WELL STIMULATION APPARATUS AND A METHOD OF USE THEREOF
The present disclosure relates to a well-stimulation apparatus with one or more elongated tie rods, at least one sealing assembly coupled to the one or more tie rods, and a stimulation material for generating a pressure event. The pressure event can stimulate a targeted portion of a geological formation that is positioned about an isolated portion of the wellbore. The pair of sealing assemblies are actuatable between a dormant condition for moving the well-stimulation apparatus in a wellbore and an active condition for defining the isolated portion of the wellbore.
The present disclosure relates generally to an apparatus, system and method for stimulating a targeted portion of a geological formation that is proximal to a well. In particular, the present disclosure relates to an apparatus, system and method that can create a sealed portion of a wellbore and that uses fluids to stimulate the targeted portion of the geological formation that is proximal the sealed portion of the well.
BACKGROUNDWell stimulation is a process that is used in oil and gas industry for collecting and extracting fluids, such as hydrocarbons, from a subterranean geological-formation. Well stimulation facilitates a production of fluids from the subterranean geological-formation and it may include the steps of perforating any wellbore tubulars, fracturing the geological formation, injecting fluids into the geological formation, and/or other stimulation operations.
Known hydraulic well-stimulation operations first isolate of a portion of the wellbore with one or more isolation mechanisms. The isolated portion of the wellbore is proximal to a region of the geological-formation that is targeted for stimulation. Next fluids are injected from the surface at high pressures for stimulating the targeted region of the formation through the isolated portion of the wellbore. After stimulation, the isolation mechanisms are deactivated, and a next wellbore portion may be isolated for stimulation. Hydraulic fracturing faces many challenges including but not limited to: long lead times to build enough pressure to cause stimulation, for example typical hydraulic fracturing operations require 10 to 100 minutes for building adequate pressure; large volumes of water are required, for example 5 million gallons of water per well can be a typical water usage; and large amounts of proppant are required, for example 300, 000 pounds to 4, 000, 000 pounds of sand can be required. Furthermore, the fractures generated during hydraulic well-stimulation operations can be limited to two radial opposed fractures within the isolated portion of the wellbore.
Propellant-based or gas-based well stimulation is also known. For example, a gas-based well stimulation creates a pressure event by generating a high-pressure gas that flows from the well to stimulate the targeted region of the formation. However, many known gas-based stimulation operations are restricted to vertical well sections, the pressure event is of a short duration and the pressure event is typically not focused within the desired target area of the geological formation. These characteristics of known gas-based stimulation operations can result in an ineffective stimulation.
SUMMARYThe embodiments of the present disclosure relate to an apparatus, system and method that create a pressure event within an isolated region of a well. The pressure event is of sufficient amplitude and duration that it can be used to stimulate a targeted region of a geological formation.
Some embodiments of the present disclosure relate to a well-stimulation apparatus that comprises: a tie rod with a first end and a second end; a stimulant-material container that is configured to be secured about the tie rod; and a sealing assembly that is couplable to the first end of the tie rod, the sealing assembly being actuatable between a dormant condition and an active condition for isolating a portion of a wellbore.
Without being bound by any particular theory, the embodiments of the present disclosure avoid the use of large volumes of water and proppant that are typically required of other known stimulation operations. Furthermore, the embodiments of the present disclosure create a pressure event by deflagrating a stimulant and focusing that pressure event from within the isolated portion of the wellbore into the target region of the geological formation so that new fractures can be created along with opening up of existing low-cohesion fractures and high-cohesion fractures. The embodiments of the present disclosure can be used to stimulate new wells, wells that require re-entry and even wells with damaged completions.
Furthermore, the embodiments of the present disclosure may provide further benefits such as, but not limited to: retaining and focusing a pressure-event from within an isolated portion of the wellbore into a target region of the geological formation; tailoring a profile of the pressure event to meet desired specifications or requirements; maintaining the position and integrity of apparatus within the isolated portion of the wellbore during the pressure event; sealing a portion of the well without exclusively relying on elastomeric materials; and positively locating the sealing elements in relation to one another without damaging or jamming other portions of the wellbore.
