Patent Application
20070039736
This documents relates to a tube system for use in a wellbore, such as for use in the delivery of fluids to a downhole heated-fluid generator device.
Fluids in hydrocarbon formations may be accessed via wellbores that extend down into the ground toward the targeted formations. In some cases, the hydrocarbon formations may have a lower viscosity such that crude oil flows from the formation, through production tubing, and toward the production equipment at the ground surface. Some hydrocarbon formations comprise fluids having a higher viscosity, which may not freely flow from the formation and through the production tubing. These high viscosity fluids in the hydrocarbon formations are occasionally referred to as “heavy oil deposits.” In the past, the high viscosity fluids in the hydrocarbon formations remained untapped due to the inability and expense of recovering them. More recently, as the demand for crude oil has increased, the commercial operations have expanded to the recovery of such heavy oil deposits.
In some circumstances, the application of heated fluids (e.g., steam) to the hydrocarbon formation may reduce the viscosity of the fluids in the formation so as to permit the extraction of crude oil and other liquids from the formation. The design of systems to deliver the steam to the hydrocarbon formations may be affected by a number of factors.
One such factor is the location of the steam generators. If the steam generator is located above the ground surface, steam boilers may be used to create the steam while a long tube extends therefrom to deliver the steam down the wellbore to the targeted formation. Because a substantial portion of the heat energy from the steam may be dissipated as the steam is transported down the wellbore, the requisite energy to generate the steam may be costly and the overall system can be inefficient. If, in the alternative, the steam generators are located downhole (e.g., in the wellbore below the ground surface), the heat energy from the steam may be more efficiently transferred to the hydrocarbon formation, but the amount of heat and steam generated by the downhole device may be limited by the size and orientation of the downhole steam generator and by constraints on the supply of water and fuels. Furthermore, installation of the downhole steam generators, including the attachment of supply tubes that provide water, air, fuel, or the like from the ground surface, may be complex and time consuming.
Some embodiments of a supply tube system for use in a wellbore may have multiple tubes—a number of which can be readily coupled to a downhole steam generator or other heated-fluid generator device. In certain embodiments, the system may include a connector that simplifies the process of coupling the supply tube system to the steam generator and provides for fluid communication between each supply conduit and the associated input port of the steam generator.
One aspect encompasses a method in which a heated-fluid generator device is lowered into a wellbore coupled to a first tube. The first tube supports at least a portion of a weight of the heated-fluid generator device while lowering the heated-fluid generator device into the wellbore. A second tube is coupled to the heated-fluid generator. One of the first and second tubes is disposed inside of the other tube to define a first fluid conduit inside of a second fluid conduit. At least one of the first tube and the second tube comprises a coiled tubing uncoiled from a spool and inserted into the wellbore.
Another aspect encompasses a method in which a heated-fluid generator device is lowered into a wellbore coupled to a first tube. The first tube supports at least a portion of a weight of the heated-fluid generator device while it is being lowered into the wellbore. The first tube is uncoiled from a spool as the heated-fluid generator device is lowered into the wellbore. A second tube is coupled to the heated-fluid generator such that one of the first and second tubes is nested within the other to define at least a portion of at least two fluid conduits.
Another aspect encompasses a system for generating heated fluid in a wellbore. The system includes a heated-fluid generator device disposed in a wellbore and adapted to output a heated fluid. A first and second tubes reside in the wellbore and are coupled to the heated-fluid generator. The first tube resides within the second tube so as to define a inner fluid conduit disposed within an intermediate fluid conduit. Both the inner and intermediate conduits are in fluid communication with the heated-fluid generator device. At least one of the first and second tubes comprises a coiled tubing.
These and other embodiments may be configured to provide one or more of the following advantages. First, the supply tube system may efficiently use the space within the wellbore to deliver fluids, such as water, air, and fuel, to the downhole heated-fluid generator device. For example, the supply tube system may comprise a plurality conduits that are substantially coaxial to one another—with the outermost conduit being at least partially defined by the wellbore casing. In such circumstances, the space within the wellbore may be efficiently used to deliver the fluids to the heated-fluid generator device. Second, the supply tube system may be partially coupled to the heated-fluid generator device before it is lowered into the wellbore. For example, at least one tube of the supply tube system may be coupled to the heated-fluid generator device above the surface while another tube is subsequently coupled to the heated-fluid generator device after it has been lowered into the wellbore. In such circumstances, the supply tube system may be readily coupled to the heated-fluid generator device and may facilitate the process of lowering the heated-fluid generator device into the wellbore. One or more of these and other advantages may be provided by the devices and methods described herein.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
Like reference symbols in the various drawings indicate like elements.
