Patent Application
20140251609
Some oil and gas wells are completed in unconsolidated formations that contain loose fines and sand. When fluids are produced from these wells, the loose fines and sand can migrate with the produced fluids and can damage equipment, such electric submersible pumps (ESP) and other systems. For this reason, completions can require screens for sand control.
Horizontal wells that require sand control are typically open hole completions. In the past, stand-alone sand screens have been used predominately in these horizontal open holes. However, operators have also been using gravel packing in these horizontal open holes to deal with sand control issues. The gravel is a specially sized particulate material, such as graded sand or proppant, which is packed around the sand screen in the annulus of the borehole. The gravel acts as a filter to keep any fines and sand of the formation from migrating with produced fluids.
A prior art gravel pack system 20 illustrated in
Initially, operators position a wash pipe 40 into a screen 25 and pump the slurry of fluid and gravel down an inner workstring 45. The slurry passes through a port 32 in a crossover tool 30 and into the annulus between the screen 25 and the borehole 10. As shown, the crossover tool 30 positions immediately downhole from the gravel pack packer 14 and uphole from the screen 25. The crossover port 32 diverts the flow of the slurry from the inner workstring 45 to the annulus downhole from the packer 14. At the same time, another crossover port 34 diverts the flow of returns from the wash pipe 40 to the casing's annulus uphole from the packer 14.
As the operation commences, the slurry moves out the crossover port 32 and into the annulus. The carrying fluid in the slurry then leaks off through the formation and/or through the screen 25. However, the screen 25 prevents the gravel in the slurry from flowing into the screen 25. The fluids passing alone through the screen 25 can then return through the crossover port 34 and into the annulus above the packer 14.
As the fluid leaks off, the gravel drops out of the slurry and first packs along the low side of the borehole's annulus. The gravel collects in stages 16a, 16b, etc., which progress from the heel to the toe in what is termed an alpha wave. Because the borehole 10 is horizontal, gravitational forces dominate the formation of the alpha wave, and the gravel settles along the low side at an equilibrium height along the screen 25.
When the alpha wave of the gravel pack operation is done, the gravel then begins to collect in stages (not shown) of a beta wave. This forms along the upper side of the screen 25 starting from the toe and progressing to the heel of the screen 25. Again, the fluid carrying the gravel can pass through the screen 25 and up the wash pipe 40. To complete the beta wave, the gravel pack operation must have enough fluid velocity to maintain turbulent flow and move the gravel along the topside of the annulus. To recirculate after this point, operators have to mechanically reconfigure the crossover tool 30 to be able to washdown the pipe 40.
Although the alpha-beta technique can be economical due to the low-viscosity carrier fluid and regular types of screens that can be used, some situations may require a viscous fluid packing technique that uses an alternate path. In this technique, shunts disposed on the screen divert pumped packing slurry along the outside of the screen.
Prior art gravel pack assemblies 20 for both techniques of
To deal with gravel packing in some openhole wells, a Reverse-Port Uphill Openhole Gravel Pack system has been developed as described in SPE 122765, entitled “World's First Reverse-Port Uphill Openhole Gravel Pack with Swellable Packers” (Jensen et al. 2009). This system allows an uphill openhole to be gravel packed using a port disposed toward the toe of the hole.
In cased hole operations, it is very common to install multiple gravel pack installations in a process referred to as “stacked packs”. Each zone is addressed in a distinct operation to perforate it, install the gravel pack equipment, pump the gravel and then the process is repeated. Other multi-zone gravel pack systems have been developed that are generally referred to as single trip, multi-zone systems. These systems are of a conventional design in that they introduce slurry into the annulus outside the screen from the topside of the screen and pump fluid towards the bottom of the zone. Additionally, these systems have been specifically used for cased hole applications and have only recently been adapted for open hole applications.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
A multi-zone apparatus and method are used for treating a formation. The apparatus can be used for formation treatments, such as frac operations, frac pack operation, gravel pack operations, or other operations. The apparatus includes a body (e.g., tubular structure, liner, production string, etc.) and a workstring. The body of the assembly is disposed in the borehole and defines a through-bore. One or more sections are disposed on the body, and each of the one or more sections comprises isolation element, a port, a screen, and a closure.
The isolation element disposed on the body isolates a borehole annulus around the section from the other sections. The port disposed on the body permits fluid communication between the through-bore and the borehole annulus, and the screen disposed on the body communicates with the borehole annulus. The closure disposed on the body at least preventing fluid communication from the through-bore to the screen.
The workstring defines an outlet and is manipulated in the body relative to each section. The workstring in a first mode of operation delivers the treatment from the outlet to the borehole annulus of section through the port. The workstring in a second mode of operation receives reverse circulation from the through-bore into the outlet.
