Key information

Title
Injection Production System
Application number
20230231
Case type
National
Status
28.02.2025 P.g.a ikke betalt årsavgift
Filed
21.02.2023
Effective date
21.02.2023
Publicly available
22.08.2024
Applicant
TG & T AS (NO)
Inventor
GILBERTO TOFFOLO (NO)

Abstract and drawing

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content.
The proposed invention, relates to hydrocarbon production wells, and allows the simultaneous production and injection in the formation. While the production fluid would flow along the main bore as usual, some lateral pipes placed inside lateral channels would allow some fluid to be injected at the extreme of the same channels. The injected fluid could be solvent to remove occlusion inside the formation, hot water or steam, or for example CO2 to dilute viscous oil.

Publications

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Documents

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Date
 Date Doc. No. Process Case number In/Out Journal description To/from
 15.09.2025 13-01 Saksbehandling 20230231 UT PT Endelig henlagt for ikke betalt årsavgift (3313) TG & T AS
 02.07.2025 12-01 Saksbehandling 20230231 UT PT Påminnelse om ikke betalt årsavgift (3329) (PT20230231) TG & T AS
 28.05.2025 11-01 Saksbehandling 20230231 UT Henlagt manglede svar ENG TG & T AS
 20.02.2025 10-01 Saksbehandling 20230231 UT Substantive examination TG & T AS
 02.01.2025 09-01 Saksbehandling 20230231 UT PT Varsel om betaling av første årsavgift (3317) (PT20230231) TG & T AS
 03.09.2024 08-02 Saksbehandling 20230231 INN HO FB INJ 2 2023 FFF ERV 2024 GILBERTO TOFFOLO
 03.09.2024 08-01 Saksbehandling 20230231 INN Korrespondanse (Hovedbrev inn) GILBERTO TOFFOLO
 22.05.2024 07-01 Saksbehandling 20230231 INN Fristforlengelse
16.05.2024 06-01 Saksbehandling 20230231 INN Korrespondanse (Hovedbrev inn) TG & T AS
 16.05.2024 05-01 Saksbehandling 20230231 UT Henlagt manglende svar ENG TG & T AS
 11.09.2023 04-02 Saksbehandling 20230231 UT PT report 10:07:44
11.09.2023 04-01 Saksbehandling 20230231 UT 20230231_1752627_PT 08 Eng TG & T AS
 08.03.2023 03-01 Saksbehandling 20230231 UT Søknadskvittering Patent TG & T AS
 08.03.2023 02-01 Saksbehandling 20230231 UT Generelt brev uten frist ENG TG & T AS
 21.02.2023 01-05 Saksbehandling 20230231 INN HO FB INJ Abstract GILBERTO TOFFOLO
 21.02.2023 01-04 Saksbehandling 20230231 INN HO FB INJ 2 2023 FFF GILBERTO TOFFOLO
 21.02.2023 01-03 Saksbehandling 20230231 INN HO FB INJ 2 2023 FFF GILBERTO TOFFOLO
 21.02.2023 01-02 Saksbehandling 20230231 INN HO FB INJ 2 2023 FFF GILBERTO TOFFOLO
 21.02.2023 01-01 Saksbehandling 20230231 INN Søknadsskjema Patent GILBERTO TOFFOLO

