Embodiments of the subject matter disclosed herein generally relate to downhole tools for perforating operations, and more specifically, to a casing string having one or more casing valves that are opened and closed with a hydraulic-powered setting tool for fracturing a desired formation.
After a well 100 is drilled to a desired depth H relative to the surface 111, as illustrated in
The typical process of connecting the casing to the subterranean formation may include the following steps: (1) placing a plug 112 with a through port 114 (known as a frac plug) above a just stimulated stage 116, and (2) perforating a new stage 118 above the plug 112. The step of perforating is achieved with a gun string 120 that is lowered into the well with a wireline 122. A controller 124 located at the surface controls the wireline 122 and also sends various commands along the wireline to actuate one or more gun assemblies of the gun string.
A traditional gun string 120 includes plural carriers 126 connected to each other by corresponding subs 128, as illustrated in
U.S. Pat. No. 6,763,892 discloses a different approach for fracturing a well, in which the individual casing tubes forming the casing string are provided with a corresponding sliding sleeve, i.e., a casing valve. The sliding sleeve can be opened or closed as desired with the help of a plurality of seals and ports. The fracturing of the formation around the casing can then be performed through the openings formed in the casing string.
However, this specific implementation is burdensome because the casing valve includes a number of individual components that are threaded to each other and use plural seals, which may fail and leak. In addition, this specific implementation cannot withstand the torque specifications of a typical wellbore casing because of the threaded components.
Thus, there is a need to provide a casing valve that can withstand the torque specifications in the wellbore casing, is not prone to leaks and is easy to open and close when a fracturing operation is desired.
According to an embodiment, there is a setting tool for opening and closing a sleeve inside a casing. The setting tool includes a body extending along a central longitudinal axis (X), a set of holding dogs located around the body, and a set of sleeve dogs located around the body. The set of sleeve dogs are configured to move along the central longitudinal axis (X) relative to the set of holding dogs.
According to another embodiment, there is system for fracturing a well. The system includes a casing having plural openings that are covered by a sleeve when the sleeve is in a close position, and a setting tool configured to open the sleeve for fracturing operations. The setting tool includes a body extending along a central longitudinal axis (X), a set of holding dogs located around the body, and a set of sleeve dogs located around the body. The set of sleeve dogs are configured to move along the central longitudinal axis (X) relative to the set of holding dogs.
According to still another embodiment, there is a method for fracturing a well. The method includes lowering a setting tool inside a casing having plural openings covered by a sleeve, engaging a set of holding dogs of the setting tool with a corresponding holding groove formed inside the casing, engaging a set of sleeve dogs of the setting tool with a corresponding sleeve groove formed in the sleeve, and opening the sleeve by translating the sleeve dogs along a central longitudinal axis X, relative to the holding dogs.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments. In the drawings:
The following description of the embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. The following embodiments are discussed, for simplicity, with regard to a casing having a valve and a hydraulic-powered setting tool that opens and closes the casing valve. However, the embodiments discussed herein are also applicable to a device that has a valve that needs to be closed and opened under tight conditions.
Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
According to an embodiment illustrated in
Plural casings 200A and 200B (only two are shown for simplicity, but a casing string may include tens or hundreds of casings) are shown in
To reveal the openings of the top casing of the casing string, a hydraulic-powered setting tool is placed into the well and controlled to attach to the sleeve of the casing. According to an embodiment illustrated in
Setting tool 400 also includes a first set of connecting elements 420, called herein holding dogs because these elements would engage corresponding grooves in the casing valve and fix the setting tool relative to the casing. The setting tool also includes a second set of connecting elements 430, called herein sleeve dogs because these elements would engage the sleeve of the casing valve and move it from the closed position to the open position and vice versa. The dogs are mechanical elements that mate with corresponding grooves formed in the body of the casing and/or the sleeve.
The setting tool 400 further includes a seal 440, located downstream from the first and second set of dogs. The setting tool 400 further includes an electronics module 450 and a fishing neck 452. The electronics module 450 includes various sensors, e.g., pressure transducer 454, velocity sensor 456, accelerometers, etc., that may be connected to a wireline for communicating and/or receiving various information to the surface. The hydraulic valve block 404 may include similar or additional sensors. In one application, the hydraulic valve block 404 includes a pressure transducer 408 and a power source 410. The power source 410 may include one or more batteries. In one application, the power source 410 includes about 100 AA lithium batteries. The hydraulic valve block 404 may also include a controller 412, that is connected to the various sensors noted above and which is configured to open and close one or more or the valves 406 so that a corresponding piston moves up and down the well.
