HK40063506B - Steam generator tool - Google Patents

Description

Steam generator tools

Technical Field

This invention relates to a steam generator tool, and more particularly to a steam generator tool and method for generating steam from input water, fuel and oxygen.

Background Technology

Many oil reservoirs around the world contain viscous hydrocarbons, commonly referred to as "bitumen," "tar," "heavy oil," or "extra-heavy oil" (collectively referred to as "heavy oil" in this article), with viscosities ranging from 3,000 to over 1,000,000 centipoise. This high viscosity hinders oil recovery because it does not readily flow from the rock formation.

To achieve economic recovery, heating heavy oil (e.g., using steam injection) to reduce its viscosity is the most common extraction method. Heavy oil reservoirs are typically produced through cyclic steam stimulation (CSS), steam drive, and steam-assisted gravity drainage (SAGD), where steam is injected from the surface into the reservoir to heat the oil, thereby reducing its viscosity to a level suitable for efficient production.

Surface steam injection faces numerous limitations due to the low efficiency of surface boilers, energy losses in surface pipelines, and energy losses in the well. Standard oilfield boilers convert 85% to 90% of the fuel energy into steam; surface pipelines lose 5% to 25% of the fuel energy depending on pipeline length and insulation quality; and finally, wellbore heat losses can reach 5% to 15% of the fuel energy, depending on well depth and the insulation methods used. Therefore, the total energy loss before steam reaches the reservoir can exceed 50% of the fuel energy. In deep heavy oil reservoirs, surface steam injection often results in hot water rather than steam reaching the reservoir due to heat losses.

Furthermore, many heavy oil reservoirs do not respond to conventional steam injection because many reservoirs themselves have little or no natural driving pressure. Even when the reservoir pressure is initially sufficient for production, it drops significantly as production progresses. Therefore, conventional steam technology is of little value in these situations because the generated steam is at a low pressure, such as a few atmospheres. Consequently, continuous steam injection or “steam-driven” operation is often not feasible. Therefore, a circulating technique commonly known as “steam huff and puff” is employed in many steam injection operations. In this technique, steam is injected for a predetermined period of time, steam injection is interrupted, and the well is shut down for a predetermined period of time, a process known as “soaking.” Afterward, the well is pumped to a predetermined wear point, and the cycle is repeated. However, the steam penetrates only a small portion of the rock formation surrounding the wellbore, especially because the steam is injected at relatively low pressure.

Another problem with traditional steam generation technologies is the generation of air pollutants, namely _CO2 , _SO2 , _NOx , and particulate emissions. Several jurisdictions have set maximum emission limits for such steam operations, which typically apply to broad areas with large heavy oil fields and commercial-scale steam operations. Therefore, the number of steam operations in a given oil field can be severely limited, and in some cases, a phased approach is necessary to limit air pollution.

Some have suggested using high-pressure combustion systems on the surface. In such systems, water is evaporated from the flue gas from the burner, and both the flue gas and steam are injected into the wellbore. This essentially eliminates or at least reduces the need to address air pollution from the combustion process, as all combustion products are injected into the reservoir, and most of the injected contaminants remain isolated within the reservoir. The injected mixture typically consists of approximately 60% to 70% steam, 25% to 35% nitrogen, approximately 4% to 5% carbon dioxide, less than 1% oxygen, depending on whether excess oxygen is used for complete combustion, and traces of _SO2 and _NOx . Of course, _SO2 and _NOx produce acidic substances. However, by properly treating the water used to generate steam and diluting the acidic compounds with the injected water, the potential corrosive effects on these materials can be significantly reduced or even eliminated.

This operation, which uses a combination of steam, nitrogen, and carbon dioxide instead of steam alone, has recognized advantages. In addition to heating the reservoir and oil to their proper positions via steam condensation, carbon dioxide dissolves in the oil, particularly in the reservoir region before the steam pressurizes or repressurizes the reservoir by nitrogen.

However, a very serious problem with the currently proposed above-ground high-pressure systems is that they involve complex compression equipment and large combustion vessels operating under high pressure and high temperature. This combination requires skilled mechanical and electrical personnel to operate the equipment safely.

One solution to the problem occurring on the surface is to place a steam generator downhole at a point adjacent to the rock formation to be evaporated, which injects a mixture of steam and flue gas into the formation. This also has the advantages mentioned above, making evaporation economically and practically feasible, and increasing production speed and yield by injecting a steam-flue gas mixture.

Although many downhole steam generators have been proposed, current designs are often very complex and prone to problems during manufacturing and operation. Furthermore, due to the extreme conditions downhole, current designs require frequent maintenance due to hard water buildup or igniter failure. Durability is critical because any maintenance required necessitates the removal of tools from the well, which is both time-consuming and costly.

Therefore, a durable steam generator tool is required. This tool can be used on the surface or downhole.

Summary of the Invention

According to one aspect, the present invention relates to a tool for generating steam and combustion gases to produce oil from an oil well, the tool comprising: a first end portion configured to receive an input including air, fuel, and water; an ignition assembly disposed within the tool and configured to ignite the fuel and air to generate a flame; a combustion chamber for containing the flame extending at a second end portion opposite the first end portion and defined by a wall and an outlet configured to allow combustion products to be discharged; and a water passage extending from the first end portion of the body and terminating at a nozzle on an outer surface of the tool, the nozzle axially guiding a flow of water at least partially along the outer length of the wall, wherein the water evaporates at least partially along the outer length of the wall to generate steam.

In another embodiment, the present invention relates to a method for generating steam from a steam generator tool to produce oil from an oil reservoir, the method comprising: supplying air, water, fuel, and electricity or control to a steam generator; injecting water from a nozzle on an outer surface of the steam generator; igniting a flame using an ignition assembly; causing the water injected from the nozzle to evaporate by allowing water to flow along the length of the outer surface of the combustion chamber wall to the outlet of the combustion chamber while combustion products from the flame flow within the combustion chamber to the outlet of the combustion chamber; and directing the steam and combustion products into the oil reservoir.

