Showing papers on "Steam injection published in 1986"

Thermally-enhanced oil recovery method and apparatus

Abstract: A thermally-enhanced oil recovery method and apparatus for exploiting deep well reservoirs utilizes electric downhole steam generators to provide supplemental heat to generate high quality steam from hot pressurized water which is heated at the surface. A downhole electric heater placed within a well bore for local heating of the pressurized liquid water into steam is powered by electricity from the above-ground gas turbine-driven electric generators fueled by any clean fuel such as natural gas, distillate or some crude oils, or may come from the field being stimulated. Heat recovered from the turbine exhaust is used to provide the hot pressurized water. Electrical power may be cogenerated and sold to an electric utility to provide immediate cash flow and improved economics. During the cogeneration period (no electrical power to some or all of the downhole units), the oil field can continue to be stimulated by injecting hot pressurized water, which will flash into lower quality steam at reservoir conditions. The heater includes electrical heating elements supplied with three-phase alternating current or direct current. The injection fluid flows through the heater elements to generate high quality steam to exit at the bottom of the heater assembly into the reservoir. The injection tube is closed at the bottom and has radial orifices for expanding the injection fluid to reservoir pressure.

Hasdrive with multiple offset producers

Abstract: The present invention is an improvement on the method of recovering viscous petroleum from a petroleum-containing formation by providing a steam injection well from the earth's surface through the formation, extending at least one lateral hole from the vicinity of the steam injection well through at least a portion of the formation, forming a flow path in the hole isolated from the formation for flow of fluid through the formation, circulating a hot fluid through the flow path to reduce the viscosity of the viscous petroleum in the formation adjacent the outside of the flow path to form a communication path for flow of petroleum in the formation outside of the flow path, and injecting a driving fluid into the formation through the steam injection well and the communication path to promote flow of petroleum in the formation to production wells penetrating the petroleum-containing formation for recovery from the formation. This improvement comprises having at least two of the production wells offset from the flow path by from 2% to 8% the distance from the steam injection well. Preferably, the offset production wells are located on both sides of the flow path and are offset from the flow path by from 3% to 6% the distance from the steam injection well. Preferably, the length of the flow path is at least 600 feet, and preferably there are at least four production wells per flow path.

Steamflood process employing horizontal and vertical wells

Abstract: An oil recovery process employing a well pattern having a horizontal well located along each of the four sides of a substantially rectangular well pattern, a vertical injection well located at the center of the well pattern, and four vertical infill wells located midway between the central injection well and the four corners of the rectangular well pattern Steam is initially injected through the central injection well and production taken at the four infill walls After the injection of about 05 to about 10 pore volumes of steam through the central injection well, central injection is converted to water, the infill production wells are converted to steam injection, and production is taken from the horizontal wells

A steam cycling model for gas production from a hydrate reservoir

Abstract: A model was developed to compute upper and lower bounds on the expected gas production and the energy efficiency ratio for a single well cyclic steam injection process. This thermal-stimulation model is a time dependent energy balance model with transient heat transfer equations. Wellbore heat losses and heat losses to strata above and below the hydrate zone are considered. The radial advance of the hydrate front is tracked during each cycle to determine gas production, and combustible energy of the produced gas is compared with the energy of the injected steam through the energy efficiency ratio. Production performance was examined for a range of reservoir cases which included variations in reservoir porosity, thickness, and depth. Results indicated that increasing the hydrate-filled porosity or increasing the zone thickness contribute to better gas production and energy efficiency ratios in all cases. Deeper reservoirs appeared to yield more favorable gas production and energy efficiency ratios (in spit...

