Sealing or packing boreholes or wells

EFIXED CONSTRUCTIONS E21Mining E21BEARTH DRILLING

E21B33/00Sealing or packing boreholes or wells

E21B33/02Surface sealing or packing E21B33/03Well heads Setting-up thereof E21B33/035specially adapted for underwater installations E21B33/0355Control systems E21B33/037Protective housing therefor E21B33/0375Corrosion protection means E21B33/038Connectors used on well heads E21B33/0385electrical connectors E21B33/04Casing heads Suspending casings or tubings in well heads E21B33/0407with a suspended electrical cable E21B33/0415rotating or floating support for tubing or casing hanger E21B33/0422a suspended tubing or casing being gripped by a slip or an internally serrated member E21B33/043specially adapted for underwater well heads E21B33/047for plural tubing strings E21B33/05Cementing-heads E21B33/06Blow-out preventers, i.e. apparatus closing around a drill pipe E21B33/061Ram-type blow-out preventers E21B33/062with sliding rams E21B33/063for shearing drill pipes E21B33/064specially adapted for underwater well heads E21B33/068having provision for introducing objects or fluids into, or removing objects from, wells E21B33/072for cable-operated tools E21B33/076specially adapted for underwater installations E21B33/08Wipers Oil savers E21B33/085Rotatable packing means E21B33/10in the borehole E21B33/12Packers Plugs E21B33/1204permanent; drillable E21B33/1208characterised by the construction of the sealing or packing means E21B33/1212including a metal-to-metal seal element E21B33/1216Anti-extrusion means E21B33/122Multiple string packers E21B33/124Units with longitudinally-spaced plugs for isolating the intermediate space E21B33/1243with inflatable sleeves E21B33/1246inflated by down-hole pumping means operated by a pipe string E21B33/126with fluid-pressure-operated elastic cup or skirt E21B33/1265with mechanical slips E21B33/127with inflatable sleeve E21B33/1272inflated by down-hole pumping means operated by a pipe string E21B33/1275inflated by down-hole pumping means operated by a down-hole drive E21B33/1277characterised by the construction or fixation of the sleeve E21B33/128with a member expanded radially by axial pressure E21B33/1285by fluid pressure E21B33/129with mechanical slips for hooking into the casing E21B33/1291anchor set by wedge or cam in combination with frictional effect, using so-called drag-blocks E21B33/1292with means for anchoring against downward and upward movement E21B33/1293with means for anchoring against downward and upward movement E21B33/1294characterised by a valve E21B33/1295actuated by fluid pressure E21B33/12955using drag blocks frictionally engaging the inner wall of the well E21B33/13Methods or devices for cementing, for plugging holes, crevices, or the like E21B33/134Bridging plugs E21B33/136Baskets E21B33/138Plastering the borehole wall Injecting into the formations E21B33/14for cementing casings into boreholes E21B33/143for underwater installations E21B33/146Stage cementing E21B33/16using plugs for isolating cement charge Plugs therefor