Mobil Oil Corporation

Peggy M Wilson

Ernest L Muegge

Julie Pao

Alfred R Jennings, Jr

James M Paul

Eve S Sprunt

Samuel H Collins

Maynard L Anderson

Silvia C Birk

Scott G Hugenberger

J George Savins

Susan O Wooten

Surface layers of the earth contaminated with precipitates of alkaline earth metal sulfates including radium sulfate derived from subterranean waters brought to the surface of the earth, are decontaminated using an aqueous chemical composition including a polyaminopolycarboxylic acid such as ETDA or DTPA in combination with a synergist, preferably oxalate or monocarboxylic acid anion such as salicylate. The surface layers may be decontaminated in situ by applying the solvent to the earth to bring the precipitates into dissolved form after which the dissolved precipitates are leached into lower layers of the earth by percolation with water. Alternatively, the earth may be removed from its original site and decontaminated in a tank or lined pond after which the decontaminated earth may be returned to its approximate original site.

Method for removing scale and radioactive material from earth

The performance of gas-liquid separators used to separate a liquid from a mixture containing at least one liquid and at least one gas, is enhanced by injecting into the mixture an additive, such as a suitable polymer, capable of imparting viscoelastic properties to the liquid. Suitable separators are those wherein crude oil is separated from a mixture obtained from an underground oil reservoir, the mixture typically containing water, hydrocarbon oil and gas.

Method of improving performance of gas-liquid separators

A core sample of an earth formation is obtained by drilling with a coring bit and circulating a coring fluid through the coring bit. The coring fluid contains no mud solids for contaminating the core sample or, in the alternative, contains drilling mud mixed with a bulk material which invades the core sample and occupies the core sample pore spaces preferentially over mud solids. This bulk material is more readily removed from the core sample by cleaning than mud solids.

Method for minimizing mud solids invasion of core samples obtained

A process wherein energy generated from a high impulse device is used to jar, loosen, or dislodge scale from a wellbore, downhole production equipment, or near well formation flow channels. Such jarred, loosened, or dislodged scale allows for increased amounts of scale-forming ions to be removed. Alterwards, an emulsified liquid membrane system containing surfactants therein sufficient to remove scale-forming ions is placed in said wellbore. Said emulsified membrane system is removed when the scale-forming ions have been absorbed therein.

High impulse energy and liquid membrane scale removal

A method for removing scale-forming ions from oil and gas production equipment. An external aqueous phase of a liquid membrane system contacts said scale and solubilizes said scale-forming compounds. Scale forming ionic compounds are then transferred into an immiscible liquid hydrocarbonaceous membrane phase having a complexing agent for scale forming ions. Said hydrocarbonaceous membrane phase envelops droplets of an internal aqueous phase which has a stronger complexing agent for scale forming ions than is contained in said hydrocarbonaceous membrane phase. Scale forming ions are transferred from said hydrocarbonaceous membrane phase and are accumulated and concentrated in said internal aqueous phase. Films of scale are thus progressively removed from surfaces where they have deposited.

Use of a liquid membrane for scale removal

A process for the recovery of oil from subterranean oil reservoirs by waterflooding employing ether-linked sulfonate surfactants in which oxidative degradation of the surfactant is retarded through the establishment of an anaerobic condition in the surfactant solution or through the use of oxidation inhibitors. The anaerobic condition may be provided by mechanical means such as scrubbing the injected water with an inert gas in order to remove oxygen or by employing produced well water which is handled under a closed system to exclude oxygen. A preferred class of oxidation inhibitors are sterically hindered phenolic compounds which function as free radical chain inhibitors.

Method of retarding degradation of surfactants employed in waterflooding

Waterflood process for the recovery of oil from a subterranean oil reservoir in which at least a portion of the injected water is thickened by the addition of a surface-active amphoteric quaternary ammonium sulfonate and an aliphatic alcohol containing from 5 to 8 carbon atoms. The alcohol is employed in a concentration to provide a ratio of the volume amount of alcohol in the solution to the weight amount of the amphoteric sulfonate within the range of 0.1-0.6 to produce a pronounced thickening effect. The alcohol-amphoteric sulfonate systems are useful viscosifiers in highly saline systems.

Waterflooding employing thickened aqueous liquids

A surfactant waterflooding process for the recovery of oil from subterranean oil reservoirs in which a water-soluble polyalkylene oxide is employed as a sacrificial agent in order to retard adsorption of the surfactant. An aqueous pretreatment slug is injected which contains a water-soluble polyalkylene oxide sacrificial agent having a molecular weight of at least 1200. Thereafter an aqueous slug containing a surfactant exhibiting a lower molecular weight than that of the polyalkylene oxide sacrificial agent is injected. The surfactant slug may also contain a polyalkylene oxide sacrificial agent as described above. In this case, concentration of sacrificial agent in the surfactant slug normally is lower than the concentration in the pretreatment slug.

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Dallas, TX, United States of America

Peggy M Wilson