Patent EA-000332-B1 (EA)
Title: Deformable well screen and method for its installation
Inventor: DONNELLY MARTIN
IPC: E21B43/08
Filed: 1996-11-07
Abstract: 1. A deformable well screen for preventing migration of solid particles into a hydrocarbon production well, which screen is arranged around a carrier tube (3,10) which is radially expandable by moving an expansion mandrel (12) in an axial direction through the interior of the tube (3,10), characterized in that the screen comprises at least one tubular filter layer (14) or a series of scaled filter sheets (4) having a sieve opening size which is tailored to the size of particles that are to be blocked by the screen, which filter layer (14) or series of scaled filters sheets (4) is deformable such that it can be expanded, bent, compressed and/or fluidised during installation of the screen in a wellbore (1,11) and that any variation of the sieve opening size of each filter layer (14) or filter sheet (4) as a result of such deformation remains within predetermined limits. 2. The well screen of Claim 1, wherein the screen is arranged around an expandable slotted carrier tube (3,10) and comprises at least one deformable tubular filter layer (14) of which the sieve opening size remains fairly constant or varies in a predetermined and uniform manner during expansion and/or other deformation of the screen. 3. The well screen of Claim 1 or 2, wherein the wells screen is coilable around a drum and installable into a well by reeling the screen from the drum. 4. The well screen of Claim 1, wherein the filter layer comprises a series of scaled filter sheets (4) which are arranged around an expandable slotted carrier tube (3) and which, when seen in a circumferential direction, are connected at or near one edge to said tube (3) and at another edge at least partly overlap an adjacent filter sheet (4). 5. The well screen of Claim 4, wherein the filter sheets (4) are connected to said carrier tube by a series of lugs (6) that are hooked onto the carrier tube (3) and wherein an expandable slotted protective tube (5) surrounds the filter layer. 6. The well screen of Claim 4 or 5, wherein the filter sheets (4) are made of a flexible permeable material which is selected from the group of a perforated metal plate, a metal plate comprising an array of substantially tangential slots, a sintered woven metal wire and a synthetic fabric. 7. The well screen of Claim 2, wherein the filter layer (14) is formed around an expandable slotted carrier tube (10) of which the slots (18) and any gaps (19) between the tube (10) and borehole wall (11) have been filled in suit with granules (14) that are bonded to each other and to the rims of the slots (18) by a bonding agent such that pore openings of a selected size remain between the granules. 8. The well screen of Claim 2, wherein the screen comprises an expandable tubular body with longitudinal micro-slots that are arranged in a staggered and overlapping pattern, which micro-slots substantially have before expansion of the tubular body a length less than 10 mm. 9. The screen of Claim 8, wherein the tubular body is made of nickel and the micro-slots substantially have a length less than 5 mm and a width less than 0.3 mm. 10. The well screen of Claim 2, comprising at least one deformable tubular filter layer which is made of a woven metal wire screen; and an outer protective layer which co-axially surrounds the filter layer or layers and an inner protective layer which is fitted co-axially within the protective layer or layers, which protective layers comprise each a woven metal wire screen having a larger sieve opening size and wire thickness than at least one of the filter layers, and wherein the filter and protective layers are sintered together. 11. The well screen of Claim 10, wherein at least one filter layer comprises wires which are oriented in a substantially helical weaving pattern relative to a central axis of said layer. 12. The well screen of Claim 11, wherein a helix defined by the helical weaving pattern is oriented at a pitch angle between 40 degree  and 50 degree  relative to said central axis. 13. The well screen of Claim 11, wherein the screen comprises filter sheets that are brought into a helical shape and welded together in a substantially non-overlapping helical pattern. 14. The well screen of Claim 10, comprising an inner and an outer filter layer which are co-axial to each other and separated by an intermediate layer which is made of a woven wire having a larger sieve opening than the filter layers and which is sintered to the filter layers, and wherein the outer filter layer has a smaller sieve opening than the inner filter layer. 15. The well screen of Claim 14, wherein a pair of outer protective layers surrounds the outer filter layer and a pair of inner protective layers is fitted within the inner filter layer and wherein the outermost outer protective layer and the innermost inner protective layer have a larger sieve opening size than the other layers. 16. The well screen of Claim 2, wherein the screen comprises at least one filter layer, which is substantially made of a fabric. 17. The well screen of Claim 16, wherein the filter layer comprises an elongate fabric strip, which is wound in an overlapping helical pattern to a substantially tubular shape. 18. The well screen of Claim 16, wherein said fabric comprises a needlefelt comprising a material selected from the group of steel wires and synthetic fibers, synthetic fibers selected from the group of aramid fibres and synthetic fibres selected from the group of "CARILON" polymer fibres. 19. A method of installing a deformable well screen in a hydrocarbon production well (1), the method comprising arranging the screen around an expandable' slotted carrier tube (3), lowering the screen and tube assembly into the well (1), inducing the tube (3) to expand by axially moving an expansion mandrel therethrough, thereby increasing the internal diameter of the screen with at least five per cent, characterized in that the screen comprises a series of scaled filter sheets (4) or tubular filter layer (14) and that any variation of the sieve opening size of each filter layer of the screen as a result of the expansion is less than fifty per cent. 20. The method of Claim 19, wherein the screen and tube assembly is wound around a drum and reeled from said drum into the well (1) during installation. 21. A method of installing a deformable well screen in a hydrocarbon production well, the method comprising lowering an expandable slotted carrier tube (11) into the well and inducing the tube (11) to expand and the slots (18) to open, characterized in that the method further comprises injecting granules (14) coated with a bonding agent into the expanded tube (11), wiping the granules (14) substantially from the interior of the tube (11) into the slots (18) and any gaps (19) between the tube (11) and the wellbore (11), and allowing the bonding agent to cure. 22. The method of Claim 19, 20 or 21, wherein the screen is installed in a compacting hydrocarbon reservoir which induces the screen to deform gradually in longitudinal and other directions after installation.