Patent Application
20110011586
This invention relates, in general, to controlling the production of particulate materials from a subterranean formation and, in particular, to a sand control screen assembly having a swellable material layer that is operable to radially expand downhole in response to contact with an activating fluid.
Without limiting the scope of the present invention, its background is described with reference to the production of hydrocarbons through a wellbore traversing an unconsolidated or loosely consolidated formation, as an example.
It is well known in the subterranean well drilling and completion art that particulate materials such as sand may be produced during the production of hydrocarbons from a well traversing an unconsolidated or loosely consolidated subterranean formation. Numerous problems may occur as a result of the production of such particulate materials. For example, the particulate materials cause abrasive wear to components within the well, such as tubing, flow control devices and safety devices. In addition, the particulate materials may partially or fully clog the well creating the need for an expensive workover. Also, if the particulate materials are produced to the surface, they must be removed from the hydrocarbon fluids by processing equipment at the surface.
One method for preventing the production of such particulate materials is gravel packing the well adjacent the unconsolidated or loosely consolidated production interval. In a typical gravel pack completion, a sand control screen is lowered into the wellbore on a work string to a position proximate the desired production interval. A fluid slurry including a liquid carrier and a particulate material, such as gravel, is then pumped down the work string and into the well annulus formed between the sand control screen and the perforated well casing or open hole production zone.
The liquid carrier either flows into the formation, returns to the surface by flowing through the sand control screen or both. In either case, the gravel is deposited around the sand control screen to form a gravel pack, which is highly permeable to the flow of hydrocarbon fluids but blocks the flow of the particulate carried in the hydrocarbon fluids. As such, gravel packs can successfully prevent the problems associated with the production of particulate materials from the formation.
It has been found, however, that a complete gravel pack of the desired production interval is difficult to achieve particularly in extended or deviated wellbores including wellbores having long, horizontal production intervals. These incomplete packs are commonly a result of the liquid carrier entering a permeable portion of the production interval causing the gravel to dehydrate and form a sand bridge in the annulus. Thereafter, the sand bridge prevents the slurry from flowing to the remainder of the annulus which, in turn, prevents the placement of sufficient gravel in the remainder of the production interval.
In addition, it has been found that gravel packing is not feasible in certain open hole completions. Attempts have been made to use expandable metal sand control screens in such open hole completions. These expandable metal sand control screens are typically installed in the wellbore then radially expanded using a hydraulic swage or cone that passes through the interior of the screen or other metal forming techniques. In addition to filtering particulate materials out of the formation fluids, one benefit of these expandable sand control screens is the radial support they provide to the formation which helps prevent formation collapse. It has been found, however, that conventional expandable sand control screens do not contact the wall of the wellbore along their entire length as the wellbore profile is not uniform. More specifically, due to the process of drilling the wellbore and heterogeneity of the downhole strata, washouts or other irregularities commonly occur which result in certain locations within the wellbore having larger diameters than other areas or having non circular cross sections. Thus, when the expandable sand control screens are expanded, voids are created between the expandable sand control screens and the irregular areas of the wellbore, which has resulted in incomplete contact between the expandable sand control screens and the wellbore. In addition, with certain conventional expandable sand control screens, the threaded connections are not expandable which creates a very complex profile, at least a portion of which does not contact the wellbore. Further, when conventional expandable sand control screens are expanded, the radial strength of the expanded screens is drastically reduced resulting in little, if any, radial support to the borehole.
Therefore, a need has arisen for a sand control screen assembly that prevents the production of particulate materials from a well that traverses a hydrocarbon bearing subterranean formation without the need for performing a gravel packing operation. A need has also arisen for such a sand control screen assembly that interventionlessly provides radial support to the formation without the need for expanding metal tubulars. Further, a need has arisen for such a sand control screen assembly that is suitable for operation in long, horizontal, open hole completions.
