A wellscreen may be used on a production string in a hydrocarbon well and especially in a horizontal section of the wellbore. Typically, the wellscreen has a perforated basepipe surrounded by a screen that blocks the flow of particulates into the production string. Even though the screen may filter out particulates, some contaminants and other unwanted materials can still enter the production string.
To reduce the inflow of unwanted contaminants, operators can perform gravel packing around the wellscreen. In this procedure, gravel (e.g., sand) is placed in the annulus between wellscreen and the wellbore by pumping a slurry of liquid and gravel down a workstring and redirecting the slurry to the annulus with a crossover tool. As the gravel fills the annulus, it becomes tightly packed and acts as an additional filtering layer around the wellscreen to prevent the wellbore from collapsing and to prevent contaminants from entering the production string.
Ideally, the gravel uniformly packs around the entire length of the wellscreen, completely filling the annulus. However, during gravel packing, the slurry may become more viscous as fluid is lost into the surrounding formation and/or into the wellscreen. Sand bridges can then form where the fluid loss occurs, and the sand bridges can interrupt the flow of the slurry and prevent the annulus from completely filling with gravel.
As shown in
To overcome sand-bridging problems, shunt tubes have been developed to create an alternative route for gravel around areas where sand bridges may form. For example, a gravel pack apparatus 100 shown in
The apparatus 100 includes a wellscreen assembly 105 having a basepipe 110 with perforations 120 as described previously. Disposed around the base pipe 110 is a screen 125 that allows fluid to flow therethrough while blocking particulates. The screen 125 can be a wire-wrapped screen, although the wellscreen assembly 105 can use any structure commonly used by the industry in gravel pack operations (e.g. mesh screens, packed screens, slotted or perforated liners or pipes, screened pipes, pre-packed screens and/or liners, or combinations thereof).
The shunt tubes 145 are disposed on the outside of the basepipe 110 and can be secured by rings (not shown). As shown in
At an upper end (not shown) of the apparatus 100, each shunt tube 145 can be open to the annulus 16. Internally, each shunt tube 145 has a flow bore for passage of slurry. Nozzles 150 disposed at the ports 147 in the sidewall of each shunt tube 145 allow the slurry to exit the shunt tube 145. As shown in
In a gravel pack operation, the apparatus 100 is lowered into the wellbore 14 on a workstring and is positioned adjacent a formation. A packer (18;
Should a sand bridge 20 form and prevent further filling below the bridge 20, the gravel slurry continues flowing through the shunt tubes 145, bypassing the sand bridge 20 and exiting the various nozzles 150 to finish filling annulus 16. The flow of slurry through one of the shunt tubes 145 is represented by arrow 102.
Due to pressure levels and existence of abrasive matter, the flow of slurry in the shunt tubes 145 tends to erode the nozzles 150, reducing their effectiveness and potentially damaging the tool. To reduce erosion, the nozzles 150 typically have flow inserts that use tungsten carbide or a similar erosion-resistant material. The resistant insert fits inside a metallic housing, and the housing welds to the exterior of the shunt tube 145, trapping the carbide insert.
For example,
A tubular carbide insert 160 of the nozzle 150 is held in alignment with the drilled port 147, and an outer jacket 165 of the nozzle 150 is attached to the shunt tube 145 with a weld 170, trapping the carbide insert 160 against the shunt tube 145 and in alignment with the drilled hole 147. The outer jacket 165 is typically composed of a suitable metal, similar to that used for the shunt tube 145. The outer jacket 165 serves to protect the carbide insert 160 from high weld temperatures, which could damage or crack the insert 160. With the insert 160 held by the outer jacket 165 in this manner, sand slurry exiting the tube 145 through the nozzle 150 is routed through the carbide insert 160, which is resistant to damage from the highly abrasive slurry.
The nozzle 150 and the manner of constructing it on the shunt tube 145 suffer from some drawbacks. During welding of the nozzle 150 to the shunt tube 145, the nozzle 150 can shift out of alignment with the drilled hole 147 in the tube 145 so that exact alignment between the nozzle 150 and the drilled hole 147 after welding is not assured. To deal with this, a piece of rod (not shown) may need to be inserted through the nozzle 150 and into the drilled hole 147 to maintain alignment during the welding. However, holding the nozzle 150 in correct alignment while welding it to the shunt tube 145 is cumbersome and requires time and a certain level of skill and experience.