Wellbore Heat Transmission and Pressure Drop for Steam/Water Injection and Geothermal Production: A Simple Solution Technique

Abstract: This paper presents a straightforward iterative procedure for the wellbore heat transmission problem during upward or downward flow of a steam/water mixture. The mathematical model is taken directly from the literature and is based on material and momentum balances in the wellbore and a heat balance on the entire system including the surrounding media. The transient heat conduction equation is solved analytically by the application of successive Fourier and Laplace transforms. A simple superimpositioning in the time domain permits a matching procedure similar to multiphase flow calculations in pipelines. This is in contrast to standard numerical schemes that involve the direct solution of a set of algebraic and ordinary and partial differential equations typical of reservoir simulation. The pressure-drop calculations in the wellbore account for the slip concept and the prevailing flow regimes by means of standard two-phase correlations. The validity of the method is demonstrated by comparison with results of other numerical simulation studies and actual field data for both steam injection and geothermal production.

Method and apparatus for steam injection in subterranean wells

Abstract: Apparatus for injecting high-temperature steam at a selected mass flow rate into a plurality of vertically spaced production formations of a subterranean well comprises a plurality of choke devices connected in series relationship in a tubing string extending to the well surface. Each choke device is positioned immediately above or adjacent to a production formation and defines a flow diversion device which extracts a predetermined portion of steam flow from the main steam flow, moving downwardly through the tubing string and directs such diverted steam portion into the inlet chamber of a Venturi passage. The steam is accelerated by the Venturi passage to its critical mass flow rate and is discharged into the production formation. In a preferred embodiment of the invention, the Venturi passage is connected in series with a fluid mixing apparatus which effects an intimate mixture of vapor and water components of the steam. A Venturi passage may also be incorporated in the steam supply line connected between the source of steam and the tubing string of the particular well.

Injectivity profile in steam injection wells via ball sealers

Abstract: A method for diverting steam injection in injection wells by the use of perforation ball sealers composed of polymer compounds covered with a thin coating of elastomer of low enough density to float in the injected fluids, yet able to stand the adverse temperatures of steam injection.

Steam injection process

Abstract: Automatic control for achieving a required temperature of a food product feed stock being heated with steam injection is effected by calculating with at least one computer the required steam flow rate from the measured feed stock temperature, the measured feed stock flow rate, and the measured and required temperature of the feed stock product after steam injection and by controlling the quantity of steam supplied in relation to the deviation between the measured and the required steam flow rates and by controlling the feed stock flow rate in relation to the deviation between the measured and the required feed stock flow rates.

Pressure-up/blowdown combustion - a channelled reservoir recovery process

Abstract: A cyclic process is described for recovering heavy oil from a reservoir having a network of generally linear, narrow permeable communication channels interconnecting outlying producing wells with an injection well. Except for the channels, the reservoir must be sufficiently impermeable so that pressure may be built up therein by the continued injection of oxidizing gas and propagation of a combustion front when the producers are choked or shut in. The process comprises: (a) initiating combustion in the reservoir at the injection well; (b) injecting oxidizing gas into the reservoir at less than fracturing pressure with the producers open, to propagate a rapid advance of the combustion front through a first channel toward a first of the producers; (c) after heat breakthrough has been established between the injector and said first producer, and before the combustion front arrives at said producer, restricting fluid production from said producer (as by choking or shutting the well in); (d) continuing to inject as before to induce widening of the hot first channel and rapid advance of the combustion front down a second channel toward an open second producer; (e) restricting the second producer after gas breakthrough has been established and before the combustion front arrives at said second producer; (f) repeating (d) and (e) for each of the other producers until all of the producers are restricted; (g) continuing to inject as before to cause a significant pressure build-up in the channel network and surrounding reservoir, said built-up pressure being less than the fracturing pressure; (h) substantially terminating oxidizing gas injection and injecting water into the network to cool it to a temperature below that at which significant coking occurs. (i) opening the producers to blowdown the reservoir; and (j) repeating steps (a) to (i) at least once. Preferably, the network of channels is provided by subjecting the wells to cyclic steam stimulation conducted at fracturing pressure, to create both on-trend and off-trend channels interconnecting a group of wells that make up the focal points of the network.

