Abstract: A method of well casing permitting thermal oil recovery includes drilling a wellbore to the top of productive formation, casing the wellbore with a casing string, drilling through the productive with a smaller diameter bit, running in a sand screen to the productive formation and subsequent drainage or heat carrier injection into the formation. The sand screen contains longitudinally-corrugated pipes with slots, mutually connected by the end cylindrical portions with a limited longitudinal shift possibility. Besides, the sand screen slots are internally hermetically sealed with a thermoplastic material. Running-in of the screen down to the target depth, include creating an internal excess pressure to expand the sand screen along its entire length except for cylindrical sections, fixing and hermetical anchoring to the casing. Pumping-in of a heat-carrier, under influence of which the thermoplastic material melts up, unseals the slots.

Abstract: A wedge deflecting device useful in drilling and workover operations on oil and gas wells. The device includes a cutting tool connected to the upper portion of the wedge by means of the shear element provided with an external circular groove, located below the wedge deflecting surface, and with a transverse slot in its upper part, the cutting tool having a longitudinal cylinder and a downwards spring-biased piston, inserted into the cylinder; above lower seal elements and below the spring the piston has a wedge nose which corresponds to a transverse slot of the shear element. Below the piston, the cylinder communicates with the drill string and the supply tube, and above-the-piston space communicates with the borehole interior. The cutting tool is provided with a radial inward spring-biased locking element, arranged to be able to fix the piston in its top position, where the piston is located above the shear element.

Abstract: A method of well casing permitting thermal oil recovery includes drilling a wellbore to the top of productive formation, casing the wellbore with a casing string, drilling through the productive with a smaller diameter bit, running in a sand screen to the productive formation and subsequent drainage or heat carrier injection into the formation. The sand screen contains longitudinally-corrugated pipes with slots, mutually connected by the end cylindrical portions with a limited longitudinal shift possibility. Besides, the sand screen slots are internally hermetically sealed with a thermoplastic material. Running-in of the screen down to the target depth, include creating an internal excess pressure to expand the sand screen along its entire length except for cylindrical sections, fixing and hermetical anchoring to the casing. Pumping-in of a heat-carrier, under influence of which the thermoplastic material melts up, unseals the slots.