Referring to
In some instances, some or all of the casing 110 may be affixed to the adjacent ground material with a cement jacket 170 or the like. The casing 110 may comprise metallic material. The casing 110 may be configured to carry a fluid, such as air, water, natural gas, or to carry an electrical line, tubular string, or other device. In some embodiments, the well 100 may be completed with the casing 110 extending to a predetermined depth proximal to the formation 130. A locating or pack-off device such as a liner hanger 400 (when deployed in the wellbore 160) can grip and, in some instances, substantially seal about the end of the casing 110. In such circumstances, a heated-fluid generator device 200 may be deployed so that the heated-fluid generator device 200 outputs heated fluid through an apertured liner 210 coupled to the liner hanger 400. The output heated fluid is thus exposed to the hydrocarbon producing formation proximal to the formation 130.
Still referring to
In some instances, the formation 130 may be an injection formation in proximity of a producing formation, whereas the heated fluid injected into the formation 130 flows from the injection formation towards the producing formation, or through a combination of conduction and convection heats the fluids in the producing formation. The producing formation is intersected by a separate producing wellbore. The heated fluid reduces the viscosity of the hydrocarbon fluids in the producing formation, thus increasing the flowrate of the hydrocarbon fluids from the producing formation into the producing wellbore. In some instances the injection formation is above the producing formation, whereas gravity assists in bringing the heated injected fluid in contact with the producing formation. This configuration is often referred to as steam assisted gravity drainage (SAGD).
The heated-fluid generator device 200 may be in fluid communication with a supply tube system 140 having one or more supply tubes. As described in more detail below in connection with
Still referring to
Referring to
The intermediate tube 610 and inner tube 710 of the supply tube system 140 may comprise a metallic or other material. If used in supporting the heated-fluid generator 200 as it is deployed into or out of the wellbore 160, the material may have sufficient strength to support the heated-fluid generator device 200. The intermediate tube 610 and inner tube 710 may be configured to carry a fluid, such as air, water, or natural gas. In some instances, the intermediate tube 610 and/or the inner tube 710 may comprise coiled tubing, a tubing that is provided to the well site coiled on a spool and uncoiled prior to or as it is deployed into the wellbore 160 (refer, for example, to
If not coiled tubing, the intermediate tube 610 and/or inner tube 710 may comprise other types of tubulars. For example, the intermediate tube 610 and/or inner tube 710 may comprise a string of consecutive jointed tubes that are attached end-to-end. Such a string of tubes may be used, for example, in embodiments that require tube walls having a thickness or diameter that would render providing the coiled tubing as undesirable, impractical, or impossible. The intermediate tube 610 and/or inner tube 710 may comprise helically wound steel tube umbilical or electrohydraulic umbilical tubing. The umbilical tubing can be provided with metallic wire, fiber optic, and/or hydraulic control lines, for example, for conveying power or signals between the heated-fluid generator 200 and the surface. Also, the intermediate tube 610 and inner tube 710 can be different types of tubes. For example, in one instance, the larger diameter intermediate tube 610 may be jointed tubing, while the inner tube 710 is coiled or umbilical tube.
In this embodiment, the intermediate tube 610 passes through an interior of the casing 110 and the resulting annulus between the casing 110 and the intermediate tube 610 at least partially defines an outer conduit 115. When the intermediate tube 610 is secured to the connector 500, the outer conduit 115 may be in fluid communication with ports 560 of the connector 500 (described in more detail below in connection with
In this embodiment, the inner tube 710 passes through an interior of the intermediate tube 610 and the resulting annulus between the inner tube 710 and the intermediate tube 610 at least partially defines an intermediate conduit 615. The inner tube 710 defines an inner conduit 715 therein. As such, the outer conduit 115 may have an annular configuration that surrounds the intermediate conduit 615, and the intermediate conduit 615 may have an annular configuration that surrounds the inner conduit 715.
