Abstract: A casing patch for providing a connection between two casing sections which comprise a body means adapted to fit over an existing casing in a well bore and guide the patch into place, a slip means actuated by upward movement of the second casing section to tightly connect the two casing sections, and a seal means also actuated by upward movement of the second casing section for sealing the connection to pressure of fluids, under conditions of high pressure and temperature. The seal comprises a lead ring inside the casing patch surrounding the existing casing and a cylindrical seal arranged below the lead ring and having a central section of a deformable material and two end sections of wire mesh.

Abstract: A well cutting tool for cutting casing in a well bore having a cutter body and at least one cutting arm pivotally mounted in a longitudinally extending slot of the cutter body. The cutting arm has removable and replaceable cutting inserts positioned along its outer front surface and its lower end surface. A removable and replaceable projection on the upper end of the cutter arm is provided for contact by a fluid pressure actuated piston for outward pivoting of the cutter arm into cutting position.

Abstract: An underreamer, hole opener, or expansible rotary drill bit including a body having a bore therethrough, an arm mounted at its upper end to the body, a conical cutter mounted for rotation on the lower end of each arm, a cup-shape thrust bearing between the cutter and the arm, a bolt through the arm to secure the cutter on the arm and means including a ball and groove between the bolt and the cutter to lock the bolt to the cutter. In the underreamer form of the present invention, the arms are pivotally mounted in slots in the body and means is provided for moving their arms to their cutting position with their lower ends positioned radially outward from the body.