Description, claims and drawings

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content. Description
INJECTION PRODUCTION SYSTEMGilberto Toffolo, Theodor Dahlsvei 4B leil nr.103 seks.20, 4355 Kverneland, NorwayThe main field of application of the innovative ideaThe present invention has, primarily, the objective of reducing one of the major problems associated with the production of viscous oil (Heavy Oil), that of low productivity caused by its viscosity.The present invention has also the objective of reducing the effect of near-wellbore damage of the reservoir rock caused by different reasons better described later, that can cause a reduction of the productivity of the wells.There are large deposits of high viscosity oil in nature, however, their exploitation is complex due to the difficulty of producing the hydrocarbon through the porous formation. Therefore, many fields are not exploited and those that can produce, do so with very low productivity and recovery factors. At the same time, many wells experience a drop in their productivity due to near-wellbore deposits of scales or asphaltenes that can partially or completely reduce their productivity.Solutions usually used in the main field of applicationSeveral solutions have been considered to improve the productivity of viscous oils, depending on the type of reservoir and its viscosity. For relatively low viscosities the wells can produce autonomously, even if with low flowrates, but to increase the flowrate, the most adopted solutions are the increase in the contact with the reservoir, for example with wells with different branches (Multilateral solutions), or even with thermal systems able to release heat near the wellbore to reduce the viscosity of the hydrocarbon and increase its flow. Examples of this type are radiofrequency heating, induction heating, or resistance heating.For higher viscosities, the preferred solution is the drilling of a couple of wells in which one is a steam injector, while in the second one the hydrocarbon is produced thanks to the reduced viscosity of the hydrocarbon mixed with the steam.To obtain a greater final recovery from a field, displacement techniques using solvents or gases, in particular carbon dioxide, are also used. However, these solutions are normally applied at the reservoir level and not at a single well level. In other words, some wells are transformed into injection wells and the fluid injected pushes the viscous hydrocarbon towards other producing wells. The injected fluid can also be miscible with hydrocarbon, reducing at the same time, its viscosity, like in the case of CO2.There are also solutions called "Huff and Puff" in which the solvent or gas is injected alternately with production in the same producer well. In this case, the injected gas or solvent mixes with the hydrocarbon reducing its viscosity. These cycles can last several weeks because it takes a long time for effective mixing and can be repeated a limited number of times.There are also solutions in which a solvent, typically diesel, is released inside the main production liner through an inner coaxial pipe with limited diameter inserted up to the end of the production tube itself.In respect to the near-wellbore damage, the systems normally used to restore productivity are for example the injection of solvents, creating vibrations in front of the formation, reopening the intervals with new perforations, or acid stimulation in case of carbonate reservoirs to expose new rock formation. Technical problem: criticality of the known art resolved by the innovative idea.The solutions now adopted allow to different degrees an improvement in productivity and final recovery, however, the quantities of hydrocarbon that cannot be produced are still extremely high and the production takes place with significant costs, above all due to the high number of wells required and their relatively high cost. Finally, production takes place in very long times and with high maintenance costs.As regards the Huff and Puff solutions, one of the limits is represented by the limited number of cycles that can be obtained since the efficiency degrades with time. Furthermore, the entire period dedicated to injection and soaking cannot be dedicated to the production and therefore the average flow rate is reduced accordingly. To be effective, the injection of gas at the reservoir level involves the drilling of numerous injection wells and represents more of a solution to increase the final recovery of an already exploited reservoir rather than an initial primary recovery solution.The system consisting of two wells, a steam injector, and a producer is advantageous for highly viscous oils but involves high costs and low efficiency. Finally, the solutions able to increase the temperature of the reservoir with the consequence of reducing the viscosity of the oil, such as the resistive system, can give important advantages even at the level of a single well, but also in this case the overall efficiency finds an important limit in the maximum amount of energy that can be brought to the bottom and in the poor thermal conductivity of the formation and the oil, preventing the heat from entering the formation effectively so that most of the heat released increase only the temperature of the oil already inside the production liner.For the removal of deposits in the near-wellbore the systems normally used have the disadvantage of being expensive, force to stop the production, and need to be repeated regularly.Technical aspects that characterize the innovative idea and distinguish it from the known art.The basic idea of the proposed solution is to combine a production system with an injection system that can be activated during production or in alternating periods. In the case of viscous oil, the injection of a solvent would be used to reduce the viscosity of the hydrocarbon, while in the case of near-wellbore damage the injection of a solvent would be used to remove possible deposits.The system will be able to get all the advantages of assisted recovery technologies used to increase the production of viscous oils at the field level but at the level of a single well. This will be possible by combining the proposed solution with new well architecture, as for example a multilateral well layout with the injection of a solvent or a gas, for example, CO2.The innovative aspect consists in the fact that a single well would be simultaneously a producer and an injector, allowing a reduction in the viscosity of the hydrocarbon given by the combination with the solvent and a consequent increase in production. Conceptually the solution is not quite different from the described "Huff & Puff" solutions, with the advantage however that the production could take place continuously rather than alternatively and does not have the limits associated with the cycles. Such a solution could also be associated