Embodiments of the present disclosure relate to an apparatus and a system that includes the apparatus. The apparatus and system can be used for isolating a portion of a well, which may also be referred to as a wellbore, and for stimulating a target region of a geological formation that is proximal to the isolated portion with a pressure event. The apparatus and system are configured to generate the pressure event by deflagrating stimulant materials and focusing the energy of the pressure event into the target region. The pressure event may be tailored to meet predetermined requirements to affect a desired stimulation of the target region of the geological formation.
In some embodiments of the present disclosure, the apparatus comprises one or more tie rods that are fixed at each end to one or more sealing-elements. The one or more tie rods maintain a substantially constant distance between the opposing sealing-elements during the pressure event.
In some embodiments of the present disclosure, the apparatus comprises a plurality of stacked, actuatable sealing elements. The sealing elements may be dry or, optionally, coated with a viscous and/or deformable sealing material such as a grease. The sealing elements may be actuated between a sealing position and a non-sealing position. The sealing position may also be referred to herein as the active condition and this position is useful for forming an imperfect fluid-tight seal against an inner surface of the well. The person skilled in the art will appreciate that when this seal is formed, while the sealing elements are in active condition, some fluids and/or energy from the pressure event may escape therepast. Permitting some fluids and/or energy to escape past the sealing elements provides a relief that may avoid causing damage to the apparatus or the wellbore the apparatus is positioned within. However, when the sealing elements are in the active condition they focus the fluids and/or energy from the pressure event into the target region for stimulation thereof. As described further below, the active condition may be a temporary condition. The non-sealing position may also be referred to herein as a dormant condition and this position may be useful for when the apparatus and/or the system are moved within the wellbore.
In some embodiments of the present disclosure, the sealing elements may be actuated to the active condition by an actuation body such as, but not limited to: an actuation gas-generator, a hydraulic-pressure driven mechanism, a pneumatic-pressure driven mechanism, a mechanical mechanism such as a spring, an electric motor, an electric solenoid, or combinations thereof. The sealing elements may be maintained in the active condition by a high-pressure gas that is generated during the pressure event by deflagrating a stimulant material that is housed by the apparatus. The sealing elements may return to the non-sealing position by a passive mechanism or: a further gas-generator, a hydraulic-pressure driven mechanism, a pneumatic-pressure driven mechanism, a mechanical mechanism such as a spring, an electric motor, an electric solenoid, or a combination thereof.
The wellsite 100 comprises a wellbore 102 formed under a rig 104 and extending down from the surface into a subterranean formation 106. The wellbore 102 may be a vertical wellbore as shown in
A line from surface 108 extends from the surface into the wellbore 102 and is connectible at one end to one or more well-stimulation apparatuses 120. In some embodiments of the present disclosure, the line 108 is a conduit for conducting fluids between the surface and proximal the one or more well-stimulation apparatus 120. Some examples of the types of conduit include, but are not limited to: jointed pipe and coiled tubing. In some embodiments of the present disclosure, the line 108 comprises one or more conductors for transmitting electrical information between the surface and the one or more well-stimulation apparatuses 102. Some examples of the types of wires include wireline, slick line and electrical line. In some embodiments of the present disclosure, the line 108 comprises both a conduit and a wire. The line 108 is connectible to one or more well-stimulation apparatuses 120 that are each located at a desired location in relation to the subterranean formation 106. Each well-stimulation apparatus 120 comprises two sets of sealing elements 122 about the two opposite ends thereof for isolating a portion of the wellbore 102. The apparatus 120 further comprises a gas-generator assembly 126 that can create a pressure event by generating a flow of high-pressure fluid 124. The high pressure-fluid flows from the sealed portion of the wellbore 102 radially outwardly to stimulate a targeted region of the subterranean formation 106 that is in proximity to the sealed portion.
