EP1046780B1 - Method of enhanced hydrocarbon production by injection of a liquid and gaseous phase at least partially miscible with water - Google Patents

Method of enhanced hydrocarbon production by injection of a liquid and gaseous phase at least partially miscible with water Download PDF

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EP1046780B1
EP1046780B1 EP00400945A EP00400945A EP1046780B1 EP 1046780 B1 EP1046780 B1 EP 1046780B1 EP 00400945 A EP00400945 A EP 00400945A EP 00400945 A EP00400945 A EP 00400945A EP 1046780 B1 EP1046780 B1 EP 1046780B1
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Prior art keywords
gas
fact
well
injection
aqueous phase
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German (de)
French (fr)
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EP1046780A1 (en
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Nicole Doerler
Gérard Renard
Alexandre Rojey
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IFP Energies Nouvelles IFPEN
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IFP Energies Nouvelles IFPEN
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
    • E21B43/20—Displacing by water
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
    • E21B43/164—Injecting CO2 or carbonated water

Definitions

  • the present invention relates to a method of assisted hydrocarbon recovery by combined injection of water and gas in a deposit.
  • the method according to the invention finds applications in particular to improve the movement of petroleum fluids to producing wells and thus increase the recovery rate of recoverable fluids, oil and gas, initially in place in the rock mass.
  • Recovery is called primary when petroleum fluids are produced under the sole action of the energy present in situ. This energy can result from the expansion of pressurized fluids in the deposit: expansion of the gas-saturated or non-saturated oil, expansion of a gas cap above the oil deposit, or a body of water active. During this phase, if the pressure in the deposit drops below the bubble point of the oil, the gaseous phase from the oil will help to increase the recovery rate. Recovery by natural drainage rarely exceeds 20% of fluids initially in place for light oils and is often below this value for heavy oil deposits.
  • Secondary recovery methods are used to avoid excessive pressure drop in the deposit.
  • the principle of these methods consists in bringing to the deposit an external energy.
  • fluids are injected into the deposit by one or more injection wells in order to move the recoverable petroleum fluids (hereinafter referred to as "oil") to production wells.
  • Oil is frequently used as a displacement fluid.
  • its effectiveness is limited. A large part of the oil remains in place because its viscosity is greater than that of water.
  • the oil remains trapped in the pore shrinkage of the formation due to the large difference in interfacial tension between it and the water.
  • the rock mass is frequently heterogeneous. In this context, the injected water will take the paths of greater permeabilities to reach the producing wells, leaving large unbrushed oil masses. These phenomena induce a significant loss of recovery.
  • Pressurized gas can also be injected into a reservoir for secondary recovery purposes, the gas has the well-known property of displacing significant amounts of oil. However, if the formation is heterogeneous, since the gas is much less viscous than the oil and the water in place, it will cross the rock mass by borrowing only some most permeable channels and will arrive quickly at the producing wells without having the expected displacement effect.
  • patent FR 2,735,524 of the applicant there is also known an improved method of adding to at least one of the water plugs injected alternately an agent decreasing the interfacial tension between water and gas. Under the effect of this agent, alcohol, for example, the oil can not spread over the water film covering the rock mass. The oil remains in the form of droplets that slow down the movement of the gas.
  • patent FR 2 764 632 of the applicant there is also known a method comprising the alternating injection of gas plugs and water plugs in which at least one of the water plugs is added gas under pressure both soluble in water and in oil. The production stage involves the relaxation of the pressure in the deposit, so as to generate gas bubbles that will drive hydrocarbons from the pores of the rock mass.
  • tertiary recovery is to improve this recovery rate, when residual oil saturation is reached.
  • This name is grouped the injection into the tank of miscible gas, microemulsion, or steam or combustion in situ.
  • the method for the assisted recovery of a petroleum fluid produced by a reservoir aims, by a combined injection of an aqueous phase and of gas coming from an external source or, as far as possible, at least in part from acid gases from the effluents from the deposit itself, to increase the recovery rate of hydrocarbons.
  • the method comprises the continuous injection by an injection well of a sweeping fluid consisting of an aqueous phase containing gas at least partially miscible in water and in the petroleum fluid, with a permanent control at the wellhead. injection, the ratio of flow rates of this aqueous phase and gas forming the sweep fluid so that, at the bottom of the injection well, the gas is in saturation or supersaturation state.
  • the sweeping fluid may be formed either at the bottom of the well with separate conveyance of the constituents to the injection zone, or at the wellhead.
  • a means disposed in the injection well may be used to create a pressure drop such as a valve or conduit restriction and thereby increase the dissolution rate of the gas in the water.
  • a packing placed in the injection well to intimately mix the gas and the aqueous phase of the sweep fluid also increases the pressure drop and the dissolution rate.
  • a multiphase pump of rotodynamic type is used, for example to compress the gas, pressurize the aqueous phase and form an intimate mixture between this aqueous phase and pressurized gas before injecting it into the well. 'injection.
  • the gas in the flushing fluid contains at least one acid gas such as carbon dioxide and / or hydrogen sulfide and optionally, in varying proportions, other gases: methane, nitrogen, etc.
  • acid gas such as carbon dioxide and / or hydrogen sulfide
  • gases can be taken from the effluents from a deposit, an operation carried out by a treatment unit adapted to separate them from other gases that can be recovered elsewhere, or from chemical units or thermal units burning lignite, coal, oil, natural gas etc.
  • the aqueous phase used to form the sweeping fluid may be, for example, water from an underground deposit (for example a groundwater table or a brine produced during the exploitation of a deposit) or any other readily available water ( sea water).
  • an underground deposit for example a groundwater table or a brine produced during the exploitation of a deposit
  • any other readily available water sea water
  • a surfactant additive is added to the aqueous phase to promote the dispersion of the gas and / or one or more additives to increase the solubility of the gas in the sweeping fluid.
  • the sweeping fluid is injected for example into one or more high offset wells, horizontal or of complex geometry located for example at the base of the deposit and the petroleum fluid is produced for example by one or several deflected wells or complex geometry can be located at the roof of the deposit.
  • the process can be implemented from the beginning of the exploitation of the deposit.
  • the aqueous phase injected preferentially at the periphery of the producing zone, sweeps the porous medium containing the hydrocarbons at recover.
  • carbon dioxide much more soluble in oil than in injected water, passes from the sweep fluid to the petroleum fluid causing its swelling and decreasing its viscosity.
  • the invention also relates to a system for assisted recovery of a petroleum fluid extracted from a reservoir, by continuous injection into the reservoir of a flushing fluid consisting of an aqueous phase with added gas at least partially miscible in the aqueous phase and in the petroleum fluid, which comprises a conditioning assembly of the sweeping fluid and a permanent control unit of the conditioning assembly adapted to control the ratio of the flow rates of this aqueous phase and of the gas forming the bottom flushing fluid. wells, so that the gas is in saturation or supersaturation.
  • the system comprises state sensors arranged in the injection zone for measuring thermodynamic parameters and connected to the control unit.
  • the recovery process which is the subject of the present invention comprises four steps:
  • non-upgraded gases such as CO 2 carbon dioxide or hydrogen sulfide are preferably used.
  • SH 2 preferably readily available non-upgraded gases such as CO 2 carbon dioxide or hydrogen sulfide are preferably used.
  • the carbon dioxide mixed with the aqueous phase reacts according to the equilibrium reaction: CO 2 + H 2 O ⁇ H 2 CO 3 giving carbonic acid.
  • the solubility of carbon dioxide in water depends on the salinity of the water, the temperature and the pressure.
  • the dissolution rate of CO 2 increases with the pressure and decreases with temperature.
  • the effect of pressure is preponderant.
  • the dissolution rate of the carbon dioxide at the bottom of an injection well is greater than the rate of dissolution at the surface, despite the temperature increase due to the geothermal gradient.
  • the solubility of the H 2 S will be about 8.3% by weight (83 kg H 2 S are dissolved in 1 m 3 of water).
  • the acid gases from oil production mainly contain carbon dioxide, it is the solubility of this gas that will be limiting when the mixture will be dissolved in an aqueous fluid.
  • flushing fluid is injected such that at the bottom of the well, in the injection zone, the solution injected water is at least saturated and preferably supersaturated with gas.
  • the volumes of acid gases and water that can be reinjected into the deposit can be available in a ratio much higher than the ratio of solubility of the acid gas in water. This ratio may change during the course of the operation or according to the constraints of production.
  • the increase in pressure at the bottom of the injection well is partially compensated by an increase in the temperature linked to the geothermal gradient. However, the effect of the pressure is generally greater, especially since the injected fluid does not reach the conditions of thermal equilibrium.
  • an injection system that can be disposed entirely on the surface or also include elements at the bottom of the well is used.
  • the sweeping fluid is produced by a packaging unit PA and its constituents, brought separately into the injection zone at the bottom of the well.
  • the gas is compressed by a compressor 1 and injected by an injection tube 2 to the bottom of the injection well IW, while the water from a pump 3 is injected into the annular space 4 between the casing and the injection tube 1.
  • the mixing between the two phases takes place under the seal 5 to the right of the injection zone.
  • the injection pressures of the compressor 1 and the pump 3 are determined by a control device 6.
  • the injection of gas requiring a high pressure at the wellhead it is preferred to perform the mixture on the surface before injecting it.
  • This simultaneous injection makes it possible to increase the weight of the liquid column in the injection well, and to reduce substantially the necessary gas pressure.
  • the mixture produced at the well head be highly supersaturated with acid gases and be particularly homogeneous, the gas being dispersed in the liquid phase.
  • FIG. 2 a conventional compression and pumping device known to those skilled in the art, for the injection of the sweep fluid under a saturation or supersaturation condition downhole.
  • the acid gases are compressed in a compressor 1 in successive steps and cooled between two compression sections.
  • the water is pressurized by a pump 3 at a pressure equal to that applied by the compressor 1.
  • the gas and the liquid are then introduced into a static or dynamic mixer 7 having a sufficient efficiency to allow the total dispersion of the gas in the liquid. Downstream of the mixer 7, the mixture can be compressed by an additional pump 8 to allow either the dissolution of an additional amount of gas or the injection of the flushing fluid into the well IW.
  • the acid gases, heated during the compression may for example be cooled by means of heat exchangers (not shown) before their introduction into the mixer 7 so as to promote their dissolution.
  • a rotodynamic type multiphase pump can advantageously replace a conventional reinjection chain and fulfill the three functions of compressing the gas, pressurizing the liquid phase and mixing intimately the two phases.
  • a rotodynamic multiphase pump suitable for this type of application is described in patents FR 2,665,224 (US 5,375,976) to the applicant or FR 2,771,024 to the applicant. By design, this type of pump can inject into a well a two-phase mixture composed of saturated carbonated water and an excess of gaseous carbon dioxide without cavitation problem.
  • a packing is also placed in the injection well IW to improve the mixing of the constituents while inducing an additional pressure drop.
  • a packing is also placed in the injection well IW to improve the mixing of the constituents while inducing an additional pressure drop.
  • it is used in the one and the another case of state sensors (not shown) down to the well bottom, in the injection zone, for measuring various thermodynamic parameters: pressures, temperatures, etc., and connected to the control device 6.
  • a transmission system adapted to transmit on the surface signals from permanent sensors permanently installed in wells for monitoring a deposit, and in particular state sensors making it possible to know, for example, the temperatures and pressures at the bottom of the well, is described in particular in the patent US 5,363,094 of the applicant.
  • the control device 6 adjusts the flow rates and their ratio in this case according to the conditions prevailing in situ.
  • the system is adapted to form a saturated or supersaturated mixture, at least in part, by controlled recombination of effluents pumped out of the deposit by one or more production wells of the PW deposit.
  • effluents include generally a liquid phase consisting of water and oil, and a gaseous phase.
  • the effluents therefore pass into a water-oil-gas separator S1.
  • the gaseous phase possibly supplemented by external inputs, passes through a separator S2 for separating the otherwise recoverable gases for other applications, acid gases that we want to recycle.
  • the water issuing from the separator S1 is then recombined with the acid gases recovered in a controlled mixing device M, so as to form the saturated or supersaturated mixture under the conditions prevailing at the bottom of the well.
  • the pressure necessary to inject the fluid into the porous mass is lower than the CO 2 liquefaction pressure, a liquid phase and a gaseous phase will be present in the injection well.
  • the user must ensure that the dispersion of the gas is maximum and that the gas plugs circulating in the injection well are driven by the liquid column at the bottom of the well, in other words that the liquid velocity is greater than the rate of rise of the gaseous plugs to avoid segregation in the injection well.
  • the pressure necessary to inject the fluid into the porous mass is greater than the CO 2 liquefaction pressure.
  • the liquefied gas will be intimately mixed with the water and an emulsion formed of fine droplets of liquefied gas in the water will then be injected.
  • a small proportion of surfactant promoting the dispersion of the gas bubbles is added to the aqueous phase.
  • the concentration of these additives in water can vary from 10 to 30% by weight.
  • the injection wells can be vertical or horizontal wells. Generally, if the tank is thin, it may be advantageous to implement the injection of carbonated water in wells of high offset or in horizontal wells.
  • the aqueous phase can be injected at the base of the reservoir to be drained by means of one or more horizontal wells and the liquid hydrocarbon phase can be withdrawn from the roof of the tank by means of one or more horizontal wells. For thick tanks the injection and production wells will be vertical, and the hydrocarbon sweep in place will be parallel to the reservoir boundaries. Wells of more complex geometry can be used without departing from the scope of the present invention.
  • the recovery principle according to the invention makes it possible to supply the deposit with additional energy.
  • the benefits of simultaneous injection of water and acid gases are numerous.
  • Carbonated water solubilizes the soluble carbonates present in the rock, calcite and dolomite, forming soluble bicarbonates according to the reactions: Ca CO 3 + H 2 CO 3 ⁇ Ca (HCO 3 ) 2 Mg CO 3 + H 2 CO 3 ⁇ Mg (HCO 3 ) 2
  • This partial dissolution of the carbonates causes an increase in the permeability of the porous medium, whether it is a sandstone, in which the dissolution will attack the cements and calcium deposits frequently present around the quartz grains, or a formation limestone in which the porous connection will be improved.
  • the permeability gain resulting from the dissolution of the carbonates can be significant, as is well known in the art.
  • the viscosity of the water increases when the CO 2 dissolves there.
  • the volume of this carbonated water increases by 2 to 7% depending on the concentration of dissolved gas and its density decreases slightly.
  • the overall effect of decreasing the density contrast between water and oil reduces the risks of segregation by gravity.
  • the water / oil mobility ratio is improved by decreasing the oil / water viscosity ratio.
  • Carbon dioxide is much less soluble in water than in oil fields. This solubility is a function of the pressure, the temperature and characteristics of the oil. Under certain conditions, carbon dioxide can be partially or completely miscible with hydrocarbons. When it is injected into the deposit in the form of carbonated water, the carbon dioxide will preferentially go from water to oil.
  • the dissolution of the carbon dioxide in the oil also causes a decrease in its viscosity. This decrease will be greater when the amount of CO 2 increases.
  • An oil having initially a high viscosity will be more sensitive to the phenomenon.
  • a density oil 12.2 API (0.99 g / cm 3 ) and having a viscosity of 900 mPa.s at ambient pressure and a temperature of 65 ° C will reduce its viscosity to 40 mPa.s under a pressure 150 bars of CO 2 .
  • a viscosity of an API density oil (0.93 g / cm 3 ) will drop from 6 to 0.5 mPa ⁇ s.
  • the swelling of the oil as the drop in its viscosity promotes an increase in the recovery of hydrocarbons initially in place in the deposit. They also help speed up the process of oil recovery.
  • the carbonated water is at least saturated with CO 2 when it is injected into the reservoir.
  • the pressure of the injected fluid will drop due to flow-related head losses.
  • gas will be released.
  • the nucleation of the carbon dioxide bubbles will preferably occur on contact with the rock and specifically in areas with a high concentration of rock / liquid interfaces. These zones correspond to low permeability massifs; magnification and migration of gas bubbles will drive oil trapped in the small diameter pores of the rock. This phenomenon significantly increases the rate of hydrocarbons mobilized during production.
  • the recovery process as described above finds an advantageous application during the production of deposit with a dual porosity system such as cracked deposits.
  • a simple representation of these deposits is a set of rock blocks of decimetric or metric size with pores of small diameters and saturated with oil, interconnected by a network of cracks offering a passage to the flow of the fluids of a few tens of micrometers on average.
  • Two types of cracked reservoirs can typically be distinguished: tanks with water-wettable rock, and intermediate wettable or oil wettable tanks (eg, some carbonate rock masses).
  • the exploitation of the deposit may include injection and depletion cycles. During the injection period, production will be stopped or decreased while the injection of carbonated water will be maintained, in order to raise the pressure in the reservoir beyond the bubble pressure of the water and thereby increase the concentration of available carbon dioxide. This injection period will be followed by a period of production and partial depletion of the deposit.
  • the hydrocarbons produced have increasing concentrations of acid gases. As we have seen above, these gases are advantageously separated from the gas that can be valorized elsewhere and reinjected into the deposit. If the gas treatment and refining units are close to producing wells, the gas and the oil will be separated by successive expansion in separation balloons S1, S2 (Fig.3) located near the production area. If the refinery unit of a heavy crude is removed from the production area, it is possible to transport under pressure the crude charged with its gas. The CO 2 which substantially reduces the viscosity of the heavy oil advantageously replaces a fluxing agent.
  • Comparative tests were conducted in the laboratory on oil-impregnated rock cores selected and adapted to represent a cracked reservoir. They have been placed in a containment cell associated with a pressurized fluid circulation system, of the same type for example as those described by patents FR 2,708,742 (US 5,679,885) or FR 2,731,073 (US 5,679,885) to the applicant. and subjected to various sweep tests by a gas phase under the gas saturation or supersaturation conditions set forth above. These tests have demonstrated the effectiveness of the process according to the present invention.