In one embodiment, the port for a given one of the one or more sections is disposed toward the toe, and the screen for the given section is disposed toward the heel. During treatment, the port delivers slurry as the treatment and gravel packs the annulus of the given section from toe to heel. The screen filters the fluid returns from the slurry into the through-bore of the body.
In another embodiment, the port for a given one of the one or more sections is disposed toward the heel, and the screen for the given section is disposed toward the toe. During treatment, the port delivers slurry as the treatment and gravel packs the annulus of the given section from heel to toe. The screen filters the fluid returns from the slurry, and the section has a bypass delivering the fluid returns to the through-bore of the body uphole of the port.
In one embodiment, the port comprises a flow valve selectively operable between opened and closed conditions permitting and preventing fluid communication between the through-bore and the borehole annulus. The flow valve can include a sleeve movable in the through-bore between (a) the closed condition preventing fluid communication through the port and (b) the opened condition permitting fluid communication through the port. The workstring can be configured to at least open the flow valves of the one or more sections. For example, the workstring can have an actuating tool operable to open and close the flow valves of the one or more sections in the same trip in the through-bore.
In one embodiment, the closure is selectively operable between (a) a closed condition preventing fluid communication between the through-bore and the screen and (b) an opened condition permitting fluid communication between the through-bore and the screen. For example, the closure can include a sleeve movable in the through-bore between (a) the closed condition preventing fluid communication through at least one flow port in the body, the at least one flow port in communication with the screen, and (b) the open condition permitting fluid communication through the at least one flow port.
In another example, the closure can include a one-way valve disposed in fluid communication between the screen and the through-bore, the one-way valve in the open condition permitting fluid communication from the screen into the through-bore and in the closed condition preventing fluid communication from the through-bore to the screen.
The foregoing summary is not intended to summarize each potential embodiment or every aspect of the present disclosure.
As shown in
Each of the ported housings 230A-B has body or flow ports 232A-B for diverting flow. Internally, each of the ported housings 230A-B has seats 234 defined above and below the outlet ports 232A-B for sealing with the distal end of the inner workstring 210 as discussed below. To prevent erosion, the flow ports 232A-B on the ported housings 230A-B can have a skirt, such as the skirt 236 for the flow ports 232A on the ported housings 230A.
The flow ports 232B on an upper one of the ported housings 230B communicate with alternate path devices 250 disposed along the length of the lower screen section 240A. These alternate path devices 250 can be shunts, tubes, concentrically mounted tubing, or other devices known in the art for providing an alternate path for slurry. For the purposes of the present disclosure, however, the alternate path devices 250 are referred to as shunts herein for simplicity. In general, the shunts 250 communicate from the flow ports 232B to side ports 222 toward the distal end of the system 200 or other directions for use during steps of the operation.
As shown in
On its distal end, the inner workstring 210 has outlet ports 212 isolated by seals 214. When running in, one of the seals 214 can seal the end of the inner workstring 210 inside the shoe track 220, as shown in
During the gravel pack operations, however, the outlet ports 212 can locate and seal by the seals 214 in the ported housings 230A-B disposed between each of the screen sections 240A-B. In particular, seals 214 located on either side of the string's outlet ports 212 seal inside seats 234 on the ported housings 230A-B. The seals 214 can use elastomeric or other types of seals disposed on the inner workstring 210, and the seats 234 can be polished seats or surfaces inside the housings 230A-B to engage the seals 214. Although shown with this configuration, the reverse arrangement can be used with seals on the inside of the housings 230A-B and with seats on the inner workstring 210.
When fluid is pumped through the inner workstring 210, pumped fluid exits from the string 210 and through the flow ports 232A-B on the ported housings 230A-B depending on the location of the string 210 to the flow ports 232A-B. In this arrangement, the flow ports 232A in the lower ported housing 230A direct the slurry directly into the annulus, whereas the flow ports 232B in the upper ported housing 230B direct the slurry into shunts 250 as discussed below. Other similar arrangements can be used. In any event, this selective location and sealing between the string 210 and housings 230A-B changes fluid paths for the delivery of slurry into the annulus around the screen sections 240A-B during the gravel pack operations discussed in more detail below.
As shown in
As shown in
Once the packer 14 is set and tested, operators begin the gravel pack operation. As shown in
When manipulating the inner workstring 210, operators are preferably given an indication at surface that the outlet ports 212 are located at an intended position, whether it is a blank position, a slurry circulating position, or an evacuating position. One way to accomplish this is by measuring tension or compression at the surface to determine the position of the inner workstring 210 relative to the ported housings 230A-B and seats 234. This and other procedures known in the art can be used.