Referring to
As shown in
In some embodiments of the present disclosure, an optional machine screw 138 may be used to further fasten each sealing assembly 128 to the tie rod 132. The machine screw 138 can help maintain the coupling between the tie rod 132 and the sealing assemblies 128 during operation of the well-stimulation apparatus 120 and in the event the fastener 136 fails.
In some embodiments of the present disclosure, the tie rod 132 may have a length suitable for isolating a wellbore portion as needed. In some other embodiments, the length of the tie rod 132 may be designed depending on how much stimulant material will be used and/or other well characteristics. In other embodiments of the present disclosure, the apparatus 120 may be provided with more than one tie rod 132 of the same or different lengths. An operator may select a tie rod 132 with a desired length when assembling the well-stimulation apparatus 120 on a wellsite 100.
The tie rod 132 establishes the positions of the sealing assemblies 128 relative to each other and, therefore, the tie rod 132 is considered to facilitate positive locating of the sealing elements 122 to define the isolated portion of the wellbore 102. The tie rod 132 prevents the sealing assemblies 128 from moving under the forces generated during the pressure event. The tie rod 132 may further serve as a support structure for the stimulant-material container 134.
As shown in
In some embodiments of the present disclosure the stimulant material 146 comprises a matrix in which a fuel or a mix of a fuel and an oxidizer can be embedded. The stimulant material 146 is preferably stable at or below the temperature (less than about 100° C.) and pressure (less than about 2000 psi) that are typically found within the wellbore 102.
In some embodiments of the present disclosure, the matrix is a polymer-based binder that is selected from, but not limited to: polysulfides; polybutadieneacrylic acids; polybutadiene-acrylonitriles; polyurethanes; carboxyl-terminated polybutadienes; hydroxyl-terminated polybutadienes; polyvinyl chlorides; acrylonitrile-butadiene-styrenes or combinations thereof. In some embodiments of the present disclosure, the preferred matrix comprises hydroxyl-terminated polybutadienes.
In some embodiments of the present disclosure the fuel may be: a metal, a non-metal or combinations thereof. For example, the metal may be one or more of, but is not limited to: aluminum, magnesium, zinc, iron or copper. The non-metal may be, but is not limited to: boron, silicon or combinations thereof. The fuel may be in a powdered form or not. The fuel may be a compound, an alloy or combinations thereof.
In some embodiments of the present disclosure the oxidizer may be: an oxygen donating salt; an inorganic perchlorate compound, such as ammonium perchlorate or potassium perchlorate; an inorganic nitrate, such as ammonium nitrate or potassium nitrate, a nitraminde, such as cyclotrimethylene trinitramine, or cyclotetramethylene, or combinations thereof. In some embodiments of the present disclosure, the preferred oxidizer is ammonium perchlorate.
In some embodiments of the present disclosure the matrix and the fuel may be the same component of the stimulant material 146. For example, this component may be polyester based, such as polystyrene or polypropylene; cellulose based such as nitrocellulose; or some other form of energetic polymer. In these embodiments, the stimulant material 146 comprises an oxidizer and a combined, single fuel/matrix component.
Optionally, the stimulant material 146 may also comprise other components such as, but not limited to: a hardening agent; a curing agent; a burn-rate catalyst; a burn-rate inhibitor or combinations thereof.
As one skilled in the art will appreciate, there are various forms of the stimulant material 146 that are suitable but not specifically named herein.
In some embodiments of the present disclosure deflagrating the stimulant material can generate the pressure event with a peak pressure of between about 10, 000 psi and 50, 000 psi. In some embodiments of the present disclosure the pressure event can have a peak pressure between about 15, 000 psi and 40, 000 psi. In further embodiments of the present disclosure the pressure event can have a peak pressure between about 20, 000 psi and about 30, 000 psi. In some embodiments of the present disclosure the time to build to the peak pressure (which is also referred to as “pressure rise time” herein) is between about 10 milliseconds to about 1000 milliseconds. In some embodiments of the present disclosure, the total duration of the pressure event is between about 10 milliseconds and 20 seconds.