The present invention disclosed herein comprises a sand control screen assembly that prevents the production of particulate materials from a well that traverses a hydrocarbon bearing subterranean formation or operates as an injection well. The sand control screen assembly of the present invention achieves this result without the need for performing a gravel packing operation. In addition, the sand control screen assembly of the present invention interventionlessly provides radial support to the formation without the need for expanding metal tubulars. Further, the sand control screen assembly of the present invention is suitable for operation in open hole completions in long, horizontal production intervals.
In one aspect, the present invention is directed to a sand control screen assembly that is operable to be positioned within a wellbore. The sand control screen assembly includes a base pipe having at least one opening in a sidewall portion thereof and an internal flow path. A swellable material layer is disposed exteriorly of at least a portion of the base pipe. A fluid collection subassembly is disposed exteriorly of the swellable material layer and is in fluid communication with the internal flow path via the opening. A drainage layer is disposed exteriorly of the fluid collection subassembly and the swellable material layer such that, in response to contact with an activating fluid, radial expansion of the swellable material layer causes at least a portion of the fluid collection subassembly and the drainage layer to be displaced toward a surface of the wellbore.
In one embodiment, the swellable material layer is disposed exteriorly of a blank pipe section of the base pipe. In another embodiment, the fluid collection subassembly includes a plurality of circumferentially distributed perforated tubulars. In some embodiments, a filter medium is operably associated with the sand control screen assembly and is disposed in a fluid path between the exterior of the sand control screen assembly and the internal flow path. For example, the filter medium may be disposed internal to the fluid collection subassembly or the filter medium may be disposed downstream of the fluid collection subassembly.
Preferably, the activating fluid is at least one of a hydrocarbon fluid, water and gas. In certain embodiments, radial expansion of the swellable material layer causes at least a portion of the drainage layer to contact the wellbore. In these embodiments, the drainage layer provides a stand off region between the fluid collection subassembly and the wellbore. In one embodiment, the drainage layer is formed from a plurality of circumferential drainage layer segments. In some embodiments, an additive is carried within the drainage layer. For example, the additive may be a reactive substance such as a degradable polymer selected from the group consisting of polysaccharides, dextran, cellulose, chitins, chitosans, proteins, aliphatic polyesters, poly(lactides), poly(glycolides), poly(ε-caprolactones), poly(anhydrides), poly(hydroxybutyrates), aliphatic polycarbonates, poly(orthoesters), poly(amino acids), poly(ethylene oxides) and polyphosphazenes. In other embodiments, the additive may be selected from the group consisting of aliphatic polyesters, poly(lactides), poly(lactic acids) and poly(anhydrides).
In another aspect, the present invention is directed to a method of installing a sand control screen assembly in a wellbore. The method includes running the sand control screen assembly to a target location within the wellbore, the sand control screen assembly having a base pipe, a swellable material layer disposed exteriorly of at least a portion of a base pipe, a fluid collection subassembly disposed exteriorly of the swellable material layer and a drainage layer disposed exteriorly of the fluid collection subassembly and the swellable material layer; contacting the swellable material layer with an activating fluid; radially expanding the swellable material layer in response to contact with the activating fluid; and displacing at least a portion of the fluid collection subassembly and the drainage layer toward a surface of the wellbore in response to the radial expansion of the swellable material layer.
For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which:
While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the present invention.
Referring initially to
Positioned within wellbore 12 and extending from the surface is a tubing string 22. Tubing string 22 provides a conduit for formation fluids to travel from formation 20 to the surface. Positioned within tubing string 22 is a plurality of sand control screen assemblies 24. The sand control screen assemblies 24 are shown in a running or unextended configuration.