with a system designed to increase the temperature of the viscous oil in the formation or along the well. In case of near-wellbore damage, the injection could be limited to specific periods required to clean the formation. Description of the innovative idea in the general formThe system can be considered an improvement of the common technical solution used in heavy oil reservoirs and reported in fig.1.A well, preferably horizontal, drilled inside a viscous oil reservoir is completed with the following basic elements: a production slotted liner, a production tubing, a downhole pump, and a small inner pipe deployed along the whole reservoir section to release some solvent at the very end of the same. Fig.1 – Layout of a heavy oil well completion system with injection of a solvent at the toe.The solvent, normally diesel, has the main purpose of decreasing the viscosity of the produced oil that entered the production liner, reducing its friction losses inside the liner and inside the production tubing, and reducing the power required by the pump. The amount of solvent pumped is chosen to maximize the well's productivity and minimize costs. The solvent is flowing from the surface through an injection line lowered at the same time with the production tubing and the produced fluid, a mixture of the viscous oil and the solvent, enters the production tubing through dedicated holes placed at the bottom of the production tubing.In the same way, the proposed solution is also composed of two basic elements, a circulation system, and a production system, both part of the completion of a single well. The main difference is that the solvent is not circulated from the end of the reservoir section but enters the formation through small diameter lateral pipes departing from the same circulation pipe (See fig.2). This solution gives numerous advantages with respect to the conventional system previously described in fig.1. Even considering the same volume of solvent injected, the injection system can release the solvent fluid into many points positioned at a predetermined distance from the main production liner.Fig.2 – Layout of the proposed solution with injection lines inside the formation.The fluid injected meets the viscous hydrocarbon to be produced and dilutes the same lowering its viscosity, not inside the production liner, but inside the formation. The fluidized hydrocarbon can flow in the annular space between the lateral pipes and the formation with lower friction losses in respect to the natural flow of a viscous oil through the same formation. Moreover, the flow is also supported by the differential pressure between the injecting point and the lower pressure along the well main wellbore. This differential pressure helps the diluted hydrocarbon move towards the main wellbore.Another important advantage would be that in the proposed solution, the injection of fluid could be done with or without the contemporary production of hydrocarbon. In other words, the solvent could be injected into the formation for a period and production resumed after a soaking time, in a similar way as in conventional huff & puff operations. This could be relevant for example in the case of injection of CO2.One possible improvement could be also the deployment of a distributed heating system for example DHEH with mineral insulated cables. In this case, the lateral pipes and the solvent could carry inside the formation also the heat released along the main wellbore with the advantage of further decreasing the viscosity of the oil with an increase of temperature of the same. A similar solution could be preheating the solvent that could in this way carry at least part of the heat inside the formation.Many lateral drains equidistant from the main hole simultaneously inject solvent at the same distance from the main hole. Since all the injection points are on a cylindrical surface, it is theoretically possible to create a cylindrical volume inside which the viscosity is reduced. This could be called a “Low viscosity chamber”. For illustrative purposes, it is shown in fig.3 a three-dimensional representation considering a hypothetical diameter of 24 meters and a well with a reservoir section 1000-1500 m long. All the viscous oil entering the volume would meet favourable conditions for the flow.For example, with a 1500 m long horizontal wellbore and lateral channels 12 m long departing from the mother bore, the volume of oil contained in the cylinder, considering a porosity of 22% would be approximately one million barrels and while producing, more heavy oil would cross the great surface and enter the low viscosity volume. The capability of the solvent to mix with the viscous hydrocarbon will depend on the nature of the solvent, its flow rate, and the type of injection, continuous, alternate, or huff & puff. The experience will indicate the best combination of the injection parameters.In the current example, the lateral channels have all equal length and depart in symmetric directions, however, with a system able to control the orientation of the lower completion, that is not part of the current patent, the length, direction, and the number of channels could be different, to maximize the productivity of the well according to the real geometry and properties of the production layer.Fig. 3 –Solution with the cylindrical chamber. Many lateral drains equidistant from the main hole simultaneously inject solvent at the same distance from the main hole. Since all injection points are on a cylindrical surface, the volume contained could be considered a low viscosity cylindrical chamber. Data, examples, and/or detailed construction descriptionThe production system consists of the main producer well and contains the injection system described above. Concerning fig.4, a well, preferably horizontal, but not limited to, is drilled in a productive formation and has a mother bore reservoir section exposed to the production (100). Inside the mother bore is run a production liner (101) anchored inside the production casing (102) through a liner hanger (103). The type of liner is not relevant to the present invention, however, just for explanation purposes in fig. 4 the liner is slotted, without cement. There might be situations where the liner could not be necessary. The oil flows from the formation and enters the mother bore and liner and finally enters the production tubing (105) through the holes (111). Once inside the production tubing, a pump (110) helps the oil to flow to the surface. The type and position of the pump are not relevant to the current invention.An injection line (109) provides the injection solvent and is connected to an injection pipe (106) that covers the whole length of the mother bore. At its end a device (112) can be placed to release part of the solvent from the end of the injection pipe if necessary. From the injection pipe depart many lateral smaller