With the ports 212/232A isolated by the engaged seals 214 and seats 234, operators pump the slurry of carrying fluid and gravel down the inner workstring 210 in a first direction to the string's ports 212. The slurry passes out of the pipe's ports 212 and through the housing's ports 232A to the open hole annulus. The carrying fluid in the slurry then leaks off through the formation and/or through the screen sections 240A-B along the length of the system 200. However, the screen sections 240A-B prevent the gravel in the slurry from flowing into the system 200. Therefore, the fluid passes alone through the screen sections 240A-B and returns through the casing annulus above the packer 14.
As described herein, the gravel can pack the annulus in an alpha-beta wave, although other variations can be used. As the fluid leaks off, for example, the gravel drops out of the slurry and first packs along the low side of the annulus in the borehole 10. The gravel collects in stages that progress from the toe (near housing 230A) to the heel in an alpha wave. Gravitational forces dominate the formation of the alpha wave, and the gravel settles along the low side at an equilibrium height along the screen sections 240A-B.
After the alpha wave, the borehole 10 fills in a beta wave along the system 200. The gravel begins to collect in the beta wave along the upper side of the screen sections 240A-B starting from the heel (near the packer 14) and progressing to the toe of the assembly 200. Again, the fluid carrying the gravel can leak through the screen sections 240A-B and up the annulus between the inner workstring 210 and the liner 225.
Eventually, the operators reach a desired state while pumping slurry at the ports 232A in this ported housing 230A. This desired state can be determined by a particular rise in the pressure levels and may be termed as “sand out” in some contexts. At this stage, operators raise the inner workstring 210 again as shown in
In general, the slurry can flow out of the ports 232B and into the surrounding annulus if desired. This is possible if one or more of the ports 232B communicate directly with the annulus and do not communicate with one of the alternate path devices or shunt 250. All the same, the slurry can flow out of the ports 232B and into the alternate path devices or shunts 250 for placement elsewhere in the surrounding annulus. Although shunts 250 are depicted in a certain way, any desirable arrangement and number of transport and packing devices for an alternate path can be used to feed and deliver the slurry.
Depending on the implementation, this second stage of pumping slurry may be used to further gravel pack the borehole. Yet, as shown in the current implementation, pumping the slurry through the shunts 250 enables operators to evacuate excess slurry from the inner workstring 210 to the borehole without reversing flow in the string 210 from the first flow direction (i.e., toward the string's port 212). This is in contrast to a reverse direction of flowing fluid down the annulus between the string 210 and the housings 230A-B/screens 240A-B to evacuate excess slurry from the string 210.
As shown in
At some point, operation may reach a “sand out” condition or a pressure increase while pumping slurry at ports 232B. At this point, a valve, rupture disc, or other closure device 256 in the shunts 250 can open so the gravel in the slurry can then fill inside the shoe track 220 after evacuating the excess around the shoe track 220. In this way, operators can evacuate excess gravel inside the shoe track 220. As this occurs, fluid returns can pass out the lower screen section 240A, through the packed gravel in the annulus, and back through upper screen section 240B to travel uphole. In other arrangements, the lower ported housing 230A can have a bypass, another shunt, or the like (not shown), which can be used to deliver fluid returns past the seals 214 and seats 234 and uphole.
The previous system 200 filled the open hole annulus with an alpha-beta type wave and then filled the annulus around the toe with an alternate path. As shown in
When operators raise the inner workstring 210 to locate in the gravel pack position shown in
As can be seen in
Moreover, the inner workstring 210 can be used to pump treatments of different types into a surrounding zone. For example, the system 200 of
In a frac packing arrangement, the disclosed system 200 can deliver the frac treatment and gravel slurry through the multiple ported housing 230A-B into the annulus around the screen sections 240A-B. Dispersing the frac treatment and slurry through the multiple ports 232A-B can provide more even distribution across a greater area. For the fracturing part of the process, the frac treatment can exit from the lower ported housing 230A, and fluid returns can pass through the screen section 240B adjacent to the casing annulus until the fracture is complete. Afterwards, the inner workstring 210 can be moved to the upper ported housing 230B so that gravel slurry can flow through shunts 250 and/or 260 to gravel pack the annulus. A reverse operation could be done in which frac treatment can exit upper housing 230B so that gravel packing can be done primarily at the lower housing 230A using toe-to-heel gravel packing.
When used for frac/gravel packing, the system 200 may reduce the chances of sticking. Because the system 200 can have a smaller volumetric area around the exit points, there may be less of a chance for proppant sticking around the gravel pack ports 212. As slurry exits near the end of the inner workstring 210, only a short length of pipe has to travel upward through remaining slurry or dehydrated sand that may be left. If sticking does occur around the gravel pack ports 212, a shear type disconnect (not shown) can be incorporated into the inner workstring 210 so that the lower part of the inner workstring 210 can disconnect from an upper part of the inner workstring 210. This allows for the eventual removal of the inner workstring 210.