Referring also to
Even though
In addition, even though
Referring to
In the illustrated embodiment and as best seen in
Base pipe 42 includes a plurality of openings 60 that allow production fluids to enter internal flow path 44. Disposed around this portion of base pipe 42 and within annular region 56 is a filter medium 62. Filter medium 62 may comprise a mechanical screening element such as a fluid-porous, particulate restricting, metal screen having one or more layers of woven wire or fiber mesh that may be diffusion bonded or sintered together to form a screen designed to allow fluid flow therethrough but prevent the flow of particulate materials of a predetermined size from passing therethrough. In the illustrated embodiment, filter medium 62 includes outer and inner drainage layers 64, 66 that have a relatively course wire mesh with a filtration layer 68 disposed therebetween having a relatively fine mesh. It should be noted that other types of filter media may be used with the sand control screen assemblies of the present invention, such as a wire wrapped screen, a prepack screen, a ceramic screen, metallic beads such as stainless steel beads or sintered stainless steel beads and the like. Filter medium 62 is sized according to the particular requirements of the production zone into which it will be installed. Some exemplary sizes of the gaps in filter medium 62 may be in the 20-250 standard mesh range.
Referring additionally now to
Various techniques may be used for contacting swellable material layer 46 with an appropriate activating fluid for causing swelling of swellable material layer 46. For example, the activating fluid may already be present in the well when sand control screen assembly 40 is installed in the well, in which case swellable material layer 46 preferably includes a mechanism for delaying the swelling of swellable material layer 46 such as an absorption delaying or preventing coating or membrane, swelling delayed material compositions or the like.
Alternatively, the activating fluid may be circulated through the well to swellable material layer 46 after sand control screen assembly 40 is installed in the well. As another alternative, the activating fluid may be produced into the wellbore from the formation surrounding the wellbore. Thus, it will be appreciated that any method may be used for causing swelling of swellable material layer 46 of sand control screen assembly 40 in keeping with the principles of the invention.
Swellable material layer 46 is formed from one or more materials that swell when contacted by an activation fluid, such as an inorganic or organic fluid. For example, the material may be a polymer that swells multiple times its initial size upon activation by an activation fluid that stimulates the material to expand. In one embodiment, the swellable material is a material that swells upon contact with and/or absorption of a hydrocarbon, such as an oil or a gas. The hydrocarbon is absorbed into the swellable material such that the volume of the swellable material increases, creating radial expansion of the swellable material. Preferably, the swellable material will swell until its outer surface and perforated tubulars 52 of fluid collection subassembly 50 contact the formation face in an open hole completion or the casing wall in a cased wellbore. The swellable material accordingly provides the energy to position perforated tubulars 52 of fluid collection subassembly 50 in contact with the formation.
Some exemplary swellable materials include elastic polymers, such as EPDM rubber, styrene butadiene, natural rubber, ethylene propylene monomer rubber, ethylene propylene diene monomer rubber, ethylene vinyl acetate rubber, hydrogenized acrylonitrile butadiene rubber, acrylonitrile butadiene rubber, isoprene rubber, chloroprene rubber and polynorbornene. These and other swellable materials swell in contact with and by absorption of hydrocarbons so that the swellable materials expand. In one embodiment, the rubber of the swellable materials may also have other materials dissolved in or in mechanical mixture therewith, such as fibers of cellulose. Additional options may be rubber in mechanical mixture with polyvinyl chloride, methyl methacrylate, acrylonitrile, ethylacetate or other polymers that expand in contact with oil.
In another embodiment, the swellable material is a material that swells upon contact with water. In this case, the swellable material may be a water-swellable polymer such as a water-swellable elastomer or water-swellable rubber. More specifically, the swellable material may be a water-swellable hydrophobic polymer or water-swellable hydrophobic copolymer and preferably a water-swellable hydrophobic porous copolymer. Other polymers useful in accordance with the present invention can be prepared from a variety of hydrophilic monomers and hydrophobically modified hydrophilic monomers. Examples of particularly suitable hydrophilic monomers which can be utilized include, but are not limited to, acrylamide, 2-acrylamido-2-methyl propane sulfonic acid, N,N-dimethylacrylamide, vinyl pyrrolidone, dimethylaminoethyl methacrylate, acrylic acid, trimethylammoniumethyl methacrylate chloride, dimethylaminopropylmethacrylamide, methacrylamide and hydroxyethyl acrylate.