Another aspect of the invention relates to a tool for generating steam and combustion gases to produce oil from an oil well, the tool comprising: a first end portion configured to receive an input including air, fuel, and water, wherein air enters at a port on the upper portion of the first end portion of the tool, the port being unconnected and configured to open the tool to an outer surface; a location at the first end portion of the tool configured to connect water and fuel input lines to the tool; an ignition assembly disposed within the body and configured to ignite the air and fuel to generate a flame; a combustion chamber containing the flame and extending at a second end opposite the first end portion, the combustion chamber being defined by a wall and an outlet configured to allow combustion products to be discharged into the well; and a passage within the tool from the port to the combustion chamber to allow air to flow from the port to the combustion chamber.

Attached Figure Description

To better understand this invention, the following figures are attached:

Figure 1 is a cross-sectional view of the steam generator tool with a flame.

Figure 2A is a cross-sectional view showing another steam generator tool in the oil reservoir of the additional nozzle and housing.

Figure 2B is a cross-sectional view of another steam generator tool in an oil reservoir with an optional embodiment of a mixing device support and a tapered cone.

Figure 2C is an isometric view of a steam generator tool including a mixing device support and a tapered cone with an extension.

Figure 3A is a perspective view of a steam generator tool showing a nozzle on the outer surface of the tool.

Figure 3B is a perspective view of a steam generator tool with a nozzle in operation.

Figure 3C is a perspective view of a steam generator tool showing a nozzle and water extension pipe in operation.

Figure 4A is a top view of a steam generator tool that is installed and connected to the ground via a coiled tubing umbilical.

Figure 4B is a top view of a steam generator tool that is installed and connected to the ground via a multi-tube umbilical cord.

Figure 4C is a top view of a steam generator tool installed and connected to the ground via a coiled tubing umbilical and an annular bypass for oxidant input.

Figure 4D is a cross-sectional view of a steam generator tool including an annular air bypass.

Detailed Implementation

The detailed descriptions and examples set forth below are intended as descriptions of various embodiments of the invention and are not intended to represent the only embodiments contemplated by the inventors. The detailed description includes specific details for providing a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without these specific details.

The present invention generally relates to a steam generator tool for injecting steam and flue gas into an oil reservoir and a method for generating steam downhole or on the surface.

While steam injection is frequently used for heavy oil recovery, aspects of this invention are not limited to heavy oil recovery but are also applicable to general steam generation. Applications include, but are not limited to, steam generation for heavy oil recovery or other industrial applications, water purification, etc. Furthermore, the steam generator tool can be used in any of a variety of configurations when used for heavy oil recovery, for example, on the surface, downhole in vertical, horizontal, or other wellbore directions.

Referring to the accompanying drawings, Figures 1, 3A, and 3B illustrate a steam generator tool 100 configured to receive a supply of fuel and water, thereby burning the fuel and generating steam from the water. This tool can be used downhole or on the surface. In the embodiment shown in Figure 1, the tool 100 includes: a tool coupling assembly 2 configured to receive an input of water, fuel, and oxidant; a flow deflection assembly 4 coupled to the coupling assembly and guiding the flow through the tool input; and an ignition assembly 5 configured to ignite the fuel to generate a flame F. The tool 100 also includes a combustion chamber 74 configured to contain the flame; and a plurality of water nozzles 6 on the outer surface of the tool. Each nozzle has an orifice and is configured to spray water onto the outer surface of the combustion chamber 74. During operation of the tool 100, the water is converted into steam. The tool coupling assembly 2 defines a first end, which can be considered as the upper end of the steam generator tool, and the combustion chamber is located at a second, opposite end of the tool.

The coupling components, flow steering components 4, ignition components 5, etc., can be separate but partially coupled to the tool, or they can be permanently coupled, for example, they are one piece but only the functional area of the tool.

In use, one or more supply lines 1 can be provided for coupling to the tool to deliver inputs. Line 1 is received at the tool coupling assembly 2. The tool coupling assembly 2 is configured to receive and couple any line 1. Inputs can be received by assembly 2 with connectors that can be properly sealed, facilitating replacement, repair, and modification. For example, the tool coupling assembly 2 may include one or more connectors that provide connection between multiple inputs and channels to a flow diversion assembly 4. Line 1 can provide pressurized delivery of inputs such as oxidizers (e.g., air), fuel, and water, or ignition control, to the tool coupling assembly 2.

The flow diversion assembly 4 delivers fuel and air from assembly 2 to ignition assembly 5 and water from assembly 2 to nozzle 6. The flow diversion assembly 4 has a first end 41 that receives the supply from tool coupling assembly 2. The flow diversion assembly 4 guides the supply within the tool for use and consumption. Fuel and air can be supplied to the tool through line 1, and the flow diversion assembly 4 diverts the fuel and air through the tool and releases them into combustion chamber 74, where they are burned. Water can be introduced into the tool from line 1, diverted by the flow diversion assembly 4 to water nozzle 6, where it is released and, in use, partially evaporates into vapor as it flows along the outer wall of the combustion chamber or into the hot combustion gases exiting the combustion chamber.

Specifically, the flow steering assembly 4 includes multiple channels 4a, 4b, and 4c through which fuel, water, and oxidant inputs flow. The channels include: an oxidant channel 4a extending from a first end of the tool (e.g., from an inlet thereon) to the combustion chamber; a water channel 4b extending from the coupling assembly 2 of the tool to the nozzle 6a; and a fuel channel 4c extending from the coupling assembly 2 of the tool to the combustion chamber 74. The flow steering assembly 4 may also accommodate electrical/control lines or channels extending between the upper end 41 and different locations within the tool, such as the ignition assembly 5.