Electric or hydraulic control lines may be disposed within one of the conduits, such as the inner conduit 715, intermediate conduit 615 or the outer conduit 115. For example, the electric or hydraulic control lines may be disposed in the conduit 115, 615, or 715 that passes air or other oxygenated gas to the heated-fluid generator 200. The electric of hydraulic control lines may be capable of conveying power or signals between the heated-fluid generator 200 and other equipment on the surface 150.
One or more of the supply tubes 610, 710 may comprise centralizers that are adapted to maintain the tubes in a substantially coaxial position. The centralizers may comprise spacers that extend in a radial direction so as to maintain proper spacing between the tubes. Alternatively, one or more tubes may be self-centralizing when the tubes are coupled to the heated-fluid generator device 200 inside the wellbore (described in more detail below).
While the intermediate tube 610, inner tube 710, connector 500 and/or heated-fluid generator device 200 can be assembled to one another in any order, on the surface or in the wellbore, in some embodiments the intermediate tube 610, connector 500, and heated-fluid generator device 200 may be assembled at the surface before being lowered into the wellbore 160. The intermediate tube 610 may include threads 622 or another mechanical engagement device adapted to seal and secure the intermediate tube 610 with connector 500. When the intermediate tube 610 is secured to the connector 500, the intermediate conduit 615 may be in fluid communication with ports 570 of the connector 500. As such, fluid may be supplied from the intermediate conduit 615, through the intermediate ports 570 and to the corresponding input of the heated-fluid generator device 200.
A stinger/seal assembly 720 may be disposed at the lower end of the inner tube 710 so that the inner tube may be readily connected with the connector 500 downhole. For example, the inner tube 710 with the stinger/seal 720 assembly may be lowered into the wellbore 160 inside of the intermediate tube 610 until a stab portion 722 of the stinger/seal assembly 720 engages an inner receptacle 522 of the connector 500. In such circumstances a latch mechanism 730 of the stinger/seal assembly 720, for example outwardly biased or adjustable dogs, may join with a mating groove 524 in the receptacle 522 so as to secure the position of the inner tube 710 relative to the connector 500. In this embodiment, stinger/seal assembly 720 may include a seal 740 that substantially seals against the wall of the connector 500 to prevent fluid in the inner conduit 715 from seeping past the stinger/seal assembly 720 into the intermediate conduit 615. When the inner tube 710 is joined with the connector 500, the wall of the inner tube 710 may act as a divider, thus providing two distinct fluid paths (e.g., the inner conduit 715 and the intermediate conduit 615) inside the intermediate tube 610. The inner conduit 715 may be substantially cylindrical and in fluid communication with an inner port 580 of the connector 500. As such, fluid may be supplied from the inner conduit 715, through the inner port 580 and to the input of the heated-fluid generator device 200.
As previously described, the connector 500 joins the heated-fluid generator device 200 to the supply tube system 140. The connector 500 may have a circumferential seal 510 that substantially seals against the polished bore receptacle 450 to prevent fluid from seeping between the outer surface of the connector 500 and the receptacle 450. In some circumstances, the seal 510 may be configured to maintain the seal between the surfaces at high operating temperatures. Furthermore, the connector 500 may include threads 440 or another mechanical engagement device to couple with the heated-fluid generator device 200. As such, the connector may be coupled to the heated-fluid generator device 200 at the surface and then collectively lowered into the well as the threads 440 secure the heated-fluid generator device 200 to the connector 500.
Still referring to
In this embodiment, the connector 500 is configured to be at least partially received in the polished bore receptacle 450 of the liner hanger 400. For example, the connector 500 may include at least one locating shoulder 550 (sometimes referred to as a no-go shoulder). The locating shoulder 550 may be configured to rest upon a mating shoulder 452 of the polished bore receptacle 450. As such, the shape of the polished bore receptacle 450 may centralize the position of the connector 500 as the device 500 is lowered into the liner hanger 400. As previously described, the circumferential seal 510 of the self centralizing connector 500 substantially seals against the polished inner wall of the polished bore receptacle 450 to prevent fluid in the outer conduit 115 from seeping past the threads 440.
