Abstract: The present invention provides a system for performing a suitable operation in a wellbore utilizing a resonator. The system includes a resonator for generating pulses of mechanical energy, an engaging device for securely engaging an object in the wellbore and a sensor for detecting the response of the object to pulses generated by the resonator. The resonator is placed at a suitable location in the wellbore and the engaging device is attached to the object. The resonator is operated at an effective frequency to induce pulses into the object. The sensor detects the response of the object to the induced pulses, which information is utilized to adjust the operating frequency. The system in different configurations can be used to fish, free a stuck drill string, aid drilling of wellbores and to perform a cementing operation. A control circuit controls the operation of the system according to programmed instructions.

Abstract: A casing patch is disclosed which uses one or more fins which elastically flex to accept a casing stub. The casing stub is prepared with a dressing tool containing a special mill to obtain the requisite finish on its outer surface prior to insertion of the casing patch. The flexible fin or fins provide a metal-to-metal seal to the outer surface of the casing patch and a grip assembly holds the joint together. In certain applications, the fins can be combined with a resilient seal where the fins preferably provide a complete extrusion barrier to the resilient seals. Using the fins which preferably are integral to the body, alone or in combination with a resilient seal or seals, the wall thickness of the joint can be maintained at thicker values for a given size as compared to prior designs, thus, ensuring a sufficient pressure rating for the joint which is at least equal to the rating of the casing stub.

Abstract: A downhole cutting tool for use in a wellbore, the cutting tool having a mandrel and a cylindrical knife body slidably mounted coaxially on the mandrel. The mandrel can be attached to or suspended from any type of workstring. The upper ends of a plurality of knife blades are pivotably mounted at fixed points on the knife body. The knife blades are suspended therefrom over a plurality of ramps formed on the exterior of the mandrel. A pressure chamber is formed between the knife body and the mandrel. Fluid from the work string can be directed through the mandrel to the pressure chamber, to drive the knife body downwardly relative to the mandrel, causing the lower ends of the knife blades to contact the ramps on the mandrel and kick or pivot outwardly to cause the lower tip of the blade to contact the downhole material to be cut. As the mandrel is rotated, the knife blades rotate with it and cut into the material.

Abstract: An apparatus and method of milling a liner extending from a deviated wellbore into a main wellbore is disclosed. The liner is inserted through a window and cemented in place with the cement extending back into the main wellbore. Mechanisms are provided on the liner to keep it away from the main wellbore casing wall to facilitate the proper operation of the washover tool. A top end taper is provided to help the washover tool reorient over the tubular liner if milling requires more than one trip into the well. A diverter is insertable prior to installation of the liner to assist in getting the liner to extend through a window. Upon milling through the liner, the washover tool straddles the diverter and latches into it to facilitate not only the removal of the diverter but also the entrapment of any debris created by the milling operation. Suitable sealing is provided with the diverter to keep the cement away from the latching mechanism during the cementing operation.