Description

La présente invention concerne un procédé de récupération assistée d'hydrocarbures par injection combinée d'eau et de gaz dans un gisement.The present invention relates to a method of assisted hydrocarbon recovery by combined injection of water and gas in a deposit.

Le procédé selon l'invention trouve des applications notamment pour améliorer le déplacement des fluides pétroliers vers les puits producteurs et de ce fait accroître le taux de récupération des fluides valorisables, huile et gaz, initialement en place dans le massif rocheux.The method according to the invention finds applications in particular to improve the movement of petroleum fluids to producing wells and thus increase the recovery rate of recoverable fluids, oil and gas, initially in place in the rock mass.

ART ANTERIEURPRIOR ART

Il existe de nombreux procédés de type dits primaire secondaire ou tertiaire pour récupérer des hydrocarbures dans des gisements, un exemple est décrit dans le brevet US-4 763 730.There are many processes of so-called secondary or tertiary primary type for recovering hydrocarbons in deposits, an example is described in US Patent 4,763,730.

La récupération est dite primaire quand les fluides pétroliers sont produits sous la seule action de l'énergie présente in situ. Cette énergie peut résulter de la détente des fluides sous pression dans le gisement : détente de l'huile saturée ou non en gaz, expansion d'un chapeau de gaz au-dessus du gisement d'huile, ou d'un plan d'eau actif. Au cours de cette phase, si la pression dans le gisement descend au-dessous du point de bulle de l'huile, la phase gazeuse issue de l'huile contribuera à augmenter le taux de récupération. La récupération par drainage naturel dépasse rarement 20% des fluides initialement en place pour des huiles légères et est souvent inférieure à cette valeur pour les gisements d'huiles lourdes.Recovery is called primary when petroleum fluids are produced under the sole action of the energy present in situ. This energy can result from the expansion of pressurized fluids in the deposit: expansion of the gas-saturated or non-saturated oil, expansion of a gas cap above the oil deposit, or a body of water active. During this phase, if the pressure in the deposit drops below the bubble point of the oil, the gaseous phase from the oil will help to increase the recovery rate. Recovery by natural drainage rarely exceeds 20% of fluids initially in place for light oils and is often below this value for heavy oil deposits.

Des méthodes de récupération secondaires sont utilisées pour éviter une baisse de pression trop importante dans le gisement. Le principe de ces méthodes consiste à apporter au gisement une énergie extérieure. Pour ce faire, des fluides sont injectés dans le gisement par un ou plusieurs puits injecteurs afin de déplacer les fluides pétroliers valorisables (ci-après désignés par " huile ") vers des puits de production. L'eau est fréquemment utilisée comme fluide de déplacement. Toutefois son efficacité est limitée. Une grande partie de l'huile reste en place du fait que notamment sa viscosité est supérieure à celle de l'eau. En outre, l'huile reste piégée dans les rétrécissements de pores de la formation en raison de la forte différence de tension interfaciale entre elle et l'eau. Enfin, le massif rocheux est fréquemment hétérogène. Dans ce contexte, l'eau injectée empruntera les chemins de plus grandes perméabilités pour atteindre les puits producteurs, en laissant de larges massifs d'huile non balayés. Ces phénomènes induisent une perte importante de récupération.Secondary recovery methods are used to avoid excessive pressure drop in the deposit. The principle of these methods consists in bringing to the deposit an external energy. To do this, fluids are injected into the deposit by one or more injection wells in order to move the recoverable petroleum fluids (hereinafter referred to as "oil") to production wells. Water is frequently used as a displacement fluid. However, its effectiveness is limited. A large part of the oil remains in place because its viscosity is greater than that of water. In addition, the oil remains trapped in the pore shrinkage of the formation due to the large difference in interfacial tension between it and the water. Finally, the rock mass is frequently heterogeneous. In this context, the injected water will take the paths of greater permeabilities to reach the producing wells, leaving large unbrushed oil masses. These phenomena induce a significant loss of recovery.