In another drawback, the carbide insert 160 actually sits on the surface of the shunt tube 145, and the hole 147 in the tube's wall is part of the exit flow path 102. Consequently, abrasive slurry passing through the hole 147 may cut through the relatively soft material of the shunt tube 145 and may bypass the carbide insert 160 entirely, causing the shunt tube 145 to fail prematurely.
To address some of the drawbacks, other nozzle configurations have been disclosed in U.S. Pat. Nos. 7,373,989 and 7,597,141, which are incorporated herein by reference. U.S. Pat. Pub. No. 2008/0314588 also discloses other nozzles for shunt tubes.
Although existing nozzles may be useful and effective, the arrangements still complicate manufacture of downhole tools, alter the effective area available in the tool for design and operation, and have features prone to potential failure. Accordingly, 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 gravel pack apparatus for a wellbore has a flow tube with a flow passage for conducting slurry during a gravel pack or other operation. The flow passage has at least one flow port for passing the conducted slurry into the wellbore. Typically, the apparatus has a basepipe having a through-bore and defining a perforation communicating into the through-bore. A screen is disposed on the basepipe adjacent the perforation for screening fluid flow into the basepipe. The flow tube is disposed adjacent the screen for conducting the slurry past any bridges or the like that may form in the wellbore annulus during the operation.
At least one insert is disposed at the at least one flow port in the flow tube. In one arrangement, the at least one insert defines at least one aperture therethrough allowing passage of the conducted slurry from the flow tube to the wellbore. The at least one insert is composed of an erodible material and erodes via the conducted slurry through the at least one aperture and allows passage of the slurry from an initial flow rate to a subsequently greater flow rate. In addition to the at least one aperture, the insert can have at least one slot defined at least partially in at least one side of the at least one insert to facilitate erosion.
In one arrangement, the at least one insert can have a thread disposed thereabout and can thread into the at least one flow port of the flow tube, although other forms of affixing can be used. Typically, multiple flow ports and nozzles are used on the flow tube. In this instance, the various inserts can be configured to erode in a predetermined pattern along the length of the flow tube. In other words, the inserts disposed toward one end (e.g., proximal end) of the flow tube may be configured to erode in the predetermined pattern before the inserts disposed toward another end (e.g., distal end) of the flow tube. One way to configure this is to use a same or different number of the at least one apertures in the various inserts, although other techniques can be used.
In another arrangement, the at least one insert disposed at the at least one flow port on the disclosed gravel pack apparatus can defining a flow passage therethrough and can have a barrier disposed across the flow passage. The barrier is breachable or breakable and allows passage of the conducted slurry through the flow passage once broken.
Therefore, when multiple inserts with barriers are used on the flow tube, the barriers can be configured to be breached in a predetermined pattern along the length of the flow tube. In this way, the inserts disposed toward one end of the flow tube can be configured to be breached in the predetermined pattern before the inserts disposed toward another end of the flow tube.
In one arrangement of the flow tube, the flow tube of the disclosed apparatus can have first and second flow tube sections—each having an internal passage conducting slurry. The insert affixes end-to-end to the first and second flow tube sections and has a flow passage communicating with the internal passages of the first and second flow tube sections.
The insert can have a plurality of exit ports communicating the conducted slurry to the wellbore. These exit ports can have flow nozzles disposed on the insert. The flow nozzles can be disposed on a same side or different sides of the insert, and the flow nozzles can be disposed in the same direction or different directions on the insert.
In yet another arrangement of the disclosed gravel pack apparatus, the nozzle disposed on the flow tube at the flow port is composed of a first material. The nozzle has inner and outer sidewalls, and the inner sidewall defines a flow passage communicating the conducted slurry therethrough. An erosion-resistant material different from the first material is disposed at least externally on the external surface of the nozzle.
The erosion-resistant material can be a sheath disposed at least externally on the external surface of the nozzle, or the erosion-resistant material comprises a buildup of the erosion resistant material that is disposed on the flow tube and disposed externally about the nozzle. Alternatively, the erosion-resistant material can be a bushing disposed in between the inner and outer sidewalls of the nozzle. A distal end connected between the inner and outer sidewalls of the nozzle can encapsulate the bushing in between the inner and outer sidewalls, or a retainer affixed to the distal end can be used.