Expanding on the versatility of the disclosed system,
The liner 325 has multiple gravel pack sections 302A-C separated by packers 360/370. The packers 360/370 and gravel pack sections 302A-C are deployed into the well in a single trip. One packer 360/370 or a combination of packers 360/370 can be used to isolate the gravel pack sections 302A-C from one another. Any suitable packers can be used and can include hydraulic or hydrostatic packers 360 and swellable packers 370, for example. Each of these packers 360/370 can be used in combination with one another as shown, or the packers 360 or 370 can be used alone.
The hydraulic packers 360 provide more immediate zone isolation when set in the borehole 10 to stop the progression of the gravel pack operations in the isolated zones. For their part, the swellable packers 370 can be used for long-term zone isolation. The hydraulic packers 360 can be set hydraulically with the inner workstring 310 and its packoff arrangement 314, or the packers 360 can be set by shifting sleeves (not shown) in the packers 360 with a shifting tool (not shown) on the inner workstring 310.
Each gravel pack section 302A-C can be similar to the assemblies 200 as discussed above in
Turning now to
As shown in
The flow devices 440 disposed on the assembly 420 include wellscreens 446 and the closures 450 (i.e., one-way or check valves, sliding sleeves, etc.). As one-way or check valves, the closures 450 can be configured in different ways and can include ball, poppet, or disk type check valves that are concentrically or eccentrically mounted on the outer radius of the screen's basepipe. The closures 450 can be part of a housing that directs flow into a basepipe and can attach to the wellscreens to ensure fluid flow is filtered of solids. Preferably, multiple closures 450 can be installed on each joint to reduce and even out pressure drops across the screen joints to promote complete development of the beta wave during gravel packing. Alternatively, the closures 450 can be mounted into the basepipe and can allow flow into a housing mounted on the radial exterior of the basepipe and attached to the wellscreen 446.
The operation for the system 400 of
In general, the shifting tool 418 can be a “B” shifting tool for shifting the inner sleeve 434 in the valve 430 relative to the valve's ports 432. Thus, opening a given valve 430 involves engaging the shifting tool 418 in an appropriate profile of the valve's inner sleeve 434 and moving the inner sleeve 434 with the workstring 410 to an opened condition so that the assembly's through-bore 425 communicates with the borehole annulus 15 via the now opened ports 432.
Once a given valve 430 is opened, the seals 416 on the workstring 410 can engage and seal against inner seats 438, surfaces, seals, or the like in the valve 430 or elsewhere in the assembly 420 on both the uphole and downhole sides of the opened ports 432. The seals 416 can use elastomeric or other types of seals disposed on the inner workstring 410, and the seats 438 can be polished seats or surfaces inside the valve 30 or other parts of the screened assembly 420 to engage the seals 416. Although shown with this configuration, the reverse arrangement can be used with seals on the inside of the valve 430 or the screened assembly 420 and with seats on the workstring 410.
Once the workstring 410 is seated, treatment fluid is flowed down the through-bore 415 of the workstring 410 to the sealed and opened ports 432 in the valve 430. The treatment fluid flows through the outlet ports 412 in the workstring 410 and through the opened ports 432 to the surrounding borehole annulus 15, which allows the treatment fluid to interact with the adjacent zone of the formation.
Once treatment is completed for the given zone 428A-C, operators manipulate the workstring 410 to engage the shifting tool 418 in the valve 430 to close the ports 432. For example, the shifting tool 418 can engage another suitable profile on the inner sleeve 434 of the valve 430 to move the sleeve 434 and close the ports 432. At this point, the workstring 410 can be moved in the assembly 420 to open another one of the valves 430 to perform treatment. Operators repeat this process up the assembly 420 to treat all of the sections 428A-C. Once the treatment is complete, the system 400 may not need a clean-out trip.
The multi-zone system 400 of
In another embodiment, the multi-zone screened system 400 of
During a treatment operation similar to that discussed above, the tubes 480 help dehydrate slurry intended to frac or gravel pack the borehole annulus 15 of the sections 428 during a frac pack or gravel pack type of operation. In addition, the tubes 480 can act as a bypass for fluid returns during the operation. As treatment fluid flows from the workstring 410 seated in a valve 430, through the opened ports 432, and into the borehole annulus 15, the wellscreen 446 screens fluid returns from the annulus 15, and the fluid returns can flow into the assembly 420 downhole of the engagement of the workstring 410 in the assembly 420. The tubes 480 can, therefore, allow these fluid returns to flow from the downhole section of the assembly 420 to the micro-annulus between the workstring 410 and the inside of the assembly 420 uphole of the sealed engagement of the workstring 410 with the ports 432. From this point, the fluid returns can then flow to the surface.
