Articulable couplings for downhole tools

An articulable assembly for connecting tools in a downhole tool string comprising:

• a first member having a first throughbore;
• a second member having a second throughbore;
• a flexible joint coupled between the first member and the second member that permits at least one of the first member and the second member to articulate relative to the other, the flexible joint defining an internal lubricant chamber at least partially filled with a lubricant that is pressure equalized with pressure of external fluid present in the surrounding environment while also sealed from external fluid;
• and
• a pressure bulkhead coupled to at least one of the first member, the second member, or the flexible joint and positioned along the electrical signal pathway for isolating communication of fluid pressure between the first throughbore and the second throughbore.

An articulable assembly for connecting tools in a downhole tool string comprising:

• a first member having a first throughbore;
• a second member having a second throughbore;
• and
• a flexible joint coupled between the first member and the second member that permits at least one of the first member and the second member to rotate relative to the other and that also connects the first throughbore and the second throughbore such that an electrical signal pathway for receiving an electrical signal conductor is formed that extends continuously through the flexible joint and between the first throughbore and the second throughbore, the flexible joint comprising a ground biasing member that forms at least part of an electrical ground pathway through the flexible joint that is separate from the electrical signal pathway.

A swivel assembly for connecting tools in a downhole tool string, comprising:

• a first member having a first throughbore;
• a second member having a second throughbore;
• a flexible joint coupled between the first member and the second member that permits at least one of the first member and the second member to rotate an unlimited number of rotations relative to the other and that also connects the first throughbore and the second throughbore such that an electrical signal pathway for receiving an electrical signal conductor is formed that extends continuously through the flexible joint and between the first throughbore and the second throughbore;
• and
• a pressure bulkhead coupled to at least one of the first member, the second member, or the flexible joint and positioned along the electrical signal pathway that divides the electrical signal pathway into a pressure exposed zone that is exposed to external pressure from the surrounding environment and a pressure isolated zone that is isolated from the external pressure, and wherein the pressure bulkhead comprises an electrical connector for transmitting electrical signals along the electrical signal pathway and between the pressure isolated zone and the pressure isolated zone such that the swivel assembly may electrically connect to tools connectable to the first member and the second member.

An articulable coupling for connecting tools in a downhole tool string comprising:

• a first member having a throughbore;
• a second member having a throughbore;
• a flexible joint between the first and second members which allows at least one of the first and second members to articulate relative to the other and wherein the respective throughbores of the first and second members are connected such that at a wireline cable may be arranged to extend from end to end of the articulable coupling through the throughbore of one of the members to and through the throughbore of the other;
• and
• a high viscosity fluid in the throughbores to resist intrusion of wellbore fluids that may carry wear imposing debris onto bearing surfaces creating freedom of articulation thereby prolonging the life of the articulable coupling.