Abstract: A metal-to-metal sealing method and apparatus for use on oil and/or gas wells, utilizes an upper seal member and a lower seal member, wherein the energizing of the seal members is staged to cause the lower seal member to become sealingly engaged. before the upper seal member becomes sealingly engaged. The seal members may have two seals of different construction; one seal is an interference type seal, and the other seal is a wedge type seal.

Abstract: A casing installation system usable with tubular casing having an upper end portion and a lower portion, for anchoring the upper end portion of the casing on an outer casing string secured to a wellhead having a housing, the wellhead housing being positioned at a fixed position over a well, said casing extending upwardly to the wellhead from a location in the well at which location the lower portion of the casing is landed, the upper end of the casing being terminated by a generally annular casing hanger secured to the casing, said outer casing string having an upwardly-facing shoulder, the system also having a locking ring located on the casing hanger and movable thereon in a direction towards the lower end portion of the casing, the locking ring having means for preventing its movement on the casing in a direction away from the lower end portion of the casing in response to a force exerted on the locking ring in said direction away from the lower end of the casing, the locking ring having a downwardly-facin