As shown in
In some embodiments of the present disclosure, the outer wall 144 of the stimulant-material container 134 is a wall that is at least partially consumable. For example, the outer wall 144 may comprise a thin layer of plastic, metal, or the like, that may be broken, disintegrated, consumed or otherwise at least partially consumed by the flow of high-pressure gas when the stimulant material 146 is ignited and deflagrates. Partial or complete consumption of the outer wall 144 allows the generated high-pressure gas to flow out of the stimulation gas-generator assembly 126 with minimal impediment. In other embodiments of the present disclosure, the outer wall 144 may be made of a rigid material such as steel, and comprise a plurality of holes for the generated high-pressure gas to flow therethrough.
The mandrel 152 may define an aperture 164 adjacent the fastener 136 for receiving a bolt member 138 (see
On the outer surface the mandrel 152 comprises a stop shoulder 170 that extends radially outwardly from the second end 158 thereof for supporting one end of a spring 192 (described further below). The outer surface of the mandrel 152 also defines a circumferential recess 172 near the second end 158, and with circumferential radial edges 174 that may be angled towards the first end 156. At least two sealing elements 122 are stacked within the circumferential recess 172 offset from each other. The sealing elements 122 are configured to be actuated between the dormant condition and the active condition for establishing the isolated portion of the wellbore 102. To actuate the sealing elements 122 between the dormant condition and the active condition an outer edge 182 (shown in
Optionally, the outer surface of the mandrel 152 may also include two or more centralizing members 153 that are each configured to extend outwardly from the outer surface of the mandrel 152 and engage an inner surface of the wellbore 102 or an inner surface of casing that may be positioned between the mandrel 152 and the inner surface of the wellbore 102. While the drawings only show one centralizing member 153, the person skilled in the art will appreciate that at least two centralizing members 153, or preferably three or more, are required to centralize the mandrel 152 and, therefore, the well-stimulation apparatus 120 within the wellbore 102. The person skilled in the art will appreciate that various types mechanisms can be used to cause the centralizing members 153 to extend outward, including but not limited to: a hydraulic-pressure based mechanism, a pneumatic-pressure based mechanism, a mechanical mechanism such as a spring, electric motor, electric solenoid, or a combination thereof.
The sealing elements 122 are made of a material or materials that are suitable for bearing the pressure generated during the pressure event. In some embodiments of the present disclosure the sealing elements 122 may be dry or coated with a viscous sealing material such as grease, when being installed on the mandrel 152. In some embodiments of the present disclosure, the sealing elements 122 are made of 4140 steel. However, those skilled in the art will appreciate that the sealing elements 122 may be made of any suitable material such as, but not limited to: a metal, a metal alloy, a ceramic, an elastomer, or combinations thereof.
In some embodiments of the present disclosure, all of the sealing element 122A through to the sealing element 122F are made of a rigid material. In some embodiments of the present disclosure, all of the sealing element 122A through to sealing element 122F are made of the same material that is a flexible material, an elastic material or combinations thereof. In some embodiments of the present disclosure, the sealing element 122A through to the sealing element 122F are made of the same material, or not. In some embodiments of the present disclosure, the sealing elements 122A and 122F are made of the same first material and the sealing elements 122B through to sealing element 122E are made of one or more materials. In these embodiments, the first material is more rigid than the one or more materials. In some embodiments of the present disclosure, the sealing element 122B is made of a material that is less rigid than the material or materials of the other sealing elements 122A and 122C through 122F are made of.