diameter pipes (108) run inside lateral holes created inside the formation (107). The type of connection between the injection pipe and the lateral smaller pipes as well as how the lateral holes are created in the formation are not part of the present invention. The oil production is therefore obtained from two main flow paths.Fig.4 – Description of the injection production system.The direct flow path of viscous oil from the formation to the mother bore and the flow of viscous oil from the formation to the annular space between the lateral holes and the lateral small diameter pipes. The oil entering the lateral channels mixes with the solvent released at the extreme of the lateral small diameter pipes reducing its viscosity. The two contributes, the first highly viscous and the second enriched with solvent, blend inside the production liner and are eventually lifted by the pump towards the surface.The system could also be made in such a way as to release only part of the solvent at the extreme of the lateral small diameter pipes and the remaining part from the very end of the injection pipe inside the production liner. The fundamental purpose of the injection system is to release deep inside the formation a fluid capable of changing the physical properties of the oil to be produced as its viscosity, and his composition. However, the lateral channels are also important because they represent flow paths for the produced hydrocarbon. The injection pressure at the end of the lateral small diameter pipes helps the flow along the lateral channels, given the important differential pressure between the injection pressure and the lower pressure along with the production liner due to the drawdown inside the formation.Furthermore, thanks to the metal needles that are left inside the lateral channels, it is possible to bring both heat and pressure into the formation. The heat, which can therefore increase the temperature of the oil produced and consequently further reduce its viscosity, could be brought in two ways, either by heating the injected fluid or by conduction, through the metal of the injection pipe and the lateral smaller injection pipes. In fig 5 is reported a description of this possibility with the use of a down-hole electrical heating system by means for example of mineral insulated cables.The heat released by the cable would heat the injection pipe and therefore the solvent to be injected flowing inside. The heat would also flow for simple conduction through the metal of the smaller diameter lateral pipes. Both would contribute to the heating of the formation and therefore to the reduction of the viscosity of the oil to be produced.Fig.5 – Solution with a downhole electrical heating system made for example with a mineral insulated cable. Another variant reported in fig.6 would be the use of sealing elements at the end of the smaller diameter lateral pipes. These elements could be useful to prevent the direct bypass of solvent along the lateral channels. With the sealing elements, the solvent would be forced inside the formation mixing with a greater volume of oil. This solution could be useful in the case, for example, of CO2 injection, to maximise the intimate contact between the gas and the viscous oil.A similar process could take place without the sealing elements, but injecting while keeping the well closed. In this case, without return, the gas would necessarily enter the formation in a similar way as for the huff & puff operations, with the difference that the contact between the gas and the viscous oil would be much more intimate with higher efficiency of the soaking process. Interestingly the lateral channels would still be able to convey the flow for most of their length during production, since the sealing elements would close only their final part. The description of the nature and shape of the sealing elements is not an object of the present invention. Fig.6 – Solution with sealing elements at the end of the lateral channels to prevent direct bypass of the solvent along the lateral channels.Alternate injection from the main holeA second solution for the simultaneous production and injection is reported in fig.7. In this case, the horizontal well is divided into independent sections by external sealing elements, for example, swell packers. In some sections, a solvent will be injected, while in other sections the hydrocarbon will be produced. In the example, the well is completed in an open hole with swell packers, however, it could be completed also with a cemented liner with perforations to enter the reservoir or creating fractures to enter deeper into the formation.Fig.7 – A second solution for the simultaneous production and injection.In the specific sections, the produced hydrocarbon will enter the production liner through a production screen and pass an AICV (Autonomous Inflow Control Valve) and production holes allowing the flow to bypass the lower completion. In the annular between the lower completion and the production liner instead will be pumped the solvent to be injected through injection holes. The injection sections might be opened with fractures to increase the reservoir contact.The solution to establish the communication between the production screens and the production liner is here described in a very general form and it is not an object of the current invention.In Fig.8 is represented another solution where every section could be independently injecting or producing. In this case there are still two independent lines for production and injection, but two valves are controlling the direction of the flow. When the specific section is open to production, the injection valve is closed, while, when the section is open for injection the production valve will be closed. The opening and closing of the valves could be automatic or controlled, however the type of valve and control is not part of the current invention. An AICV or similar valve could limit the production phase in case of excess solvent.This solution is very similar to a Huff and Puff system, with the difference that production of hydrocarbon will be continuous since at any time half of the section will be producing while half of them will be injecting. In a specific period, some sections will inject the solvent while some sections will produce the hydrocarbon. At the end of the period the sections where the solvent was injected will start the production and vice versa.Ideally the formation should have been previously fractured to achieve the best possible reservoir contact.Fig.8 – A solution with independent sections able to both produce and inject.The solvent pumping could take place simultaneously with the production in a limited number of sections (Which would change regularly to gradually affect each section) or alternate phases of injection to production phases for the entire well.When the solvent is injected, it enters