Un gaz sous pression peut également être injecté dans un gisement à des fins de récupération secondaire, le gaz a la propriété bien connue de déplacer des quantités non négligeables de pétrole. Toutefois, si la formation est hétérogène, le gaz étant beaucoup moins visqueux que l'huile et l'eau en place, il traversera le massif rocheux en n'empruntant que quelques chenaux les plus perméables et arrivera rapidement aux puits producteurs sans avoir l'effet de déplacement attendu.Pressurized gas can also be injected into a reservoir for secondary recovery purposes, the gas has the well-known property of displacing significant amounts of oil. However, if the formation is heterogeneous, since the gas is much less viscous than the oil and the water in place, it will cross the rock mass by borrowing only some most permeable channels and will arrive quickly at the producing wells without having the expected displacement effect.

Il est également connu de combiner des injections d'eau et de gaz suivant une méthode dite de WAG pour " Water Alternate Gas ". Selon cette méthode, l'eau et le gaz sont injectés successivement tant que les fluides pétroliers sont produits dans des conditions économiques. Le rôle des bouchons d'eau est de réduire la mobilité du gaz et accroître la zone balayée. De nombreuses améliorations de cette technique sont proposées : l'ajout de tensioactifs à l'eau afin de décroître la tension interfaciale eau - huile, l'ajout d'agent moussant dans l'eau : la mousse formée en présence du gaz réduira de façon significative la mobilité de ce dernier. Une telle méthode est par exemple décrite dans le brevet US N° 3,893,511. Par le brevet FR 2,735,524 du demandeur, on connaît également un procédé amélioré consistant à additionner à au moins un des bouchons d'eau injectés en alternance un agent diminuant la tension interfaciale entre l'eau et le gaz. Sous l'effet de cet agent, de l'alcool par exemple, l'huile ne peut s'étaler sur le film d'eau recouvrant le massif rocheux. L'huile reste sous forme de gouttelettes qui freinent le déplacement du gaz. Par le brevet FR 2 764 632 du demandeur, on connaît également un procédé comportant l'injection alternée de bouchons de gaz et de bouchons d'eau dans lequel au moins un des bouchons d'eau est additionné de gaz sous pression à la fois soluble dans l'eau et dans l'huile. L'étape de production comporte le relâchement de la pression régnant dans le gisement, de manière à générer des bulles de gaz qui vont chasser les hydrocarbures des pores du massif rocheux.It is also known to combine water and gas injections according to a so-called WAG method for "Water Alternate Gas". According to this method, water and gas are injected successively as long as the fluids oil tankers are produced under economic conditions. The role of water plugs is to reduce the mobility of the gas and increase the swept area. Many improvements of this technique are proposed: the addition of surfactants to water in order to decrease the water-oil interfacial tension, the addition of foaming agent in water: the foam formed in the presence of gas will reduce significant mobility of the latter. Such a method is for example described in US Patent No. 3,893,511. By patent FR 2,735,524 of the applicant, there is also known an improved method of adding to at least one of the water plugs injected alternately an agent decreasing the interfacial tension between water and gas. Under the effect of this agent, alcohol, for example, the oil can not spread over the water film covering the rock mass. The oil remains in the form of droplets that slow down the movement of the gas. By patent FR 2 764 632 of the applicant, there is also known a method comprising the alternating injection of gas plugs and water plugs in which at least one of the water plugs is added gas under pressure both soluble in water and in oil. The production stage involves the relaxation of the pressure in the deposit, so as to generate gas bubbles that will drive hydrocarbons from the pores of the rock mass.

Ces techniques de récupération secondaire conduisent à des taux de récupération de 25 à 50% de l'huile initialement en place.These secondary recovery techniques lead to recovery rates of 25 to 50% of the oil initially in place.

La récupération tertiaire a pour objectif d'améliorer ce taux de récupération, quand la saturation résiduelle en huile est atteinte. On regroupe sous cette appellation l'injection dans le réservoir de gaz miscible, de micro émulsion, ou de vapeur ou encore la combustion in situ.The objective of tertiary recovery is to improve this recovery rate, when residual oil saturation is reached. Under this name is grouped the injection into the tank of miscible gas, microemulsion, or steam or combustion in situ.

La définition de ces techniques de récupération primaire, secondaire et tertiaire comme leur application chronologique lors de la mise en production d'un réservoir, datent de quelques années. On assiste actuellement à la mise en place de techniques de maintien de pression dès le début d'exploitation des réservoirs et d'injection de fluides antérieurement qualifiés de tertiaires avant un déclin prononcé de la pression initiale du réservoir.The definition of these primary, secondary and tertiary recovery techniques as their chronological application when a reservoir is put into production, dates back a few years. Pressure maintenance techniques are being implemented from the beginning of reservoir operation and the injection of fluids previously described as tertiary prior to a pronounced decline in the initial reservoir pressure.

Plus de 30 % des champs d'hydrocarbures mis en production contiennent des composés acides tels que CO2 et H2S. L'exploitation de ces champs nécessite la mise en place de procédés de traitement permettant de séparer les gaz valorisables des gaz acides. Le dioxyde de carbone issu de ces installations, est fréquemment rejeté à l'atmosphère, augmentant les perturbations climatiques et l'effet de serre. La gestion de l'hydrogène sulfuré est problématique de par la grande toxicité de ce gaz. Il sera généralement transformé en soufre solide par une chaîne Claus. Ce procédé demande un investissement élevé qui n'est pas rentabilisé à une époque où la production mondiale de soufre solide excède les besoins. La réinjection de ces gaz acides dans le gisement après solubilisation complète ou partielle dans une phase aqueuse, qui peut être tout ou partie de l'eau de production, de l'eau douce ou une saumure issue d'une nappe phréatique, de l'eau de mer ou autre, présente un double intérêt : se débarrasser des gaz acides à faible coût sans rejet atmosphérique polluant et accroître la productivité du réservoir.More than 30% of hydrocarbon fields put into production contain acid compounds such as CO 2 and H 2 S. The exploitation of these fields requires the establishment of treatment processes to separate the recoverable gases from acid gases. The carbon dioxide from these facilities is frequently released into the atmosphere, increasing climate disturbances and the greenhouse effect. The management of hydrogen sulphide is problematic because of the high toxicity of this gas. It will usually be converted to solid sulfur by a Claus chain. This process requires a high investment that is not profitable at a time when global production of solid sulfur exceeds requirements. The reinjection of these acid gases into the deposit after complete or partial solubilization in an aqueous phase, which may be all or part of the production water, fresh water or brine from a water table, the sea water or other, has a dual interest: to get rid of low-cost acid gases without atmospheric pollutant discharge and increase the productivity of the reservoir.

DEFINITION DE L'INVENTIONDEFINITION OF THE INVENTION

Le procédé de récupération assistée d'un fluide pétrolier produit par un gisement selon l'invention vise, par une injection combinée d'une phase aqueuse et de gaz venant d'une source extérieure ou, dans la mesure du possible, au moins en partie de gaz acides provenant des effluents issus du gisement lui-même, à augmenter le taux de récupération des hydrocarbures.The method for the assisted recovery of a petroleum fluid produced by a reservoir according to the invention aims, by a combined injection of an aqueous phase and of gas coming from an external source or, as far as possible, at least in part from acid gases from the effluents from the deposit itself, to increase the recovery rate of hydrocarbons.

Le procédé comporte l'injection continue par un puits d'injection d'un fluide de balayage constitué d'une phase aqueuse additionnée de gaz au moins partiellement miscible dans l'eau et dans le fluide pétrolier, avec un contrôle permanent en tête du puits d'injection, du rapport des débits de cette phase aqueuse et de gaz formant le fluide de balayage pour que, en fond du puits d'injection, le gaz y soit en état de saturation ou de sursaturation.The method comprises the continuous injection by an injection well of a sweeping fluid consisting of an aqueous phase containing gas at least partially miscible in water and in the petroleum fluid, with a permanent control at the wellhead. injection, the ratio of flow rates of this aqueous phase and gas forming the sweep fluid so that, at the bottom of the injection well, the gas is in saturation or supersaturation state.

Le fluide de balayage peut être formé soit en fond de puits avec acheminement séparé des constituants jusqu'à la zone d'injection, soit en tête de puits.The sweeping fluid may be formed either at the bottom of the well with separate conveyance of the constituents to the injection zone, or at the wellhead.

On peut utiliser un moyen disposé dans le puits d'injection pour créer une perte de charge tel qu'une vanne ou une restriction de conduit et ainsi augmenter le taux de dissolution du gaz dans l'eau. Un garnissage placé dans le puits d'injection afin de mélanger intimement le gaz et la phase aqueuse du fluide de balayage, augmente également la perte de charge et le taux de dissolution.A means disposed in the injection well may be used to create a pressure drop such as a valve or conduit restriction and thereby increase the dissolution rate of the gas in the water. A packing placed in the injection well to intimately mix the gas and the aqueous phase of the sweep fluid also increases the pressure drop and the dissolution rate.

Suivant un mode de mise en oeuvre, on utilise une pompe polyphasique de type rotodynamique par exemple pour comprimer le gaz, pressuriser la phase aqueuse et former un mélange intime entre cette phase aqueuse et de gaz sous pression avant de l'injecter dans le puits d'injection.According to one embodiment, a multiphase pump of rotodynamic type is used, for example to compress the gas, pressurize the aqueous phase and form an intimate mixture between this aqueous phase and pressurized gas before injecting it into the well. 'injection.

Pour bien s'assurer que le gaz est au moins en condition de saturation (et de préférence en sursaturation en fond de puits), on utilise de préférence des données produites de capteurs d'état en fond de puits (capteurs de pression, capteurs de température, etc., installés à demeure) pour contrôler que le gaz du fluide de balayage est au moins en état de complète saturationTo ensure that the gas is at least in saturation condition (and preferably supersaturation at the bottom of the well), it is preferable to use data produced from downhole state sensors (sensors). pressure, temperature sensors, etc., permanently installed) to control that the flushing gas gas is at least fully saturated

Le gaz dans le fluide de balayage contient au moins un gaz acide tel que du dioxyde de carbone et / ou de l'hydrogène sulfuré et éventuellement, dans des proportions variables, d'autre gaz : du méthane, de l'azote, etc. Ces gaz peuvent être prélevés dans les effluents issus d'un gisement, opération réalisée par une unité de traitement adaptée à les séparer d'autres gaz valorisables par ailleurs ou bien provenir d'unités chimiques ou d'unités thermiques brûlant de la lignite, du charbon, du fioul, du gaz naturel etc.The gas in the flushing fluid contains at least one acid gas such as carbon dioxide and / or hydrogen sulfide and optionally, in varying proportions, other gases: methane, nitrogen, etc. These gases can be taken from the effluents from a deposit, an operation carried out by a treatment unit adapted to separate them from other gases that can be recovered elsewhere, or from chemical units or thermal units burning lignite, coal, oil, natural gas etc.

La phase aqueuse utilisée pour former le fluide de balayage peut être par exemple de l'eau issue d'un gisement souterrain (une nappe phréatique par exemple ou une saumure produite durant l'exploitation d'un gisement) ou tout autre eau facilement disponible (eau de mer).The aqueous phase used to form the sweeping fluid may be, for example, water from an underground deposit (for example a groundwater table or a brine produced during the exploitation of a deposit) or any other readily available water ( sea water).

