1. Field of the Invention
Embodiments of the invention generally relate to gravel packing of wells. In particular, the invention relates to methods and apparatuses suitable for injecting gravel slurry at high flow rates within the well bore being packed.
2. Description of the Related Art
Hydrocarbon wells, especially those having horizontal wellbores, typically have sections of wellscreen comprising a perforated inner tube surrounded by a screen portion. The screen blocks the flow of unwanted materials into the wellbore. Despite the wellscreen, some contaminants and other unwanted materials like sand, still enter the production tubing. The contaminants occur naturally and are also formed as part of the drilling process. As production fluids are recovered, the contaminants are also pumped out of the wellbore and retrieved at the surface of the well. By controlling and reducing the amount of contaminants that are pumped up to the surface, the production costs and valuable time associated with operating a hydrocarbon well will likewise be reduced.
One method of reducing the inflow of unwanted contaminants includes gravel packing. Normally, gravel packing involves the placement of gravel in an annular area formed between the screen portion of the wellscreen and the wellbore. In a gravel packing operation, a slurry of liquid, sand and gravel (“slurry”) is pumped down the wellbore where it is redirected into the annular area with a cross-over tool. As the gravel fills the annulus, it becomes tightly packed and acts as an additional filtering layer along with the wellscreen to prevent collapse of the wellbore and to prevent the contaminants from entering the stream of production fluids pumped to the surface. Ideally, the gravel uniformly packs around the entire length of the wellscreen, completely filling the annulus. However, during gravel packing, the slurry may become less viscous due to loss of fluid into the surrounding formations or into the wellscreen. The loss of fluid causes sand bridges to form. Sand bridges create a wall bridging the annulus and interrupting the flow of the slurry, thereby preventing the annulus from completely filling with gravel.
The problem of sand bridges is illustrated in
Also illustrated in
In response to the sand-bridging problem, shunt tubes have been developed creating an alternative path for gravel around a sand bridge. According to this conventional solution, when a slurry of sand encounters a sand bridge, the slurry enters an apparatus and travels in a tube, thereby bypassing the sand bridge to reenter the annulus downstream.
Both the method of constructing the nozzle 50 and the nozzle itself suffer from significant drawbacks. Holding the nozzle assembly 50 in correct alignment while welding is cumbersome. A piece of rod (not shown) must be inserted through the nozzle assembly 50, into the drilled hole 80, to maintain alignment. This requires time, and a certain level of skill and experience. During welding, the nozzle assembly 50 can shift out of exact alignment with the drilled hole in the tube due to either translational or rotational motion. After welding, exact alignment between the nozzle 50 and the drilled hole 80 is not assured. Because the carbide insert 60 actually sits on the surface of the tube 55, the hole 80 in the tube wall is part of the exit flow path 75. Abrasive slurry, passing through the hole, may cut through the relatively soft tube 55 material, and bypass the carbide insert 60 entirely, causing tube failure.
Therefore, there exists a need for an improved nozzle assembly for a shunt tube and a method for attaching the nozzle to the shunt tube.
For some embodiments, a nozzle assembly for use in a gravel pack tool having an aperture through a wall of a shunt along the tool includes an insert having a proximal end at least partially lining the aperture, wherein the insert has an outward facing shoulder distal to the aperture, and a jacket concentrically surrounding the insert, wherein the jacket is secured to an outer surface of the wall and has a face in abutment with the shoulder.
In some embodiments, an apparatus for use in a wellbore includes a wellscreen assembly, at least one shunt disposed on the wellscreen assembly and having an aperture through a wall of the shunt, an insert having a proximal end at least partially lining the aperture, wherein the insert has an outward facing shoulder distal to the aperture, a jacket concentrically surrounding the insert, wherein a first end of the jacket is secured to an outer surface of the wall and a second end of the jacket terminates in abutting contact with the shoulder, and an open cap secured to the jacket, wherein an inward facing shoulder of the cap abuts a distal terminus of the insert.