A variety of hydrophobically modified hydrophilic monomers can also be utilized to form the polymers useful in accordance with this invention. Particularly suitable hydrophobically modified hydrophilic monomers include, but are not limited to, alkyl acrylates, alkyl methacrylates, alkyl acrylamides and alkyl methacrylamides wherein the alkyl radicals have from about 4 to about 22 carbon atoms, alkyl dimethylammoniumethyl methacrylate bromide, alkyl dimethylammoniumethyl methacrylate chloride and alkyl dimethylammoniumethyl methacrylate iodide wherein the alkyl radicals have from about 4 to about 22 carbon atoms and alkyl dimethylammonium-propylmethacrylamide bromide, alkyl dimethylammonium propylmethacrylamide chloride and alkyl dimethylammonium-propylmethacrylamide iodide wherein the alkyl groups have from about 4 to about 22 carbon atoms.
Polymers which are useful in accordance with the present invention can be prepared by polymerizing any one or more of the described hydrophilic monomers with any one or more of the described hydrophobically modified hydrophilic monomers. The polymerization reaction can be performed in various ways that are known to those skilled in the art, such as those described in U.S. Pat. No. 6,476,169 which is hereby incorporated by reference for all purposes.
Suitable polymers may have estimated molecular weights in the range of from about 100,000 to about 10,000,000 and preferably in the range of from about 250,000 to about 3,000,000 and may have mole ratios of the hydrophilic monomer(s) to the hydrophobically modified hydrophilic monomer(s) in the range of from about 99.98:0.02 to about 90:10.
Other polymers useful in accordance with the present invention include hydrophobically modified polymers, hydrophobically modified water-soluble polymers and hydrophobically modified copolymers thereof. Particularly suitable hydrophobically modified polymers include, but are not limited to, hydrophobically modified polydimethylaminoethyl methacrylate, hydrophobically modified polyacrylamide and hydrophobically modified copolymers of dimethylaminoethyl methacrylate and vinyl pyrollidone.
As another example, the swellable material may be a salt polymer such as polyacrylamide or modified crosslinked poly(meth)acrylate that has the tendency to attract water from salt water through osmosis wherein water flows from an area of low salt concentration, the formation water, to an area of high salt concentration, the salt polymer, across a semi permeable membrane, the interface between the polymer and the production fluids, that allows water molecules to pass therethrough but prevents the passage of dissolved salts therethrough.
Referring to
In the illustrated embodiment, screen element 82 is formed from a plurality of circumferential screen segments that overlap one another in the running configuration of sand control screen assembly 70. Even though screen element 82 has been depicted as including four segments, it should be understood by those skilled in the art that other numbers of segments both greater than and less than four, including one segment, could alternatively be used in keeping with the principles of the present invention.
Referring additionally now to
Preferably, screen element 82 has the reactive substance impregnated therein. For example, the reactive substance may fill the voids in screen element 82 during installation. Preferably, the reactive substance is degradable when exposed to a subterranean well environment. More preferably, the reactive substance degrades when exposed to water at an elevated temperature in a well. Most preferably, the reactive substance is provided as described in U.S. Pat. No. 7,036,587 which is hereby incorporated by reference for all purposes.
In certain embodiments, the reactive substance includes a degradable polymer. Suitable examples of degradable polymers that may be used in accordance with the present invention include polysaccharides such as dextran or cellulose, chitins, chitosans, proteins, aliphatic polyesters, poly(lactides), poly(glycolides), poly(ε-caprolactones), poly(anhydrides), poly(hydroxybutyrates), aliphatic polycarbonates, poly(orthoesters), poly(amino acids), poly(ethylene oxides), and polyphosphazenes. Of these suitable polymers, aliphatic polyesters such as poly(lactide) or poly(lactic acid) and polyanhydrides are preferred.
The reactive substance may degrade in the presence of a hydrated organic or inorganic compound solid, which may be included in sand control screen assembly 70, so that a source of water is available in the well when the screens are installed. Alternatively, another water source may be delivered to the reactive substance after sand control screen assembly 70 is conveyed into the well, such as by circulating the water source down to the well or formation water may be used as the water source.
