Abstract: An improved method for mobility control application in viscous oil reservoirs including (a) heating a lignosulfonate solution, prior to injection into an oil bearing formation, for a period of time sufficient to produce a more viscous lignosulfonate solution (e.g., 8% sodium lignosulfonate held at 375.degree. F. for 50 hours yielding a 86 cp fluid @ 84 sec.sup.-1 measured at room temperature), (b) cooling the resulting heat treated lignosulfonate fluid to a reservoir condition and (c) injecting this fluid into the formation. Fluids produced in this manner are useful as mobility buffers during a waterflood or a micellar flood process.

Abstract: A relatively nonvolatile, high molecular weight sulfur solvent produced by adding at least 40 parts by weight of elemental sulfur per 100 parts by weight dialkyl disulfide to an amine activated dialkyl disulfide oil. Such a sulfur solvent is particularly useful in sustaining a liquid phase at bottomhole conditions for high temperature, high pressure wells.

Abstract: A method for dissolving a deposit of elemental sulfur by contacting the deposit with dialkyl disulfides catalyzed with an aliphatic amine in which a small amount of sulfur is added to the disulfide amine mixture before it is used as a sulfur solvent. The small percentage of sulfur added increases the rate at which the disulfide dissolves such sulfur deposit.

Abstract: This specification discloses an automatic computer-implemented technique for filtering a two-dimensional array of data in the frequency domain. The program converts the array of numbers by Fourier transformation into the real and imaginary part of the frequency domain. In this domain, undesired waves present in the original array can be completely removed by the elimination from the frequency domain of the components of the Fourier-transformed array which fall within (or, if desired, outside of) a convex polygon of arbitrary shape. The system then re-transforms the remaining data back to the time domain, but the undesired components have been filtered. The program can cause the computer to produce a visual reproduction of the filtered array, or it may simply re-format the data of this array on a tape for further computer processing. Accordingly, this invention permits precision spatial filtering of undesired components from the original array.

Abstract: An improved method for reducing fluid loss during high pressure hydraulic fracturing of well formations using an aqueous foam involving adding to the foam from about 0.0005 to 0.5% by weight of an additive selected from the group consisting of a C.sub.5 to C.sub.10 unsubstituted monocarboxylic aliphatic acid, a C.sub.5 to C.sub.10 unsubstituted aliphatic alcohol, malonic acid, lower n-alkyl diesters of malonic acid and their mixtures. The new additives are shown to be as effective in reducing fluid loss during fracturing as the commercial practice employing hydroxy ethyl cellulose at a fraction of the cost of hydroxy ethyl cellulose without depositing polymer within the formation.

Abstract: The operation of a demethanizer being used to cryogenically separate high carbon dioxide content hydrocarbon feed into liquid ethane essentially free of both methane and carbon dioxide with simultaneous production of overhead gas comprising methane and carbon dioxide without carbon dioxide icing to foul equipment by virtue of maintaining pressure at which non-gaseous carbon dioxide remains dissolved in liquid hydrocarbon, can be improved by intentionally injecting a dehydrated methane-rich stripping gas to the bottom of the demethanizer. At temperatures below about -80.degree. F., the addition of a stream such as dehydrated inlet gas stabilizes the demethanizer operation by making the carbon dioxide to ethane ratio of the liquid bottoms product less sensitive to temperature fluctuations in the reboiler system heating the bottoms. In this manner, product recovery is increased while acceptable carbon dioxide as well as methane content can be maintained.

Abstract: A method for locating the position of a flame front within a rubbled oil shale retort of known dimension and location during an in situ combustion of the retort involving initiating a seismic signal at a selected position on the earth's surface relative to the retort, detecting the reflected seismic energy, and determining the position of the flame front by virtue of a maximum in the received reflected/refracted seismic signal. Repeating the process at a plurality of positions relative to the burning retort establishes the inclination of the flame front.