the formation following the sections with the least resistance, generating geometries that are in part unpredictable and spread based on the characteristics of the oil and the solvent. So, the pumped volume will have an exchange area with viscous oil that depends on the formation in that specific point. In the case of fracturing, a large surface of contact between viscous oil and solvent would be created and mixing would take place with greater efficiency. The fracture represents an ideal geometry since it maximizes the ratio between the exchange surface and the pumped volume.Alternative solution for heat miningThe proposed production injection system could be useful also for the particular purpose of heat mining, i.e., the possibility to extract heat from the formation for electricity generation or for other purpose, see fig.9. In this case a low temperature fluid, that could be water, CO2 or any other fluid would be circulated in the annular space between the production casing and the production tubing. Through a bypass, the cold fluid would enter an injection pipe placed inside a motherbore open hole, and from there enter several lateral injection pipes drilled inside the hot formation. Once reached the end of the lateral pipes the fluid would return towards the main well through the annular between the lateral pipes and the formation first, and after through the annular space between the open hole motherbore and the injection pipe. During this return trip the fluid temperature would increase due to the warmer formation. Once reached the production casing, the hot fluid would enter the production tubing through a bypass and would return to the surface.Fig.9 – A solution for heat miningBRIEF DESCRIPTION OF THE DRAWINGSThe drawings of this document are illustrated by way of example and are included to provide a further understanding of the invention for illustrative discussion of the embodiments of the invention. No attempt is made to show structural details of the embodiments in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. Identical reference numerals do not necessarily indicate an identical structure. Rather, the same reference numeral may be used to indicate a similar feature with similar functionality. In the drawings:Fig. 1 represents the layout of a conventional heavy oil well completion system. A well, preferably horizontal, drilled inside a viscous oil reservoir is completed with the following basic elements: a production slotted liner, a production tubing, a downhole pump, and a small inner pipe deployed along the whole reservoir section to release some solvent at the very end of the same. The solvent, normally diesel, has the main purpose of decreasing the viscosity of the produced oil that enters the production liner, reducing its friction losses inside the liner and the production tubing, and reducing the power required by the pump. The amount of solvent pumped is chosen to maximize the well's productivity and minimize costs. The solvent is flowing from the surface through an injection line lowered at the same time with the production tubing and the produced fluid, a mixture of the viscous oil and the solvent, enters the production tubing through dedicated holes placed at the bottom of the production tubing.Fig.2 represents the main concept of the proposed invention that has an important difference in respect to the conventional solution described in fig. 1. The main difference is that the solvent is not circulated from the end of the production liner, but inside the productive formation through small diameter lateral pipes departing from the same circulation pipe. The numerous advantages have been previously described in the present document. Fig. 3 represents the concept of a low viscosity chamber. Since many lateral pipes equidistant from the main hole simultaneously inject solvent at the same distance from the main borehole the solvent is released from a cylindrical surface, and while gradually mixing with the viscous oil flows towards the main borehole. In this way, all the volume of formation contained inside the cylindrical surface might somehow be considered a low viscosity cylindrical chamber, even if the local distribution of viscosity inside might vary according to the properties of the oil, the properties of the solvent, and time.Fig.4 represents a detailed description of the system. A well, preferably horizontal, but not limited to, is drilled in a productive formation and has a mother bore reservoir section exposed to the production (100). Inside the mother bore is run a production liner (101) anchored inside the production casing (102) through a liner hanger (103). The type of liner is not relevant to the present invention, however, just for explanation purposes in fig.4 the liner is slotted, without cement. There might be situations where the liner could not be necessary. The oil flows from the formation and enters the mother bore and liner and finally enters the production tubing (105) through the holes (111). Once inside the production tubing, a pump (110) helps the oil to flow to the surface. The type and position of the pump are not relevant to the current invention.An injection line (109) provides the injection solvent and is connected to an injection pipe (106) that covers the whole length of the mother bore. At its end, a device (112) can be placed to release part of the solvent from the end of the injection pipe if necessary.From the injection pipe depart many lateral smaller diameter pipes (108) run inside lateral holes created inside the formation (107).The type of connection between the injection pipe and the lateral smaller pipes as well as how the lateral holes are created in the formation are not part of the present invention.The oil production is therefore obtained from two main flow paths. The direct flow path of viscous oil from the formation to the mother bore and the flow of viscous oil from the formation to the annular space between the lateral holes and the lateral small diameter pipes. The oil entering the lateral channels mixes with the solvent released at the extreme of the lateral small diameters pipes reducing its viscosity. The two contributes, the first highly viscous and the second enriched with solvent, blend together inside the production liner and are eventually lifted by the pump towards the surface.The system could also be made in such a way as to release only part of the solvent at the extreme of the lateral small diameter pipes and the remaining part from the very end of the injection pipe inside the production liner. Fig. 5 represents the same basic concept described in fig. 4, with the only difference being that the solvent is heated before entering the small diameter lateral pipes to increase its temperature and carry some heat inside the formation. There might be different ways of increasing the temperature of the solvent, in fig 5 is