Abstract: Dewatering of coal seams for facilitating the production of gas therefrom through a well is effected by treating the coal seam utilizing a well treatment fluid containing a dewatering aid which both enhances the permeability of the formation to water production and binds tenaciously to the coal surface so that the permeability enhancement benefits are realized over a long production term. The preferred dewatering surfactants used in the treatment fluid and the process of treating the well are selected from a group consisting of:(a) organic surfactant compounds having the formulaR.sub.1 --O([EO].sub.x --[PO]Y--[BO].sub.z)Hwherein R.sub.1 is an alcohol, phenol or phenol derivative or a fatty acid having 1 to 16 carbon atoms; EO is an ethylene oxide radical and x is 1 to 20; PO is a propylene oxide radical and y is 0 to 15 and BO is a butylene oxide radical and z is 1-15;(b) an organic polyethylene carbonate having the formula ##STR1## wherein R.sub.

Abstract: The invention relates to the treatment by a fluid, or more generally by an acid fluid, of subterranean formations located in particular around an oil, gas, water or geothermal well.Acid is diverted towards the zone to be treated by a surfactant flush, the injection of a foam and then the injection of an acid/surfactant composition. These operations are repeated as often as required, increasing at each stage representing approximately 80 cm (20 to 25 inches) of treatment in terms of height the quantity of foam injected.

Abstract: Gas channeling to the surface in the setting of surface casing can be avoided by employing a cementing process in which a right-angle setting cement is positioned within a wellbore annulus between the wellbore and the casing above a gas-bearing zone with a low fluid loss cement slurry being placed below the right-angle setting cement. Pumping of the cement slurry is stopped for a period of time to allow the setting of the right-angle setting cement at which point pressurized pumping is resumed to displace remaining portions of the low fluid loss cement slurry into the wellbore annulus against the plug created by the set right-angle setting cement to block off gas migration and squeeze the low fluid loss cement into the gas-bearing zone.

Abstract: In accordance with illustrative embodiments of the present invention, the mainline valves in a crude oil, gas, water or other product pipeline are positively sealed off to allow a hydrotest to be made of a section or segment of the pipeline between the valves. The section is packed with water, and then a mixture of a highly viscous, aqueous-based gel material and a lost-circulation material are injected into the pipeline segment adjacent each valve to form a plug in the line. The gel plugs then are squeezed under pressure against the internal components of each valve to cause all leakage paths therein to be bridged over and sealed off. Then the pipeline segment is hydrotested to determine if there are any leaks therein, after which the gel is flushed out of the line, broken down into a linear pumpable state, and disposed of.

Abstract: A method of producing a gel of an organic liquid, using a metal phosphate ester in which all of the reagents are substantially free of water and pH-affecting substances. The gel is particularly useful in fracturing subterranean formations by entraining a solid particulate proppant therein and pumping the resultant mixture into the subterranean rock formation at sufficient pressure to fracture the formation. The organic liquid is preferably a hydrocarbon such as diesel or crude oil, and the metal phosphate ester is preferably an aluminum phosphate diester. The metal phosphate diester may be prepared by the reaction of a triester with P.sub.2 O.sub.5 to produce a polyphosphate, which is then reacted with an alcohol to produce a phosphate diester. The latter diester is then added to the organic liquid along with a non-aqueous source of aluminum, such as aluminum isopropoxide in diesel, to produce the metal phosphate diester.

Abstract: A chemical method of removing thiourea from spent hydrochloric acid cleaning solutions comprising the steps of: adjusting the pH to not less than 12 by addition of base to remove metal hydroxides; oxidizing thiourea to urea by the addition of at least a stoichimetric amount of oxidant per mole of thiourea; and further oxidizing urea to nonregulated/nonhazardous compounds by the addition of at least 3 moles of a hypochlorite per mole of urea. UV analysis confirms a greater than 98% removal of thiourea from solutions containing 0.4 to 2.7 wt. % thiourea after as little as 3 hours with an exotherm, .DELTA.t, of less than 105.degree. F.

Abstract: A method an apparatus are shown for forming a flange on an end of a plastic pipe liner of the type used to line a tubular member. A reinforced disc having a rigid portion and an elastomeric portion is placed about the liner exterior and moved into position flush with the flanged end of the tubular member. A retaining ring is placed about the reinforced disc and the disc and liner exposed end are heated to render the materials malleable. A forming unit is then used to apply force to the liner to flow the liner into a reformed shape having a greater external diameter than the remainder of the liner. The forming operation also bonds the reinforced disc to the reformed liner end to further resist any tendency of the liner end to be retracted into the interior of the tubular member.

Abstract: Cement plugs used in the cementing of casing in a borehole drilled into a subterranean formation are restrained from rotation by being forced into a portion of the casing and check valve apparatus which includes a reduced diameter section formed as a continuous annular liner of material having a coefficient of friction. Compression of the plug against the high-friction liner avoids rotation of the plugs when they are drilled subsequent to the cementing operation.

Abstract: A packing is disclosed for piston and valve machine, an annular metal body (20) intended to be immobilized in the first recess by a clamping nut and, in its internal pheripheral face (24), an annular second recess (25), a gasket holding and stress ring (27) disposed in the second recess while being immobilized against the bottom thereof, a gasket (28) formed by at least two packing rings (29) split over the whole of their axial length and over their thickness, side by side, deformable radially and not axially and whose radial thickness is greater than the measurement complementary to the thickness of the ring to equalize the depth of the second recess, and a stop ring (35) in abutment againt the bottom of the second recess, on which the gasket bears.

