Abstract: There is disclosed a method of recovering oil from a subterranean oil formation having the vertical thickness of 40 ft or more. The method exploits the effect of gravity on the various slugs of diverse materials injected into the oil column of the formation. The method comprises injecting a surfactant slug into the lower 50-75% of the vertical thickness of the oil column, then injecting a slug of a mobility control polymer into the upper 50-75% portion of the thickness of the oil column, followed by the injection of a slug of a drive fluid over substantially the entire vertical thickness of the oil formation. Optionally, a low-salinity pre-flush slug may be injected to reduce contact of high salinity water with the surfactant slug, and an alkaline pre-treat solution may be injected to precipitate divalent cations prior to the injection of the surfactant slug.

Abstract: Improved sweep efficiency is obtained in an oil recovery process wherein oil is recovered from a subterranean, viscous oil containing formation having relatively highly permeable zones and relatively low permeability zones penetrated by at least one injection well and at least one spaced apart production well in fluid communication with a substantial portion of the formation. First, a predetermined amount of gel solution is injected into the formation at high pressure to deeply penetrate and plug the fracture face and highly permeable zones of the formation. Thereafter, a breaker material such as hydrochloric acid is injected into the formation at a low pressure to break the gel and displace it from the fracture face and highly permeable zones in the vicinity of the injection well thereby reestablishing injectivity into the formation in the vicinity of the injection well.

Abstract: A process for improving the effectiveness of control pulse fracturing in a carbonate formation wherein a high energy impulse device having a metallic sheath reactive with a retarded acid is utilized in combination with a retarded acid. Upon placement of such device within a wellbore, the metallic sheath reacts with the retarded acid and generates heat which activates said acid. Afterwards, the high energy impulse device is ignited which fractures the formation and forces the activated acid into the created fractures thereby enhancing acid contact with said formation.

Abstract: A process for improved acidizing in carbonate formations, where controlled pulse fracturing (CPF) is utilized in combination with a retarded acid. The retarded acid comprises hydrochloric, formic, acetic acid or mixtures thereof which is placed in a wellbore adjacent the area to be treated. Said acid can contain retarders and corrosion inhibitors sufficient to make said acid stable in the wellbore. At least one CPF device is placed in said acid near the interval to be treated. Upon detonation of said device, acid is forced into the desired interval, thereby enhancing the acidizing treatment.

Abstract: Oil recovery from a subterranean, oil-containing formation having relatively highly permeable and/or fractured zones and relatively low permeability zones is improved by first injecting a predetermined amount of a plugging agent into the formation, preferably inorganic, non-polymeric solids suspended in a fluid such as drilling muds or bentonite or clay suspensions, that plugs the face of the highly permeable and/or fractured zones of the formation. Thereafter, injection of the plugging agent is continued or in the alternative a displacing fluid at a flow rate and pressure sufficient to initiate and propagate new fractures and/or extensions of existing fractures in the formation. Thereafter, a displacing fluid is injected into the formation at a pressure sufficient to maintain the new fractures and/or extensions of existing fractures open and displace oil from zones communicating with the new fractures and/or extensions of existing fractures toward a production well where it is recovered.

Abstract: A composition for making an in situ disposable propellant canister for utilization in controlled pulse fracturing. Said canister is composed of a porous light fabric material in combination with a gel solution. The gel creates a formable mass after solidification. Said mass can be made of a gel thickness sufficient to support and contain a propellant. Upon ignition of said propellant, the gelled canister is destroyed thereby alleviating a clean up operation.

Abstract: A controlled pulse fracturing ("CPF") process where a viscous fluid is used as a tamp or fluid cushion above a propellant device. Use of said fluid increases the vertical drag in the open wellbore thereby maximizing injection into the formation. Increasing the vertical drag during the fracturing procedure maximizes the number, extent, and length of fractures.

Abstract: There is disclosed a method of recovering oil from a subterranean oil formation having the vertical thickness of 40 ft or more. The method exploits the effect of gravity on the various slugs of diverse materials injected into the oil column of the formation. The method comprises injecting a surfactant slug into the lower 50-75% of the vertical thickness of the oil column, then injecting a slug of a mobility control polymer into the upper 50-75% portion of the thickness of the oil column, followed by the injection of a slug of a drive fluid over substantially the entire vertical thickness of the oil formation. Optionally, a low-salinity pre-flush slug may be injected to remove high salinity water from contact with the oil and an alkaline pre-treat solution may be injected to remove divalent ions prior to the injection of the surfactant slug.

Abstract: A process for improving the effectiveness of control pulse fracturing in a carbonate formation wherein a two stage high energy impulse device is utilized in combination with a retarded acid. Upon placement of such device within a wellbore, the first impulse stage activates said acid. Afterwards, the second impulse stage fractures the formation and forces the activated acid into the created fractures thereby enhancing acid contact with said formation.

Abstract: A method for the recovery of oil from a subterranean, oil-containing formation by a cyclical steam flood-pressurization and production program. During the first cycle, steam is injected into the formation and oil is recovered until there is steam breakthrough at the production well. Thereafter, a pressurization cycle is initiated by throttling or shutting-in the production well while continuing injection of the steam until the bottomhole injection pressure is greater than the vertical pressure created by the overburden thereby causing the formation to fracture horizontally. After the horizontal fracture is formed, the third cycle or production cycle is initiated in which oil is recovered from the formation from either the production well or the injection well or both until the amount of oil recovered is unfavorable.

Abstract: A controlled pulse fracturing (CPF) process conducted with the addition of a proppant. Said proppant can comprise sand or similar material which is injected into the fluid adjacent to the perforations. Upon ignition of the CPF device, said proppant is injected into the created fractures, thereby propping said fractures open. This causes a production increase from the well. Said fluid can comprise water, a gel, a thixotropic fluid, or similar type fluids.

Abstract: A method and apparatus for making an in situ disposable propellant canister for utilization in controlled pulse fracturing. Said canister is composed of a porous light fabric material in combination with a gel solution. The gel creates a formable mass after solidification. Said mass can be made of a gel thickness sufficient to support and contain a propellant. Upon ignition of said propellant, the gelled canister is destroyed thereby alleviating a clean up operation.

Abstract: Hydrocarbons are recovered from a fractured or stratified subsurface formation by means of at least one injection well and at least one production well. A first flooding agent having a high viscosity is injected into the formation to form a filtercake on the walls of the fractures or permeable streaks of the formation only in the near vicinity of the injection well. A second flooding agent having an inorganic thickener is injected deep into the formation to completely fill the thief zones provided by the fractures or permeable streaks of the formation between the injection and production wells. A first flushing agent is then injected to clear the fractures or permeable streaks of the formation only in the near vicinity of the injection well of the inorganic thickener. A second flushing agent having a breaker material is injected to remove the filtercake from the walls of the fractures or permeable streaks of the formation only in the near vicinity of the injection well.

Abstract: This specification discloses a method of providing an ice structure at a desired offshore, frigid location. The structure is constructed at a first offshore location by accumulating ice on a base of naturally occurring ice. The existing extreme temperature is utilized to quickly freeze water sprayed or flooded on the base to form the accumulating ice. The base sinks under the weight of the accumulated ice to form the structure having a desired thickness. A cavity is then formed, preferably by melting, in the interior of the structure to provide the structure with sufficient buoyancy to float the structure and allow it to be towed to its desired location. There the cavity is filled with a material dense enough to again cause the structure to sink and become grounded at said desired location.