Abstract: A percussion boring machine for destructive replacement of buried pipelines, having an opening-out cone at the back of the machine housing and cutters spaced in front of said cone, wherein the cutters form part of a breaking-up head slipped on to the housing and the opening-out cone is likewise slipped on to the housing.

Abstract: Directional drilling is carried out with a rotary drilling tool having a drill string, a drill bit, a drill motor for rotating the drill bit independently of the drill string, an extension sub having both axially contracted and axially extended positions for providing weight to the drill bit when moving from a contracted to an extended position so as to effect a drilling stroke by the drill bit into the wellbore bottom when drilling with the drill bit independently of rotation of the drill string, and a measuring-while-drilling unit acting in conjunction with spiral-bladed stabilizers for effecting proper orientation of the drill bit prior to each drilling stroke.

Abstract: An improved bearing system for the driven shaft of a downhole motor is shown that provides a main thrust and radial bearing system having means for sealing the bearings in oil at equal or slight pressure above that of the drilling mud inside the drill pipe and insulating the fluid seals and bearings from all possibility of contact with cuttings and debris from the drilling operation. A durable seal having a restricted flow path permitting slow leakage is positioned below the main bearing system in such a relationship to the drilling fluid distribution path that the seals for the oil bath for the bearings are subjected to essentially the same pressure on all sides.

Abstract: A seal construction for a dock leveler having a platform with opposite sides which moves vertically relative to the sides of a pit, including a pair of curtain members each having first and second opposite edges, with the first edges removably attached to the sides of the platform and the second edges removably attached to the sides of the pit, the curtain members sealing the clearance openings between the sides of the platform and the sides of the pit and also sealing the opening which would otherwise be produced between the sides of the pit and the platform when the latter is in an elevated position.

Abstract: This specification discloses a method of cementing pipe in a well and discloses the use of a designed oil-wetting liquid and cement slurry for cementing pipe against evaporite sections penetrated by the well. The cement slurry is formulated from hydraulic cement, silica flour, ionization control agent, sodium chloride, weighting agent, dispersing and retarding agent, and water, and has a density within the range of about 15.8 to 21.0 pounds per gallon.

Abstract: Gelled acidic compositions suitable for either matrix acidizing or fracture-acidizing of subterranean formations, and methods of using said compositions in acidizing operations, are provided. Said compositions comprise water, a water-dispersible polymer of acrylamide, an acid, and an aldehyde capable of causing gelation of an aqueous dispersion of said polymer, said acid, and said aldehyde. Preferably a mixture of aldehydes is used. However, either a mixture of aldehydes or a single aldehyde can be used with certain polymers, and in certain methods comprising particular combinations of steps.