The multi-zone system 400 of
As noted above, the multi-zone system 400 can use flow devices 440 disposed on the assembly 420, and the flow device 440 includes the wellscreen 446 and the closure 450 (i.e., one-way or check valves). Turning now to
The flow device 540 is deployed on a completion string (422:
As noted above, the inflow control device 560 can be similar to a FloReg deploy-assist (DA) device available from Weatherford International. As best shown in
For its part, the screen jacket 550 is disposed around the outside of the basepipe 542. As shown, the screen jacket 550 can be a wire wrapped screen having rods or ribs 554 arranged longitudinally along the base pipe 542 with windings of wire 552 wrapped thereabout to form various slots. Fluid can pass from the surrounding borehole annulus to the annular gap between the screen jacket 550 and the basepipe 542. Although shown as a wire-wrapped screen, the screen jacket 550 can use any other form of screen assembly, including metal mesh screens, pre-packed screens, protective shell screens, expandable sand screens, or screens of other construction.
Internally, the inflow control device 560 has a number (e.g., ten) of flow ports 570. Rather than providing a predetermined pressure drop along the screen jacket 550 by using multiple open or closed nozzles (not shown), the inflow control device 560 as shown in
Internally, however, the inflow control device 560 does include port isolation balls 572, which allow the device 560 to operate as a one-way or check valve. Depending on the direction of flow or pressure differential between the inner spaces 576 and 578, the port isolation balls 572 can move to an open condition (to the right in
In general, the inflow control device 560 can facilitate fluid circulation during deployment and well cleanup and can be used in interventionless deployment and setting of openhole packers. In deployment, for example, the isolation balls 572 maximize fluid circulation through the completion shoe (420:
Should a pressure drop be desired from the screen jacket 550 to the basepipe 542, the flow ports 570 can include nozzles (not shown) that restrict flow of screened fluid (i.e., inflow) from the screen jacket 550 to the pipe's inner space 578. For example, the inflow control device 560 can have ten nozzles, although they all may not be open. Operators can set a number of these nozzles open at the surface to configure the device 560 for use downhole in a given implementation. Depending on the number of open nozzles, the device 560 can thereby produce a configurable pressure drop along the string of such flow devices 540.
As shown, a service packer 17 can be used between the workstring 410 and the casing 12 to isolate the internal through-bore 425 of the assembly 420. As also shown, the workstring 410 has a service tool 417 disposed above the liner packer 16. The service tool 417 can be used for hydraulically setting the packer 16. Regardless of the configuration used, the uphole components of the system 400 can be used for circulating, squeeze, and reverse out operations as is known in the art.
The workstring 410 has one or more outlet ports 412 and has hydraulically actuated shifting tools 418a-b. Both of the shifting tools 418a-b can be actuated with applied pressure against a ball when seated in the workstring 410. One shifting tool 418b can open the valves 430 when the workstring 410 is run downhole in the assembly 420, while the other shifting tool 418a can close the valves 430 when the workstring 410 is run uphole in the assembly 420. The same can be true for opening and closing the flow devices 440 with the shifting tools 418a-b as discussed below. Thus, one shifting tool 418b is run facing down, while the other tool 418a is run facing up. Other arrangements can be used, and other types of shifting tools can be used as well.
As an example, the shifting tools 418a-b can each be a hydraulically actuated version of an industry standard B shifting tool. When the shifting ball (74) is dropped in the workstring 410, the application of hydraulic pressure down the workstring 410 actuates the shifting tools 418a-b so that they expose spring-loaded keys for shifting the valves 430 and flow devices 440 open or closed. The shifting tools 418a-b may be actuated together with the same ball 414 or actuated separately with different sized balls 414 depending on the configuration.
As before, the assembly 420 has a production string 422 supported from a packer 16 in the casing 12. Along its length, the string 422 has isolation devices 429, valves 430, and flow devices 440. The isolation devices 429, which can be packers, seal the borehole annulus 15 around the assembly 420 and separate the annulus 15 into various zones or sections 428A-C. Each section 428A-C has at least one of the valves 430 and at least one of the flow devices 440, both of which can selectively communicate the string's through-bore 425 with the borehole annulus 15 as detailed below. At its downhole end, the assembly 420 has a bottom seat 422 for engaging a setting ball 424 to close off the shoe 420 during frac, gravel pack, or frac pack operations.
As shown, the selective valve 430 is disposed uphole of the flow device 440 in each of the various sections 428A-C. As an alternative, the selective valve 430 can be disposed downhole of the flow device 440 in each section 428A-C. Moreover, a given section 428A-C may have more than one valve 30 and/or flow device 440.
The selective valves 430 have one or more ports 432 that can be selectively opened and closed during operation. In this arrangement as with others discussed above, each of the selective valves 430 can be opened to communicate their ports 432 with the surrounding annulus 15 by using the shifting tool 418a on the workstring 410. As before, the valves 430 can be sliding sleeves having a movable closure element 434, such as an inner sleeve or insert, which isolates or exposes ports 432 in the sliding sleeve's housing.