represented the solution with a down-hole electrical heating cable (113).Fig. 6 represents the same basic concept described in fig. 4, with the difference that at the end of the smalldiameter lateral pipes a sealing element (114) prevents the direct return of the solvent along the lateral channels. This is to force the solvent inside the formation gaining in this way a more intimate contact between solvent and viscous oil inside a bigger volume of the formation.Fig. 7 represents a second solution for the simultaneous production and injection. In this case, the horizontal well is divided into independent sections by external sealing elements, for example, swell packers. In some sections, a solvent will be injected, while in other sections the hydrocarbon will be produced. In the example, the well is completed in an open hole with swell packers, however, it could be completed also with a cemented liner with perforations to enter the reservoir or creating fractures to enter deeper into the formation.Fig. 8 represents another solution where every section could be independently injecting or producing. In this case there are still two independent lines for production and injection, but two valves are controlling the direction of the flow. When the specific section is open to production, the injection valve is closed, while, when the section is open for injection the production valve will be closed. The opening and closing of the valves could be automatic or controlled, however the type of valve and control is not part of the current invention. An AICV or similar valve could limit the production phase in case of excess solvent.Fig.9 represents a solution where the proposed system could be useful for heat mining, i.e. extracting heat from a hot formation. In this case a low temperature fluid, that could be water, CO2 or any other fluid would be circulated in the annular space between the production casing and the production tubing. Through a bypass, the cold fluid would enter an injection pipe placed inside a motherbore open hole, and from there enter several lateral injection pipes drilled inside the hot formation. Once reached the end of the lateral pipes the fluid would return towards the main well through the annular between the lateral pipes and the formation first, and after through the annular space between the open hole motherbore and the injection pipe. During this return trip the fluid temperature would increase due to the warmer formation. Once reached the production casing, the hot fluid would enter the production tubing through a bypass and would return to the surface.Optimization of the interaction between solvent and viscous oilOptimization of contact timesSince the injection and the production systems are independent, they could take place simultaneously or independently.Naturally, the solvent would tend to channel from the injection point into its movement towards the main producing well, a phenomenon also called fingering, reducing the efficiency of the displacement.While this will be surely true, there might be ways of reducing the channelling by injecting the solvent at low flow rates or flow rates following a particular injection law, alternating, pulsating, or other. If fingering occurs, once the injection is temporarily reduced or closed, the path created by the CO2 will be filled with new viscous oil that will decrease its viscosity given the CO2 still present in the channel, therefore it will flow faster. In other words, the “Fingers” would become preferential paths for the viscous oil, once the CO2 injection is reduced. Fingering is seen as a serious problem in CO2 injection at a reservoir level because all the CO2 injected has the tendency to move only along the channels, however in this case, particularly with pulsating injection, the channels would become ramified volumes where the viscous oil could blend better with the CO2 or the solvent used. Furthermore, the fluid will diffuse from the injection points, not with spherical geometry, but in agreement with the type and layers of the reservoir. Even without assuming the creation of a fracture, the surface available for mixing will have a surface-to-volume ratio surely higher than that of a sphere, further increasing the mixing efficiency.In general, there are two possibilities, continuous injection of solvent in limited quantity to maximize the exchange time between solvent and oil or an alternate injection. In the first case, the function carried over time can be a constant or variable function, for example pulsating, or variable according to a certain law that maximizes the speed and therefore the turbulence, obtaining a more effective mixing between solvent and oil. In the second case, instead, pumping could be followed by an interval to allow a more effective mixing and therefore a production period. The duration of these three periods should be optimized to maximize the total flow, minimize the volume of injected solvent and minimize production downtime. The formation of channels will be inevitable, in any case, there will still be a minimum flow rate that will minimize this effect while allowing an increase in production thanks to the solvent. In the case of continuous injection, the solvent could also be heated, being able in this way to carry also heat to increase the temperature of the oil, therefore reducing its viscosity.To limit the effect of the channeling and therefore of the excessive solvent recirculation, it could be useful to consider some ICDs (Inflow Control Devices) or AICD (Autonomous Inflow Control Devices). They could be applied both in the injection section to limit the injection when the channel is formed, or in the screens inside the production liner. The first solution would give the possibility of achieving a uniform injection pattern along the well, while the second would be useful to achieve a uniform production pattern. The choice of the best type of flow control is not an object of the present invention.In conclusion, it can be said that channelling will always be expected, however, there would be also several variables to reduce the effect and maximize the productivity of the well, the most important being the injection flowrate, the injection law, the presence of autonomous valves and the possibility to alternate the injection points.Gravitational aspect and well architectureIn the case of the solution with lateral holes, there is the possibility of orienting them according to particular needs. The first concern is the difference in specific gravity between solvent and viscous oil that could cause a light solvent to migrate upwards, the second is associated with the presence of an OWC or a GOC near the well. In the first case the lateral drains could extend in a vertical direction so that the injection point is under the well and while during the injection the light solvent rises, it would be easily captured by