According to some embodiments, a nozzle assembly for use in a gravel pack tool having an aperture through a wall of a shunt along the tool includes an insert having a proximal end at least partially lining the aperture, wherein the insert has an enlarged outer diameter at a distal end of the insert relative to the aperture, a jacket concentrically surrounding the insert, wherein the jacket is secured to an outer surface of the wall at a first end and has an inner diameter smaller than the enlarged outer diameter of the insert, which abuts a second end of the jacket at the enlarged outer diameter, and an open cap secured to the second end of the jacket and extending beyond the enlarged outer diameter of the insert, wherein an opening through the cap has a restricted diameter smaller than the enlarged outer diameter of the insert, which is thereby trapped relative to the jacket.
So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
Apparatus 100 includes a wellscreen assembly 105. As shown, wellscreen assembly 105 comprises a base pipe 110 having perforations 120 through a wall thereof. Wound around an outer side of the base pipe 110 is a wire wrap 125 configured to permit the flow of fluids therethrough while blocking the flow of particulates. Alternatively, wellscreen assembly 105 may be any structure commonly used by the industry in gravel pack operations which permit flow of fluids therethrough while blocking the flow of particulates (e.g. commercially-available screens, slotted or perforated liners or pipes, screened pipes, prepacked screens and/or liners, or combinations thereof).
Also disposed on the outside of the base pipe 110 are two shunts 145. The number and configuration of shunts 145 is not essential to the invention. The shunts 145 may be secured to the base pipe 110 by rings (not shown). At an upper end (not shown) of the apparatus 100, each shunt 145 is open to the annulus. Each one of the shunts 145 is rectangular with a flow bore therethrough; however, the shape of the shunts is not essential to the invention. Disposed on a sidewall of each shunt is a nozzle 150.
Disposed on the outside of the base pipe 110 are a plurality of centralizers 130 that can be longitudinally separated from a length of the base pipe 110 that has the perforations 120 and the wire wrap 125. Additionally, a tubular shroud 135 having perforations 140 through the wall thereof can protect shunts 145 and wellscreen 105 from damage during insertion of the apparatus 100 into the wellbore. The perforations 140 are configured to allow the flow of slurry 13 therethrough.
In operation, apparatus 100 is lowered into wellbore 14 on a workstring and is positioned adjacent a formation. A packer 18 (see
Assembly of the nozzle assembly 150 is as follows. The insert 160 is inserted into the hole 170 until the taper of the outer surface 160c of the hard insert 160 is press fit with the shunt surface 145a defining the hole 170 and the shoulder 160b is seated on the shunt surface 145b proximate the hole 170, so that the lip 160a lines the surface 145a and the insert 160 is secured to the shunt 145. In other words, the smallest end of the taper is inserted into the hole 170 first, and the tapered surface of the insert 160 self-centers until it becomes snugly seated against the side of the hole 170 at the surface 145a. This contact occurs in the approximate area of surface 160c on the carbide insert. The outer jacket 155 can be disposed over an outer surface of the insert 160 and securely welded with minimal handling. Assembly time is greatly reduced, as is the required skill level of the assembler. Once seated, the nozzle assembly 150 is restrained from translating or rotating relative to the shunt 145. Alignment of the insert bore and the jacket bore with the drilled hole 170 in the shunt 145 is assured. Sand slurry 13 exiting the tube, represented by arrows 175, passes through the lip 160a of the hard insert, not the surface 145a of the hole 170. The possibility of flow cutting the surface 145a of the hole 170 is greatly diminished.
An outer jacket 255 of the nozzle assembly 250 includes a bore therethrough configured to receive the insert 260. Specifically, a recess 256 along an inner diameter of the outer jacket 255 proximate the aperture 270 accommodates an outer diameter of a medial length of the insert 260. A distal extension 260d extends from an opposite end of the insert 260 than the proximal lip 260a and has a reduced outer diameter with respect to the medial length of the insert 260 to form an outward shoulder 261. Accordingly, the outer jacket 255 easily slips over the insert 260 and secures to the shunt 145 with a weld 265. Once welded, an inward shoulder 258 defined by the recess 256 of the outer jacket 255 mates with the outward shoulder 261 of the insert 260 to prevent outward movement of the insert 260 with respect to the aperture 270.