Similar to the valves 430, the flow devices 440 also have one or more ports 442 that can be selectively opened and closed during operation. Each of the flow devices 440 also includes a closure and a screen 446. The closure in this arrangement includes a first closure element 444 that selectively opens and closes flow through the flow ports 442 and includes a second closure element 450 that at least prevents fluid flow from the through-bore 425 through the screen 446.
This system 400 is a single trip, multi-zone system as discussed in previous embodiments. Briefly, the assembly 420 is run downhole as part of the production string 422 or liner system deployed in the borehole, and the liner packer 16 is set hydraulically. Treatments are then performed for the various zones or sections 428A-B of the borehole annulus 15 by selectively opening the valves 430.
After treatment (e.g., gravel packing or fracing) is completed, excess gravel or proppant is cleaned out of the assembly 420, and the valves 430 are closed because they are used primarily for outlet ports for the treatment. To prepare the assembly 420 for production, the flow devices 40 are then opened in the assembly 420 with the workstring 410 in the same trip in the wellbore by opening the first closure element 444 (e.g., inner sleeve) to expose the flow ports 442. Once open, the flow devices 440 screen fluid from the borehole annulus 15 into the string's through-bore 425. At the same time, the flow device's second closure element 450 functions to prevent flow in the reverse direction. As discussed in more detail below, for example, the flow device's second closure element 450, which can use one-way or check valve, can prevent fluid loss into the formation while pulling out the workstring 410 from the assembly 420 and while performing production.
With a general understanding of how the assembly 420 is used, discussion now turns to how treatment operations are performed in more detail. Initially, all of the valves 430 and flow devices 440 are closed on the assembly 420 when run in the borehole. After setting the liner packer 16 and closing off the bottom seat 450 with the setting ball 454, operators set the packers 429 along the assembly 420 with the appropriate procedures to create the multiple isolated sections 428A-C down the borehole annulus 15. Once the packers 429 are set, operators can then commence with applying treatment successively to each of the isolated sections 428A-C by selectively opening and then closing the selective valves 430 with the shifting tools 418a-b on the workstring 410.
As shown in
For example, the flow device 440 can be a sliding sleeve having a movable closure element 444, such as an inner sleeve or insert, which isolates or exposes the ports 442 in the sliding sleeve's housing. The flow device 440 can be opened to communicate its ports 442 with the surrounding annulus 15 through its screen 446 by using the shifting tool 418a on the workstring 410. In this way, the flow device 440 when closed does not communicate the string's through-bore 425 with the borehole annulus 15 through screens 446, but the flow device 440 when opened allows screened fluid from the annulus 15 to pass through the screen 446 on the device 440 and into the through-bore 425.
Now, operators position the workstring 410 uphole of the open valve 30 as shown in
Without sealing the workstring 410 in the assembly's section 428A, operators apply the treatment down the workstring 410 to treat the borehole annulus 15 for this section 428A. The fluid leaves the ports 412 in the workstring 410 and flows along a first flow path through the open ports 432 of the valve 430 and into the formation around the open section's borehole annulus 15. To maintain the pressure in the assembly 420 during the operation, the system 400 can use a live annulus technique (if the service packer 17 is not used or can be removed, or the system 400 can use a pure squeeze technique with the service packer 17 in the casing 12.
At the same time as the treatment, the closure on the flow device 440 at least prevents fluid flow through the ports 442 and screen 446 from the through-bore 425 to the borehole annulus 15. Preventing the flow out of the screen 446 can be accomplished by either the first or second closure elements 444 and 450 or by both. Preferably, the first closure element 444 also prevents fluid flow from the borehole annulus 15 into the through-bore 425 via the screen 446.
Once treatment of the first section 428A is done, operators reverse out at least some of the excess slurry from the workstring 410 so treatment can commence with the next section 428B. Operators drop the shifter ball (not shown) down the workstring 70 again, and pressure up the workstring 410 to actuate the shifting tools 418a-b with the seated ball 414. With the tools 418a-b actuated, operators close the open valve 30 for the lower section 428A with the closing tool 418a. After bleeding off the pressure, the workstring 410 is raised to the valve 430 in the next section 428B. At this point, operators then pressure up on the seated shifter ball 414 in the workstring 410 again and open this valve 430 with the actuated opening tool 418b. After bleeding off the applied pressure in the workstring 410 and reversing out the seated ball 414, the treatment process for this new section 428B is then repeated as before.
