A completion string includes at least one isolation packer positioned between well zones of a plurality of well zones, and a sand control assembly and a circulating assembly each disposed uphole of a washdown shoe in the bottom-most well zone. A top well zone includes a return valve assembly, a production packer, and a second circulating assembly and a second sand control assembly downhole of the production packer. The completion string also includes an outer string spanning from the bottom-most well zone to the top well zone, and an inner production string concentrically arranged within the outer string, creating an inner-annulus between the outer string and inner production string. The inner-annulus is continuous from the washdown shoe to the return valve assembly, and the inner production string includes a production valve disposed between the sand control assembly and the circulating assembly in each of the bottom-most and top well zones.

A downhole vibration tool includes a body, a mandrel, a spring, and a balance piston. The body may be generally tubular and may have one or more helical slots formed on an inner surface thereof. The mandrel may be generally tubular, may have a bore, and may be positioned at least partially within the body. The mandrel may have one or more helical splines formed on an outer surface of the mandrel, the helical splines engaging the helical slots of the body such that the mandrel is translatable axially relative to the body. The spring may be positioned in an annular space formed between the mandrel and the body defined as a spring chamber. The balance piston may be in an annular space formed between the mandrel and the body, wherein the balance piston separates an oil-filled chamber from an internal pressure chamber.

An anchor for securing a well tool can include a longitudinally extending central axis, an outwardly extendable grip member, and a mechanical linkage including multiple pivotably connected links. The links pivot relative to each other in a plane laterally offset from the central axis. A method of anchoring a well tool can include flowing a fluid through an anchor connected to the well tool, thereby outwardly extending a grip member into contact with a well surface, and applying a tensile force to the anchor, thereby increasingly biasing the grip member against the well surface and securing the well tool relative to the well surface. A method of anchoring a tubing cutter in a tubular string can include applying a tensile force from an anchor to the tubular string, and cutting the tubular string while the tensile force is applied from the anchor to the tubular string.

An anchor for securing a well tool can include a longitudinally extending central axis, an outwardly extendable grip member, and a mechanical linkage including multiple pivotably connected links. The links pivot relative to each other in a plane laterally offset from the central axis. A method of anchoring a well tool can include flowing a fluid through an anchor connected to the well tool, thereby outwardly extending a grip member into contact with a well surface, and applying a tensile force to the anchor, thereby increasingly biasing the grip member against the well surface and securing the well tool relative to the well surface. A method of anchoring a tubing cutter in a tubular string can include applying a tensile force from an anchor to the tubular string, and cutting the tubular string while the tensile force is applied from the anchor to the tubular string.

An uphole end for a compression-set straddle packer has a multicomponent mandrel and a multicomponent sliding sleeve that reciprocates within a limited range on the multicomponent mandrel. A bias element constantly resists relative movement between the multicomponent mandrel and the multicomponent sliding sleeve.

An uphole end for a compression-set straddle packer has a multicomponent mandrel and a multicomponent sliding sleeve that reciprocates within a limited range on the multicomponent mandrel. A bias element constantly resists relative movement between the multicomponent mandrel and the multicomponent sliding sleeve.

A technique provides a desired control over incremental actuation of hydraulic devices. A hydraulically actuated tool is combined with a control module. The hydraulically actuated tool has an actuator piston positioned in a piston chamber and movable between operating positions. The control module comprises a hydraulic indexing circuit arranged to enable incremental movement of the actuator piston in a first direction and full stroke movement in a second direction based on hydraulic input delivered via control lines. The hydraulic indexing circuit comprises an indexing piston system and at least one check valve working in cooperation with the indexing piston system to enable the incremental and full stroke movements.

A technique provides a desired control over incremental actuation of hydraulic devices. A hydraulically actuated tool is combined with a control module. The hydraulically actuated tool has an actuator piston positioned in a piston chamber and movable between operating positions. The control module comprises a hydraulic indexing circuit arranged to enable incremental movement of the actuator piston in a first direction and full stroke movement in a second direction based on hydraulic input delivered via control lines. The hydraulic indexing circuit comprises an indexing piston system and at least one check valve working in cooperation with the indexing piston system to enable the incremental and full stroke movements.

A downhole tool actuation system including: a tubing having a longitudinal axis and a main flowbore supportive of tubing pressure; an indexing mechanism in fluidic communication with the main flowbore, the indexing mechanism configured to count N number of tubing pressure cycles; a port isolation device movable between a blocking condition and an actuation condition, the port isolation device in the blocking condition for N−1 cycles of the indexing mechanism, and movable to the actuation condition at the Nth cycle of the indexing mechanism; and, a chamber sealed from the main flowbore in the blocking condition of the port isolation device, the chamber exposed to the tubing pressure in the actuation condition of the port isolation device. The downhole tool actuation system is configured to actuate a downhole tool upon exposure of the chamber to tubing pressure.

Piston-less downhole tools and piston-less pressure compensation tools are presented. The piston-less downhole tool includes a first chamber comprising a first fluid, the first fluid being a fluid that thermally expands in response to an increase in a temperature of the first fluid. The piston-less downhole tool also includes a tubular having a first end that is fluidly sealed and a second end that is in fluid communication with the first fluid, wherein the tubular is configured to expand in response to thermal expansion of the first fluid. The piston-less downhole tool further includes a second chamber configured to store a second fluid. The tubular of the piston-less downhole tool is configured to contract in response to pressure applied by the second fluid.