The insert 260 and the outer jacket 255 preferably share a common terminus due to a sufficiently sized length of the distal extension 260d of the insert 260. In other words, the insert 260 concentrically disposed within the outer jacket 255 lines substantially the entire length of the inner diameter of the outer jacket 255. Threads 259 on an outside end of the outer jacket 255 can replace inner threads to enable securing of a cap (not shown) to the nozzle assembly 250 if desired.
Preferably, the outer jacket 255 and insert 260 are tubular members; however, their shape is not essential to the invention. As with other embodiments described herein, sand slurry 13 exiting the shunt 145, represented by arrows 275, passes through the proximal lip 260a of the insert in order to reduce wear on the surface 245a of the aperture 270. In addition, sand slurry 13 exiting the nozzle assembly 250 passes through the distal extension 260d of the insert 260 without flowing through and contacting an end of the outer jacket 255, which may be made of a softer material similar to the shunt 145. In this manner, the distal extension 260d protects the shoulders 258, 261 that cooperate to keep the insert 260 from escaping and causing failure at the nozzle assembly 250. Thus, the insert 260 can provide a carbide conduit that protects all other portions of the nozzle assembly 250 from flow cutting since sand slurry exiting the shunt 145 passes substantially entirely through the carbide conduit. The possibility of flow cutting the surface 245a of the aperture 270 or the end of the outer jacket 255 is greatly diminished.
The outer jacket 355 may define a tubular shape that receives the insert 360 and may be secured to the shunt 345 with a weld 365. A distal end 361 of the insert 360 includes an enlarged outer diameter portion that creates an outward facing shoulder 367. A mating surface such as a distal terminal face 358 of the jacket 355 abuts the outward facing shoulder 367 of the insert 360 since the inner diameter of the jacket 355 is smaller than the enlarged outer diameter portion of the insert 360. The jacket 355 thus retains the insert 360 from further inward movement into the aperture 370 and ensures that the proximal end 363 of the insert 360 lines the aperture 370 due to the corresponding lengths of the jacket 355 and of the insert 360 from the proximal end 363 to the outward facing shoulder 367.
An annular nut or otherwise open cap 357 prevents outward movement of the insert 360 with respect to the aperture 370 of the shunt 345. Once the nozzle assembly 350 is put together, the insert 360 becomes trapped by the jacket 355 and the cap 357 from sliding movement relative to the jacket 355. The cap 357 includes internal threads 353 threaded with external threads 359 on the jacket 355 and a central opening 352 aligned with a bore of the insert 360. The cap 357 extends beyond the enlarged diameter portion of the insert 360 and has an inward facing shoulder 351 retaining a mating surface such as a distal terminus 369 of the insert 360.
Sand slurry (represented by arrows 375) exiting the shunt 345 passes through the insert 360 in order to reduce wear on the shunt 345 at the aperture 370. The sand slurry 375 passes through the nozzle assembly 350 without contacting the outer jacket 355, which may be made of a softer material similar to the shunt 345. For some embodiments, the cap 357 may also be constructed of a hard material, e.g., carbide, like the insert 360. The cap 357 further enables replacement of the insert 360 without removing the jacket 355 from the shunt 345 such that a selected type of the insert 360 or a new replacement of the insert 360 may be installed at any time.
As shown, the nozzle assemblies 150, 250, 350 are used with a shunt of a gravel pack apparatus; however, the nozzle assemblies described herein may be used with various other apparatuses. While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 11/148,405, filed Jun. 8, 2005, which is a continuation-in-part of U.S. patent application Ser. No. 10/876,249, filed Jun. 23, 2004, which are all herein incorporated by reference.
Number | Date | Country | |
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Parent | 11148405 | Jun 2005 | US |
Child | 11551571 | Oct 2006 | US |
Parent | 10876249 | Jun 2004 | US |
Child | 11148405 | Jun 2005 | US |