Abstract: An improved method of regenerating a low temperature Claus catalyst bed having elemental sulfur deposited on the catalyst involving initially using a moderately hot effluent gas (typically 600.degree. to 650.degree. F.) from the first conventional Claus reactor to warm up the low temperature Claus reactor and remove deposited sulfur and after the outlet temperature of said low temperature reactor reaches a value high enough to decompose COS and CS.sub.2 (typically 600.degree. to 650.degree. F.), supplementing the moderately hot first conventional Claus reactor effluent gas with hot (typically 1000.degree. to 1200.degree. F.) waste heat boiler effluent such that the temperature of the regenerating catalyst bed can be elevated to about 700.degree. F. or higher. The intentional temperature excursion to about 700.degree. F. during catalyst regeneration improves the degree of regeneration of the catalyst bed, promotes higher catalyst activity and extends the catalyst life.

Abstract: A passive method for locating the position and inclination of a flame front, within an oil-shale retort of known dimensions and location during an in situ combustion of the retort involving detecting the sound generated by the flame front, by two matched detectors separated by a fixed known distance. The pair of matched detectors are suspended vertically in a liquid-filled well which was drilled essentially parallel to the side wall of the retort. The outputs of the two detectors are fed directly to a differential amplifier and the resulting difference signal is monitored as a function of depth as the pair of detectors are raised and/or lowered in the well. The minimum in this signal corresponds to the position of the flame front within the retort. Repeated measurements in various observation wells establish the inclination of the flame front.

Abstract: The precipitation of scale-forming salts is inhibited by adding to an aqueous solution partially neutralized phosphate esters of an ethoxylated or propoxylated urea. The compositions are particularly useful in oil wells, oil well brines, cooling or boiler water, and the like.

Abstract: A process and composition are described for use in removing calcium sulfate scale from a well. An aqueous converter solution of sodium (for potassium or possibly ammonium) gluconates, hydroxides, and carbonates is used to convert the calcium sulfate into an acid soluble form, which can be removed by an acid rinse. In the aqueous converter solution, the weight ratio of hydroxide to carbonate is between about 3:2 and about 5:1, and the weight ratio of gluconate to the total amount of hydroxide and carbonate is between about 2:1 and about 5:1. The concentration of the combination of gluconate, hydroxide, and carbonate is between about 15% and about 50%. Preferably, the solution is by weight approximately 25% sodium gluconate, 5.3% sodium hydroxide, 1.8% sodium carbonate, and the remainder water.

Abstract: A process and composition are described for use in drilling shale and especially in drilling the troublesome types of shale which heretofore have been impossible to drill effectively. The aqueous drilling fluid of this invention so effectively stabilizes the shale that additions to maintain the special drilling fluid can be discontinued or drastically reduced, once the shale formation has been penetrated and drilling below the shale could even be done with conventional drilling fluids.The drilling fluid contains between about 0.2 to 1.5 pounds per barrel of flaxseed gum together with potassium and/or ammonium salts. The potassium and/or ammonium salts are used in quantities to provide a concentration of the cation of the salt of at least 10,000 ppm. As the drilling fluid is a non-clay type, a non-clay viscosifier is used. Preferably, the cation concentration is tailored to drilling fluid salinity such that the cation concentration in parts per million is approximately equal to at least 10,000.times.(1+0.025.

Abstract: An improved method for reducing the sulfur losses associated with leakage across closed valves in a Claus type sulfur recovery plant involving the recirculating of low sulfur content Claus tail gas to the high pressure side of the closed valves. This improved method for compensating for leakage across a closed valve is particularly useful in sealing a valve in the so-called Cold Bed Adsorption plant. Thus, allowing a conventional carbon steel valve of an undercut design to be used at a temperature range from under 250.degree. F to over 650.degree. F while meeting contemporary emission standards.

Abstract: A process and composition are described for use in removing calcium sulfate scale from a well. An aqueous converter solution of sodium (or potassium or possibly ammonium) gluconates, hydroxides, and carbonates is used to convert the calcium sulfate into an acid soluble form, which can be removed by an acid rinse. In the aqueous converter solution, the weight ratio of hydroxide to carbonate is between about 3:2 and about 5:1, and the weight ratio of gluconate to the total amount of hydroxide and carbonate is between about 2:1 and about 5:1. The concentration of the combination of gluconate, hydroxide, and carbonate is between about 15% and about 50%. Preferably, the solution is by weight approximately 25% sodium gluconate, 5.3% sodium hydroxide, 1.8% sodium carbonate, and the remainder water.