Suivant un autre mode de mise en oeuvre, on ajoute à la phase aqueuse un additif tensioactif pour y favoriser la dispersion du gaz et/ou un ou plusieurs additifs pour augmenter la solubilité du gaz dans le fluide de balayage.In another embodiment, a surfactant additive is added to the aqueous phase to promote the dispersion of the gas and / or one or more additives to increase the solubility of the gas in the sweeping fluid.

Suivant un autre mode de mise en oeuvre, le fluide de balayage est injecté par exemple dans un ou plusieurs puits de fort déport, horizontaux ou de géométrie complexe localisé par exemple à la base du gisement et le fluide pétrolier est produit par exemple par un ou plusieurs puits déviés ou de géométrie complexe pouvant être localisé au toit du gisement.According to another embodiment, the sweeping fluid is injected for example into one or more high offset wells, horizontal or of complex geometry located for example at the base of the deposit and the petroleum fluid is produced for example by one or several deflected wells or complex geometry can be located at the roof of the deposit.

Le procédé peut être mis en oeuvre dès le début de l'exploitation du gisement. La phase aqueuse injectée préférentiellement en périphérie de la zone productrice, balaie le milieu poreux contenant les hydrocarbures à récupérer. Dans les premiers temps de cette circulation, le dioxyde de carbone, beaucoup plus soluble dans l'huile que dans l'eau injectée, passe du fluide de balayage au fluide pétrolier provoquant son gonflement et diminuant sa viscosité. Ces deux phénomènes favorisent un accroissement de la récupération des hydrocarbures en place. Lorsque le fluide approche des puits de production, sa pression chute, sous l'effet conjugué des pertes de charges liées à l'écoulement et de la déplétion naturelle du gisement. Si la pression est inférieure à la pression de bulle de l'eau contenant le gaz solubilisé, des bulles de gaz vont se former par nucléation dans les pores du massif rocheux, en chassant l'huile qui s'y trouve vers les zones les plus perméables où elle sera balayée. Ce dernier phénomène non seulement accroît le taux de récupération global de l'huile en place mais diminue le temps nécessaire pour atteindre un taux de récupération donné.The process can be implemented from the beginning of the exploitation of the deposit. The aqueous phase injected preferentially at the periphery of the producing zone, sweeps the porous medium containing the hydrocarbons at recover. In the early stages of this circulation, carbon dioxide, much more soluble in oil than in injected water, passes from the sweep fluid to the petroleum fluid causing its swelling and decreasing its viscosity. These two phenomena favor an increase in the recovery of hydrocarbons in place. When the fluid approaches the production wells, its pressure drops, under the combined effect of the flow losses due to the flow and the natural depletion of the deposit. If the pressure is less than the bubble pressure of the water containing the solubilized gas, bubbles of gas will form by nucleation in the pores of the rock mass, chasing the oil that is there towards the zones most permeable where it will be swept. This last phenomenon not only increases the overall recovery rate of the oil in place but decreases the time required to reach a given recovery rate.

L'invention concerne également un système de récupération assistée d'un fluide pétrolier extrait d'un gisement, par injection continue dans le gisement d'un fluide de balayage constitué d'une phase aqueuse additionnée de gaz au moins partiellement miscible dans la phase aqueuse et dans le fluide pétrolier, qui comporte un ensemble de conditionnement du fluide de balayage et une unité de contrôle permanent de l'ensemble de conditionnement adapté à contrôler le rapport des débits de cette phase aqueuse et de gaz formant le fluide de balayage parvenu en fond de puits, pour que le gaz y soit en état de saturation ou de sursaturation. De préférence, le système comporte des capteurs d'état disposés dans la zone d'injection pour mesurer des paramètres thermodynamiques et reliés à l'unité de contrôle.The invention also relates to a system for assisted recovery of a petroleum fluid extracted from a reservoir, by continuous injection into the reservoir of a flushing fluid consisting of an aqueous phase with added gas at least partially miscible in the aqueous phase and in the petroleum fluid, which comprises a conditioning assembly of the sweeping fluid and a permanent control unit of the conditioning assembly adapted to control the ratio of the flow rates of this aqueous phase and of the gas forming the bottom flushing fluid. wells, so that the gas is in saturation or supersaturation. Preferably, the system comprises state sensors arranged in the injection zone for measuring thermodynamic parameters and connected to the control unit.

D'autres caractéristiques et avantages du procédé selon l'invention, apparaîtront à la lecture de la description ci-après d'exemples non limitatifs de mise en oeuvre, en se référant aux dessins annexés où :

  • la Fig.1 montre un premier mode de mise en oeuvre du procédé où le fluide de balayage est formé en fond de puits dans la zone d'injection ;
  • la Fig.2 montre un deuxième mode de mise en oeuvre du procédé où le fluide de balayage est formé en surface ; et
  • la Fig.3 montre un mode de mise en oeuvre où le gaz dans le fluide de balayage, est constitué de fractions acides de gaz issus du sous-sol ou produits par des unités de traitement chimiques ou d'unités thermiques brûlant des matériaux divers.
Other characteristics and advantages of the method according to the invention will appear on reading the following description of nonlimiting examples of implementation, with reference to the appended drawings in which:
  • Fig.1 shows a first embodiment of the method wherein the flushing fluid is formed downhole in the injection zone;
  • Fig.2 shows a second embodiment of the method wherein the sweeping fluid is formed on the surface; and
  • FIG. 3 shows an embodiment in which the gas in the sweeping fluid consists of acid fractions of gas from the subsoil or produced by chemical treatment units or thermal units burning various materials.

Description détaillée :Detailed description :

Le procédé de récupération faisant l'objet de la présente invention comprend quatre étapes :The recovery process which is the subject of the present invention comprises four steps:

1. La préparation du fluide de balayage.1. The preparation of the sweeping fluid.

Bien que ceci ne soit pas limitatif, on utilise de préférence des gaz facilement disponibles non valorisés par ailleurs tels que le dioxyde de carbone CO2 ou le sulfure d'hydrogène. SH2.Although this is not limiting, preferably readily available non-upgraded gases such as CO 2 carbon dioxide or hydrogen sulfide are preferably used. SH 2 .

Le dioxyde de carbone mélangé à la phase aqueuse (ci-après désignée par eau) réagit suivant la réaction équilibrée :

        CO 2 + H 2 O ↔ H 2 CO 3

donnant de l'acide carbonique. La solubilité du dioxyde de carbone dans l'eau dépend de la salinité de l'eau, de la température et de la pression. Le taux de dissolution du CO2 augmente avec la pression et diminue avec la température. Dans le domaine de pression et température rencontré pour les applications d'injection, typiquement une pression variant de 7,5·106 Pa à 30·106 Pa (75 à 300 bars) et une température variant de 50 à 100°C, l'effet de la pression est prépondérant. En d'autres termes, le taux de dissolution du dioxyde de carbone au fond d'un puits d'injection est supérieur au taux de dissolution en surface et ce malgré l'augmentation de température due au gradient géothermal.The carbon dioxide mixed with the aqueous phase (hereinafter referred to as water) reacts according to the equilibrium reaction:

CO 2 + H 2 O ↔ H 2 CO 3

giving carbonic acid. The solubility of carbon dioxide in water depends on the salinity of the water, the temperature and the pressure. The dissolution rate of CO 2 increases with the pressure and decreases with temperature. In the pressure and temperature range encountered for injection applications, typically a pressure ranging from 7.5 · 10 6 Pa to 30 · 10 6 Pa (75 to 300 bar) and a temperature ranging from 50 to 100 ° C, the effect of pressure is preponderant. In other words, the dissolution rate of the carbon dioxide at the bottom of an injection well is greater than the rate of dissolution at the surface, despite the temperature increase due to the geothermal gradient.

A des pressions inférieures à 10·106 Pa (100 bars), le CO2 se dissout moins dans l'eau salée que dans l'eau pure. A une pression supérieure, la salinité affecte beaucoup moins la solubilité du gaz. Dans l'eau pure, sous une pression de 150 bars (15Mpa) et pour une température de 70 °C, la solubilité du CO2 sera d'environ 4.5% poids (45 kg de CO2 sont dissous dans 1 m3 d'eau). La dissolution du gaz acide dans l'eau entraîne une augmentation de sa viscosité, ce qui améliore le rapport de mobilité eau / huile. Le taux de dissolution de l'hydrogène sulfuré dans l'eau est supérieur, approximativement d'un facteur 2, à celui du dioxyde de carbone, quelles que soient la température, la pression et la composition de la phase aqueuse. À titre d'exemple, sous une pression de 15·106 Pa (150 bars)et pour une température de 70°C, la solubilité de l'H2S sera d'environ 8.3% poids (83 kg de H2S sont dissous dans 1 m3 d'eau). Les gaz acides issus de la production pétrolière contiennent majoritairement du dioxyde de carbone, c'est la solubilité de ce gaz qui sera limitative quand le mélange sera dissous dans un fluide aqueux.At pressures below 10 · 10 6 Pa (100 bar), CO 2 dissolves less in salt water than in pure water. At a higher pressure, salinity affects much less the solubility of the gas. In pure water, under a pressure of 150 bars (15 MPa) and at a temperature of 70 ° C., the solubility of CO 2 will be about 4.5% by weight (45 kg of CO 2 are dissolved in 1 m 3 of water). The dissolution of the acid gas in the water leads to an increase in its viscosity, which improves the water / oil mobility ratio. The dissolution rate of hydrogen sulfide in water is approximately 2-fold higher than that of carbon dioxide, regardless of the temperature, pressure and composition of the aqueous phase. For example, under a pressure of 15 · 10 6 Pa (150 bar) and at a temperature of 70 ° C, the solubility of the H 2 S will be about 8.3% by weight (83 kg H 2 S are dissolved in 1 m 3 of water). The acid gases from oil production mainly contain carbon dioxide, it is the solubility of this gas that will be limiting when the mixture will be dissolved in an aqueous fluid.

2. Injection du fluide de balayage2. Injecting the sweeping fluid

Un point important qui rend le procédé selon l'invention particulièrement efficace dans le balayage d'un gisement, c'est que le fluide de balayage est injecté de telle sorte qu'en fond de puits, dans la zone d'injection, la solution d'eau injectée soit au moins saturée et de préférence sursaturée en gaz.An important point which makes the process according to the invention particularly effective in the scanning of a deposit is that the flushing fluid is injected such that at the bottom of the well, in the injection zone, the solution injected water is at least saturated and preferably supersaturated with gas.

Les volumes de gaz acides et d'eau susceptibles d'être réinjectés dans le gisement peuvent être disponibles dans un ratio très supérieur au rapport de solubilité du gaz acide dans l'eau. Ce ratio peut évoluer au cours de l'exploitation ou au gré des contraintes de production. L'augmentation de la pression en fond de puits d'injection est partiellement compensée par une augmentation de la température liée au gradient géothermal. Toutefois, l'effet de la pression est généralement plus important, d'autant plus que le fluide injecté n'atteint pas en écoulement les conditions d'équilibre thermique.The volumes of acid gases and water that can be reinjected into the deposit can be available in a ratio much higher than the ratio of solubility of the acid gas in water. This ratio may change during the course of the operation or according to the constraints of production. The increase in pressure at the bottom of the injection well is partially compensated by an increase in the temperature linked to the geothermal gradient. However, the effect of the pressure is generally greater, especially since the injected fluid does not reach the conditions of thermal equilibrium.