the pressure gradient and would re-enter the well itself.In the second case, it would be appropriate for the lateral drains not to be facing upwards, while it would not be a problem if they were directed downwards as this is an injection that would not have a depression that could lead to a recall of water, or rather the risk of water coning could be reduced.In the case of CO2 and if a part of it does not enter production, this would accumulate above the reservoir forming a CO2 gas cap, or positioning itself at the base of the existing gas cap. If this did not represent a safety problem, an accumulation of CO2 above the reservoir could be useful for maintaining the pressure and contributing to the dilution of a part of the viscous oil. This could also be seen as useful CO2 disposal.CLAIMSWhat is claimed is:1 - A method and apparatus for increasing the productivity of viscous oil or reduce the near wellbore damage of a production well comprising:• A production casing possibly cemented but not necessarily, from surface to the top pf the productive reservoir.• A production liner placed inside a mother bore productive formation and anchored inside the production casing utilizing a liner hanger or other suitable system; the liner being slotted or cemented.• A production tubing to convey the oil to the surface by means of a lifting system, but not necessarily, and anchored to the production casing utilizing a packer or other suitable anchoring system; • An injection line providing a solvent able to reduce the viscosity of the oil (Or remove the near wellbore damage) departing from the surface and deployed together with the production tubing;• A smaller diameter circulation pipe connected to the injection line and placed coaxially inside the production liner;• At least one lateral smaller diameter pipe departing from the smaller diameter circulation pipe and entering the productive formation to release the solvent inside the formation;2 - The system of claim 1, further comprising one or more heating elements able to increase the temperature of the injected solvent deployed along the injection line or along the circulation pipe.3 - The system of claim 1, further comprising at least one sealing element placed on the small diameter lateral pipes to prevent the direct circulation of solvent along the lateral channels.4 - The system of claim 1, further comprising an orientation system able to control the direction of the lateral holes and therefore also give the possibility of having different directions and distance from the motherbore of the lateral channels.5 – The system of claims 1 to 5 with the difference that the well would be divided in a number of independent and hydraulically separated sections in such a way that, with specific valves that are not object of this invention, injection might be higher in section with higher need.6 – The system of claims 1 to 6 with the difference that the solvent would not be injected simultaneously with the production through a dedicated line, but rather in a Huff & Puff mode from the same production tubing, alternating production with injection, with intervals that would maximise the production and minimize the need for solvent, therefore maximise the efficiency.7 - A method and apparatus for increasing the productivity of viscous oil comprising:• A production casing possibly cemented but not necessarily, from surface to the top of the productive reservoir.• A lower completion placed inside a mother bore productive formation and anchored inside the production casing utilizing a liner hanger or other suitable system; the liner being normally cemented, but not necessarily. The lower completion run with some external sealing elements to divide the reservoir section in hydraulically isolated parts, some dedicated to the injection of solvent and some to the production.• A production liner run inside the lower completion tubing to collect the oil produced.• A production screen placed externally to every single section of the reservoir dedicated to the production to collect the oil and make it flow through a controlled valve like for example an AICV (Autonomous Inflow Control Valve) and a mechanical bypass to enter the lower completion.• A production tubing connected to the production liner to convey the oil to the surface by means of a lifting system, but not necessarily, and anchored to the production casing utilizing a packer or other suitable anchoring system.• An injection line providing a solvent able to reduce the viscosity of the oil (Or remove the near wellbore damage) departing from the surface and deployed together with the production tubing and connected with the annular space between the lower completion and the production screen so that the injected fluid will enter the formation in the injection sections.8 - The system of claim 8, with the reservoir section divided into different sections by sealing elements such that every section will be able to both inject or produce in different moments given the presence of one injection valve and one production valve. The injection valve able to open or close the hydraulic continuity between the formation and the annular space between the lower completion and the production liner conveying the solvent.
Claims
The production valve able to open or close the hydraulic continuity between the formation and the production liner.9 – The system of claims 8 or 9 further comprising one or more heating elements able to increase the temperature of the injected solvent deployed along the injection line or along the production liner.10 – A method and apparatus to extract heat from a hot formation comprising:• A production casing cemented, but not necessarily to the top of the hot formation.• A motherbore open hole section drilled inside the hot formation• A production tubing properly insulated as for example a vacuum insulated tubing, but not necessarily, conveying the heated fluid towards the surface• An injection pipe run all along the open hole and connected mechanically to the production tubing, but separated hydraulically from the same by a separation element placed internally and dividing the tubing and the injection pipe into hydraulically independent sections.• At least one lateral injection pipe placed inside a lateral channel such that the injected cold fluid could heat while returning towards the main open hole wellbore through the annular space between the lateral injection pipe and the lateral channel• An anchoring system to anchor the production tubing and the injection pipe to the production casing.• A bypass to deviate the cold injection fluid from the annular between the production casing and the production tubing to the internal of the injection pipe• A bypass to deviate the hot fluid from the annular between the injection pipe and the hot formation to the internal of the production tubingPÅSTANDERDet som hevdes er:1 - En fremgangsmåte og et apparat for å øke produktiviteten til viskøs olje eller redusere skaden på nær brønnhull i en produksjonsbrønn, omfattende:• Et produksjonsrør, muligens sementert, men ikke nødvendigvis, fra overflaten til toppen av det produktive reservoaret.