As shown in the embodiments of
Referring to
Referring again to the non-limiting embodiment shown in
The sealing assembly 128 also comprises an actuation assembly 200 for overcoming the biasing force of the biasing assembly 190 and actuating the sealing elements 122 to the active condition. As shown in
The actuation-propellant chamber 208 is configured to be in fluid communication with one or more gas channels 212 and therethrough with an interior plenum of the piston housing 202. So that when ignited, the actuation propellant will deflagrate and generate a pressurized gas that can flow through the one or more gas channels 212, through the interior plenum and act against a face of the piston 204. Optionally, the actuation-propellant chamber 208 comprises a burst disc 210 that retains the actuation propellant within the actuation-propellant chamber 208 until such time that a pressure within the actuation-propellant chamber 208 exceeds the pressure rating of the burst disc 210. In some embodiments of the present disclosure the one or more pistons 204 can be a single annular piston that extends within a similarly annular piston housing 202 about an outer surface of the sealing assembly 128. In these embodiments, the interior plenum also extends annularly about the outer surface of the sealing assembly 128.
Referring again to
Referring now back to
As described above, the sealing elements 122 are conditioned at the acute angle of attack β facing the center of the well-stimulation apparatus 120 to engage the casing or the wall of the wellbore 102. Such a configuration provides an advantage that the casing or the wall of the wellbore 102 supports the sealing elements 122 against the high pressure applied thereto.
In some embodiments of the present disclosure, the actuation of the sealing elements 122 by the actuation pressure event and the pressure event created by the gas-generator assembly 126 occur at about the same time or the actuation pressure event may occur earlier. The actuation gas is released after the sealing elements 122 are configured to the angle of attack β (i.e., to the active condition). The pressure event generated by the stimulation gas-generator assembly 126 may facilitate and maintain the sealing elements 122 in at the angle of attack β during the stimulation process of the isolation wellbore portion.
After stimulation, the pressure in the isolated wellbore portion is reduced with the high-pressure gas being released into the formation 106. The biasing assembly 190 then forces the sealing elements 122 to move back to the angle of repose α, thereby configuring the well-stimulation apparatus 120 to the dormant condition.
As described above, one or more well-stimulation apparatuses 120 may be used for well stimulation. A controller is used for controlling the ignition of the stimulant material and the actuation propellant in each well-stimulation apparatus 120. In some embodiments, fluid pressure may be used for triggering the controller to sequentially activate each well-stimulation apparatus 120 in a desired timing pattern. The switching pressures (described in more detail herein below) are provided by pumping down fluid from the surface through the line 108. In these embodiments, the switching pressures may be any suitable pressures such as between the ambient pressure and about 10, 000 psi. In some alternative embodiments, the switching pressures are between ambient and about 20, 000 psi. In some other embodiments, the switching pressures are between ambient and about 25, 000 psi. In some other embodiments, the switching pressures are between ambient and about 50, 000 psi.
As shown in
In operation, a fluid is directed through the line 108 to the controller 234. The fluid applies a pressure P to the controller 234 with P2>P>P1 to close switch 238A. The actuation-activation devices 214 and the simulation-activation device 148 of the well-stimulation apparatus 120A is activated. As a result, the sealing elements 122 of the well-stimulation apparatus 120A are actuated to form the isolated portion of the wellbore 102. At substantially the same time, or later, the stimulation gas-generator assembly 126 generates the pressure event defined by the flow of high-pressure gas into the formation 106 within the isolated portion of the wellbore 102.
Then, the fluid pressure P is increased to P3>P>P2 to close switch 238B. As a result, the sealing elements 122 of the well-stimulation apparatus 120B are actuated and seal the wellbore portion, and the stimulation gas-generator assembly 126 thereof generates high-pressure gas to stimulate the formation 106 about the sealed wellbore portion.
Then, the fluid pressure P is further increased to P>P3 to close switch 238C. As a result, the sealing elements 122 of the well-stimulation apparatus 120C are actuated and seal the wellbore portion, and the stimulation gas-generator assembly 126 thereof generates high-pressure gas to stimulate the formation 106 about the sealed wellbore portion.
In some embodiments of the present disclosure the wiring and the ignition circuit are usually destroyed after the activation of a well-stimulation apparatus 120, but there is a risk that short-circuit may still occur, thereby causing damage to the controller 234 and/or other well-stimulation apparatus 120. In some alternative embodiments, such a risk may be prevented by including time delay fuses in the controller 234, which will open the circuit after a pre-determined period of time.