Method and apparatus for secondary and tertiary recovery of hydrocarbons

Abstract: A process is provided for secondary and tertiary recovery of hydrocarbon from hydrocarbon bearing formations. Apparatus for carrying out the process is also provided. Combustion products are formed in a bipropellant generator, the combustion products being at supercritical pressures and temperatures relative to steam. Water and steam are combined with the combustion gases, which may include steam, and forced through the center of a cooling jacket which is provided to cool the walls of the well bore. Chemical additives may be added to the mixture of combustion gases and steam between the bipropellant generator and well bore or below the cooling jacket.

Method of reducing permeability in subterranean formation by use of alkali metal silicate foam

Abstract: A method of reducing the permeability of an area of a subterranean formation is disclosed. An alkali metal silicate foam is produced by injecting into the formation a solution of alkali metal silicate and a chemical surfactant, and a non-condensible gas. The foam hardens into a substantially impermeable solid. The foam may be used to reduce permeability in areas of the formation which have been steam swept during steam stimulation cycles. Thus, subsequent steam stimulation cycles will be directed to uncontacted areas of the formation.

Method of viscous oil recovery

Abstract: A process for recovering viscous heavy oil from a substantially shallow reservoir having a low temperature and pressure Following a steam flood, liquid carbon dioxide is injected into the reservoir where said carbon dioxide remains in its liquid state Afterwards, a spacer volume of a vaporizable drive fluid is injected into the reservoir behind said carbon dioxide Subsequently, steam injection is commenced which causes the drive fluid to vaporize and the liquid carbon dioxide to gasify Vaporization of the drive fluid along with gasification of the carbon dioxide causes a pressure increase in the formation allowing the thinned oil to be removed therefrom

Thermal visbreaking of heavy oil during steam-recovery processes

Abstract: This paper describes a simulation study on the effect of visbreaking on heavy oil recovery during steam injection processes. The kinetic rate constant for in-situ visbreaking was derived from in-house kinetic data and then used in conjunction with a thermal compositional simulator to assess the effect of visbreaking on recovery through a series of numerical experiments. Various steam injection strategies were tested and the effect of visbreaking studied. In some cases physical heating, not thermal visbreaking, was the dominant recovery mechanism. In other cases, visbreaking had a large effect on recovery. The difference was found to be primarily due to the placement of the visbroken oil with respect to the direction of flow. In cases where the visbroken oil zone was perpendicular to the flow, it formed a mobility transition zone which improved sweep, thus enhancing oil recovery.

Method of recovering oil from heavy oil reservoirs

Abstract: A steam flooding method for recovering oil from an underground formation penetrated by an injection and at least one production well is modified by initially lowering the permeability of the lower vertical portion of the formation, e.g., by plugging thereof with gravel sand pack, capped by a plaster of paris or cement, thereafter continuing to inject the steam into the injection well and maintaining high level of production from the production well until thermal breakthrough is achieved in the production well. Subsequently, the initial permeability of the lower vertical portion of the formation is restored, e.g., by removing the gravel sand pack, and oil is recovered from the production well. In a preferred embodiment, the permeability of substantially the entire initial completed interval of the production well is decreased in the aforementioned manner, the well is recompleted higher in the formation and steam is continuously injected into the injection well. Subsequently, the secondary completed interval is plugged, and the permeability of the primary completed interval is restored substantially to its original level. The method of the invention decreases the time necessary for thermal breakthrough in the production well, thereby accelerating thermal communication between the injection and the production wells and improving vertical sweep efficiency of the cyclic steam or steam flooding methods of heavy oil recovery.