In one application, the setting tool shown in
Once the sets of dogs are in position, they are attached to corresponding pistons (to be discussed later) and can be moved relative to the body of the casing, both toward or away (i.e., radially) from a central longitudinal axis X of the body and also along the central longitudinal axis X. To move the dogs radially along axis X, ramps are sliding under the dogs and the ramps are powered by the pistons noted above. The pistons in turn are actuated with hydraulics, provided through the valves 406. In one application, instead of using hydraulics and solenoids for actuating the pistons, it is possible to use electrical motors with power screws. The hydraulics energy is supplied by the pressure established inside the casing. For this reason, the setting tool includes one or more accumulators (e.g., spring-loaded accumulators) that can store enough hydraulic energy to open and close several casing valve sleeves. The setting tool may use solenoid valves 406 for reducing the electrical energy required to open and close the valves. These pistons are shown and discussed in the next figures.
A method for moving the setting tool inside the casing, engaging the holding dogs followed by the sleeve dogs, and opening the sleeve of the casing for fracturing operations is now discussed with regard to
In step 802, a top portion 420A (see
The movement of the pistons is controlled by the processor 412, valves 406, and at least an accumulator that stores hydraulic energy as now discussed. When the setting tool is approaching the top most casing, the operator of the setting tool may send a signal along the wireline to the processor 412 for moving the holding dogs along the radial direction. Upon receiving this command, processor 412 opens one of the valves 406, which corresponds to piston 424, and allows the pressurized fluid inside the accumulator to move the piston along the longitudinal axis X, as illustrated by the corresponding arrow in
In step 804, the sleeve dogs 430 are engaged with the corresponding sleeve grooves 226. Because controller 412 has determined that the setting tool has stopped and knowing that the holding dogs are engaged, it can instruct the sleeve dogs 430 to engage the sleeve groove 226. In this regard, note that in
In step 806, the sleeve 210 is opened as illustrated in
In step 808, the fracturing fluid is pumped from the casing and exits through aligned openings 212 and 214 into the formation 106, as indicated by arrow B in
When the fracturing operation is concluded for the current stage, the sleeve 210 needs to be moved back to the closed position, to close the sleeve openings 212. Thus, in step 810, the sleeve is closed. To instruct the controller 412 to close the sleeve, the following mechanism may be used. Suppose that the operator of the well has finalized the fracturing operation. The operator may send a signal to the controller 412 for closing the sleeve. The signal may be transmitted in various ways, i.e., as an electrical signal along a wire, as an acoustic signal with a modem, etc. The embodiment presented in
The controller 412 connects another valve 406 to the hydraulic pressure in the accumulator so that the second piston 438 moves in the opposite direction relative to the configuration shown in
After the sleeve 210 has been closed, it is time to move the setting tool to the next casing. To achieve this objective, the holding dogs 420 and the sleeve dogs 430 are disengaged in step 812 (or closed, i.e., retracted along the radial axis R toward the center axis of the setting tool), as illustrated in
In step 814, the operator pumps the setting tool 400 downward toward the next casing. The setting tool monitors its movement with its velocity sensor 456 (e.g., the velocity sensor may include one or more accelerometers). After a given distance D, which is calculated to be less than a distance from the openings 212 of one casing to the openings of an adjacent casing, the controller 412 is configured to open the holding dogs (i.e., to move the corresponding rams) so that the holding dogs catch and engage the holding groove of the next casing. This means that the process disclosed in
The setting tool needs now to be retrieved to the surface. For this action, a retrieval tool is sent in the well. The retrieval tool is configured to latch onto the fishing neck 452 of the setting tool 400. The retrieval tool may be attached to the wireline (or another line, e.g., slickline) to be lowered into the well. Once the retrieval tool latches on the fishing neck 452, the wireline is pulled up to bring to the surface the setting tool. The controller 412 of the setting tool, based on measurements received from the velocity sensor, determines that the setting tool is moving toward the surface and can instruct the valves 406 to actuate the corresponding pistons to make sure that the dogs sit at the bottom of the corresponding ramps, so that neither the holding dogs nor the sleeve dogs engage a corresponding groove in the interior wall of the casings.