In
Switch 238A is connected to the power source 236 and the common terminal of switch 238B. The normally-closed terminals of switches 238B and 238C are connected to the ignition units 232A and 232B. The normally-open terminal of switch 238B is connected to the common terminal of switch 238C. The normally-open terminal of switch 238C is connected to the ignition unit 232C.
As shown in
In some embodiments shown in
In some embodiments of the present disclosure, the controller 234 is at the surface and is wired to the well-stimulation apparatuses 120 through the line 108. An operator may manually operate the controller 234 for well stimulation. Alternatively, the controller 234 may be programmed to automatically control the apparatus 120.
In some alternative embodiments as shown in
One of the two coupling portions 266 is used for coupling the knuckle connector 262 to the line 108 and the other is used for coupling the knuckle connector 262 to a well-stimulation apparatus such as the well-stimulation apparatus 120 described above.
The knuckle connector 262 provides flexibility in positioning the well-stimulation apparatus 120 relative to the line 108 when one is misaligned from the other. As shown in
In some situations, as shown in
In some situations, as shown in
In some embodiments of the present disclosure, the knuckle connector 262 is a separate component from the apparatus 120. In some alternative embodiments, the knuckle connector 262 may be an integrated portion of the apparatus 120. In these embodiments, the well-stimulation apparatus 120 is rotatably coupled to the central portion 264 via a first u-joint 268. The central portion 264 is rotatably coupled to a coupling portion 266 via a second u-joint 268. Therefore, the well-stimulation apparatus 120 may be coupled to line 108 or other subs via the coupling portion 266. In some embodiments of the present disclosure, the knuckle connector 262 may be an integrated portion of the line 108.
As will be appreciated by those skilled in the art the knuckle connector 262 is not limited to hinged connections and other types of flexible connections that can compensate between a misaligned position of the line 108 relative to the well-stimulation apparatus 120 are useful.
In some embodiments of the present disclosure, the sealing elements 122 are first actuated to form the isolated portion of the wellbore 102, and then the stimulation gas-generator assembly 126 is activated to generate the high-pressure gas for stimulating the isolated portion of the wellbore 102.
In some embodiments of the present disclosure, the actuation gas is not maintained after it actuates the sealing elements 122 to their active condition. In some alternative embodiments, the actuation gas behind the pistons 204 is maintained during the stimulation process to maintain the sealing elements 122 in the active condition, and then the pressure generated by the actuation gas is released for articulating the well-stimulation apparatus 120 into the dormant condition.
In some embodiments of the present disclosure, the sealing elements 122 are actuated by using the actuation gas generated by the actuation body 154. In some alternative embodiments, the sealing elements 122 may be actuated by other types of actuation mechanisms including, but not limited to: a hydraulic-pressure based mechanism, a pneumatic pressure based mechanism, a mechanical mechanism such as a spring, electric motor, electric solenoid, or a combination thereof.
In some embodiments of the present disclosure, the spring 192 is used for biasing the sealing elements 122 to the dormant condition. In some alternative embodiments, the sealing elements 122 may be biased to the dormant condition by multiple springs, or by other mechanisms such as a gas generator, a hydraulic-pressure based mechanism, a pneumatic-pressure based mechanism, a mechanical mechanism such as a spring, electric motor, electric solenoid, or a combination thereof.
In some embodiments of the present disclosure, the electrical ignition circuit 232, including the electrical actuation-activation devices 214 and the electrical stimulation-activation device 148, are used for well stimulation. In some further embodiments, other means such as pressure-activated firing heads, explosive primer cord, and the like, may be used for igniting the propellant for actuating the sealing elements 122 and the stimulant material 146 for stimulating production of hydrocarbons from the geological formation 106 into the wellbore 102.
