Abstract: The addition of fibrous materials in intimate mixture with particulates for fracturing and gravel packing decreases or eliminates the flowback of proppant and/or formation fines while stabilizing the sand pack and lowering the demand for high polymer loadings in the placement fluids. Preferred fibers include glass, aramide, nylon and other natural and synthetic organic and inorganic fibers and metal filaments.

Abstract: Preferential disconnection of a valve-actuating subassembly from a temporary abandonment safety valve and packer assembly is provided by stops which limit relative rotation between the valve-actuating subassembly within the valve along with a locking collar associated with the interconnection between the safety valve and the packer assembly so that high torque associated with rotational movement of a drill string in a highly deviated hole effects the release of the proper portion of the assembly without danger of undesirable release of other interconnections.

Abstract: In accordance with an illustrative embodiment of the present invention, a circulating valve for use in sand control and related well operations includes a mandrel that can be rotated in a housing after a weight-responsive clutch is released. As the mandrel is rotated to the right, a reverse lead groove system engaged by a pawl causes a valve sleeve element to shuttle down and up between positions closing and opening a flow path between the annulus above a packer and a zone in the well below the packer.

Abstract: The outer, sealing cover of an inflatable packer comprises an alternating series of thick and thin annular portions which act to effect greater sealing stresses and to inhibit the propagation of cracks or tears in the elastomeric cover. Bonding with only portions of the underlying slats as well as a tapered contour and spacing from an end fitting act to help to retain the cover in its proper position during running and retrieval as well as decreasing the likelihood of the development of cracks and/or tears.

Abstract: Where on the valve seating surfaces due to the high pressure pumping of abrasive slurry through an in-line valve is greatly reduced by providing first and second valve seating surfaces which are engaged, respectively by first metal and first elastomeric closure surfaces and second metal and elastomeric closure surfaces located on an annular valve closure means. Pumping efficiency is maintained by providing for high velocity sweep in an annular space between the annular valve closure means and the cylinder in which it rides.

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 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: 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: 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.