A downhole assembly includes a bit and a cutting tool uphole of the bit. The cutting tool has one or more expandable cutter arms. The one or more expandable cutter arms include at least one stabilizer portion having a radial position that is about the same as a gauge of the bit when the one or more expandable cutter arms are in an expanded position. A spline on the cutter arms are used by a cutting tool to move the cutter arms.

A downhole tool includes a housing; a first piston arranged within the housing such that it can move axially under the action of fluid flowing through the tool; and an indexer configured to control axial movement of the first piston between a first, second and third axial position. The indexer is configured such that the first piston can be selectively moved into the third position in accordance with a variation of a flow of fluid through the tool. A second piston is movable between a closed position in which fluid flowing through the tool is restricted from communicating with an activation chamber and an open position in which fluid flowing through the tool is permitted to communicate with the activation chamber; wherein the second piston is configured to move between the closed position and the open position in response to the first piston moving to the third axial position.

To condition a wellbore with a reamer on a wireline, a portion of a wellbore is formed from a surface of the earth toward a subsurface hydrocarbon reservoir using a wellbore drilling assembly. After forming the portion of the wellbore, the wellbore drilling assembly is removed from the portion of the wellbore. Using a wireline, a wellbore sampling tool and a reamer are lowered into the portion of the wellbore. While maintaining the wellbore sampling tool and the wireline in a non-rotational state, the portion of the wellbore is cleaned using the reamer

Drill bits are provided for a drilling while driving machine. In some cases, the drill bit is a multi-stage bit capable of selectively cutting at two different diameters. In others, the bit is an expanding bit that can be passed through a foundation component while its being driven. The bit has a pair of cutting wings that can move between a retracted orientation where the bit's diameter is narrower than the inner diameter of the driven component, to a splayed orientation where the diameter is equal to or larger than the driven component's outside diameter.

A section mill including a housing, a cutter pivotally connected to the housing, a drive piston operably connected to the cutter to radially expand or retract the cutter depending upon longitudinal position of the drive piston relative to the housing, and a limit configuration in operable contact with the drive piston to limit drive piston stroke responsive to hydraulic pressure on the drive piston. A method for cutting casing including determining condition of a structure radially outward of a casing to be cut, selecting an amount of expansion of a cutter based upon the determining, and cutting the casing. A borehole system including a borehole in a subsurface formation, a string in the borehole, and a section mill as in any prior embodiment disposed in the borehole.

A single trip casing cutting and pulling assembly which includes a casing spear (12), a mud motor (16) and a casing cutter (18), wherein a valve (14) is located between the casing spear (12) and the mud motor (16). The casing spear is operated by fluid flow from surface and the valve (14) prevents operation of the casing cutter (18) until the casing spear (12) is set and casing cutting is required. A method is described for cutting and pulling casing which does not require any rotation of the drill string to operate any part of the casing cutting and pulling assembly. An embodiment is described which includes retrieving the seal assembly (48) on the same trip. Further embodiments describe performing an integrity test and a circulation test on the same trip with the option of making further cuts at shallower depths on the same trip until a section of cut casing can be recovered.

Apparatus (10) and method for removing a section of well tubing. A work string including a hydraulic tensioning device (14) and a section mill (12) a run in a rigless arrangement to provide continuous upward milling of the tubing (24) by raising the work string at a desired rate of progress. The hydraulic tensioning device (14) has a lower end (34) moveable longitudinally relative to the work string by application of fluid pressure in the work string to apply a weight on the section mill. The hydraulic tensioning device includes a self-correcting mechanism (30) to maintain the lower end at a position between a fully extended position and a fully retracted position to provide continuous milling of the tubing by the section mill at a milling rate matching the rate at which the work string is lifted. Embodiments are described for use in a rigless well abandonment procedure.

A compression-set straddle packer with fluid pressure-boosted packer set has a two-part multicomponent mandrel and a multicomponent sliding sleeve that reciprocates within a limited range on an upper part of the two-part multicomponent mandrel. A two-part lower packer element compression sleeve in a lower part of the two-part multicomponent mandrel reciprocates on a packer element piston mandrel component and pressure-boosts compression of a lower packer element when high-pressure fluid is pumped into the straddle packer. A bias element constantly resists relative movement between the multicomponent mandrel and the multicomponent sliding sleeve and balances pressure-boost between the lower packer element and an upper packer element supported by the upper part of the two-part multicomponent mandrel.

A cutter block includes a formation facing surface having a staged cutting profile and one or more stabilizer pads may be located between reaming portions. A shorter stabilizer pad or no stabilizer pad may be at the gauge of the cutter block. A spline on the cutter block and used by a downhole cutting apparatus to move the cutter block may intersect the formation facing surface. The spline may form an extension that increases a width of the formation facing surface. The extension may be located at a stabilizer pad to expand the stabilizer pad, such that the extension rotationally leads or trails cutting structure of the cutter block. When the cutter block is expanded, a stabilizer pad may be at a pilot diameter of a wellbore, while some cutting elements may be radially outside, and others radially within, the pilot diameter of the wellbore.

The present invention relates to a combined crushing super-variable-diameter drill bit for natural gas hydrate exploitation, including a joint, an outer cylinder connected to the joint by thread, a nozzle I mounted in the outer cylinder, a mechanical locking mechanism, a blade telescoping mechanism, an end cap connected to the outer cylinder by thread, a seal ring IV mounted to the end cap, and a nozzle II mounted in the end cap by threaded connection. The present invention achieves integrated operation of conventional drilling and draw-back expanding, which can effectively solve the problems that the existing hydrate drill bit cannot drill a large borehole, cannot mechanically lock an extending position of the blade to stabilize the size of the borehole, and a single crushing method is inefficient.