Ignition assembly 5 is configured to ignite fuel and oxidant flowing into the combustion chamber; for example, in a typical embodiment, ignition assembly 5 has a portion open to the combustion chamber 74. Once ignited, the fuel and oxidant flow continues into the combustion chamber 74 and burns therein. The ignition assembly may be a spark generator, a heated surface, etc. In another embodiment, the ignition assembly may include a delivery system for an igniting or self-igniting liquid.

The ignition assembly 5 can be controlled by a control system that determines when the ignition assembly operates. The control system may also perform other operations, such as regulating flame stability, the degree of fuel combustion, or measuring stoichiometric data, the pressure of air and fuel supplied to the tool. Therefore, the control system may include sensors such as those located within the flow steering assembly 4, the ignition assembly 5, or the combustion chamber 74. For example, the tool may have an ignition control line coupled to a control line 19 in line 1. The ignition control line 19 may require an electrical connection at assembly 2.

Combustion chamber 74 extends at a second end of the tool opposite to the upper end. The combustion chamber is defined as the space within the tubular wall 7 extending from the second end. The tubular wall has a length L extending axially from the closed end, bottom wall 50, to the open end, which forms the outlet 40 of the chamber. Depending on the tool's operating parameters and output requirements, the length L between the closed end and the open end can be between 300 and 1000 mm.

The combustion chamber wall 7 has an inner surface 71 and an outer surface 72 facing the combustion chamber. In the embodiment of FIG1, the outer surface 72 is part of the outer surface of the tool. The wall 7 can be generally cylindrical, for example, a hollow cylinder. In this case, the inner surface 71 and the outer surface 72 can be generally cylindrical, with the inner surface being the inner diameter of the wall 7 and the outer surface 72 being the outer diameter of the wall 7, and the outer surface 72 defining the outer cylindrical surface of the wall 7.

Combustion chamber 74 is defined within the area of bottom wall 50 and inner surface 71, and its length L lies between bottom wall 50 and outlet 40. Length L also defines the major axis of the tool and combustion chamber 74. During operation, the flame remains in combustion chamber 74, and combustion products are discharged from combustion chamber at outlet 40.

The diameter of the combustion chamber outlet 40 can vary. In one embodiment, the diameter of the outlet 40 is smaller than the maximum diameter of the combustion chamber 74. In other words, the diameter of the opening at the outlet 40 can be smaller than the maximum dimension of the inner diameter of the wall 7. Therefore, the wall 7 can include a tapered end defining a tapered outlet 40. This tapered end can be referred to as a combustion nozzle 75. The combustion nozzle 75 affects the exhaust combustion gases because they converge as they pass through the tapered diameter. Therefore, the combustion nozzle 75 generates back pressure in the chamber 74, thereby affecting the fluid discharge from the chamber and mitigating the upward backflow of fluid into the combustion chamber.

As will be understood, as fuel and oxidizer enter the combustion chamber at or near the bottom wall 50, the flame is anchored near the bottom wall and protected within wall 7. The flame generates high heat from its anchoring point and downstream along the path of the flame and the combustion products from it. Therefore, wall 7 of the combustion chamber becomes very hot radially outward from the flame anchoring point and downstream to outlet 40. Heat is transferred from inner surface 71 to outer surface 72.

Nozzle 6 is connected to the end of water channel 4b. The nozzle is positioned on the outer surface of assembly 4, adjacent to wall 7, and is oriented and configured to spray water from the nozzle to outlet 40 along the outer surface 72 of the combustion chamber wall. As the water flows along the combustion chamber wall 7 to the combustion chamber outlet 40, the heated outer surface 72 of the combustion chamber at least partially evaporates the water into steam. Specifically, heat from the flame F at the outer surface 72 causes the water sprayed from the nozzle to evaporate at least partially into steam. Notably, the nozzle is not positioned to spray water into the combustion chamber, which could adversely affect the flame, but rather on the outer surface 72 outside the combustion chamber. Similarly, the nozzle orifice opens near the radially outward-facing surface 72 of the combustion chamber wall and, in one embodiment, is configured to spray water axially at least partially along the outer surface 72 of the wall 7.

In addition to their position on the outer surface of the tool, the nozzles 6 can also be positioned approximately at the location where fuel and oxidizer enter the combustion chamber. For example, the flame is anchored at or slightly downstream of the location in the combustion chamber where air and fuel are mixed and ignited. Therefore, when the nozzles 6 are located on the outer surface of the tool outside the combustion chamber, the nozzles can be positioned at approximately the same axial position as the openings of the passages for air 4a and fuel 4c to the chamber 74. This positions the nozzles at approximately the same axial position as the location where fuel and air enter the combustion chamber, and exactly upstream of the location where fuel and air burn. Therefore, the position of the nozzles 6 at approximately the same axial position as the openings of the passages for air 4a and fuel 4c to the chamber 74 allows water to be released from the passage 4b through the nozzles in the cooler areas of the outer surface of the tool, while the water is guided radially outward from the location of flame formation or impacts the hotter tool surface.

In the illustrated embodiment, the openings of the air passage 4a and the fuel passage 4c leading to the combustion chamber 74 are located at the bottom wall 50, so the nozzle 6 is approximately located at the bottom wall 50, which is the upper closed end of the combustion chamber. The nozzle is positioned radially outward from the bottom wall 50 of the combustion chamber 74 on or near the outer surface of the combustion chamber wall. In one embodiment, the nozzle may be located on the outer surface of the flow steering assembly 4, positioned approximately horizontally, for example, approximately coplanar with the openings of the ignition assembly 5 and the air passage 4a and the fuel passage 4c within the combustion chamber 74, all of which are located at the bottom wall 50.

The nozzle's position at the same axial location as the bottom wall 50 ensures that water is released from the channel 4b through the nozzle before reaching the hottest area of the tool. This position is on the wall 7 between the location where the flame is anchored and the outlet end 40. Therefore, the water channels 4b extend only through the coupling assembly 2 and the flow deflection assembly 4 to reach the nozzle 6, and they do not extend through the tool adjacent to its hottest area. In one embodiment, the channels 4b terminate at the nozzle 6 without passing through the wall 7.