• En produksjonsforing plassert inne i en moderbore produktiv formasjon og forankret inne i produksjonsforingsrøret ved bruk av en foringshenger eller annet passende system; foringen er slisset eller sementert.• Et produksjonsrør for å transportere oljen til overflaten ved hjelp av et løftesystem, men ikke nødvendigvis, og forankret til produksjonsforingsrøret ved bruk av en pakning eller annet egnet forankringssystem;• En injeksjonslinje som tilveiebringer et løsningsmiddel som er i stand til å redusere viskositeten til oljen (Eller fjerne skaden nær borehullet) som går fra overflaten og utplasseres sammen med produksjonsrøret;• Et sirkulasjonsrør med mindre diameter koblet til injeksjonslinjen og plassert koaksialt inne i produksjonsforingen;• Minst ett lateralt rør med mindre diameter som går fra sirkulasjonsrøret med mindre diameter og går inn i den produktive formasjonen for å frigjøre løsningsmidlet inne i formasjonen;2 - Systemet ifølge krav 1, videre omfattende ett eller flere varmeelementer som er i stand til å øke temperaturen til det injiserte løsningsmidlet utplassert langs injeksjonslinjen eller langs sirkulasjonsrøret.3 - Systemet ifølge krav 1, videre omfattende minst ett tetningselement plassert på siderørene med liten diameter for å forhindre direkte sirkulasjon av løsemiddel langs sidekanalene.4 - Systemet ifølge krav 1, videre omfattende et orienteringssystem som er i stand til å kontrollere retningen til sidehullene og derfor også gi muligheten til å ha forskjellige retninger og avstand fra moderhullet til sidekanalene.5 – Systemet ifølge kravene 1 til 5 med den forskjell at brønnen vil være delt i et antall uavhengige og hydraulisk adskilte seksjoner på en slik måte at, med spesifikke ventiler som ikke er gjenstand for denne oppfinnelsen, kan injeksjonen være høyere i seksjon med høyere behov.6 – Systemet ifølge kravene 1 til 6 med den forskjell at løsningsmidlet ikke injiseres samtidig med produksjonen gjennom en dedikert linje, men snarere i en Huff & Puff-modus fra samme produksjonsrør, alternerende produksjon med injeksjon, med intervaller som ville maksimere produksjonen og minimere behovet for løsemiddel, og dermed maksimere effektiviteten.7 - Fremgangsmåte og apparat for å øke produktiviteten til viskøs olje, omfattende:• Et produksjonshylster muligens sementert, men ikke nødvendigvis, fra overflaten til toppen av det produktive reservoaret.• En nedre komplettering plassert inne i en produktiv formasjon med moderbor og forankret inne i produksjonshuset ved bruk av en foringshenger eller annet egnet system; foringen er normalt sementert, men ikke nødvendigvis. Den nedre kompletteringen kjøres med noen eksterne tetningselementer for å dele opp reservoardelen i hydraulisk isolerte deler, noen dedikert til injeksjon av løsemiddel og noen til produksjon.• En produksjonsforing løper inne i den nedre kompletteringsslangen for å samle opp oljen som produseres.• En produksjonsskjerm plassert eksternt til hver enkelt seksjon av reservoaret dedikert til produksjonen for å samle opp oljen og få den til å strømme gjennom en kontrollert ventil som for eksempel en AICV (Autonomous Inflow Control Valve) og en mekanisk bypass for å gå inn i den nedre kompletteringen.• Et produksjonsrør koblet til produksjonsforingen for å transportere oljen til overflaten ved hjelp av et løftesystem, men ikke nødvendigvis, og forankret til produksjonsforingsrøret ved bruk av en pakning eller annet egnet forankringssystem.• En injeksjonslinje som tilveiebringer et løsemiddel som er i stand til å redusere viskositeten til oljen (Eller fjerne skaden i nærheten av borehullet) som går fra overflaten og utplasseres sammen med produksjonsrøret og kobles til det ringformede rommet mellom den nedre kompletteringen og produksjonssilen slik at den injiserte væsken vil komme inn i formasjonen i injeksjonsseksjonene.8 - Systemet ifølge krav 8, med reservoarseksjonen delt inn i forskjellige seksjoner av tetningselementer slik at hver seksjon vil være i stand til både å injisere eller produsere i forskjellige øyeblikk gitt tilstedeværelsen av en injeksjonsventil og en produksjonsventil. Injeksjonsventilen er i stand til å åpne eller lukke den hydrauliske kontinuiteten mellom formasjonen og det ringformede rommet mellom den nedre kompletteringen og produksjonsforingen som transporterer løsningsmidlet. Produksjonsventilen kan åpne eller lukke den hydrauliske kontinuiteten mellom formasjonen og produksjonsforingen.9 - Systemet ifølge krav 8 eller 9, videre omfattende ett eller flere varmeelementer som er i stand til å øke temperaturen til det injiserte løsningsmidlet utplassert langs injeksjonslinjen eller langs produksjonsforingen.10 – Fremgangsmåte og apparat for å trekke ut varme fra en varm formasjon omfattende:• Et produksjonsrør sementert, men ikke nødvendigvis til toppen av den varme formasjonen.• En åpen hullseksjon med hovedboring boret inne i den varme formasjonen• Et produksjonsrør som er riktig isolert som for eksempel et vakuumisolert rør, men ikke nødvendigvis, som fører den oppvarmede væsken mot overflaten• Et injeksjonsrør løper langs hele det åpne hullet og koblet mekanisk til produksjonsrøret, men adskilt hydraulisk fra det samme ved et separasjonselement plassert internt og deler røret og injeksjonsrøret i hydraulisk uavhengige seksjoner.• Minst ett lateralt injeksjonsrør plassert inne i en lateral kanal slik at den injiserte kalde væsken kan varmes opp mens den returnerer mot hovedborehullet med åpent hull gjennom det ringformede rommet mellom det laterale injeksjonsrøret og sidekanalen• Et forankringssystem for å forankre produksjonsrøret og injeksjonsrøret til produksjonsrøret.• En bypass for å lede den kalde injeksjonsvæsken fra ringrommet mellom produksjonshuset og produksjonsrøret til det indre av injeksjonsrøret• En bypass for å avvike den varme væsken fra ringrommet mellom injeksjonsrøret og den varme formasjonen til det indre av produksjonsrøret

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IPC classesE21B 43/25E21B 43/30F24T 10/00E21B 41/00CPC classesE21B 43/255E21B 43/305F24T 10/00E21B 41/0035

Citations

US 2007/0107902 A1 (A1)WO 2020/185236 A1 (A1)EP 2891763 A2 (A2)US 2016/0245550 A1 (A1)GB 2520719 A (A)CA 3087645 A1 (A1)US 2015/0021924 A1 (A1)CA 2991871 A1 (A1)

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TG & T AS
TG & T AS

Org. number: 926448455

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Theodor Dahls veg 4B 4355 KVERNALAND NO (TIME Municipality, Rogaland county)Org. number: 926448455Inventors
GILBERTO TOFFOLO
Rossåskroken 6 4332 FIGGJO NO (SANDNES Municipality, Rogaland county)

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