The foregoing summary is not intended to summarize each potential embodiment or every aspect of the present disclosure.
The shunt tubes 200 are disposed on the outside of the basepipe 110 and can be secured by rings (not shown). As shown, centralizers 130 can be disposed on the outside of the basepipe 110, and a tubular shroud 135 having perforations 140 can protect the shunt tubes 200 and the wellscreen 105 from damage during insertion of the apparatus 100 into the wellbore 14. In other arrangements, the centralizers 130 and shroud 135 may not be used. Although not shown, it will be appreciated that transport tubes (not shown) lacking nozzles or exit ports can be used on the assembly 105 to transport slurry from joint to joint and can connect to the transport shunt tubes having the exit ports or nozzles.
At an upper end (not shown) of the apparatus 100, each shunt tube 200 can be open to the annulus to receive flow of slurry during a gravel pack operation when bridging or other problems occur. Alternatively, the upper end of a shunt tube 200 may connect to a transport tube running along the assembly 105. Internally, each shunt tube 200 has a flow bore 204 for passage of the slurry, and exit ports 206 in the sidewall 202 of each shunt tube 200 allow the slurry to exit the tube 200 to the surrounding wellbore.
Rather than having conventional nozzles on the exit ports 206, the shunt tubes 200 have a plurality of erosion inserts 210 disposed in the exit ports 206. As shown in the side view of a shunt tube 200 in
Each erosion insert 210 has one or more internal apertures, holes, or openings 212 defined therein. Thinned areas 214 from slots may also be provided to facilitate erosion and/or to facilitate insertion of the insert 210 in the exit ports 206. As shown in the cross-section of
The shunt tube 200 is composed of a suitable metal, such as 316L grade stainless steel. By contrast, the inserts 210 can be composed of an eroding material, such as a soft metal, including brass, aluminum, or the like. The number, size, and placement of the initial openings 212 and other features of the erosion insert 210 can be configured for a particular implementation with consideration for slurry grain size, slurry flow rate, pressure levels, desired erosion rate of the insert 210, type of material used for the insert 260, etc. The openings 212 and/or the exit ports 206 can be sized relative to a mean diameter of the gravel by a given factor to reduce the chances of a blockage from forming.
During gravel pack operations, slurry may eventually enter an open end (not shown) of the shunt tube 200 and may travel along the tube's flow passage 204. For example, the shunt tube 200 may be open at its uphole end, and the slurry may flow into the shunt tube 200 and the annulus. As the slurry loses carrier fluid to a high permeability portion of the surrounding formation, the gravel carried by the slurry is deposited and collects in the annulus to form the gravel pack. If the liquid is lost to a permeable stratum in the formation before the annulus is filled, however, a sand bridge may form that blocks flow through the annulus and prevent further filling below the bridge. If this occurs, the gravel slurry continues flowing through the shunt tube 200, bypassing the sand bridge, and exiting the various exit ports 206 with erosion inserts 210 to finish filling the annulus. As the slurry is diverted to the shunt tubes 200, and the gravel pack progresses from heel to toe, the slurry may only travel the distance between exit ports 206, which may be 3 ft. or so separate from one another, in the open hole.
Looking at
Eventually, the slurry exiting the first insert 210a erodes the openings 212 so that the flow is less restricted. As more flow passes in a subsequently greater flow rate, the first insert 210a erodes away as shown in
When sandout begins to occur, the slurry begins to flow primarily out the next exit port 206b and its erosion insert 210b further down the shunt tube 200. This insert 210b begins to erode with the flow of slurry eventually until sandout is reached. This process then repeats itself sequentially along the length of the shunt tube 200. Of course, depending on the flow of the slurry, the path of least resistance for its flow, and other given variables, the progression of the slurry exiting the exit ports 206 may be uphole, downhole, or a combination of both along the shunt tube 200.
Accordingly, the inserts 210 can be configured to erode in a predetermined pattern along the length of the shunt tube 200. Thus, the inserts 210 disposed toward one end (e.g., uphole end) of the shunt tube 200 can be configured to erode in the predetermined pattern before the inserts 210 disposed toward another end (e.g., downhole end) of the shunt tube 200. The reverse arrangement or some mixed arrangement can also be used. To achieve the desired configuration, each of the inserts 210 can have a same or different number of the at least one aperture therein and can be configured with thicknesses, diameters, and/or materials to control their erosion characteristics.