Water is applied from nozzle 6 to the outer surface 72, creating a cooling effect on the wall 7, where some of the water evaporates to form steam. Therefore, this nozzle positioning protects the combustion chamber wall 7 from thermal degradation and provides a uniform temperature distribution around it. Furthermore, while existing tools suffer from scale buildup and clogging in water channels and nozzles, this tool positions the nozzle upstream of the hottest area of the tool to prevent scale formation in the water channels and nozzles. Although scale may form on the outer surface of the tool (e.g., on the outer surface 72 of wall 7), the large open surface area ensures that such scale will not clog the water jet and is easily detached or knocked off. While previous tools sometimes required softened water, this current tool, with its unique nozzle positioning, can use impure water sources such as process water, surface water, brackish water, etc.

In one embodiment, the outer surface 72 of the wall 7 is treated to prevent scale buildup due to water evaporation. For example, at least the outer surface between the nozzle 6 and the outlet end 40 may be polished or coated with a non-stick coating, such as Teflon ^™ , titanium ceramic compounds, or similar materials. This surface treatment facilitates scale removal during use and routine maintenance.

The nozzles 6 can be spaced around the circumference of the tool, so that water is applied around the entire periphery of the outer surface 72. The number of nozzles 6 depends on the flow rate, expected pressure loss, and combustion chamber length.

In one embodiment, as shown in Figures 3A and 3B, nozzles 6 may be mounted in a shoulder 65 on the outer surface of the tool. The shoulder can be defined by the variation of the tool's outer diameter from a larger outer diameter at the upper end to a smaller outer diameter at the lower end. The shoulder may be located between the flow steering assembly 4 and the combustion chamber wall 7. The shoulder forms an annular surface that is substantially perpendicular to the long axis of the tool. The shoulder 65 faces downwards such that the outer diameter of the outer surface approximately at and above the bottom wall 50 is larger than the outer diameter of the outer surface 72 of the combustion chamber wall. In one embodiment, nozzles 6 are mounted on the annular surface of the shoulder, with their orifices opening near the annular surface and facing the outlet 40 of the combustion chamber. Thus, water is axially ejected from the shoulder along the outer surface of the tool, parallel to the combustion chamber wall 7. The nozzles 6 may be spaced evenly around the periphery of the shoulder to ensure sufficient water coverage of the combustion chamber wall 7. Figure 3B shows nozzles 6 in operation, where water is concentrically ejected from around the tool toward the outlet 40. This provides a water film along the outer surface 72 of the combustion chamber wall 7.

Nozzles 6 can be selected for various jet delivery types, including fan, jet/flow, mist, or spray. Furthermore, water pressure and flow rate can be varied according to tool size, design specifications, and tool power requirements.

If higher steam quality is required or the combustion products at the exhaust outlet are found to be too hot, it may be beneficial to further provide a water extension conduit 12 with a nozzle 12a at its distal end, as shown in Figures 2A and 3C. The extension conduit 12 can be connected to some channels 4b, such as those terminating at the shoulder 65. As shown in Figure 3C, each tubular water extension conduit 12 can be connected to the assembly 4, for example, to the shoulder 65, spaced apart and distributed between the nozzles 6, and can extend along the length L of the combustion chamber wall 7, terminating near the outlet 40 of the combustion chamber. In addition to the nozzles 6, the water extension conduit 12 can also be used to provide an additional water source. Water supplied to the tool can be supplied to the water nozzles 6 at the bottom wall 50 and the water nozzles 12a mounted on the extension conduit 12, and ejected from the water nozzles 6 and 12a. Figure 3C illustrates how water is ejected simultaneously from the water extension conduit nozzles 12a and 6.

Nozzle 12a is positioned near outlet 40, where hot combustion gases are discharged from the tool and enter space 21. Therefore, nozzle 12a of extension conduit 12 can be positioned to spray water near or directly into the combustion gases. Water supplied to the tool is guided into water extension conduit 12 and sprayed by nozzle 12a into space 21, where hot combustion gases are discharged from outlet 40 of the combustion chamber, thereby evaporating the water into steam. As shown in Figure 3C, multiple water extension conduits 12 and nozzles 12a may be present.

The water extension conduit 12 can deliver water directly to the outlet 40, where combustion gases are discharged into the space 21. Directly introducing water into the discharged combustion gases allows for more direct cooling. Specifically, the water extension conduit 12 allows for direct cooling of the hot combustion gases 21 passing through the outlet 40 of the combustion chamber. The water extension conduit 12 can spray water axially relative to the wall or can be inclined inwards towards the outlet 40 of the combustion chamber. Therefore, water sprayed from the nozzle 12a can be directed axially or radially inwards at an angle towards the outlet or below the outlet. For example, the distal end of the water extension conduit 12 can be inclined at least 45° α towards the outlet 40, thereby spraying water into the space 21 below the outlet, where hot combustion gases are discharged from the combustion chamber. The number of water extension conduits 12 can vary depending on the desired steam quality, well size, tool application, and design. For example, for tools intended for use in wells with an inner diameter of less than 229 mm or less than 178 mm, four to eight water extension conduits 12 can be provided.

The water extension conduit 12 with nozzle 12a is most effective at low power settings, such as 5 million BUT/hr. In this case, the water sprayed from nozzle 12a helps to cool the hot combustion gases exiting the combustion chamber outlet 40.

The water extension conduit 12 is connected to the tool by mechanical coupling or welding. As shown in FIG2A, the water extension conduit may hardly contact or be separated from the outer surface 72 of the combustion chamber. In one embodiment, there is a space 66 between each conduit 12 and the surface 72. Thus, the water extension conduit 12 can be insulated from the high temperature of the wall 7 by a water film supplied from the nozzle 6, which can flow into the space 66 between the water extension conduit 12 and the outer surface 72 of the combustion chamber.