Method of improving conformance in steam floods with carboxylate steam foaming agents

Abstract: A METHOD OF IMPROVING CONFORMANCE IN STEAMFLOODS WITH CARBOXYLATE STEAM FOAMING AGENTS (D#78,530-F) ABSTRACT The disclosed invention is a group of steam foaming agents for injection with steam and a non-condensable gas to decrease permeability in steam swept zones and increase oil recovery. The foaming agents have the general formula: RO(R'O)nR"CO2M where R is an alkyl radical, branched or linear, having from about 8 to about 24 carbon atoms in the alkyl chain, R' is ethylene, propylene or a mixture of ethylene and propylene, n has an average value of about 3 to about 11, R'' is methylene or ethylene, and M is an alkali metal or ammonium ion. pg:EX8F

Viscous oil recovery method

Abstract: Our invention concerns a method for treating a well completed in a subterranean petroleum-containing formation which will improve the rate at which steam can be injected into the formation for a steam push-pull or steam drive oil recovery method. This preconditioning process is applied to formations exhibiting very limited steam receptivity because the formation contains high oil viscosity and has high oil saturation and is completely liquid filled. The method involves injecting a mixture of a non-condensable oil-insoluble gas such as nitrogen and an oil soluble gas such as carbon dioxide all in the gaseous phase into the formation at a controlled rate which will avoid permanently fracturing the formation and also avoid the immediate formation of an oil bank due to dissolution of the injected oil soluble gaseous fluid into the oil. Ideally by controlling the injection rate, the gaseous mixture first displaces water from the flow channels and then carbon dioxide slowly dissolves in the oil while nitrogen remains in the flow channels. Steam injection can then be applied to the formation without the previously experienced loss in steam injectivity.

Apparatus for gasifying pulverized coal

Abstract: An apparatus for gasifying pulverized coal, the apparatus comprising a housing with a granulated slag discharge opening in a bottom of the housing, and a producer gas outlet opening in a lower part of the housing; a layer of thermal insulation lining the housing; a pulverized coal burner having a discharge area in the top of the housing; a layer of heat-resistant lining located above the producer gas outlet opening; a steam injection inlet; and a plurality of ducts arranged between the heat-resistant lining and the thermal insulation and extending between the steam injection inlet to the discharge area, each of the ducts having an outlet opening arranged at a level of the discharge area and an inlet opening arranged above the steam injection means. Steam is injected into the housing and the producer gas is cooled with a plurality of cooling medium supply nozzles arranged in the housing.

Method of and apparatus for injection of steam into multiple well zones

Abstract: A method and apparatus for injecting steam containing water into a plurality of separated oil bearing zones for substantially equally dividing the injection of the water equally into the zones. A sidepocket mandrel with multiple pockets is positioned in the well tubing and includes a plug in the open bore for collecting water and directing the water substantially equally into each of the sidepockets for transmittal to the separated well zones.

Steam profile liquid/vapour separator

Abstract: A network of bristles extending across a steam injection well provides affirmative liquid/vapour separation and control. The orientation of the bristles is controlled to direct the liquid toward or away form the borehole wall as desired.

Steamflood recovery method for an oil-bearing reservoir in a dipping subterranean formation

Abstract: A plurality of production wells penetrate an oil-bearing reservoir in a dipping subterranean formation. Steam injection wells are located up-dip and down-dip of each oil-bearing reservoir. Some time after steam breakthrough in the upper-most one of the production wells, this well is converted to a steam injection well, and the original up-dip steam injection well is shut in. Some time after steam breakthrough in the lower-most one of the production wells, this well is converted to a steam injection well, and the original down-dip steam injection well is shut-in. Some time after steam breakthrough occurs at the remaining up-dip and down-dip production wells, these wells are sequentially converted to steam injection wells, and the preceding up-dip and down-dip steam injection wells are shut in.