As noted above, the erosion insert 210 can have any number of openings or other features to control erosion and flow during gravel pack operations.
A series of small apertures, orifices or holes 212 are defined through the insert 210 and allow a limited amount of flow to pass from the shunt tube (200). In this particular example, the orifices 212 are arranged in a peripheral cross-pattern around the center, and joined slots 214 in the inner surface 211 can pass through the peripheral orifices 212. Initial flow through the orifices 212 may be small enough to restrict the flow of slurry as disclosed herein. As the slurry continues to pass through the small orifices 212, however, rapid erosion is encouraged by the pattern of the orifices 212 and the slots 153. In general, the central portion 218 of the insert 210 erodes due to the several orifices 212. Erosion can also creep along the slots 214 where the insert 210 is thinner, essentially dividing the insert 210 into quarters. These and other patterns and arrangement of holes and features can be used on the erosion inserts 210 of the present disclosure.
Turning now to
Being breachable, the barrier 224 breaks or bursts when subject to a pressure differential as slurry in the flow passage 204 of the shunt tube 200 acts against one side of the barrier 224. Once the barrier 224 is broken, the slurry in the tube's flow passage 204 can pass to the surrounding annulus. The various barriers 224 for the inserts 220 can be configured to burst at a predetermined pressure differential suited for the implementation. All of the barriers 224 may be configured the same along the shunt tube 200, or the barriers 224 may be configured to burst at increasing or decreasing pressures from one another along the length of the tube 200. These and other arrangements can be used.
As shown in
For example,
The nozzle-style burst insert 220 has a burst disc or barrier 224 disposed therein. As before, the barrier 224 is configured to burst from the buildup of slurry pressure at a predetermined point. This can be configured for a particular pressure buildup and can be designed for a particular implementation.
In another example,
As also shown here, a nozzle-style insert 260 (a.k.a. “nozzle”) is integrally formed on the tube body 250, although it could be a separately welded component. The nozzle-style insert 260 in this example is a burst insert as before having a burst disc or barrier 264 disposed in the nozzle's passage 262, although the body 250 can use any of the other types of inserts disclosed herein, including an erosion insert (210:
Previous embodiments have disclosed the use of independent and discrete flow inserts or nozzles disposed at exit ports along a shunt tube 200. In some implementations, it may be advantageous to use a cluster or collection of multiple inserts or nozzles at a given location on a shunt tube. For instance,
Rather than having a single flow nozzle as in previous embodiments, the tube body 250 has two or more nozzles or inserts 260a-b disposed together or in tandem on the tube body 250. Although two inserts 260a-b are shown in close connection to each other, any number of localized inserts 260a-b can be used. As shown in
Finally, as shown in
As discussed previously, the typical configuration for preventing erosion at a flow nozzle of a shunt tube involves disposing an insert of erosion-resistant material inside a flow nozzle. See e.g.,
As an alternative,
A different configuration is shown in
Yet another configuration shown in
The external buildup 340, even though not directly subject to erosive flow, fortifies the nozzle 310. Additionally, should the material of the inner flow nozzle 310 erode during use, the external buildup 340 can operate as the flow nozzle 310 and even maintain the overall diameter of the exit port 306 to an extent. Finally, by having the nozzle 310 affixed in place first on the exit port 306, the nozzle 310 can help to contain the application of the hardened buildup 340 and to maintain a uniform opening on the shunt tube 302 for the exit port 306 once the buildup 340 is applied.
Finally, an erosion-resistant nozzle of
Should erosion begin to wear the inside of the flow nozzle 310 (e.g., the surface of the inner sidewall exposed to the conducted slurry) and the inside of the cap 360, the erosion-resistant bushing 350 can act to reduce the erosive effects. Although not shown, a combination of the arrangements in
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 features described above in accordance with any embodiment or aspect of the disclosed subject matter can be utilized, either alone or in combination, with any other described feature, in any other embodiment or aspect of the disclosed subject matter. Thus, the insert or nozzle of one embodiment can be combined for use with an insert, nozzle, sheath, cap, bushing, etc. of another embodiment on a same shunt tube. Additionally, the tube bodies 250 of
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 application claims the benefit of U.S. Appl. No. 61/770,443, filed 28 Feb. 2013, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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61770443 | Feb 2013 | US |