Smart Stabilizer Systems Limited

Rockatek Limited

Robert Donald John Sedgeman

Daniel Brendan Crowley

Colin Walker

Daryl Richard Henry Stroud

A high frequency torsional oscillation mitigation tool for use in a downhole drilling assembly. The tool has a first end, a second end, and a one-way coupling therebetween. The one-way coupling has a first part connected to rotate with the first end and a second part connected to rotate with the second end. The one-way coupling has an engaged condition in which the first part and the second part can rotate together in a first rotational direction whereby drill string rotation can be communicated to the drill bit. The one-way coupling has a disengaged condition in which the first part can rotate relative to the second part in a second rotational direction. The one-way coupling can have multiple sets of driving elements along its longitudinal axis. The tool can include a locking mechanism to override the one-way coupling for recovering a stuck downhole assembly.

High frequency torsional oscillation mitigation tool

A piston and cylinder assembly of a downhole tool including a rotary steerable tool. The piston has an outer wall in direct sliding contact with a wall of the cylinder. The cylinder has a retainer for the piston, the retainer has a retaining part and the piston has a retained part, such that the retaining part and the retained part cooperate to retain the piston in the cylinder. The invention separates the function of retaining the piston from sealing the piston to cylinder interface. The invention also relates to a method of assembling the piston and cylinder including rotating the piston relative to the cylinder so that at least a portion of the retained part becomes aligned with at least a portion of the retaining part, and locking the piston against subsequent rotation relative to the cylinder.

Piston and cylinder assembly of a downhole tool, downhole tool with a piston and cylinder assembly, and method of assembling the piston and cylinder

A downhole assembly to mitigate high frequency torsional oscillation, in particular the high frequency torsional oscillation which can occur in a drilling operation for geothermal energy or for oil and gas. The downhole assembly has a rotary steerable tool and a high frequency torsional oscillation mitigation tool, the high frequency torsional oscillation mitigation tool having a one-way coupling, the high frequency torsional oscillation mitigation tool being located above the rotary steerable tool. Also relates to an oscillation mitigation tool suitable for use in a downhole assembly.

Downhole assembly to mitigate high frequency torsional oscillation, and oscillation mitigation tool suitable for use in a downhole assembly

A commutating valve for a downhole steering tool. The downhole steering tool has a sleeve which surrounds an annular body which in turn surrounds a driveshaft. A plurality of steering cylinders are located in the annular body and a steering piston is located in each steering cylinder, the steering pistons engaging the sleeve. A pump pressurizes hydraulic fluid within a reservoir, the reservoir having a closable outlet whereby the pressure of the hydraulic fluid within the reservoir can be raised by closing the outlet and lowered by opening the outlet. The valve comprises a number of discrete valve members which are all in communication with the reservoir and can be opened sequentially whereby to deliver hydraulic fluid to the steering cylinders sequentially. The pressure within each steering cylinder can be controlled in order to control the position of the driveshaft within the sleeve.

Valve for a downhole tool

This invention relates to braking mechanism for a downhole tool such as a steering tool. The braking mechanism comprises:

Braking mechanism for a downhole tool

This invention relates to a downhole assembly and to a cutter assembly, and in particular to a downhole assembly including an apparatus for breaking up large-scale material which is present behind a drill bit, and to a cutter assembly for use in such a downhole assembly. The downhole assembly is suitably for use in a drillstring, the downhole assembly comprising a drill bit, a sensitive component, and at least one rotatable set of cutter blades located between the drill bit and the sensitive component.

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Gloucester, United Kingdom

Robert Donald John Sedgeman