As described above, this tool can be used downhole or on the surface. When used downhole, the tool is equipped with a combustion chamber 74 and a nozzle 6 that leads to an area of the well, such as the rock formation 11 to be steam-treated. Figures 2A and 2B show each tool 100 installed in the well. An isolation packer 3 secures the tool within the wellbore wall, shown here as casing 9. The isolation packer 3 isolates the lower steam-generating end of the tool from the well above the packer. Thus, the packer 3 retains the steam and heat from the combustion chamber 74 downhole and prevents steam from flowing upwards along the annulus away from the reservoir 11. The tool can be installed near the perforation 10 and the reservoir 11 to reduce potential damage and energy loss to the well casing 9 and other rock formations above the reservoir. The isolation packer 3 has one or more of mechanical, hydraulic, pneumatic, inflatable, or non-slip packer elements.

The packer 3 is concentrically mounted around the outer surface of the tool, above the tool, on a connected but separate tool, or on line 1. When not in use or when released into the well, the packer 3 is initially in the retracted position, but when in place in the well, the packer 3 is set by expanding the packer element.

In one embodiment, the packer is mounted around the periphery of the tool between the coupling assembly 2 and the nozzle 6. Therefore, when installed in a well, the coupling assembly is located above the packer, while the nozzle 6 and outlet 40 are located below the packer 3. The packer 3 discharges the contents of the coupling assembly 2 and the nozzle through communication channels 4a, 4b, and 4c.

When installed in a well, an annular cooling system 23 can be used on the tool above the packer 3.

Figures 2A and 2C also illustrate possible steam generator tools. The tools shown have a converging structure for forcibly mixing any unevaporated water, steam, and combustion gases downstream of the combustion chamber outlet 40. The converging structure can be used to control the heat and steam output from the tool. The converging structure forces any unevaporated water and steam to flow radially inward, thereby mixing with the flue gas exiting outlet 40, thus vaporizing the water and cooling the flue gas. The converging structure may include a reducing cone 14 on a second lower end of the tool below outlet 40, with a space 21 therebetween.

The reducing cone includes tapered, funnel-shaped, tapering sidewalls that converge from the inlet, upper opening 14a, to the outlet, lower opening 14b. The lower end of the cone has a smaller diameter opening than its upper end. The wider upper end is located on the tool closer to the outlet 40 than the lower end 14b.

In one embodiment, the diameter of the upper end 14a of the reducing cone 14 is larger than the diameter of the outlet 40, forcing any unevaporated water or vapor to converge along the outer surface 72 with the combustion gases exiting the outlet 40. Specifically, the upper end 14a forces fluid in space 21 to converge through the smaller diameter lower outlet 14b. In one embodiment, the diameter of the upper end of the reducing cone 14 is approximately the same as the diameter of the well casing in which the tool will be used, and when the packer 3 is configured, the diameter of the upper end of the reducing cone 14 is approximately the same as the diameter of the packer 3. Therefore, any fluid in region 21 below outlet 40 must pass through the reducing cone when exiting the tool. The smaller diameter lower outlet 14b can be lengthened by a cylindrical solid-walled extension of uniform diameter to control the hydrodynamics of the exiting steam and combustion gases. For example, this extension can mitigate vortex formation as fluid exits cone 14.

The reducing cone 14 can be coupled to the tool in any of a variety of ways, positioning it substantially concentric with and spaced below the outlet 40. If there are concerns about tool control or sleeve damage, the converging structure can include a substantially solid cylindrical housing 8 to properly couple the cone 14 to the tool. Such a tool is shown in Figure 2A. In this tool, the housing 8 surrounds the lower end of the tool, including the wall 7, and the nozzle 6 is located between the housing 8 and the lower end of the tool. The housing 8 supports the reducing cone 14 at its lower end, which is spaced apart from and below the combustion chamber outlet 40. The housing can be a cylindrical solid wall. Because the nozzle 6 opens into the annular space between the housing 8 and the wall 7, the housing 8 and the reducing cone 14 contain water from the nozzle 6, as well as steam and flue gas initially generated within the tool. For example, water ejected from the nozzle 6 creates a flow of water between the combustion chamber wall 7 and the interior of the housing 8. Tools with a housing 8 can operate at higher steam quality (>80%) without damaging the well casing 9. Therefore, the housing 8 is sacrificial and protects the casing 9 from the high heat generated alongside the wall 7. The housing 8 can be detachably attached to the tool, for example, to assembly 4, and can be replaced during maintenance.

Alternatively, a non-stick treatment, such as the coating described above, can be applied to the inner surface of the housing.

In another embodiment, as shown in Figures 2B and 2C, the tool includes a support arm 13 with a tapered joint 14 at a second end spaced apart from and below the outlet 40. The support arm 13 extends beyond the lower end of the wall 7. Several options are available for the support arm 13. While the support arm 13 can be configured to more completely surround the outer outlet 40 and region 21, in one embodiment, the support arm 13 is a plurality of spaced, elongated, axially extending rods with an open region between them, as shown in Figure 2C. Having only a plurality of spaced rods instead of a solid cylindrical wall reduces the tool's weight, complexity, and material requirements, and allows the annular surface around the wall 7 below the nozzle 6 to be as open as possible.

In one embodiment, the support arm 13 is connected via a collar 13a, which is concentrically fixed to a tool above the nozzle 6, for example, to the outer surface of the component 4 below the packer 3. The support arm 13 extends downward along the body and combustion chamber wall and axially beyond the outlet 40. Thus, the support arm 13 is longer than the length L of the wall 7 to extend from above the nozzle 6 to terminate below the outlet 40.