Referring now to
In some embodiments, the outer ports 560 may feed a fluid from the outer conduit 115 to the input of the heated-fluid generator device 200. Also, the intermediate ports 570 may feed another fluid from the intermediate conduit 615 to the input of the heated-fluid generator device 200. Furthermore, the inner port 580 may feed a third fluid from the inner conduit 715 to the input of the heated-fluid generator device 200. In one instance, the heated-fluid generator device 200 is a steam generator, the outer conduit 115 can contain water, the intermediate conduit 615 air, and the inner conduit 715 fuel (e.g. natural gas). In other instances where the heated-fluid generator device 200 is a steam generator, depending on the specifics of the application, the outer conduit 115 can contain air or fuel, the intermediate conduit 615 water or fuel, and the inner conduit 715 water or air.
In operation, the supply tube system 140 and the heated-fluid generator device 200 may be deployed into the wellbore 160 separately or partially assembled. Referring to
After the intermediate tube 610 and the heated-fluid generator device 200 are coupled to one another via the connector 500, the method 800 may further include the operation 815 of lowering the intermediate tube 610 and the heated-fluid generator device 200 into the wellbore 160. As previously described, the intermediate tube 610 may comprise a continuous metallic tubing that is uncoiled at the surface 150 as the intermediate tube is lowered into the wellbore 160. In such instances, the continuous metallic tubing may be plastically deformed from a coiled state to an uncoiled state (e.g., generally straightened or the like) as the intermediate tube is lowered into the wellbore 160. The wall thickness and material properties of the intermediate tube 610 may provide sufficient strength to support at least a portion of the weight of the heated-fluid generator device as it is lowered into the wellbore.
When heated-fluid generator device 200 is lowered to a position proximal to the formation 130, the method may include the operation 820 of aligning and coupling the heated-fluid generator device 200 to the liner hanger 400. For example, the heated-fluid generator device 200 may be aligned with and couple to the liner hanger 400 when the shoulder 550 of the connector 500 engages the polished bore receptacle 450 in the liner hanger 400. In some circumstances, the method 800 may also include the operation 825 of spacing out, landing, and packing off the intermediate tube 610 proximal to the ground surface 150. Such an operation may facilitate the deployment of the inner tube 710 from the ground surface 150 and through the intermediate tube 610.
The method 800 may further include the operation 830 of lowering the inner tube 710 into the wellbore 160 inside the intermediate tubing 610. As previously described, the inner tube 710 may comprise continuous metallic tubing having a smaller diameter than that of the intermediate tube 610 (refer, for example, to
When the inner tube 710 reaches the appropriate depth, the method 800 may include the operation 835 of coupling the inner tube 710 to the heated-fluid generator device 200. In some embodiments, the inner tube 710 may be coupled to the heated-fluid generator device 200 when the stinger/seal assembly 720 engages the connector 500 and the latch mechanism 730 engages the mating groove 524. As such, the wall of the inner tube 710 may separate the inner conduit 715 from the intermediate conduit 615.
The method 800 may also be used to supply fluids to the downhole heated-fluid generator device 200. As shown in operation 840, fluids (e.g., water, air, and fuel such as natural gas) may be supplied separately into an associated conduit 115, 615, and 715. For example, natural gas may be supplied through the inner conduit 715, air or oxygen gas may be supplied through the intermediate conduit 615, and water may be supplied through the casing conduit 115. The method 800 may also include the operation 845 of feeding the fluids (e.g., water, air, and fuel such as natural gas) inside the conduits 715, 615, 115 of the supply tube system 140 into the heated-fluid generator device 200. For example, the air and natural gas may be used in a combustion process or a catalytic process, which heats the water into steam. The method 800 may also include the operation 850 of applying the heated fluids (e.g., steam) to at least a portion of the formation 130. As previously described, the heated-fluid generator device 200 may be disposed in the wellbore so that the exhaust port 210 is proximal to the formation 130. When the water is converted into steam by the downhole heated-fluid generator device 200, the steam may be applied to the formation 130 as it is output from the port 210.
It should be understood that the supply tube system 140 and the heated-fluid generator device 200 may be coupled and lowered into the wellbore 160 using methods other than those described in
A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.