In some embodiments of the present disclosure, the stimulation gas-generator assembly 126 may comprise two or more tie rods 132 that are positioned within one stimulant-material container 134. In some other embodiments of the present disclosure, the stimulation gas-generator assembly 126 may comprise a plurality of tie rods 132 and one or more stimulant containers 134.
In some embodiments of the present disclosure, the stimulation gas-generator assembly 126 may comprise a single type of stimulant material 149, or a mixture of two or more types of materials. Similarly, the actuation body 154 may comprise a single type of propellant or a mixture of two or more types of propellants. Moreover, the stimulation gas-generator assembly 126 and the actuation body 154 may use the same propellant material and the same propellant mixture or different propellants and/or different propellant mixtures.
In some embodiments of the present disclosure, the controller 234 comprises a power source 236. In some alternative embodiments, the controller 234 does not comprise any power source. Rather, a power source 236 external to the controller 234 is used.
Table 1 below lists some non-limiting examples of dimensions of the above described well-stimulation apparatus 120 in some embodiments of the present disclosure for use in a 13.51b-4.5 inches wellbore casing (with an inner dimension (ID) of 3.92 inches):
Without being bound by any particular theory, the well-stimulation apparatus 120 described herein avoids the massive use of water for fracturing. Moreover, by using the well-stimulation apparatus 120, the rapid generation of high-pressure gas causes local disaggregation and shear dislocation along the fracture planes. Therefore, no proppant or sand is required.
Without being bound by any particular theory, the well-stimulation apparatus 120 described herein creates longer fractures through a longer deflagration time (for example between about 10 milliseconds to about 20 seconds), and is suitable for fracturing in horizontal wellbores. The well-stimulation apparatus 120 described herein substantially isolates a portion of the wellbore to focus the energy of the pressure event into the target portion of the geological formation. Moreover, a plurality of the apparatus 120 may be cascaded on a single line 108 for stimulating a plurality of wellbore zones in one run.
Table 2 below shows a comparison between the prior-art hydraulic fracking, the prior-art propellant-based fracturing, and the well-stimulation apparatus 120.
Claims
1. A well-stimulation apparatus comprising:
- a tie rod with a first end and a second end;
- a stimulant-material container that is configured to be secured about the tie rod; and
- a sealing assembly that is couplable to the first end of the tie rod, the sealing assembly being actuatable between a dormant condition and an active condition for isolating a portion of a wellbore.
2. The well-stimulation apparatus of claim 1, further comprising a second sealing assembly that is couplable to the second end of the tie rod.
3. The well-stimulation apparatus of claim 1, further comprising a fastener for coupling the first sealing assembly and the second sealing assembly to the first end and the second ends respectively of the tie rod.
4. The well-stimulation apparatus of either claim 1, wherein the stimulant-material container comprises one or more sleeves that are configured to receive stimulant material therein.
5. The well-stimulation apparatus of claim 4 wherein the stimulant material is deflagratable for generating a pressure event.
6. The well-stimulation apparatus of claim 5, wherein the tie rod is configured to bear a tensile load that is generated by the pressure event.
7. The well-stimulation apparatus of claim 5, wherein when the sealing assemblies are in the active condition, the pressure event is directed in a radial outward direction from the well-stimulation apparatus.
8. The well-stimulation apparatus of claim 5, wherein the pressure event has a peak pressure of between about 10, 000 pounds per square inch (psi) and 50, 000 psi.
9. The well-stimulation apparatus of claim 1, further comprising at least one stimulation-activation device for igniting the stimulant material.
10. The well-stimulation apparatus claim 1, wherein each of the first sealing assembly and the second sealing assembly comprises:
- a mandrel;
- a plurality of sealing elements positioned about the mandrel, each of the plurality of sealing elements comprises an outer edge that is configured to engage an inner wall of a wellbore or a tubular therein; and
- an actuation body for actuating the plurality of sealing elements to move from the dormant condition to the active condition.
11. The well-stimulation apparatus of claim 10, wherein the actuation body is at least one of: an actuation gas-generator, a hydraulic-pressure driven mechanism, a pneumatic-pressure driven mechanism, a mechanical mechanism such as a spring, an electric motor, an electric solenoid, and combinations thereof.