The support arm 13 and/or collar 13a can also be configured to function as a centralizer for the tool relative to the casing in which the tool is mounted. For example, the support arm and/or collar 13a may protrude radially beyond the diameter of the tool body, assemblies 2 and 4 to define an effective outer diameter that is substantially the same as the diameter of the well casing in which the tool will be used. In the case where the support arm functions as a centralizer, at least three spaced-apart support rods may be present, extending axially from or above the shoulder 65 and circumferentially spaced to define an effective outer diameter substantially the same as the diameter of the well casing in which the tool is used, and whose diameter is substantially the same as the diameter of the upper end of the cone 14 and packer 3, which, when configured, is larger than the outer diameter of each of the tool assemblies 2, 4 and wall 7.

The upper end 14a of the reducing cone approaches or abuts the well casing 9 because, as described above, the upper diameter is approximately the same as that of the casing in which the tool is installed. In one embodiment, a seal 15 is provided at the upper end of the reducing cone 14. The seal may be a ring extending around the entire periphery of the upper end 14a, and the ring diameter is selected to bias onto the well casing 9. The seal 15 may be made of a variety of high-temperature elastic materials, such as high-temperature rubber compounds, Teflon, or similar materials.

In this embodiment, the casing 9 is used to contain water, steam, and combustion products within the downhole nozzle. For example, water and generated steam from the nozzle 6 flow along the space between the casing 9, arm 13, and wall 7 until it reaches the seal 15 and cone 14, where they converge inward into the flue gas discharged from the outlet 40.

Figures 4A to 4C show top views of multiple tools installed in the well casing 9. These figures illustrate optional configurations of the input lines 1, such as lines for air 17, fuel 18, ignition control/electricity 19, and water 20. In the embodiment of Figure 4A, all lines are bundled together with a larger diameter pipe that houses a smaller diameter pipe. The fuel, water, and control lines 18, 19, and 20 are the smaller diameter lines, while the air line 17 is essentially the remaining space within the larger diameter pipe. The tool coupling assembly 2 includes connection points for the larger diameter pipe through which air flows and connection points for each of the water 20, fuel 18, and ignition control 19.

In another embodiment, multiple lines can be bundled together, for example configured as a multi-duct umbilical tube 1a, as shown in Figure 4B. The multi-duct umbilical tube 1a can be coupled to the tool at the tool coupling assembly 2. The multi-duct umbilical tube can be bundled using tubing, concentric coils, flexible braided hoses, or wrapping materials. One type of multi-duct umbilical tube is called an Armorpak ^™ tube and is described in U.S. Patent No. 10,273,790.

The outer diameter of lines 1 and 1a can depend on the pressure requirements of the tool application. For example, for heavy oil production, the outer diameter of the tubing can be between 60 and 114 mm, and for Armorpak tubing, it can be between 15 and 60 mm. Compared to water 20, input lines such as air line 17 or fuel line 18 can deliver the maximum volume of input to the tool and can therefore be configured to rigidly hold the tool 100 to the surface during downhole applications.

In the alternative embodiments shown in Figures 4C and 4D, the tool is configured to receive air from the environment via a port 90 on its outer surface, rather than from a supply source via a pipeline. In such an embodiment, the tool 100 includes an oxidizer inlet 90 at its upper end (e.g., on tool assembly 2 or 4). Air is supplied through the torus of the well and enters the tool at port 90 when the fuel line 18, water line 20, and control line 19 are each connected to the tool individually or in a bundle. Port 90 may not have any type of input line connection, such as quick-connect, threaded, Armorpak, coiled, or bundled connections. Port 90 communicates with a passage leading to the combustion chamber. The passage may be configured to allow air to flow from port 90 to the combustion chamber. Debris or dehydrators, such as a screen 92, may be present at port 90 to prevent port 90 and its passage from becoming clogged with debris or impurities. In this embodiment, instead of a pipeline supplying air to the tool, air can be drawn into the tool from the tool's wellbore. An oxidizer, such as air, can be pumped into the tool's wellbore. Port 90 provides a ring bypass through the tool. For example, a ring bypass can be used in situations requiring large volumes of air. In these cases, using a ring bypass can reduce both surface and injection pressures to manage the overall pressure on the system.

Air from the casing 9 can flow into port 90 and be diverted to chamber 74 via flow diversion assembly 4. During downhole operations, the annular bypass through port 90 allows the working pressure at the well surface to be lower than that of the oxidizer line delivery, because the flow area in the annulus is several times larger than the flow area through input line 1. Therefore, port 90 can be useful when the casing 9 is narrow, in order to provide optimal working pressure at the tool surface. Furthermore, when air is delivered through port 90, the compressor used for downhole input delivery may be more economical. By using the annulus to deliver air through port 90, supplementary fuel 17 and water 20 can be delivered through input line 1.

In another aspect of the invention, as shown in FIG4C, the tool includes a temperature sensor 24, which can be monitored via pipeline 1 or remotely. Other sensors, such as pressure or chemical sensors, may also be used. The sensors can detect parameters indicating operation or malfunction (e.g., overheating or leakage). Sensors may be located above (as shown) and below the packer 3.

The outer diameter of the steam generator tool 100 can vary depending on the inner diameter of the well casing 9. The outer diameter of the steam generator tool must be smaller than the inner diameter of the well casing 9. Typically, the inner diameter of the well can be less than 200 mm or less than 125 mm, in which case the tool can have a maximum outer diameter of approximately 190 to 120 mm to fit inside the well casing 9.

In downhole applications of steam generator tools, the outer diameter of the tool may be limited by the size of the well casing 9, while in surface applications of the tool, there are no size limitations.

In another embodiment, a method for generating steam is provided, for example, for injecting into an oil reservoir 11 to produce oil from the reservoir. The method includes: supplying air, water, and fuel to a steam generator tool; igniting the fuel to generate a flame within a combustion chamber 74; spraying water from a nozzle 6 along the exterior of the combustion chamber wall 7, such that the water partially evaporates to form steam and flows along the outer surface 72 of the combustion chamber wall 7, while combustion gases from the flame flow within the combustion chamber through an inner diameter defined within the inner surface 71 of the wall; and mixing the steam and combustion gases at an outlet 40 of the combustion chamber. The mixture of steam and combustion gases can be delivered to the oil reservoir.

