Dehydrator screen for downhole gravel packing

Certain aspects and features relate to dehydrator screens that are inexpensively made wire, mesh, or stamped metal screens that can direct carrier fluid from a gravel pack slurry efficiently to one or more screens associated with a base pipe.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a U.S. national phase under 35 U.S.C. 371 of International Patent Application No. PCT/US2012/037217, titled “Dehydrator Screen for Downhole Gravel Packing,” filed May 10, 2012, the entirety of which is incorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to dehydrator screens in wellbores in subterranean formations and, more particularly (although not necessarily exclusively), to a dehydrator screen that can direct fluid from a gravel pack slurry to a main screen associated with a base pipe in the wellbore.

BACKGROUND

Various devices can be installed in a wellbore traversing a hydrocarbon-bearing subterranean formation. For example, screens can be positioned with sections of base pipe in a wellbore. The screens can filter particulate material from fluid prior to the fluid being received by an inner section of the base pipe. Another example is gravel packs that may be provided downhole in a slurry that includes a carrier fluid, gravel and other material. The gravel packs may be positioned between a base pipe and components associated with a base pipe and an inner wall of the wellbore to provide support or other functions.

Carrier fluid is removed from the slurry for a gravel pack to form downhole. The screens may allow the carrier fluid to drain from the slurry to create the gravel pack. It can be difficult to create a gravel pack, however, between screens and around a coupling between portions of a base pipe since fluid drainage may be limited or non-existent in those areas. Drainage tubes may be used to provide an alternate path for carrier fluid to drain from these areas, for example. The drainage tubes include precision-cut slots and can allow carrier fluid to drain from those areas to the screens.

Drainage tubes are made by making precise cuts using a laser to a tubing to create slots. Precise cuts are expensive, time intensive, and may result in a flow area of less than desirable size.

Accordingly, devices and assemblies are desirable that can filter and direct carrier fluid from a gravel pack slurry using a more desirable flow area and avoiding precise cuts.

SUMMARY

Certain aspects of the present invention are directed to a dehydrator screen that can direct fluid from a gravel pack slurry toward one or more main screens and that are made while avoiding precise cuts.

One aspect relates to an assembly that includes a dehydrator screen. The dehydrator screen can be positioned exterior to a base pipe in a wellbore. The dehydrator screen can direct fluid from a gravel pack slurry exterior to the base pipe toward a main screen that is associated with the base pipe. The dehydrator screen includes openings and is formed from at least one of stamped metal, wire wrap, or mesh material.

Another aspect relates to an assembly that includes a base pipe, at least two main screens, and a dehydrator screen. The main screens can circumferentially surround portions of the base pipe in the wellbore. The dehydrator screen includes an elongated element, openings in the elongated element, and at least two sealed ends. The dehydrator screen is (i) positionable exterior to part of the base pipe and the main screens in the wellbore and (ii) adapted for directing fluid from a gravel pack slurry exterior to the base pipe toward at least one of the main screens.

Another aspect relates to a dehydrator screen that includes an elongated element, openings in the surface of the elongated element, and sealed ends. The dehydrator screen is positionable in a wellbore exterior to a base pipe and a main screen associated with the base pipe. The dehydrator screen is adapted for directing fluid from a gravel pack slurry exterior to the base pipe toward the main screen.

These illustrative aspects are mentioned not to limit or define the invention, but to provide examples to aid understanding of the inventive concepts disclosed herein. Other aspects, advantages, and features of the present invention will become apparent after review of the entire document and drawings.

DETAILED DESCRIPTION

Certain aspects and features relate to dehydrator screens that are inexpensively made wire, stamped metal, or mesh screens that can direct carrier fluid from a gravel pack slurry efficiently to one or more screens associated with a base pipe. Dehydrator screens according to some aspects can be any shape, easy and inexpensive to manufacture, increase flow area by twenty to thirty percent, and increase efficiency of dehydration or filtering of carrier fluid from a gravel pack slurry.

One example of a dehydrator screen is a wire screen that may act as a drainage tube or be used with a drainage tube. The wire screen may be a wire wrap tube or other elongated member with two ends and openings in an outer surface. Both ends can be sealed by welding plates to the ends, shrink caps on the ends, or crush each end and weld any gap. Sealed ends may help direct fluid toward one or more other screens that may be main screens of a downhole assembly.

Another example of a dehydrator screen is a mesh screen that includes a mesh material seam welded to form a tube or other elongated member. The ends of the mesh screen may or may not be sealed.

Another example of a dehydrator screen is a screen formed by stamping a strip of metal, such as by using a louvered-type stamp, to create punched openings. The size and shape of the openings can be controlled through stamping. The metal strip can be formed into a tube or other shaped elongated member by helically welding the metal strip or by rolling the metal strip longitudinally and welding the seam. The ends of the tube or other elongated member can be sealed in ways similar to the wire screen described above.

Certain aspects provide a dehydrator screen that can be made anywhere, even at a wellbore site, at low cost, and can be made to a customized length for a given application. A dehydrator screen according to various aspects can avoid the need for precisely cut slots. Certain dehydrator screens can allow openings in the surface of the dehydrator screens to be adjusted, such as depending on the type or size of gravel.

FIG. 1depicts a well system100with a dehydrator screen116according to one aspect of the present invention. The well system100includes a bore that is a wellbore102extending through various earth strata. The wellbore102has a substantially vertical section104and a substantially horizontal section106. The substantially vertical section104and the substantially horizontal section106may include a casing string108cemented at an upper portion of the substantially vertical section104. The substantially horizontal section106extends through a hydrocarbon bearing subterranean formation110.