12. The well-stimulation apparatus of claim 10, wherein the plurality of sealing elements are stacked about the mandrel at an acute angle with respect to a longitudinal direction of the well-stimulation apparatus.
13. The well-stimulation apparatus of claim 10, wherein the plurality of sealing elements are swingable between an angle of repose α in the dormant condition and an angle of attack β>α in the active condition.
14. The well-stimulation apparatus of claim 13 wherein the angle of repose α is between about 0° and about 75°.
15. The well-stimulation apparatus of claim 13, wherein the angle of attack β is between about 10° and about 80°.
16. The well-stimulation apparatus of any claim 1, further comprising a knuckle that is couplable to one end of the well-stimulation apparatus, and the knuckle comprises:
- a central portion rotatably coupled to well-stimulation apparatus via a first joint; and
- a coupling portion rotatably coupled to the central portion via a second joint.
17. A sealing assembly for isolating a portion of a wellbore, the sealing assembly comprising:
- a plurality of sealing elements that are actuatable between a dormant condition and an active condition; and
- an actuation gas-generator for generating a gas flow for actuating the plurality of sealing elements from the dormant condition to the active condition.
18. A knuckle connector for coupling a first downhole apparatus to a second downhole apparatus, the knuckle connector comprising:
- a central portion rotatably coupled to a first joint and a second joint;
- a first coupling portion rotatably coupled to the central portion via the first joint; and
- a second coupling portion rotatably coupled to the central portion via the second joint.
19. A knuckle connector for coupling a first downhole apparatus to a line from surface, the knuckle connector comprising:
- a central portion rotatably coupled to having a first joint and a second joint;
- a first coupling portion rotatably coupled to the central portion via the first joint; and
- a second coupling portion rotatably coupled to the central portion via the second joint.
20. A well-stimulation system comprising:
- a plurality of n well-stimulation apparatuses for isolating a plurality of n downhole portions of a wellbore and stimulating the plurality of isolated wellbore portions, n being an integer greater than or equal to 1, and each well-stimulation apparatus comprising an activation circuit for activating at least a well stimulation process thereof; and
- a controller for controlling the activation circuits of the plurality of well-stimulation apparatuses, the activation circuits being numbered from downhole to uphole as the first, second,..., the n-th activation circuit;
- wherein the controller comprises n pressure-actuated switches, with the 0-th switch being a normally-open two-way switch and the first to the (n−1)-th switches being three-way switches,
- wherein the first terminal of the 0-th switch is connected to a power source and the second terminal thereof is connected to the common terminal of the 1st switch,
- wherein for the k-th switch (k being an integer and 0<k<n−1), the common terminal thereof is connected to the normally-open terminal of the (k−1)-th switch, the normally-closed terminal thereof is connected to the k-th activation circuit, and the normally-open terminal thereof is connected to the common terminal of the k-th switch, and
- wherein for the (n−1)-th switch, the common terminal thereof is connected to the normally-open terminal of the (n−2)-th switch, the normally-closed terminal thereof is connected to the (n−1)-th activation circuit, and the normally-open terminal thereof is connected to the n-th activation circuit.
21. The well-stimulation system of claim 20 wherein the m-th switch is switchable under a threshold switching pressure P_m, with m being an integer and 0≤m≤n−1; and wherein P_0<P_1<... <P_(n−1).
22. A method for stimulating a targeted portion of a geological formation, the method comprising steps of:
- isolating a portion of a wellbore that is proximal the target portion by actuating one or more sealing elements into an active condition;
- deflagrating a stimulant material for generating a pressure event; and
- focusing at least part of an energy of the pressure event into the targeted portion.
Type: Application
Filed: Sep 26, 2017
Publication Date: Oct 1, 2020
Inventors: Spencer Eric Freeman (Calgary), Michael Geoffrey Harcourt (Calgary)
Application Number: 16/650,752