Various methods can be used to supply air, water, and fuel to the tool. For example, a multi-conduit umbilical can provide an input to the tool. Alternatively, the space between the tool and the casing 9, particularly the torus, can provide a path for an input such as air, where the tool includes port 90. An ignition assembly 5 can be used to ignite the supplied fuel and air to produce a flame inside the combustion chamber. Water flowing into the tool via the multi-conduit umbilical can be sprayed through a water nozzle 6 to the outside of the combustion chamber anchored to the flame. The nozzle 6 can be oriented such that water can be sprayed at least partially axially toward the outlet 40 of the combustion chamber. Water flowing along the length L of the heated combustion chamber wall 7 cools the wall and evaporates into steam. Only when the steam and any unevaporated water reach the lower end of the wall do they come into contact with the flue gas discharged at outlet 40.

Steam and combustion gases, along with any unevaporated water, can be guided to converge, for example, by passing through a reducing cone 14 before entering the oil reservoir 11. After traveling along the combustion chamber wall 7, the reducing cone forms a funnel shape and forces the steam and/or water to mix with the combustion gases exiting the combustion chamber at outlet 40. This improves steam quality and reduces flue gas exhaust temperature.

Because water evaporates from the tool's outer surface, the water supplied to tool 100 may be impure, such as fresh water, alkaline water, or seawater. The steam generated by tool 100 may include superheated steam.

A variety of different fuels can be used, such as natural gas, syngas, propane, hydrogen, or liquid fuels.

For use in typical oil reservoirs, the air or gas pressure can be controlled from approximately 20 atmospheres (2,000 kPa) to approximately 70 atmospheres (7,000 kPa), and the tool output can be controlled above 10 mm Btu/hr.

The tool is made of materials selected to suit the harsh downhole conditions (e.g., high temperatures, steam, and corrosive fluids).

The steam generator tool 100 features simple and flexible components, making it easy to use, inspect, repair, and modify. The tool and the method of generating steam using it reduce or mitigate environmental pollution. Due to the design and configuration of its components, the tool can withstand the high temperatures and pressures of repeated use. Furthermore, the tool can pressurize and/or repressurize reservoirs when combustion gases and steam can be injected into the well at various pressures. The tool's high power output provides extended operation in many applications.

Terms:

a. A tool for generating steam and combustion gases to produce oil from an oil well, the tool comprising: a body having a first end configured to receive an input including air, fuel, and water; an ignition assembly configured within the tool to ignite the fuel and air to generate a flame; a combustion chamber for containing the flame, the combustion chamber extending at a second end of the body opposite the first end and defined by a wall and an outlet configured to discharge combustion products; and a water passage extending from the first end through the body and terminating at a nozzle on an outer surface of the tool, the nozzle being configured to axially guide a flow of water at least partially along the outer length of the wall outside the combustion chamber, wherein the water evaporates at least partially along the outer length of the wall to generate steam.

b. The tool described in any of the clauses, wherein the nozzle is located near the location where air and fuel enter the combustion chamber.

c. The tool described in any of the clauses, wherein the nozzle is located radially outside the ignition device within the combustion chamber.

d. The tool according to any of the clauses, wherein the first end includes a connection position configured to receive an input line.

e. The tool according to any clause, wherein the first end includes a port configured to receive air from an outer surface of the tool remote from the input line.

f. The tool described in any of the clauses, wherein the input also includes electrical or ignition control.

g. The tool described in any of the clauses, wherein the inputs are bundled.

h. The tool according to any of the clauses also includes a reducing cone spaced below the outlet of the combustion chamber, the reducing cone having an open upper end and an open lower end narrower than the upper end, the reducing cone being configured to collect and mix steam and flue gas below the outlet.

i. The tool described in any of the clauses also includes a resilient seal surrounding the upper end of the opening of the reducing cone.

j. The tool according to any clause further includes a different diameter cone coupled to the outer housing of the tool, the outer housing having a solid wall surrounding the wall of the combustion chamber, and the nozzle being located in an annular space between the solid wall and the wall.

k. The tool according to any of the clauses also includes a support arm that couples the different diameter cone to the tool, each of the support arms being a rod-like structure extending beyond the outlet of the combustion chamber.

1. The tool described in any of the clauses further includes a packer surrounding the tool between the first end and the nozzle.

m. The tool according to any of the clauses, wherein the nozzle is one of a plurality of nozzles positioned around the outer circumference of the tool.

n. The tool according to any of the provisions further includes a water extension conduit having a tubular structure that extends along the outer length of the wall and terminates at an orifice near the outlet of the combustion chamber, the orifice being configured to inject water through the outlet of the combustion chamber.

o. The tool according to any clause, wherein the distal end of the water extension conduit terminates at an inward angle relative to the outer length of the wall toward the outlet of the combustion chamber.

p. A method for generating steam from a steam generator tool to produce oil from an oil reservoir, the method comprising: burning air and fuel in a combustion chamber of the steam generator tool; injecting water from a nozzle on an outer surface of the steam generator tool, thereby causing the water to evaporate and generate steam outside the combustion chamber; and mixing the steam and flue gas from the combustion chamber only after the flue gas has exited the combustion chamber and before the steam and flue gas have contacted the oil reservoir.

q. The method according to any clause, wherein water injection includes directing water to the outer wall surface of the combustion chamber.

r. The method according to any of the provisions, wherein the combustion chamber is defined within a tubular sidewall and includes fuel and air inlets to the combustion chamber, and combustion includes anchoring a combustion flame within the sidewall downstream of the fuel and air inlets, and water injection includes supplying water through a tool and releasing water from the tool against the outer wall surface of the sidewall.