Pour que cette condition de saturation ou de sursaturation en fond de puits soit respectée en permanence, on va'donc utiliser un système d'injection qui peut être disposé tout entier en surface ou bien comporter aussi des éléments en fond de puits.In order for this condition of saturation or supersaturation at the bottom of the well to be observed at all times, an injection system that can be disposed entirely on the surface or also include elements at the bottom of the well is used.

Suivant le mode de mise en oeuvre schématisé à la Fig.1, le fluide de balayage est produit par un ensemble de conditionnement PA et ses constituants, amenés séparément dans la zone d'injection en fond de puits. Le gaz est comprimé par un compresseur 1 et injecté par un tube d'injection 2 jusqu'au fond du puits d'injection IW, alors que l'eau issue d'une pompe 3, est injectée dans l'espace annulaire 4 entre le cuvelage et le tube d'injection 1. Le mélange entre les deux phases s'effectue sous la garniture d'étanchéité 5 au droit de la zone d'injection. Les pressions d'injection du compresseur 1 et de la pompe 3 sont déterminées par un dispositif de contrôle 6.According to the embodiment shown diagrammatically in FIG. 1, the sweeping fluid is produced by a packaging unit PA and its constituents, brought separately into the injection zone at the bottom of the well. The gas is compressed by a compressor 1 and injected by an injection tube 2 to the bottom of the injection well IW, while the water from a pump 3 is injected into the annular space 4 between the casing and the injection tube 1. The mixing between the two phases takes place under the seal 5 to the right of the injection zone. The injection pressures of the compressor 1 and the pump 3 are determined by a control device 6.

Suivant un mode de réalisation préféré, l'injection de gaz requérant une forte pression en tête de puits, on préfère réaliser le mélange en surface avant de l'injecter. Cette injection simultanée permet d'accroître le poids de la colonne liquide dans le puits d'injection, et de réduire sensiblement la pression de gaz nécessaire. Pour obtenir la condition requise de saturation et de préférence de sursaturation en fond de puits, il faut que le mélange réalisé en tête de puits soit fortement sursaturé en gaz acides et particulièrement homogène, le gaz étant dispersé dans la phase liquide.According to a preferred embodiment, the injection of gas requiring a high pressure at the wellhead, it is preferred to perform the mixture on the surface before injecting it. This simultaneous injection makes it possible to increase the weight of the liquid column in the injection well, and to reduce substantially the necessary gas pressure. In order to obtain the saturation and preferably supersaturation condition at the bottom of the well, it is necessary that the mixture produced at the well head be highly supersaturated with acid gases and be particularly homogeneous, the gas being dispersed in the liquid phase.

On peut utiliser à cet effet (Fig.2) un dispositif de compression et pompage conventionnel connu des spécialistes, pour l'injection du fluide de balayage en condition de saturation ou sursaturation en fond de puits. Dans ce cas, les gaz acides sont comprimés dans un compresseur 1 par étapes successives et refroidis entre deux sections de compression. En parallèle, l'eau est pressurisée par une pompe 3 à une pression égale à celle appliquée par le compresseur 1. Le gaz et le liquide sont ensuite introduits dans un mélangeur statique ou dynamique 7 ayant une efficacité suffisante pour permettre la dispersion totale du gaz dans le liquide. En aval du mélangeur 7, le mélange peut être comprimé par une pompe supplémentaire 8 pour permettre, soit la dissolution d'une quantité supplémentaire de gaz, soit l'injection du fluide de balayage dans le puits IW. Les gaz acides, chauffés au cours de la compression, peuvent par exemple être refroidis, au moyen d'échangeurs de chaleur (non représentés) avant leur introduction dans le mélangeur 7 de façon à favoriser leur dissolution.For this purpose, it is possible to use (FIG. 2) a conventional compression and pumping device known to those skilled in the art, for the injection of the sweep fluid under a saturation or supersaturation condition downhole. In this case, the acid gases are compressed in a compressor 1 in successive steps and cooled between two compression sections. In parallel, the water is pressurized by a pump 3 at a pressure equal to that applied by the compressor 1. The gas and the liquid are then introduced into a static or dynamic mixer 7 having a sufficient efficiency to allow the total dispersion of the gas in the liquid. Downstream of the mixer 7, the mixture can be compressed by an additional pump 8 to allow either the dissolution of an additional amount of gas or the injection of the flushing fluid into the well IW. The acid gases, heated during the compression, may for example be cooled by means of heat exchangers (not shown) before their introduction into the mixer 7 so as to promote their dissolution.

Une pompe polyphasique de type rotodynamique peut avantageusement remplacer une chaîne conventionnelle de réinjection et remplir les trois fonctions : comprimer le gaz, pressuriser la phase liquide et mélanger intimement les deux phases. Une pompe polyphasique rotodynamique convenant pour ce type d'application, est décrite dans les brevets FR 2 665 224 (US 5 375 976) du demandeur ou FR 2 771 024 du demandeur. De par sa conception, ce type de pompe peuvent injecter dans un puits un mélange diphasique composé d'eau carbonatée saturée et d'un excès de dioxyde de carbone gazeux sans problème de cavitation.A rotodynamic type multiphase pump can advantageously replace a conventional reinjection chain and fulfill the three functions of compressing the gas, pressurizing the liquid phase and mixing intimately the two phases. A rotodynamic multiphase pump suitable for this type of application is described in patents FR 2,665,224 (US 5,375,976) to the applicant or FR 2,771,024 to the applicant. By design, this type of pump can inject into a well a two-phase mixture composed of saturated carbonated water and an excess of gaseous carbon dioxide without cavitation problem.

Il est également possible d'introduire une perte de charge supplémentaire dans la conduite d'injection sous forme d'une vanne de laminage ou d'une restriction du conduit d'injection. Suivant un mode particulier de mise en oeuvre, on place également un garnissage dans le puits d'injection IW pour d'améliorer le mélange des constituants tout en induisant une perte de charge supplémentaire.De préférence, on utilise dans l'un et l'autre cas des capteurs d'état (non représentés) descendus jusqu'en fond de puits, dans la zone d'injection, pour mesurer différents paramètres thermodynamiques : pressions, températures etc., et reliés au dispositif de contrôle 6. Un système de transmission adapté à transmettre en surface des signaux issus de capteurs permanents installés à demeure dans des puits pour surveiller un gisement, et notamment de capteurs d'état permettant de connaître par exemple les températures et pressions régnant en fond de puits, est décrit notamment dans le brevet US 5,363,094 du demandeur. Le dispositif de contrôle 6 ajuste les débits et leur ratio dans ce cas en fonction des conditions régnant in situ.It is also possible to introduce an additional pressure drop in the injection line in the form of a rolling valve or a restriction of the injection conduit. According to a particular mode of implementation, a packing is also placed in the injection well IW to improve the mixing of the constituents while inducing an additional pressure drop. Preferably, it is used in the one and the another case of state sensors (not shown) down to the well bottom, in the injection zone, for measuring various thermodynamic parameters: pressures, temperatures, etc., and connected to the control device 6. A transmission system adapted to transmit on the surface signals from permanent sensors permanently installed in wells for monitoring a deposit, and in particular state sensors making it possible to know, for example, the temperatures and pressures at the bottom of the well, is described in particular in the patent US 5,363,094 of the applicant. The control device 6 adjusts the flow rates and their ratio in this case according to the conditions prevailing in situ.

Suivant le mode de mise en oeuvre schématisé à la Fig.3, le système est adapté à former un mélange saturé ou sursaturé au moins en partie à par recombinaison contrôlée d'effluents pompés hors du gisement par un ou plusieurs puits de production du gisement PW. Ces effluents comprennent généralement une phase liquide constituée d'eau et d'huile, et une phase gazeuse. Les effluents passent donc dans un séparateur eau-huile-gaz S1. La phase gazeuse, éventuellement complétée par des apports extérieurs, traverse un séparateur S2 destiné à séparer les gaz récupérables par ailleurs pour d'autres applications, des gaz acides que l'on veut recycler. L'eau issue du séparateur S1, est ensuite recombinée avec les gaz acides récupérés dans un dispositif M de mélange contrôlé, de manière à former le mélange saturé ou sursaturé dans les conditions régnant en fond de puits.According to the embodiment shown diagrammatically in FIG. 3, the system is adapted to form a saturated or supersaturated mixture, at least in part, by controlled recombination of effluents pumped out of the deposit by one or more production wells of the PW deposit. . These effluents include generally a liquid phase consisting of water and oil, and a gaseous phase. The effluents therefore pass into a water-oil-gas separator S1. The gaseous phase, possibly supplemented by external inputs, passes through a separator S2 for separating the otherwise recoverable gases for other applications, acid gases that we want to recycle. The water issuing from the separator S1 is then recombined with the acid gases recovered in a controlled mixing device M, so as to form the saturated or supersaturated mixture under the conditions prevailing at the bottom of the well.

Si la pression nécessaire pour injecter le fluide dans le massif poreux est inférieure à la pression de liquéfaction du CO2, une phase liquide et une phase gazeuse seront présentes dans le puits d'injection. L'utilisateur doit veiller à ce que la dispersion du gaz soit maximale et que les bouchons de gaz circulant dans le puits d'injection soient entraînés par la colonne liquide en fond de puits, en d'autres termes que la vitesse liquide soit supérieure à la vitesse de remontée des bouchons gazeux afin d'éviter la ségrégation dans le puits d'injection.If the pressure necessary to inject the fluid into the porous mass is lower than the CO 2 liquefaction pressure, a liquid phase and a gaseous phase will be present in the injection well. The user must ensure that the dispersion of the gas is maximum and that the gas plugs circulating in the injection well are driven by the liquid column at the bottom of the well, in other words that the liquid velocity is greater than the rate of rise of the gaseous plugs to avoid segregation in the injection well.

Il est également possible que la pression nécessaire pour injecter le fluide dans le massif poreux, soit supérieure à la pression de liquéfaction du CO2. Le gaz liquéfié sera intimement mélangé à l'eau et une émulsion formée de fines gouttelettes de gaz liquéfié dans l'eau sera alors injectée.It is also possible that the pressure necessary to inject the fluid into the porous mass is greater than the CO 2 liquefaction pressure. The liquefied gas will be intimately mixed with the water and an emulsion formed of fine droplets of liquefied gas in the water will then be injected.