In one embodiment, as shown in
In one embodiment, the setting tool may be used to open the sleeve of each casing valve while the setting tool moves from the bottom of the well toward the top so that well production can commence. For this situation, the holding dogs are open, i.e., the corresponding ramp is moved under the dogs to push them outward along the radial direction. The setting tool is moved upward with the wireline until the holding dogs engage a corresponding groove in a casing. The velocity sensors of the setting tool determine that the setting tool has stopped. The controller of the setting tool then instructs the sleeve dogs to engage the sleeve groove of the casing and open the sleeve. The casing sleeve is opened. Then all the dogs are disengaged and the setting tool can move upwards towards the next casing.
In one embodiment, it is possible that the setting tool gets stuck in a casing. In this situation, as shown in
A method for opening a sleeve of a casing and then fracturing a stage associated with the casing is now discussed with regard to
Another method for fracturing a well, with the setting tool discussed in the previous embodiments, is now discussed with regard to
In step 1602, the wiper plug is pumped down. When the wiper plug bottoms-out, the operator of the well will note a pressure spike at the surface. Then, in step 1604, the well is pressured up to test the casing string. If the pressure holds, then the operator applies more pressure to rupture the burst disk in the toe valve. At this time, the openings in the toe valve are opened and in step 1606, the stage associated with the toe valve is fractured. After the fracturing of this stage is completed, the well may be cleaned.
In step 1608, the setting tool 400 is inserted into the well and pumped down. Because the setting tool is moving only in water, there is less chance of getting stuck in the casing. The setting tool has a pressure transducer and a fluid velocity sensor at least at the top of the body. The setting tool has holding dogs that are spring-loaded open. However, they default to closed if there is a loss of power. The setting tool has a spring-loaded accumulator 480 with enough hydraulic energy to open and close several casing valve sleeves. The setting tool may use solenoid valves 406 to reduce the electrical energy required to activate the dogs. The accumulator 480 stores fluid under pressure and is configured to actuate a holding piston, a first sleeve piston and a second sleeve piston for moving the set of holding dogs and the set of sleeve dogs. In one application, the holding piston, the first sleeve piston and the second sleeve piston are concentric to each other.
The spring-loaded holding dogs latch in step 1610 into a profile (e.g., holding groove) in the first casing valve near its heel and holds the setting tool in position with its seal 440 under the casing valve. The well is now plugged and the operator of the well notices a pressure spike at this point.
In step 1612, the setting tool knows it stopped (because of the measurement received from the velocity sensor and/or pressure transducer) and is in position. In step 1614, the operator increases the casing's pressure to re-charge the hydraulics (e.g., accumulator 480) in the setting tool 400. In step 1616, the setting tool uses its stored energy to open the sleeve dogs and to open the casing valve's sleeve. Once the sleeve is open, the upper-most stage is fractured in step 1618. In step 1620, if the well sands out, the operator can cycle the flow to clear it up, because the setting tool is held below the flow, and not in the sand.
After finishing the fracturing operation, the operator sends in step 1622 a stop and start fluid flow pattern so that the setting tool recognizes as the “Finished Frac-ing Pattern” signal indicating that the fracturing operation has been concluded (if no signal is received, it times out based on a timer started by the controller 412). The setting tool closes in step 1624 the casing valve's sleeve, the setting tool's sleeve dogs, and then closes the setting tool's holding dogs. In step 1626, the operator pumps the setting tool to the next casing valve, still moving in water only. Next, the setting tool spring-opens the holding dogs and latch onto the next casing valve (i.e., repeats step 1610), and seals. The process repeats now the steps 1612 to 1626 of holding in position with the seal, pressurizing the casing to charge the setting tool, opening the sleeve, fracturing the current stage, closing the sleeve, closing the holding dogs, moving the setting tool to the next casing valve, spring-opening the holding dogs, latching to the next casing valve and so on.
