Tubing anchor

A tubing string anchor for anchoring a tubing string having a passage therein in a well bore having a wall, comprising:

• an annular section forming a portion of the tubing string and having an internal passage aligned with the passage in the tubing string;
• at least one roller slip rotatably mounted on said annular section for rolling frictional engagement with the walls of the well bore, a portion of said annular section opposite said roller slip being in sliding engagement with the wall of the well bore, the wall contacting portions of said roller slip being contoured to the wall of the well bore, said roller slip further having a plurality of notches formed on a portion of the outer surface thereof;
• at least one pawl assembly slidably mounted in said annular section, said pawl assembly including a pawl for engagement with selected ones of said plurality of notches to resist rotational motion of said roller slip in at least one direction to anchor the tubing string in the well bore, a portion of said pawl assembly having a non-circular cross section received within a portion of said annular section having a non-circular cross section to limit motion of said pawl into and out of engagement with said selected ones of said plurality of notches;
• and
• engaging means for moving said pawl into engagement with said selected ones of said plurality of notches to anchor the tubing string.

A tubing string anchor for anchoring a tubing string having a passage therein in a well bore having a wall, comprising:

• an annular section forming a portion of the tubing string and having an internal passage aligned with the passage in the tubing string;
• at least one roller assembly slidably secured to said annular section, said roller assembly including:
• a roller block having opposed elongate slots formed therein for receiving bolt means secured to said annular section for permitting the roller block to slide between retracted and extended positions, said roller block further having an extension for slidable sealing engagement within a port formed in said annular section, said extension having an aperture formed therein in fluid communication with the internal passage of said annular section;
• at least one roller slip rotatably mounted on said roller block between extending arms thereof for rolling frictional engagement with the walls of the well bore when the roller block is in the extended position, said roller slip including a multiply curved friction surface for rolling and contoured to conform to the wall of the well bore, said roller slip further having a plurality of notches defined on its external surface;
• a pawl assembly slidably received in said roller block, said pawl assembly having a pawl for engagement with selected ones of said plurality of notches to resist rotational motion of said roller slip in at least one direction to anchor the tubing string in the well bore, said pawl assembly further having a pin for sliding sealed contact with said aperture with one end thereof exposed to fluid in said internal passage;
• a wear plate secured on said annular section for slidable contact with the wall opposite the roller slip contacted surface of the wall;
• and
• fluid pressure in the internal passage of said annular section acting against the exposed end of the extension of the roller block to urge the roller block to the extended position and acting against the exposed end of said pin to urge said pawl into engagement with said selected ones of said plurality of notches.