De préférence, on ajoute à la phase aqueuse une faible proportion d'agent tensioactif favorisant la dispersion des bulles de gaz. Pour réduire l'excès de gaz par rapport aux conditions de saturation prévalant en surface, il est intéressant d'augmenter la solubilité du dioxyde de carbone dans l'eau en ajoutant dans cette dernière des additifs favorisant sa dissolution tels que du monoéthanol amine, de la diéthanol amine, de l'ammoniac, du carbonate de sodium, du carbonate de potassium, de l'hydroxyde de sodium ou de potassium, des phosphates de potassium, de la diamino-isopropanol, du méthyl diéthanol amine, du tri-éthanol amine et autres bases faibles. La concentration de ces additifs dans l'eau peut varier de 10 à 30 % en poids. On vérifie qu'un agent de solubilité tel que le mono-éthanol amine ajouté à de l'eau dans la proportion de 15% en poids, augmente par exemple d'un facteur 7 la solubilité du CO2 dans l'eau. Les puits d'injection peuvent être des puits verticaux ou horizontaux. En règle générale, si le réservoir est peu épais, il peut être avantageux de mettre en oeuvre l'injection d'eau carbonatée dans des puits de fort déport ou dans des puits horizontaux. La phase aqueuse peut être injectée à la base du réservoir à drainer au moyen d'un ou de plusieurs puits horizontaux et la phase hydrocarbure liquide peut être soutirée au toit du réservoir au moyen d'un ou plusieurs puits horizontaux. Pour des réservoirs de forte épaisseur les puits d'injection et de production seront verticaux, et le balayage des hydrocarbures en place sera parallèle aux limites du réservoir. Des puits de géométrie plus complexe peuvent être utilisés sans sortir du cadre de la présente invention.Preferably, a small proportion of surfactant promoting the dispersion of the gas bubbles is added to the aqueous phase. To reduce the excess of gas with respect to the saturation conditions prevailing at the surface, it is advantageous to increase the solubility of carbon dioxide in water by adding in the latter additives that promote its dissolution, such as monoethanolamine, diethanolamine, ammonia, carbonate of sodium, potassium carbonate, sodium or potassium hydroxide, potassium phosphates, diaminoisopropanol, methyl diethanol amine, triethanol amine and other weak bases. The concentration of these additives in water can vary from 10 to 30% by weight. It is verified that a solubility agent such as mono- ethanol amine added to water in the proportion of 15% by weight increases, for example by a factor of 7, the solubility of CO 2 in water. The injection wells can be vertical or horizontal wells. Generally, if the tank is thin, it may be advantageous to implement the injection of carbonated water in wells of high offset or in horizontal wells. The aqueous phase can be injected at the base of the reservoir to be drained by means of one or more horizontal wells and the liquid hydrocarbon phase can be withdrawn from the roof of the tank by means of one or more horizontal wells. For thick tanks the injection and production wells will be vertical, and the hydrocarbon sweep in place will be parallel to the reservoir boundaries. Wells of more complex geometry can be used without departing from the scope of the present invention.

3. Balayage du réservoir3. Tank sweeping

Le principe de récupération selon l'invention permet de fournir au gisement une énergie supplémentaire. Les bénéfices de l'injection simultanée d'eau et de gaz acides sont nombreux.The recovery principle according to the invention makes it possible to supply the deposit with additional energy. The benefits of simultaneous injection of water and acid gases are numerous.

L'eau carbonatée solubilise les carbonates solubles présents dans la roche, calcite et dolomite, en formant des bicarbonates solubles selon les réactions :

        Ca CO 3 + H 2 CO 3 ↔ Ca (HCO 3 ) 2

        Mg CO 3 + H 2 CO 3 ↔ Mg (HCO 3 ) 2
Carbonated water solubilizes the soluble carbonates present in the rock, calcite and dolomite, forming soluble bicarbonates according to the reactions:

Ca CO 3 + H 2 CO 3 ↔ Ca (HCO 3 ) 2

Mg CO 3 + H 2 CO 3 ↔ Mg (HCO 3 ) 2

Cette dissolution partielle des carbonates provoque une augmentation de la perméabilité du milieu poreux, qu'il s'agisse d'un grès, dans lequel la dissolution va attaquer les ciments et dépôts calciques fréquemment présents autour des grains de quartz, ou d'une formation calcaire dans laquelle la connexion poreuse sera améliorée. Le gain de perméabilité résultant de la dissolution des carbonates peut être notable, comme il est bien connu des spécialistes.This partial dissolution of the carbonates causes an increase in the permeability of the porous medium, whether it is a sandstone, in which the dissolution will attack the cements and calcium deposits frequently present around the quartz grains, or a formation limestone in which the porous connection will be improved. The permeability gain resulting from the dissolution of the carbonates can be significant, as is well known in the art.

Il est également connu que l'eau carbonatée prévient le gonflement des argiles fréquemment présentes dans les réservoirs pétroliers. Cet effet est particulièrement sensible pour les argiles dont l'ion de base est le sodium. La dissolution du calcium a aussi une influence sur la stabilisation des argiles à ions sodium par le remplacement du sodium par le calcium qui donne des argiles plus stables résistant à l'écoulement sans se déliter et colmater le milieu poreux.It is also known that carbonated water prevents the swelling of clays frequently present in petroleum reservoirs. This effect is particularly noticeable for clays whose base ion is sodium. Calcium dissolution also influences the stabilization of sodium ion clays by the replacement of sodium with calcium which results in more stable clays resistant to flow without disintegrating and clogging the porous medium.

La viscosité de l'eau augmente lorsque le CO2 s'y dissout. Le volume de cette eau carbonatée augmente de 2 à 7% selon la concentration de gaz dissous et sa masse volumique diminue légèrement. L'effet global de la diminution du contraste de masse volumique entre l'eau et l'huile réduit les risques de ségrégation par gravité. En même temps, le rapport de mobilité eau / huile est amélioré par la diminution du rapport des viscosités huile / eau. Ces faits contribuent à améliorer sensiblement l'efficacité du balaye de l'huile par l'eau.The viscosity of the water increases when the CO 2 dissolves there. The volume of this carbonated water increases by 2 to 7% depending on the concentration of dissolved gas and its density decreases slightly. The overall effect of decreasing the density contrast between water and oil reduces the risks of segregation by gravity. At the same time, the water / oil mobility ratio is improved by decreasing the oil / water viscosity ratio. These facts help to significantly improve the efficiency of oil scavenging by water.

Le dioxyde de carbone est beaucoup moins soluble dans l'eau que dans les huiles de gisement. Cette solubilité est fonction de la pression, la température et les caractéristiques de l'huile. Sous certaines conditions, le dioxyde de carbone peut être partiellement ou totalement miscible avec les hydrocarbures. Lorsqu'il est injecté dans le gisement sous forme d'eau carbonatée, le dioxyde de carbone va passer préférentiellement de l'eau à l'huile.Carbon dioxide is much less soluble in water than in oil fields. This solubility is a function of the pressure, the temperature and characteristics of the oil. Under certain conditions, carbon dioxide can be partially or completely miscible with hydrocarbons. When it is injected into the deposit in the form of carbonated water, the carbon dioxide will preferentially go from water to oil.

La dissolution du dioxyde de carbone dans l'huile provoque un accroissement important de son volume. Pour un même taux de dissolution du dioxyde de carbone, ce phénomène sera plus sensible pour les huiles légères que pour les huiles lourdes.The dissolution of carbon dioxide in the oil causes a significant increase in its volume. For the same rate of dissolution of carbon dioxide, this phenomenon will be more sensitive for light oils than for heavy oils.

La dissolution du dioxyde de carbone dans l'huile provoque également une diminution de sa viscosité. Cette diminution sera plus importante quand la quantité de CO2 augmentera. Une huile ayant initialement une forte viscosité sera plus sensible au phénomène. A titre d'exemple, une huile de densité 12.2 API (0.99 g/cm3) et ayant une viscosité de 900 mPa.s à pression ambiante et une température de 65°C verra sa viscosité diminuer à 40 mPa.s sous une pression de 150 bars de CO2. Dans des conditions identiques une viscosité d'une huile de densité 20 API (0.93 g/cm3), chutera de 6 à 0.5 mPa.s.The dissolution of the carbon dioxide in the oil also causes a decrease in its viscosity. This decrease will be greater when the amount of CO 2 increases. An oil having initially a high viscosity will be more sensitive to the phenomenon. By way of example, a density oil 12.2 API (0.99 g / cm 3 ) and having a viscosity of 900 mPa.s at ambient pressure and a temperature of 65 ° C will reduce its viscosity to 40 mPa.s under a pressure 150 bars of CO 2 . Under identical conditions a viscosity of an API density oil (0.93 g / cm 3 ) will drop from 6 to 0.5 mPa · s.

Le gonflement de l'huile comme la baisse de sa viscosité, favorise un accroissement de la récupération des hydrocarbures initialement en place dans le gisement. Ils permettent également d'accélérer le processus de récupération des hydrocarbures.The swelling of the oil as the drop in its viscosity, promotes an increase in the recovery of hydrocarbons initially in place in the deposit. They also help speed up the process of oil recovery.

L'eau carbonatée est au moins saturée en CO2 lors de son injection dans le réservoir. Dans le milieu poreux, la pression du fluide injecté va chuter à cause des pertes de charge liées à l'écoulement. Quand la pression sera inférieure à la pression de bulle de l'eau contenant le gaz solubilisé, du gaz sera libéré. La nucléation des bulles de dioxyde de carbone va se produire de préférence au contact de la roche et spécifiquement dans les zones présentant une forte concentration d'interfaces roche / liquides. Ces zones correspondent aux massifs de faible perméabilité ; le grossissement et la migration des bulles de gaz vont chasser l'huile se trouvant piégée dans les pores de faible diamètre de la roche. Ce phénomène augmente sensiblement le taux des hydrocarbures mobilisés lors de la production.The carbonated water is at least saturated with CO 2 when it is injected into the reservoir. In the porous medium, the pressure of the injected fluid will drop due to flow-related head losses. When the pressure will be lower than the bubble pressure of the water containing the solubilized gas, gas will be released. The nucleation of the carbon dioxide bubbles will preferably occur on contact with the rock and specifically in areas with a high concentration of rock / liquid interfaces. These zones correspond to low permeability massifs; magnification and migration of gas bubbles will drive oil trapped in the small diameter pores of the rock. This phenomenon significantly increases the rate of hydrocarbons mobilized during production.

Le procédé de récupération tel qu'il est décrit ci-dessus, trouve une application avantageuse lors de la mise en production de gisement présentant un double système de porosité tel que les gisements fissurés. Une représentation simple de ces gisements est un ensemble de blocs de roche de taille décimétriques ou métriques présentant des pores de faibles diamètres et saturés en huile, reliés entre eux par un réseau de fissures offrant un passage à l'écoulement des fluides de quelques dizaines de micromètres en moyenne.The recovery process as described above, finds an advantageous application during the production of deposit with a dual porosity system such as cracked deposits. A simple representation of these deposits is a set of rock blocks of decimetric or metric size with pores of small diameters and saturated with oil, interconnected by a network of cracks offering a passage to the flow of the fluids of a few tens of micrometers on average.

On peut typiquement distinguer deux types de réservoirs fissurés : les réservoirs dont la roche est mouillable à l'eau, et les réservoirs de mouillabilité intermédiaire ou mouillable à l'huile (par exemple certains massifs rocheux carbonatés).Two types of cracked reservoirs can typically be distinguished: tanks with water-wettable rock, and intermediate wettable or oil wettable tanks (eg, some carbonate rock masses).

