surface; and a collar receiving surface on a second end of the rotor receiving surface. The collar receiving surface may be un-threaded. In use, a collar is press fit on to the collar receiving surface.

A simple centralizer, comprising a mandrel extending between box couplings, a rotor receiving surface between the box couplings, a shoulder on the mandrel defining a first end of the rotor receiving surface; and a collar receiving surface on a second end of the rotor receiving surface. The collar receiving surface may be un-threaded. In use, a collar is press fit on to the collar receiving surface.

A rotary downhole tool, for example in the form of a drill bit, is described that includes a tool body, the body defining a gauge region, and at least one gauge roller rotatably mounted to the body.

A drilling tool includes a pilot bit coupled to an eccentric reamer that has a reaming side and a stabilizing side. A fluid passageway extends between the reamer and the pilot bit, and the tool includes at least one upwardly-directed nozzle in fluid communication with the fluid passageway and positioned on the stabilizing side of the reamer. The reamer may include a plurality of angularly spaced blades on the reaming side that radially extend a first distance, the reamer blades being disposed within a first arcuate segment defined by the two most distant reamer blades. One or more stabilizing blades extend a second distance that is less than the first distance, the stabilization blades being disposed within a second arcuate segment defined by the two most distant reamer blades and that has the angular measure equal to 360 degrees minus the first arcuate segment.

An apparatus and method for alleviating spiraling in boreholes is disclosed. The apparatus includes a sub, which adjusts the length of the bottom-hole assembly in response to tension/compression, flexural bending and/or torque measurements made above and below the reamer so that the drill bit and the reamer cut at the same depth rate. The sub is connected between the drill bit and the reamer. The apparatus further includes measurement devices disposed on the bottom-hole assembly above and below the reamer, which are capable of measuring the tension/compression, flexural bending and torque in the bottom-hole assembly. The method includes use of a data processor, which determines which operational output signals to supply to the sub in order to adjust its length and thereby accomplish the desired drilling rates.

Provided is a two part drilling and running tool, a downhole tool, a well system, and a method for forming a well system. The two part drilling and running tool, in at least one aspect, includes a smaller assembly coupled to an end of a conveyance, the smaller assembly having a spline or slot located along an entire length (L.sub.S) thereof. The two part drilling and running tool, in accordance with this aspect, further includes a larger bit assembly slidably coupled to the conveyance, the larger bit assembly including an other of the slot or spline, wherein the spline or slot in the smaller assembly and the other of the slot or spline in the larger bit assembly are configured to engage one another to rotationally fix the smaller assembly relative to the larger bit assembly as the smaller assembly and the larger bit assembly slidingly engage one another.

Provided is a two part drilling and running tool, a downhole tool, a well system, and a method for forming a well system. The two part drilling and running tool, in at least one aspect, includes a smaller assembly coupled to an end of a conveyance, the smaller assembly having a spline or slot located along an entire length (L.sub.S) thereof. The two part drilling and running tool, in accordance with this aspect, further includes a larger bit assembly slidably coupled to the conveyance, the larger bit assembly including an other of the slot or spline, wherein the spline or slot in the smaller assembly and the other of the slot or spline in the larger bit assembly are configured to engage one another to rotationally fix the smaller assembly relative to the larger bit assembly as the smaller assembly and the larger bit assembly slidingly engage one another.

A reaming tool includes a tool body having a longitudinal axis and an upper end opposite a lower end and at least one blade extending outwardly from the external surface of the tool body. The blade includes a rolling element defining the gauge of the reaming tool, and a blade surface arranged undergauge of the rolling element and comprising a cutting surface.

A reaming tool includes a tool body having a longitudinal axis and an upper end opposite a lower end and at least one blade extending outwardly from the external surface of the tool body. The blade includes a rolling element defining the gauge of the reaming tool, and a blade surface arranged undergauge of the rolling element and comprising a cutting surface.