s. The method according to any clause, wherein the release occurs between the upper end of the steam generator tool and the radially outward position where the combustion flame is anchored.

t. The method according to any of the clauses, wherein the water injection further includes injecting water into the flue gas exiting the combustion chamber through the outlet of the combustion chamber.

u. The method according to any of the provisions further includes forcing steam and flue gas through a converging cone located downstream of the combustion chamber.

v. The method described under any of the clauses, wherein the air for the steam generator tool is derived from a well above the tool away from the inlet line.

w. The method according to any clause, wherein air enters the steam generator tool through a port on the outer surface of the tool away from the inlet line.

x. A tool for generating steam and combustion gases to produce oil from an oil well, the tool comprising: a body having a first end having a connection location for receiving an input line for fuel and/or water, and an air inlet port configured to receive air from the atmosphere surrounding the tool; an ignition assembly disposed within the body and configured to ignite air and fuel to generate a flame; a combustion chamber for containing the flame and extending at a second end of the body opposite to the first end, the combustion chamber being defined by a wall and an outlet configured to allow combustion products to exit from the combustion chamber; and a passage within the tool from the air inlet port to the combustion chamber to allow air to flow from the air inlet port to the combustion chamber; and optionally, at least one further comprising an isolation packer surrounding the tool, wherein the air inlet port is positioned between an upper end of the first end and the isolation packer, and wherein the air inlet port includes components for preventing water or debris from entering the passage.

y. A method for generating steam from a steam generator tool, the method comprising: receiving air from the atmosphere within a well into the steam generator tool, the well being open to an outer surface of the steam generator tool; burning air and fuel in a combustion chamber of the steam generator tool to generate heat; and injecting water through the heat generated by the steam generator tool to evaporate into steam, and optionally, wherein receiving air includes sieving water and debris from the air from an outer surface of the tool.

The description and accompanying drawings are provided to enable those skilled in the art to better understand the invention. The invention is not limited to the description and drawings, but rather a general explanation is given.

Claims (21)

1. A tool for generating steam and combustion gases to produce oil from an oil well, said tool comprising: The main body has a first end configured to receive inputs, including air, fuel, and water; An ignition assembly, configured within the tool, is used to ignite fuel and air to generate a flame; A combustion chamber for containing the flame, the combustion chamber extending at a second end of the body opposite the first end, and the combustion chamber being defined by a wall and an outlet configured to allow combustion products to exit; and A water channel extends from the first end through the body and terminates at a nozzle on the outer surface of the tool, the nozzle being located near the location where the air and fuel enter the combustion chamber and radially outside the ignition device within the combustion chamber, the nozzle being configured to guide water flow axially outside the combustion chamber at least partially along the outer length of the wall, wherein the water evaporates at least partially along the outer length of the wall to generate steam. 2. The tool of claim 1, wherein the first end includes a connection position configured to receive an input line. 3. The tool of claim 1, wherein the first end portion includes a port configured to receive air from an outer surface of the tool remote from the input conduit. 4. The tool of claim 1, wherein the input further includes power or ignition control. 5. The tool of claim 1, wherein the input is bundled. 6. The tool of claim 1 further includes a reducing cone spaced below the outlet of the combustion chamber, the reducing cone having an open upper end and an open lower end narrower than the upper end, the reducing cone being configured to collect and mix steam and flue gas below the outlet. 7. The tool of claim 6 further includes a resilient seal surrounding the upper end of the opening of the reducing cone. 8. The tool of claim 6, further comprising coupling the different diameter cone to an outer housing of the tool, the outer housing having a solid wall surrounding the wall of the combustion chamber, and the nozzle being located in an annular space between the solid wall and the wall. 9. The tool of claim 6, further comprising a support arm coupling the differential cone to the tool, each of the support arms being a rod-like structure extending beyond the outlet of the combustion chamber. 10. The tool of claim 1, further comprising a packer surrounding the tool between the first end and the nozzle. 11. The tool of claim 1, wherein the nozzle is one of a plurality of nozzles positioned around the outer circumference of the tool. 12. The tool of claim 1 further includes a water extension conduit having a tubular structure extending along the outer length of the wall and terminating at an orifice near the outlet of the combustion chamber, the orifice being configured to spray water through the outlet of the combustion chamber. 13. The tool of claim 12, wherein the distal end of the water extension conduit terminates at an inward angle toward the outlet of the combustion chamber relative to the outer length of the wall. 14. A method for generating steam from a steam generator tool to generate oil from an oil reservoir, the method comprising: burning air and fuel in a combustion chamber of the steam generator tool; injecting water from a nozzle on an outer surface of the steam generator tool to evaporate the water and generate steam outside the combustion chamber, the nozzle being located near the location where the air and fuel enter the combustion chamber and radially outside an ignition device within the combustion chamber; and mixing the steam and the flue gas from the combustion chamber only after the flue gas has exited the combustion chamber and before the steam and the flue gas contact the oil reservoir. 15. The method of claim 14, wherein spraying water comprises directing water toward the outer wall surface of the combustion chamber. 16. The method of claim 14, wherein the combustion chamber is defined within a tubular sidewall and further includes fuel and air inlets to the combustion chamber, and combustion includes anchoring a combustion flame within the sidewall downstream of the fuel and air inlets, and water injection includes supplying water through the tool and releasing water from the tool against the outer wall surface of the sidewall. 17. The method of claim 16, wherein the release occurs between the upper end of the steam generator tool and the radially outward position where the combustion flame is anchored. 18. The method of claim 15, wherein the water injection further comprises injecting water through an outlet of the combustion chamber into the flue gas exiting the combustion chamber. 19. The method of claim 14, further comprising forcing the steam and the flue gas through a converging cone located downstream of the combustion chamber. 20. The method of claim 14, wherein the air for the steam generator tool originates from a well above the tool, away from the inlet line. 21. The method of claim 20, wherein the air enters the steam generator tool through a port on the outer surface of the tool away from the inlet line.