Lorsque ces réservoirs sont soumis à une injection d'eau dans le cadre de la récupération améliorée des effluents pétroliers, l'eau va préférentiellement envahir les fissures. L'eau aura ensuite tendance à imbiber les blocs de faible perméabilité en en chassant l'huile piégée dans les pores vers le réseau de fissures. Si le réservoir est mouillable à l'eau, l'imbibition se fera sous l'effet des forces capillaires et de la gravité. Si le réservoir est mouillable à l'huile, seule la gravité favorisera le phénomène d'imbibition.When these tanks are subjected to a water injection as part of the improved recovery of petroleum effluents, the water will preferentially invade the cracks. The water will then tend to soak the low permeability blocks by driving oil trapped in the pores to the network of cracks. If the tank is wettable with water, the imbibition will be under the effect of capillary forces and gravity. If the tank is wettable with oil, only the gravity will favor the phenomenon of imbibition.

Quand de l'eau carbonatée est injectée dans le milieu fissuré, dans le cas d'un réservoir mouillable à l'eau, le déplacement de l'huile par imbibition dans des blocs de faible porosité est suivi par l'expansion du gaz carbonique quand la pression sera inférieure à la pression de bulle de l'eau carbonatée. Le développement de bulles de gaz piégées dans les massifs de faible perméabilité induit une récupération d'huile considérablement accrue.When carbonated water is injected into the cracked medium, in the case of a water-wettable tank, the displacement of the oil by imbibition in blocks of low porosity is followed by the expansion of the carbon dioxide when the pressure will be lower than the bubble pressure of the carbonated water. The development of trapped gas bubbles in the low permeability massifs induces significantly increased oil recovery.

Dans le cas d'un réservoir de faible mouillabilité intermédiaire à l'eau ou mouillable à l'huile, le phénomène d'imbibition par l'eau sera moins efficace, les forces capillaires n'étant pas favorables au déplacement de l'huile par l'eau. Le dioxyde de carbone libéré lors de la déplétion remplace très avantageusement l'eau et envahit les blocs matriciels.In the case of a reservoir of low wettability intermediate water or oil wettable, the phenomenon of imbibition by water will be less effective, the capillary forces not being favorable to the displacement of the oil by the water. The carbon dioxide released during depletion very advantageously replaces the water and invades the matrix blocks.

L'exploitation du gisement peut comprendre des cycles d'injection et de déplétion. Pendant la période d'injection, la production sera arrêtée ou diminuée alors que l'injection d'eau carbonatée sera maintenue, afin de faire remonter la pression dans le réservoir au-delà de la pression de bulle de l'eau et de ce fait augmenter la concentration de dioxyde de carbone disponible. Cette période d'injection sera suivie d'une période de production et de déplétion partielle du gisement.The exploitation of the deposit may include injection and depletion cycles. During the injection period, production will be stopped or decreased while the injection of carbonated water will be maintained, in order to raise the pressure in the reservoir beyond the bubble pressure of the water and thereby increase the concentration of available carbon dioxide. This injection period will be followed by a period of production and partial depletion of the deposit.

4. Production4. Production

Au cours du temps les hydrocarbures produits présentent des concentrations croissantes de gaz acides. Comme on l'a vu plus haut, ces gaz sont avantageusement séparés du gaz valorisable par ailleurs et réinjectés dans le gisement. Si les unités de traitement de gaz et de raffinage sont proches des puits producteurs, le gaz et l'huile seront séparés par détentes successives dans des ballons séparateurs S1, S2 (Fig.3) localisés près de la zone de production. Si l'unité de raffinage d'un brut lourd est éloignée de la zone de production, il est possible de transporter sous pression le brut chargé de son gaz. Le CO2 qui diminue sensiblement la viscosité de l'huile lourde remplace avantageusement un agent fluxant.Over time, the hydrocarbons produced have increasing concentrations of acid gases. As we have seen above, these gases are advantageously separated from the gas that can be valorized elsewhere and reinjected into the deposit. If the gas treatment and refining units are close to producing wells, the gas and the oil will be separated by successive expansion in separation balloons S1, S2 (Fig.3) located near the production area. If the refinery unit of a heavy crude is removed from the production area, it is possible to transport under pressure the crude charged with its gas. The CO 2 which substantially reduces the viscosity of the heavy oil advantageously replaces a fluxing agent.

Des essais comparatifs ont été menés en laboratoire sur des carottes de roche imprégnés d'huile choisies et adaptées pour représenter un réservoir fissuré. Elles ont été placées dans une cellule de confinement associés à un système de circulation de fluides sous pression, du même type par exemple que celles décrites par les brevets FR 2 708 742 (US 5,679,885) ou FR 2.731.073 (US 5,679,885) du demandeur et soumises à différents tests de balayage par une phase gazeuse dans les conditions de saturation ou de sursaturation en gaz énoncées plus haut. Ces essais ont permis de démontrer toute l'efficacité du procédé selon la présente invention.Comparative tests were conducted in the laboratory on oil-impregnated rock cores selected and adapted to represent a cracked reservoir. They have been placed in a containment cell associated with a pressurized fluid circulation system, of the same type for example as those described by patents FR 2,708,742 (US 5,679,885) or FR 2,731,073 (US 5,679,885) to the applicant. and subjected to various sweep tests by a gas phase under the gas saturation or supersaturation conditions set forth above. These tests have demonstrated the effectiveness of the process according to the present invention.

A température égale, on a vérifié qu'une concentration croissante de CO2 dans l'eau carbonatée, induisait une forte augmentation de la récupération de l'huile en place. Cette augmentation est très sensible quand le fluide de balayage est sursaturé en gaz.At equal temperature, it was verified that an increasing concentration of CO 2 in the carbonated water, induced a strong increase in the recovery of the oil in place. This increase is very noticeable when the flushing fluid is supersaturated with gas.

Claims (19)

  1. Process for assisted recovery of a petroleum fluid produced by a deposit, including the continuous injection into the deposit, through an injection well (IW), of a displacement fluid consisting of water to which gas at least partially miscible with an aqueous phase and with the petroleum fluid has been added, characterised by the fact that it includes continuous control at the injection well head of the ratio of the flow-rates of the aqueous phase and of gas forming the displacement fluid, so that the gas therein is in a saturated or super-saturated state at the injection well bottom.
  2. Process as described in claim 1, characterised by the fact that the displacement fluid is formed by mixture of the gas with the aqueous phase at the well bottom.
  3. Process as described in claim 1, characterised by the fact that the displacement fluid is formed by mixture of the gas with the aqueous phase at the well head.
  4. Process as described in one of claims 2 or 3, characterised by the fact that a control means arranged in the well is used to increase the degree of dissolution of the gas in the aqueous phase.
  5. Process as described in one of claims 1 to 4, characterised by the fact that it includes the use of a packing located in the injection well in order to intimately mix the gas and the aqueous phase of the displacement fluid.
  6. Process as described in one of claims 1 to 5, characterised by the fact that it includes the use of a polyphase pump to form an intimate mixture between the aqueous phase and gas and inject it into the injection well.
  7. Process as described in one of claims 1 to 6, characterised by the fact that it includes the use of data from well bottom state sensors to monitor that the gas of the displacement fluid is at least in a saturated state.
  8. Process as described in one of the preceding claims, characterised by the fact that the gas in the displacement fluid contains at least one acidic gas such as carbon dioxide and/or hydrogen sulphide.
  9. Process as described in one of the preceding claims, characterised by the fact that it includes the use of a treatment device suitable to extract at least a part of the gas in the displacement fluid from the effluents from a deposit.
  10. Process as described in one of the preceding claims, characterised by the fact that it includes the use of gaseous effluents from chemical or thermal units to form at least a part of the gas in the displacement fluid.
  11. Process as described in one of the preceding claims, characterised by the fact that water is used from a subsurface deposit to inject perhaps all or part of an aqueous phase associated with hydrocarbon production.
  12. Process as described in one of the preceding claims, characterised by the fact that a surfactant additive is added to the aqueous phase to favour the dispersion of the gas in it.
  13. Process as described in one of the preceding claims, characterised by the fact that at least one additive is added to the aqueous phase to increase the solubility of the gas in the displacement fluid.
  14. Process as described in one of the preceding claims, characterised by the fact that the injection of carbonated water is performed in wells with large offset, horizontal wells, or wells with complex geometry.
  15. Process as described in claim 14, characterised by the fact that the injection of the displacement fluid is performed in at least one well with large offset, horizontal well, or well with complex geometry located at the bottom of the deposit.
  16. Process as described in one of claims 1 to 14, characterised by the fact that the recovery of the petroleum fluid is effected in at least one directional well or well with complex geometry.
  17. Process as described in claim 16, characterised by the fact that each directional well or well with complex geometry is located at the top of the deposit.
  18. System for assisted recovery of a petroleum fluid extracted from a deposit, by continuous injection into the deposit of a displacement fluid formed of an aqueous phase to which has been added gas at least partially miscible with this aqueous phase and with the petroleum fluid, including an assembly for processing (PA) the displacement fluid and a unit (6) for continuous control of the processing assembly suitable to control the ratio of the flow-rates of the aqueous phase and of gas forming the displacement fluid reaching the well bottom, so that the gas therein is in a saturated or super-saturated state.
  19. Assisted recovery system as described in claim 18, characterised by the fact that it includes state sensors arranged in the injection zone to measure thermodynamic parameters and connected to the control unit (6).
EP00400945A 1999-04-23 2000-04-06 Method of enhanced hydrocarbon production by injection of a liquid and gaseous phase at least partially miscible with water Expired - Lifetime EP1046780B1 (en)