Similar procedures are then repeated for all of the subsequent sections (i.e., 428C) of the assembly 420. Once treatment is complete for all of the sections 428A-C, all of the valves 430 and flow device 440 on the assembly 420 are closed. Operators perform a washout operation. To do this, the workstring 410 is lowered down toward the shoe 420 of the assembly 420, and operators pump a washout fluid down the casing 12 to reverse out any residual gravel, proppant or other treatment up the workstring 410. Because all of the valves 430 are closed, operators have no issues with reversing flow for the washout operation.
When washout is complete, operators then open all of the flow devices 440 so their ports 442 communicate with the string's through-bore 425 to accept production. The workstring 410 positions toward the bottom shoe 426, and operators drop the shifter ball 414 again. Pressure is applied to the seated ball 414 to actuate the shifter tools 418a-b on the workstring 410, and operators raise the workstring 410 and open the first closure elements 444 (e.g., inner sleeve) of the flow devices 440 up the assembly 420 using the opening tool 418b.
As the flow devices 440 are opened, fluid from the borehole annulus 15 can flow along a second flow path through the screens 446, closure elements 450, and opened ports 442. As the flow devices 440 are opened up the assembly 420, the second closure elements 48 (e.g., one-way or check valves) of the flow devices 440 prevent fluid loss from the string's through-bore 425 to the annulus 15 during this process. As shown in
As can be seen, operation of this system 400 can reduce the time and risk involved in performing the treatment because no service tool needs to seal in the assembly 420. Moreover, pickup and operations time are reduced. Essentially, the workstring 410 can be run in during the liner setting trip so that no added runs are needed. Cleanout and opening/closing of the ports 432 and 442 in the valves 430 and flow devices 440 are all done in the same trip.
The present example of the system 400 is described for an open hole, but the system 400 for a cased hole would be the same except that the isolation packers 429 may be different. Because the system 400 does not use dropped balls in the assembly 420 to open the valve 430 or flow devices 440, the number of stages that can be deployed downhole is not limited by the required step-down sizes in balls and seats. Moreover, no balls or seats are left in the assembly 420 after treatment operations so the operation does not need a separate milling operation, which can be time consuming and can encounter its own issues. In essence, the wellbore is ready to receive production tubing after the operation is completed.
As noted above, in a conventional gravel pack systems, sand slurry is introduced into the annulus uphole of the wellscreens and is circulated downhole (i.e., from heel to toe). The toe-to-heel system as disclosed for example in
To allow for reverse circulating, the systems of
To that end, a toe-to-heel system 600 disclosed in
Turning to
The assembly 620 and packers 670 are run downhole in a single trip. This system 600 segments several compartmentalized reservoir zones so that multiple gravel pack operations as well as frac operations can be performed. As shown herein, the system 600 has several gravel pack sections 602A-C separated by packers 670, which seal in the open hole to isolate one zone from another. One or more packers 670 can be used to isolate each of the gravel pack sections 602A-C from one another. Any suitable packers can be used and can include hydraulic packer, hydrostatic packers, and swellable packers, for example. The packers 670 provide zone isolation when set in the borehole 10 to stop the progression of the treatment operations in the isolated zones.
Each section 602A-C can be similar to the systems 200, 300, and 400, as discussed above. Each section 602A-C has a screen 640 and ports 650. The screens 640 include a closure element 645 (e.g., one-way valve, check valves, or the like). Ports 650 adjacent the screens 640 may or may not include valves 652 or selective sleeves.
This system 600 has a workstring 610 that disposes in the assembly 620 to treat (e.g., gravel or frac pack) portions of the formation. As shown, the workstring 610 has external seals 612 disposed near outlet ports 614. A dropped ball 414 can seat in a distal seat of the workstring 610 to divert fluid flow down the workstring 610, out the outlet ports 612, and to the ports 650 in the assembly 620 to treat the surrounding formation. However, other configurations can be used for the workstring 610.
The workstring 610 deploys in the first section 602A and performs washdown by communicating the string's outlet port 612 with the float valve 626 on the float shoe 620 of the system 600. After washdown, the packers 670 are set to create the multiple isolated sections down the borehole annulus 15. The packers 670 can be set hydraulically, hydrostatically, with RFID tags, or with pressure pulses.
Once the packers 670 are set, operators can begin applying a treatment (i.e. fracture, gravel pack, frac-pack, etc.) successively to each of the isolated sections 602A-C. In particular, the string 610 can be selectively positioned at any one of the various sections 602A-C along the system 600. In the selective position, the string's outlet ports 612 with its seals 614 isolate to the flow ports 650 to gravel pack and/or frac pack the annulus 15 around given gravel pack section 602A-C. Then, the inner workstring 610 can be moved so that the outlet ports 612 isolate from these flow ports 650 so reverse circulation can be performed to remove excess slurry from the workstring 610 before moving it to the next gravel pack section 602A-C. A similar process can then be repeated up the hole for each gravel pack section 602A-C separated by the packers 670.