When this process is completed, all of the stages are fractured and their sleeves are re-closed. The retrieval tool is pumped down in step 1628, on a Slickline, or a Wireline and latched onto the setting tool. The setting tool would be chased down to the toe valve. However, the fluid flow is allowed to go around the setting tool. The setting tool's holding dogs are still sprung open. The setting tool is pulled up the casing spring in step 1628 until the holding dogs latch to the lowermost casing valve. The well is again plugged. In step 1630, the operator pressures the well to charge the accumulator of the setting tool. In step 1632, the setting tool opens the casing valve's sleeve so that oil and/or gas from the formation can enter the casing. In step 1634 the setting tool closes its holding dogs and the setting tool is pulled up in step 1636 toward the next casing valve and the previous steps are repeated to open the next sleeve. In this way all the sleeves are open and the exploration of the well can commence as the oil and/or gas is now flowing through the openings into the well.
The method discussed above may be modified as now discussed. In one embodiment, instead of pumping the retrieval tool to the bottom of the well to hook it to the setting tool, the setting tool can be moved up-hole by using the flow-back of each of the stages. When the setting tool finishes opening the last casing valve, it closes its holding dogs and then can flow-back the well. The setting tool moves up toward the next casing valve. As the setting tool arrives at the next casing valve, the setting tool spring-opens the dogs and latches onto the next casing valve. Then, the setting tool opens the sleeve, and the operator pressures up the formation and the setting tool. Next, the setting tool closes the holding dogs and flows-back the well so that the setting tool moves upward. This process continues until the setting tool arrives at the last casing valve near the heel. After opening the last sleeve, the setting tool is kept latched to the casing valve and the retrieval tool is pumped in the vertical section of the well. After the retrieval tool is connected to the setting tool, the holding dogs of the setting tool are released from the groove of the casing, and both tools are retrieved from the well. Those skilled in the art would be able, having the benefit of this disclosure, to practice different variations of the methods discussed herein. Note that while the above embodiments have discussed using a wireline to convey the setting tool inside the well (or at least to retrieve the setting tool), it is possible to have the setting tool move autonomously inside the well, or to be attached at the end of a slickline or wire rope, or wireline, or coiled tubing or coiled tubing with wireline inside.
The setting tool discussed above may have the hydraulics implemented with solenoids for powering the holding dogs open and closed, and open and close the casing valve's sleeve. The holding dogs are configured to “Fail safe” in the closed position. The controller and sensors may be selected to work with “AA” lithium batteries. Thus, no high power electrical devices are used except for the solenoids. In one application, the setting tool would carry enough batteries for a 100 casing valve stages per run. In another application, the setting tool could carry enough batteries to complete the entire job, so that recharging is not required.
During pressurizing the casing, the upper pressure may move a piston in the setting tool that has check valves. This “pump” mechanism re-charges the hydraulic accumulator during every pressurization cycle.
“Time Based,” “Velocity Pattern Recognition,” or “Pressure Pattern Recognition” signals based communication is possible between the operator of the well and the controller of the setting tool. These types of communication are enhanced by the presence of the pressure transducers, fluid velocity sensor, and accelerometer. In one application, the setting tool may have an information storing device (e.g., a memory) for post-job analysis (as an example, it will know if all the sleeves were opened).
The setting tool may act as a moving, resettable plug, rated at 10,000 psi differential pressure, with dogs that open and close the casing valve's sleeves. In one application, the setting tool may be designed to have the upper section made of materials that are acid resistant. The setting tool may be designed for multiple jobs, with minimal maintenance.
One or more advantages of the setting tool discussed above are as follows:
The disclosed embodiments provide methods and systems for selectively actuating one or more casing valves in a casing string. It should be understood that this description is not intended to limit the invention. On the contrary, the exemplary embodiments are intended to cover alternatives, modifications and equivalents, which are included in the spirit and scope of the invention as defined by the appended claims. Further, in the detailed description of the exemplary embodiments, numerous specific details are set forth in order to provide a comprehensive understanding of the claimed invention. However, one skilled in the art would understand that various embodiments may be practiced without such specific details.
Although the features and elements of the present exemplary embodiments are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the embodiments or in various combinations with or without other features and elements disclosed herein.
This written description uses examples of the subject matter disclosed to enable any person skilled in the art to practice the same, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims.
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PCT/US2018/022841 | 3/16/2018 | WO | 00 |
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WO2019/027509 | 2/7/2019 | WO | A |
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