A tubing string112that is a base pipe extends from the surface within wellbore102. The tubing string112can provide a conduit for carrier and formation fluids to travel from the substantially horizontal section106to the surface. Screens114are positioned circumferential to portions of the tubing string112to define intervals. The dehydrator screen116is positioned exterior to the tubing string112. The dehydrator screen116is depicted as being proximate to both screens114. In other examples, the dehydrator screen116is proximate to one, but not both screens114, or otherwise positioned with respect to one or more of the screens114.

A gravel pack slurry may be provided down the wellbore102to the screens114. The dehydrator screen116can direct carrier fluid away from the gravel pack slurry, even the slurry between the screens114, to one or more of the screens114such that the carrier fluid is substantially removed from the gravel pack slurry.

AlthoughFIG. 1depicts screens114and the dehydrator screen116positioned in the substantially horizontal section106, screens114and the dehydrator screen116according to other examples can be located, additionally or alternatively, in the substantially vertical section104. Furthermore, any number of screens114and dehydrator screens116, including one of each, can be used in the well system100generally. In some embodiments, screens114and the dehydrator screen116can be positioned in simpler wellbores, such as wellbores having only a substantially vertical section. Screens114and the dehydrator screen116can be positioned in open hole environments, such as is depicted inFIG. 1, or in cased wells.

FIGS. 2-4depict an example of a dehydrator screen200that is a wire screen. The wire screen may be formed from a wire wrap tube202with ends204,206sealed by a sealing mechanism208. The sealing mechanism208may include plates welded on each of the ends204,206(as shown inFIGS. 2 and 4). Other examples of the sealing mechanism208include shrinking caps on each of the ends204,206and crushing each of the ends204,206and welding any gap.

The wire wrap tube202includes wires210with openings212between the wires210. Framing wires214, shown inFIG. 3with the sealing mechanism removed and in the side view cross-section ofFIG. 4, may be located in an inner region of the wire wrap tube202to provide stability to the dehydrator screen structure.

The openings212can allow carrier fluid from a gravel pack slurry to enter the inner region of the wire wrap tube202and be directed toward one or more main screens with respect to which the dehydrator screen is positioned, as shown for example inFIG. 1.

FIGS. 5-8depict another example of a dehydrator screen300that is formed from stamped metal. The dehydrator screen300includes punched openings302formed by stamping a metal strip and forming the metal strip into a tube304, shroud, or other elongated structure. The ends306,308can be sealed using a sealing mechanism310, such as those described above in connection withFIGS. 2 and 4. In one example, the punched openings302can be formed using a louvered-type stamp on a metal strip that is a shroud. The metal strip can be rolled and a seam welded to form the tube or other elongated structure.FIG. 6is a close-up view of a surface of the dehydrator screen300that includes punched openings302and a welded seam312.

FIG. 7depicts an example of a punched opening302. The punched opening302includes two gaps314,316formed after the metal strip is punched. The gaps314,316can allow fluid to enter an inner region of the dehydrator screen, as shown inFIG. 8, and directed towards one or more main screens.

Dehydrator screens according to other aspects may be formed using mesh. Mesh material may be interweaved or interlaced material forming a structure having openings.FIGS. 9-11depict examples of dehydrator screens at least partially formed using mesh.

FIG. 9depicts a dehydrator screen400that includes an elongated element402of mesh material404. The mesh material404can be rolled and coupled using a mechanism such as a welded seam406to form the elongated element. The mesh material404includes openings through which carrier fluid from a gravel pack slurry can be received and directed towards one or more main screens. The ends of dehydrator screen400may or may not be sealed. If the ends are sealed, the ends can be sealed using any suitable sealing mechanism, such as those discussed above.

FIG. 10is a dehydrator screen500that includes two elongated elements. The first elongated element502can be formed by stamping a strip of metal to form punched openings504and rolling or otherwise coupling the strip of metal together. The second elongated element506can be formed from mesh material as inFIG. 9and can circumferentially surround at least part of the first elongated element502. In other examples, the second elongated element506completely surrounds the first elongated element502. The second elongated element506can be coupled to the first elongated element502via a weld508or other suitable mechanism.

The ends of each of the first elongated element502and the second elongated element506may or may not be sealed. In some examples, the ends of the first elongated element502are not sealed and the ends of the second elongated element506are sealed.

Openings in the mesh material of the second elongated element506can allow carrier fluid from a gravel pack slurry to flow to openings in the first elongated element502and be received in an inner region of the first elongated element502. The dehydrator screen500can direct the fluid toward one or more main screens.

FIG. 11is a dehydrator screen600that includes three elongated elements. The first elongated element602and the second elongated element604may be similar to the first elongated element502and the second elongated element506ofFIG. 10, except that the first elongated element502and the second elongated element506are not welded together. The third elongated element606partially or completely surrounds the first elongated element602and the second elongated element604. The third elongated element606can be formed by stamping a strip of metal to form punched openings608and rolling or otherwise coupling the strip of metal together.

The ends of each of the first elongated element602, the second elongated element604, and the third elongated element606may or may not be sealed.

The dehydrator screen600can filter carrier fluid from a gravel pack slurry and allow the fluid to flow to an inner region defined by the first elongated element602, and direct the fluid toward one or more main screens.