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Families Citing this family (54)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7186673B2 (en) 2000-04-25 2007-03-06 Exxonmobil Upstream Research Company Stability enhanced water-in-oil emulsion and method for using same
GB0022688D0 (en) * 2000-09-15 2000-11-01 Ingen Process Ltd Removal and disposal of sour reservoir components
MY129091A (en) * 2001-09-07 2007-03-30 Exxonmobil Upstream Res Co Acid gas disposal method
WO2003033865A1 (en) * 2001-10-11 2003-04-24 Weatherford/Lamb, Inc. Combination well kick off and gas lift booster unit
CA2470440A1 (en) 2001-12-17 2003-07-17 Exxonmobil Upstream Research Company Solids-stabilized oil-in-water emulsion and a method for preparing same
US7178592B2 (en) * 2002-07-10 2007-02-20 Weatherford/Lamb, Inc. Closed loop multiphase underbalanced drilling process
US7303006B2 (en) * 2003-05-12 2007-12-04 Stone Herbert L Method for improved vertical sweep of oil reservoirs
US7259258B2 (en) * 2003-12-17 2007-08-21 Illumina, Inc. Methods of attaching biological compounds to solid supports using triazine
CA2632526C (en) 2005-12-22 2014-03-11 Exxonmobil Upstream Research Company Method of oil recovery using a foamy oil-external emulsion
US7809538B2 (en) 2006-01-13 2010-10-05 Halliburton Energy Services, Inc. Real time monitoring and control of thermal recovery operations for heavy oil reservoirs
US7770643B2 (en) 2006-10-10 2010-08-10 Halliburton Energy Services, Inc. Hydrocarbon recovery using fluids
US7832482B2 (en) 2006-10-10 2010-11-16 Halliburton Energy Services, Inc. Producing resources using steam injection
EP2076714B1 (en) * 2006-10-18 2016-08-31 Lean Flame, INC. Energy release/conversion device
WO2008058298A1 (en) * 2006-11-07 2008-05-15 Geoffrey Jackson Method and apparatus for the delivery of under-saturated sour water into a geological formation
US20090260812A1 (en) * 2008-04-18 2009-10-22 Michael Anthony Reynolds Methods of treating a hydrocarbon containing formation
EP2414074A1 (en) * 2009-03-30 2012-02-08 Shell Internationale Research Maatschappij B.V. Process for producing purified synthesis gas
US20120094337A1 (en) * 2009-03-30 2012-04-19 Isaac Cornelis Van Den Born Process for producing a purified synthesis gas stream
MX2012003096A (en) 2009-09-13 2012-08-03 Lean Flame Inc Vortex premixer for combustion apparatus.
RU2498056C2 (en) * 2009-10-12 2013-11-10 Открытое акционерное общество "Акционерная нефтяная компания "Башнефть" (ОАО "АНК "Башнефть") Oil deposit development method
US9176245B2 (en) * 2009-11-25 2015-11-03 Halliburton Energy Services, Inc. Refining information on subterranean fractures
US8437962B2 (en) * 2009-11-25 2013-05-07 Halliburton Energy Services, Inc. Generating probabilistic information on subterranean fractures
US8886502B2 (en) * 2009-11-25 2014-11-11 Halliburton Energy Services, Inc. Simulating injection treatments from multiple wells
US8898044B2 (en) 2009-11-25 2014-11-25 Halliburton Energy Services, Inc. Simulating subterranean fracture propagation
US9798042B2 (en) 2013-02-01 2017-10-24 Halliburton Energy Services, Inc. Simulating an injection treatment of a subterranean zone
US9416642B2 (en) 2013-02-01 2016-08-16 Halliburton Energy Services, Inc. Modeling subterranean rock blocks in an injection treatment simulation
WO2014158436A1 (en) * 2013-03-24 2014-10-02 Schlumberger Canada Limited System and methodology for determining properties of a substance
US9239407B2 (en) 2013-08-27 2016-01-19 Halliburton Energy Services, Inc. Injection treatment simulation using condensation
RU2016102695A (en) * 2013-08-30 2017-10-05 Лэндмарк Графикс Корпорейшн METHOD, SYSTEM AND TECHNOLOGY OF OPTIMIZATION TO INCREASE OIL TRANSFER OF THE LAYER IN THE PROCESS OF ALTERNATIVE PUMPING OF WATER AND GAS USING WELL DOWN CONTROL VALVES (WAG-CV)
WO2015118444A1 (en) * 2014-02-04 2015-08-13 Eni S.P.A. Method for the simultaneous re-injection, without compressors, of low-pressure gas and water into partially exhausted reservoirs with the generation of electric energy by the re-pressurized gas
GB201411213D0 (en) * 2014-06-24 2014-08-06 Maersk Olie & Gas Enhanced oil recovery method and apparatus
US10934821B2 (en) 2014-09-09 2021-03-02 Baker Hughes Oilfield Operations, Llc System and method for extracting resources from a reservoir through customized ratios of fluid and gas injections
US10961831B2 (en) 2016-01-19 2021-03-30 Saudi Arabian Oil Company Polymer flooding processes for viscous oil recovery in carbonate reservoirs
US10550312B2 (en) 2016-01-19 2020-02-04 Saudi Arabian Oil Company Oil recovery process using an oil recovery composition of aqueous salt solution and dilute polymer for carbonate reservoirs
US10457851B2 (en) 2016-01-19 2019-10-29 Saudi Arabian Oil Company Polymer flooding processes for viscous oil recovery in carbonate reservoirs
US10781362B2 (en) 2016-01-19 2020-09-22 Saudi Arabian Oil Company Oil recovery process using an oil recovery composition of aqueous salt solution and dilute polymer for carbonate reservoirs
US10287486B2 (en) 2016-01-19 2019-05-14 Saudi Arabian Oil Company Oil recovery process using an oil recovery composition of aqueous salt solution and dilute polymer for carbonate reservoirs
US10723937B2 (en) 2016-01-19 2020-07-28 Saudi Arabian Oil Company Oil recovery process using an oil recovery composition of aqueous salt solution and dilute polymer for carbonate reservoirs
RU2613404C1 (en) * 2016-03-21 2017-03-16 Федеральное государственное бюджетное образовательное учреждение высшего образования "Российский государственный университет нефти и газа (национальный исследовательский университет) имени И.М. Губкина" Method for formation water-gas simulation during oil deposits development
CA2972203C (en) 2017-06-29 2018-07-17 Exxonmobil Upstream Research Company Chasing solvent for enhanced recovery processes
US11131177B2 (en) 2017-07-10 2021-09-28 Exxonmobil Upstream Research Company Methods for deep reservoir stimulation using acid-forming fluids
CA2974712C (en) 2017-07-27 2018-09-25 Imperial Oil Resources Limited Enhanced methods for recovering viscous hydrocarbons from a subterranean formation as a follow-up to thermal recovery processes
CA2978157C (en) 2017-08-31 2018-10-16 Exxonmobil Upstream Research Company Thermal recovery methods for recovering viscous hydrocarbons from a subterranean formation
CA2983541C (en) 2017-10-24 2019-01-22 Exxonmobil Upstream Research Company Systems and methods for dynamic liquid level monitoring and control
CN107764718A (en) * 2017-11-14 2018-03-06 北京科技大学 Fractured shale gas-water phases flowing fracture condudtiviy evaluating apparatus and method
WO2019200135A1 (en) * 2018-04-12 2019-10-17 Lift Ip Etc, Llc Systems and processes for performing artificial lift on a well
US10648305B2 (en) 2018-06-11 2020-05-12 Saudi Arabian Oil Company Systems and methods for carbonated water flooding of hydrocarbon reservoirs
CN112302592B (en) * 2019-07-30 2023-04-07 中国石油天然气股份有限公司 Simulation experiment equipment for water displacement of sand body of point dam of meandering river
CA3169754A1 (en) * 2020-02-28 2021-09-02 Eor Etc Llc System and method for enhanced oil recovery utilizing alternating stacked liquid and gas slugs
CN111810098B (en) * 2020-07-02 2022-05-27 重庆科技学院 Oil pipe suitable for foam drainage gas production of highly deviated well
JP7139546B2 (en) * 2020-09-14 2022-09-20 石油資源開発株式会社 METHOD FOR ENHANCED OIL RECOVERY USING INJECTION WELL CONSTRUCTED WITH TWO CHANNEL
US11624264B2 (en) * 2020-10-15 2023-04-11 Saudi Arabian Oil Company Controlling corrosion within wellbores
US20230038447A1 (en) * 2021-08-09 2023-02-09 Protostar Group Ltd. System and method for permanent carbon dioxide sequestration using a renewable energy source
CN114113550B (en) * 2021-08-17 2023-04-25 大连理工大学 Experimental method for improving petroleum recovery ratio by utilizing carbon dioxide microbubbles
CN114658402A (en) * 2022-04-26 2022-06-24 国油伟泰(北京)科技有限公司 Method for improving oil field recovery ratio

Family Cites Families (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2875831A (en) * 1951-04-16 1959-03-03 Oil Recovery Corp Dissemination of wetting agents in subterranean hydrocarbon-bearing formations
US2875833A (en) * 1954-02-04 1959-03-03 Oil Recovery Corp Process of recovering oil from oil fields involving the use of critically carbonated water
US3893511A (en) 1971-06-09 1975-07-08 Sun Oil Co Foam recovery process
US4319635A (en) * 1980-02-29 1982-03-16 P. H. Jones Hydrogeology, Inc. Method for enhanced oil recovery by geopressured waterflood
US4601337A (en) * 1984-05-10 1986-07-22 Shell Oil Company Foam drive oil displacement with outflow pressure cycling
US4676313A (en) * 1985-10-30 1987-06-30 Rinaldi Roger E Controlled reservoir production
US4653583A (en) * 1985-11-01 1987-03-31 Texaco Inc. Optimum production rate for horizontal wells
US4683948A (en) * 1986-05-23 1987-08-04 Atlantic Richfield Company Enhanced oil recovery process employing carbon dioxide
US4763730A (en) * 1986-08-11 1988-08-16 Chevron Research Company Miscible gas enhanced oil recovery method using oil-brine compatible pre-formed foam
US4721158A (en) * 1986-08-15 1988-01-26 Amoco Corporation Fluid injection control system
US5056596A (en) * 1988-08-05 1991-10-15 Alberta Oil Sands Technology And Research Authority Recovery of bitumen or heavy oil in situ by injection of hot water of low quality steam plus caustic and carbon dioxide
US4953618A (en) * 1989-01-12 1990-09-04 Haliburton Company Injection manifold and method
FR2665224B1 (en) 1990-07-27 1992-11-13 Inst Francais Du Petrole POLYPHASTIC PUMPING OR COMPRESSION DEVICE AND ITS USE.
US5375976A (en) * 1990-07-27 1994-12-27 Institut Francais Du Petrole Pumping or multiphase compression device and its use
JP3183886B2 (en) 1991-12-16 2001-07-09 アンスティテュ フランセ デュ ペトロール Stationary device for active and / or passive monitoring of underground deposits
FR2708742B1 (en) 1993-07-29 1995-09-01 Inst Francais Du Petrole Method and device for measuring physical parameters of porous samples wettable by fluids.
US5421408A (en) * 1994-04-14 1995-06-06 Atlantic Richfield Company Simultaneous water and gas injection into earth formations
US5503226A (en) * 1994-06-22 1996-04-02 Wadleigh; Eugene E. Process for recovering hydrocarbons by thermally assisted gravity segregation
US5515919A (en) * 1994-07-01 1996-05-14 Chevron U.S.A Inc. Enhanced oil recovery process including the simultaneous injection of a miscible gas and water
FR2731073B1 (en) 1995-02-27 1997-04-04 Inst Francais Du Petrole METHOD AND DEVICE FOR DETERMINING DIFFERENT PHYSICAL PARAMETERS OF SAMPLES OF POROUS MATERIALS IN THE PRESENCE OF DI- OR TRIPHASIC FLUIDS
FR2735524B1 (en) 1995-06-13 1997-07-25 Inst Francais Du Petrole ASSISTED RECOVERY OF OIL FLUIDS FROM AN UNDERGROUND DEPOSIT
FR2764632B1 (en) * 1997-06-17 2000-03-24 Inst Francais Du Petrole ASSISTED RECOVERY OF PETROLEUM FLUIDS IN A SUBTERRANEAN DEPOSIT
FR2771024B1 (en) 1997-11-19 1999-12-31 Inst Francais Du Petrole DEVICE AND METHOD FOR DIPHASIC COMPRESSION OF A SOLUBLE GAS IN A SOLVENT

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US6325147B1 (en) 2001-12-04
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