Steam-injection Profile Control Using Limited-Entry Perforations

Abstract: A completion technique for steam-injection wells that ensures improved profile distribution of steam into several independent sands is being used at the South Belridge field in California. Previously, steam profiles were poor for many of the conventionally perforated (two 3/8-in. (9.5-mm) -diameter holes per foot) injection wells. This standard completion does not guarantee that the thicker, higher-permeability sands will not act as thief zones with respect to the thinner, tighter sands open in the same wellbore. Limited-entry perforating (typically one hole per 15 to 20 ft (4.6 to 6.1m) of gross interval with at least one in each major sand member) provides the best assurance of achieving a uniform injection profile in single-wellbore multisand completions.

Cyclic Steaming of Tar Sands Through Hydraulically Induced Fractures

Abstract: Fracture dimensions and process mechanisms that resulted from cyclic steam stimulation above fracturing pressure in German and Canadian tar sands are analyzed with numerical modeling. Horizontal fracture radii of 100 ft (30.5 m) and vertical fracture half-lengths of 250 ft (76.2 m) with fracture surface areas of 30,000 to 70,000 sq ft (2787 to 6503 m/sup 2/) are sufficient to reproduce steam injectivity into reservoirs containing highly viscous oil and negligible amounts of movable water saturation. Mechanisms that are important during fluid loading and unloading of induced fractures include thermal expansion of tar oil, countercurrent imbibition of water and oil caused by capillary pressure effects, and fracture compressibility.

Viscous oil recovery method

Abstract: Our invention concerns a method for treating a well completed in a subterranean petroleum containing formation which will improve the rate at which steam can be injected into the formation for a steam push-pull or steam drive oil recovery method. This preconditioning process is applied to formations exhibiting very limited steam receptivity because the formation contains high oil viscosity and has high oil saturation and is completely liquid filled. The method involves injecting a heated non-condensable and oil soluble gas all in the gaseous phase into the formation at a controlled rate which will avoid permanently fracturing the formation and also avoid the immediate formation of an oil bank due to dissolution of the injected gaseous fluid into the oil. Ideally by controlling the injection rate, carbon dioxide first displaces water from the flow channels and then slowly dissolves in the oil. Steam injection can then be applied to the formation without the previously experienced loss in steam injectivity.

Steam converting valve

Abstract: PURPOSE:To prevent damage of a constituting member through prevention of boiling vaporization of cooling waterdrops, by a method wherein, by injecting pressure reduced steam through atomization of cooling water, the heat volume of the cooling waterdrops is reduced, and a temperature difference between a constituting member, such as valve box of the pressure reducing part, and cooling water is decreased. CONSTITUTION:An annular coolant chamber 4 is located in internal contract with the intermediate part of a valve box 1, and a coolant injection nozzle 6, communicated from the coolant chamber 4 with and open to a pressure reducing part, is formed. A sprayed steam chamber 7 is communicated with a high pressure part 1a of the inner side of a cage type valve drum 2 through a sprayed steam introduction hole 8, a sprayed steam nozzle 9, communicated from a sprayed steam chamber 7 with and open to the interior of a pressure reducing part 1b, is formed in a state in that it crosses the coolant injection nozzle 6, and a coolant injected through the coolant injection nozzle 6 is sprayed by means of sprayed steam injected through the sprayed steam injection nozzle 9.

New Methods for Controlled Injection of Steam Into Multiple Sands

Abstract: Chevron has been employing two new completion methods to control steam injection into multiple oil-bearing horizons using a single injection well. The two methods, parallel tubing injection and limited entry injection, are used to improve steam utilization and to reduce the need to drill new injection wells. One of the methods used previously was concentric injection in which steam is injected down two concentric pipes placed inside the wellbore and thereby distributed to two separate sands. The outer pipe can be the well casing itself. This method, however, proved unsatisfactory because one of the strings became plugged due to scale buildup. As a result, injection into both sands was no longer possible. For this reason, the concentric injection method is no longer used. Instead, parallel tubing injection and limited entry injection methods are currently used. This paper reviews the concentric injection method and presents conceptual details of the two new methods. Theoretical calculations supporting application of these methods are also presented.