Abstract: This is a method of prospecting for accumulations of hydrocarbons or other minerals. At least two (and preferably more) samples of subsurface rock units are taken at different vertical depths in a plurality of locations. Each such sample is processed to recover organic material present in the rocks. From this organic residue, a number of specimens of the same palynomorph taxon are selected, and a characteristic of light absorbed or transmitted by the specific organic particles is determined. The difference in the values obtained in the same location for two sets of palynomorphs at different vertical distances (preferably same well) is called the translucency differential. This differential or the gradient (differential divided by the corresponding vertical distance between sampling points) is then plotted on a map at the location of the various points of sample collection, and a contour map or cross section is drawn.

Abstract: Claus-type processes used in the past to recover sulfur from low H.sub.2 S acid gas, in the presence of hydrocarbon or other impurities which are harmful to the Claus catalyst, have required the use of straight-through operation with the burning of supplemental fuel gas to maintain the required combustion temperature in the furnace. A method for conserving the amount of additional fuel gas required involving utilization of the excess heat of combustion to preheat the acid gas and oxygen-containing streams to a temperature in excess of 600.degree. F prior to combustion is described. Additional energy savings are achieved by preheating the Claus tail gas effluent prior to incineration.

Abstract: A method of selective plugging of undesirable high permeability streaks and channels in oil-bearing reservoirs during high temperature (250.degree. F or higher) injection recovery processes such as steamflooding, underground combustion, flooding of a naturally occurring high-temperature reservoir or the like. Improved sweep efficiency can be effected by injecting a gel-forming solution consisting essentially of sodium or ammonium lignosulfonate and water or brine in the absence of other gelation promoters and then allowing the high temperatures of the underground formation to promote gelation. Optionally, a precooling water injection step can be used prior to placement of the gel-forming solution. This system has the advantage of gel times which are sufficiently long at temperatures in excess of 250.degree. F to permit placement of large volumes characteristic of commercial use. This method is particularly useful in selectively forming firm, strong gels in thief zones for steamflooding recovery operations.

Abstract: A process for reducing the waiting-on-cement (WOC) time associated with the cementing of a casing string in an oil well involving the specific improvement of pumping into the well a highly retarded cement slurry containing a dispersed encapsulated accelerator, such as calcium chloride or anhydrous sodium metasilicate, wherein the encapsulating material is specifically selected such that it will melt at a temperature above the bottom-hole circulating temperature but below the bottomhole static temperature of the well to be cemented. Petroleum-derived waxes and petroleum-derived waxes in combination with vinyl resins, such as wax-compatible copolymers of ethylene and vinyl acetate, are particularly suitable as the meltable encapsulating material exhibiting excellent strength and abrasion resistance as well as serving as a moisture barrier. The improved process is particularly useful in cementing deep hot wells.

Abstract: An improved method for further removal of sulfur from the tail gas of a conventional Claus plant by the use of a Cold Bed Adsorption process involving the specific improvement of maintaining at all times the lead Claus reactor of a series of such reactors at sufficiently high temperatures to promote hydrolysis of COS and CS.sub.2 and then utilizing part or all of the hot effluent gases of this lead reactor to regenerate the sulfur-fouled Cold Bed Adsorption catalyst by passing the hot stream through the fouled reactor, removing the deposited sulfur and then returning the stream to the Claus plant at a point essentially immediately downstream from where it was originally withdrawn. Such a method is useful in maintaining ultra-high sulfur conversion levels on a commercial scale.

Abstract: A method for cleaning and stimulating an oil, gas or injection well, in which wax, tar and/or bituminous materials are either already deposited or would be precipitated by the injection of an acidizing solution consisting of a mixture of an octanol and a lower alcohol with an aqueous acid solution, involving the injection of an aromatic solvent either before and/or after the alcohol-acidizing solution. To enhance the interfacial miscibility of the aromatic solvent and the alcohol-acidizing solution, a small amount of amine having no more than eight carbon atoms may be added to the aromatic solvent. This method is useful in both production and injection wells.