As shown in
As shown, the ports 650 may have selective valves or sleeves 652 that can be opened with a shifting tool 616 on the workstring 610, although these components may not be necessary in every embodiment. In general, the shifting tool 616 can be a “B” shifting tool for shifting the valve 652 relative to the ports 650. Thus, opening a given valve 652 involves engaging the shifting tool 616 in an appropriate profile of the valve 652 and moving the valve 652 with the workstring 610 to an opened condition so that the assembly's through-bore 625 communicates with the borehole annulus 15 via the now opened ports 650.
As shown in
Once the workstring 610 is seated, treatment fluid is flowed down the through-bore of the workstring 610 to the ports 650 at the first zone 602A. The treatment fluid flows through the outlet ports 612 in the workstring 610 and through the ports 650 to the surrounding borehole annulus 15, which allows the treatment fluid to interact with the adjacent zone of the formation. For example, fracture treatment with proppant can be pumped, or gravel in a slurry can be pumped into the annulus.
Gravel packing from toe-to-heel in the system 600 allows fluid returns to pass through the screen 640 and dehydrate the slurry intended to gravel pack the borehole annulus 15 of the sections 602A-C during a gravel or frac pack type of operation. Different from the arrangement in
Eventually, sandout will occur when the first section 602A is sufficiently gravel packed. As then shown in
At this point, the workstring 610 can be moved in the assembly 620 to an intermediate position that allows for excess slurry to be removed from the workstring 610 before moving the workstring 610 to a new zone 602B. As will be appreciated, any excess slurry in the workstring 610 can flow into the assembly 620 while the workstring 610 is manipulated, and any gravel, proppant, sand, or the like in the slurry can cause problems with the workstring 610 sticking, fouling valves, etc.
Therefore, in the intermediate position, the outlet ports 612 on the workstring 610 are exposed to the through-bore 625 of the assembly 620. Reverse circulation can then be pumped down the borehole 12 and into the annular space between the workstring 610 and assembly 620. This clears the excess slurry, which travels back up the workstring 610.
Once reverse circulation is complete, the workstring 610 can be moved in the assembly 620 to another zone 602B to perform treatment. Operators repeat this process up the assembly 620 to treat all of the sections 602A-C. Once the treatment is complete, the system 600 may not need a clean-out trip.
Having the system 600 noted above, gravel packing can be accomplished where the wellscreens 640 are able to be pressurized on the inside. This allows the system 600 to be operated under reverse circulation that exerts pressure inside the assembly 620. Being able to reverse circulation this way makes it possible to perform single zone toe-to-heel gravel packs and subsequently reverse out the excess slurry. The system 600 also makes it possible to perform multiple gravel packs at different points in the wellbore, reversing out after each individual gravel pack operation. The workstring 610 inside the assembly 620 can be positioned at each pumping point in the assembly 620, starting at the lowest point for example, and deliver the gravel pack slurry into the annulus 15, circulating in a toe-to-heel fashion. Once sufficient sand has been pumped, the workstring 610 is repositioned so that pressure applied to the casing 12 and inside the assembly 620 results in reverse circulating of any excess slurry up the workstring 610. Once that slurry has been removed, the workstring 610 is raised to the next pumping location, and the steps are repeated.
The foregoing description of preferred and other embodiments is not intended to limit or restrict the scope or applicability of the inventive concepts conceived of by the Applicants. It will be appreciated with the benefit of the present disclosure that elements of one embodiment can be combined with or exchanged for components of other embodiments disclosed herein. References have been made herein to use of the gravel pack assemblies in boreholes, such as open boreholes. In general, these boreholes can have any orientation, vertical, horizontal, or deviated. For example, a horizontal borehole may refer to any deviated section of a borehole defining an angle of 50-degrees or greater and even over 90-degrees relative to vertical.
In exchange for disclosing the inventive concepts contained herein, the Applicants desire all patent rights afforded by the appended claims. Therefore, it is intended that the appended claims include all modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof.
This is a continuation-in-part of U.S. application Ser. No. 12/913,981, filed 28 Oct. 2010, entitled “Gravel Pack Assembly for Bottom Up/Toe-To-Heel Packing” by Ronald van Petegem and John P. Broussard and of U.S. application Ser. No. 13/670,125, filed 6 Nov. 2012, entitled “Multi-Zoned Screened Fracturing System” by John P. Broussard, Ronald van Petegem, and Christopher A. Hall, which are both incorporated herein by reference in their entities.
| Number | Date | Country | |
|---|---|---|---|
| 61506897 | Jul 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12913981 | Oct 2010 | US |
| Child | 14282692 | US | |
| Parent | 13670125 | Nov 2012 | US |
| Child | 12913981 | US | |
| Parent | 13545908 | Jul 2012 | US |
| Child | 13670125 | US |
