The permeability of a siliceous formation is increased by injecting in sequence, a fluoboric acid solution followed by a mud acid (HCl/HF) solution. The method is particularly advantageous in formations which have a tendency to plug initially upon contact with mud acid, or with HCl commonly used as a preflush ahead of mud acid. When contacted initially with fluoboric acid, such formations show little or no plugging effects when subsequently treated with mud acid.

A barrier in a subterranean structure is provided by the form of a sealing wall consisting of glass panels or panes in spaced-apart relationship within the packing mass between the panes and also embedding the sealing wall in the slit which is found in the subterranean structure.

A method of fracturing a formation with a fracturing fluid wherein the formation has particulate material that swells or migrates upon exposure to the fracturing fluid comprises preparing a fracturing fluid comprising (1) a thickening compound comprising a first surfactant selected from the group consisting of a cationic surfactant having only a single cationic group, an amphoteric surfactant and a mixture thereof; and, an anionic surfactant; and, (2) water, wherein no or essentially no inorgani...

Tunnel excavating apparatus comprises a hollow cylindrical shield adapted to be axially forced through subterranean material and having a circular cutting edge at a leading end portion. An inclined baffle and guide member has a central opening spaced upwardly from a lower edge of the baffle and guide member and an auger-like member extends across the shield adjacent the opening. Sections of the auger-like member extending on horizontally opposite sides of the baffle opening have oppositely direc...

A porous, or semi-permeable, pipe is placed below the surface of the soil in the area to be irrigated and a flow of water maintained therein. This avoids such practices as sprinkling, furrowing or ditching, and subsequent cultivation, and thereby permits the surface of the land being irrigated to be continuously maintained in the condition most conducive to vegetation growing thereon. It also greatly avoids excessive loss of water by evaporation, puts the water in that position in the soil where...

A method is given in which there is delayed release from the treatment fluid of solid chemicals that are obtained in bulk powder form. The method is used in situations in which it is difficult to encapsulate the chemical to achieve delayed release because the chemical is obtained in powdered form. The method involves delivering the powdered chemical in capsules consisting of encapsulated granulates obtained by aggregating the bulk powder under pressure to form a densified material and, optionall...

The present invention provides improved compositions and methods of using the compositions for sealing subterranean zones. The compositions are basically comprised of water, an aqueous rubber latex, an organophillic clay, sodium carbonate, an epoxy resin and a hardening agent for said epoxy resin.

A fluid transmission conduit welding habitat is provided, having an outer air supportable arcuate dome which is mounted over a point to entrap welding slag, sparks, and the like. A fire-resistant shield is disposed around the interior of the dome. Air supplied to the dome for selectively suspending the habitat. A conduit, filter, or the like is provided through the top of the dome to permit discharge of smoke including particulate matter resulting from the welding procedure. The air supply may b...

The present invention provides a method of widening or extending fractures in a subterranean formation which intersect a wellbore to enhance the flow of fluids from the formation. The enhancement is achieved by introducing an explosive gas comprising a gaseous oxidizer and a gaseous fuel and optionally a quantity of inert gas into at least one fracture intersecting the wellbore and then detonating the explosive gas. The detonation produces a pressure wave which passes down the length of the frac...

The present invention provides improved compositions and methods of using the compositions for sealing subterranean zones. One composition of the invention is comprised of water, a silane coupling agent, an organophilic clay, an epoxy resin and a hardening agent for said epoxy resin.