Abstract: A composition and method for inhibiting the corrosion of steel containing greater than about 9% chromium in the presence of at least one mineral acid, especially at temperatures above 250.degree. F. The composition is made of a corrosion inhibitor selected from phenyl ketone, phenyl ketone with a quaternary salt of a nitrogen-containing heterocyclic aromatic compound, or cinnamaldehyde with a quaternary salt of a nitrogen-containing heterocyclic aromatic compound and an acid soluble metal from antimonium or bismuth.

Abstract: In accordance with illustrative embodiments of the present invention, a method of determining fracture behavior from downhole pressure measurements that are made during a hydraulic well fracturing operation includes pumping fracturing fluids at a constant rate under high pressure against a formation to create fractures therein, and obtaining measurements representative of downhole pressures as pumping progresses. The logarithmic derivatives of such pressure measurements are used to determine the type of fracture behavior, as well as the onset of screenout where the fracturing fluid carries a proppant. In-situ stress or closure pressure also can be determined by finding a value thereof which makes a logarithmic net pressure plot have the same slope as the logarithmic plot of the values of the pressure derivatives.

Abstract: Method of reducing the viscosity of a fracturing fluid containing a polymer by introducing both delayed breaker and nondelayed breaker into the fracturing fluid. Preferably, the relative amounts of delayed and undelayed breaker are determined by first determining the concentration of polymer in the fracture, determining the relationship of breaker concentration for a polymer concentration to proppant pack permeability, picking a desired proppant pack permeability, calculating the amount of breaker necessary to lessen the viscosity of the polymer concentration in the fracture to the desired permeability. This amount of breaker is X. Next, the minimum viscosity of the fracturing fluid which maintains the proppant in suspension in the fracture is determined. The amount of breaker Y which lessens the viscosity of the fracturing fluid no lower than this minimum viscosity is calculated for the bottom hole static temperature and an interval of time.

Abstract: The invention comprises a selective plugging treatment with good penetration for acid diversion or water control. The fluid comprises a foamed delayed gelation system.

Abstract: The high temperature stability of an aqueous fracturing fluid is extended for use in high temperature (above 300.degree. F.) subterranean formations through the addition of quantities of unhydrated, particulate guar or guar derivative polymers prior to the pumping of the fracturing fluid into the formation. Additional high temperature stability is achieved through the addition of soluble bicarbonate to the fracturing fluid and raising the pH of the fracturing fluid to about 9.2 to 10.4.

Abstract: An aqueous spacer composition, compatible with drilling muds and cement slurries including saline slurries, and application there of drilling oil and gas wells.Preferred spacer bases in accordance with the invention comprise a biopolymer of the type produced by Azotobacter indicus, a high molecular weight sulfonated styrene or toluene-styrene polymer, and a dispersing agent. This base fluid has no solid particles. The final spacer composition additionally contains a weighting agent (barite) and water. Total compatibility is provided with muds and/or cement slurries whether or not they are saline, together with excellent fluid loss controlling, rheological, and anti-settling properties. A wetting agent may be added to provide compatibility with oil-based muds.

Abstract: A composition and method for inhibiting corrosion of iron and steel in the presence of aqueous acid at high temperatures, containing an alkenylphenone having the following structure: ##STR1## wherein R.sub.1 may be aryl of 6 to about 10 carbons, and R.sub.2 and R.sub.3 may be the same or different and each may be hydrogen, halogen, or aliphatic of about 3 to about 12 carbons, and R.sub.2 may also be alkanol, ether, or aryl of 6 to about 10 carbons, provided that the total number of carbons in said alkenylphenone does not exceed 16, anda substituted 1-azanaphthalene of the structure: ##STR2## wherein R.sub.4 is alkyl of about 4 to about 16 carbons, or alkylaryl of about 7 to about 20 carbons, and X is chloro or bromo.

Abstract: An apparatus is shown for cleaning a pipe. The apparatus includes a rigid stem and a motor stationarily mounted on the stem. An outer body surrounds the motor and is rotatably mounted on the rigid stem. A fluid conduit is connected to the stem and to a source of fluid under pressure for supplying fluid to the motor for driving the motor. The fluid conduit also connected to a pulling unit for pulling the apparatus through the pipe to be cleaned. Fluid supplied through the fluid conduit to the stem and through the stem to the fluid powered motor provides rotational propulsion to turn the outer body as the apparatus is moved through the pipe to be cleaned.

Abstract: The invention concerns delayed gelation systems which are injected under the shape of a foam in the chosen formations.The choise of an either oil compatible, or water compatible foaming agent allows obtaining a remarkable process selectivity.Plugging; acid diversion; water control treatments are carried out.

Abstract: A gravel packer and service tool combination for use in subterranean wells operates sequentially to lock and seal the packer in the well at a producing formation, release a mechanical connection between the packer and service tool, and open a passage through which gravel packing can be performed. Each operational step can be performed in primary and secondary fluid pressure-responsive modes of operation. The secondary mode of operation can be employed in the event the primary mode of operation fails.

Abstract: Plug flow through a series of tanks in fluid communication is effected by the addition of radial flow impeller means to at least one of the tanks. Plug flow through the tanks allows for sufficient residence time in the series of tanks to effect complete hydration of a hydratable gel for using in well treatment operations such as fracturing, acidizing and gravel packing.