Referring to
In certain embodiments, it may be desirable to selectively allow and prevent flow through a sand control screen assembly of the present invention such as sand control screen assembly 90. In such embodiments, a valve or other flow control device may be placed in the fluid flow path between the exterior of sand control screen assembly 90 and internal flow path 94. For example, a sliding sleeve (not pictured) may be operably associated with base pipe 92 and openings 96. The sliding sleeve may be disposed internally of base pipe 92 within internal flow path 94 or may preferably be disposed externally of base pipe 92 within annular region 98. The sliding sleeve may have an open position wherein fluid flow through openings 96 is allowed and a closed position wherein fluid flow though openings 96 is prevented. In addition, the position of the sliding sleeve may be infinitely variable such that the sliding sleeve may provide a choking function. The sliding sleeve may be operated mechanically, electrically, hydraulically or by other suitable means.
Referring next to
Fluid discriminator section 126 is configured in series with sand control section 124 such that fluid must pass through sand control section 124 prior to entering fluid discriminator section 126. Fluid discriminator section 126 includes an outer housing 144 that defines an annular chamber 146 with a nonperforated section of base pipe 132. Fluid discriminator section 126 also includes retainer ring 148 that has a plurality of outlets 150 circumferentially spaced therein designed to provide a fluid passageway from chamber 146 to flow restrictor section 128.
One or more flow blocking members 152, depicted as spherical members or balls are disposed within chamber 146 between retainer ring 148 and filter medium 142, cooperate with outlets 150 to restrict the flow of any undesired portion of the production fluids that enter fluid discriminator section 126. For example, in the case of a production fluid containing both oil and water, the density of members 152 is such that certain of the outlets 150 are blocked by certain of the members 152 to shut off or choke the flow of water therethrough. Thus, when the production fluid is mainly oil, members 152 will be positioned relatively distant from outlets 150, for example, at the bottom of chamber 146. When a sufficient proportion of water is present in the production fluid, however, members 152 will restrict flow of the water by shutting off or choking flow through certain ones of the outlets 150.
Flow restrictor section 128 is configured in series with fluid discriminator section 126 such that fluid must pass through fluid discriminator section 126 prior to entering flow restrictor section 128. Flow restrictor section 128 includes an outer housing 154 that is suitably coupled to or integral with outer housing 144 of fluid discriminator section 126. Outer housing 154 defines an annular chamber 156 with a nonperforated section of base pipe 132. Disposed within chamber 156 is a flow rate controller 158. Flow rate controller 158 includes one or more tubular passageways 160 that provide a relative long, narrow and tortuous pathway for the fluids to travel within flow restrictor section 128 and that provide a more restrictive pathway than the unrestricted pathway through fluid discriminator section 126. As such, flow restrictor section 128 is operable to restrict the flow rate of the production fluids through sand control screen assembly 120.
Once the production fluids pass through flow rate controller 158 of flow restrictor section 128, they enter annular chamber 162 and eventually enter the interior flow path 134 of base pipe 132 via openings 164 which are depicted in the form of slots. Once inside base pipe 132, the production fluids flow to the surface within the tubing string.
Fluid discriminator section 126 is operable in various flow regimes and with various configurations of flow blocking members 152. For example, members 152 may have a single density and be designed to block a single type of undesirable fluid such as water or gas in an oil production operation, or may have two densities and be designed to block multiple types of undesirable fluids such as water and gas in an oil production operation. Also, all of the members intended to block a certain undesired fluid do not necessarily have the same density. Instead, the members in each category could have a range of different densities so that the members are neutrally buoyant in different densities of production fluids.
Even though
Referring to
Fluid collection subassembly 184 includes a plurality of perforated tubulars 186 that operate substantially in a manner as described above with reference to fluid collection subassembly 50. Preferably, perforated tubulars 186 are circumferentially distributed about the portion of sand control screen assembly 170 that includes swellable material layer 182. Disposed around the perforated portion of base pipe 172 and within annular region 178 is a filter medium 188. Filter medium 188 may comprise any suitable mechanical screening element or elements and is depicted as a multi-layer wire or fiber mesh screen designed to allow fluid flow therethrough but prevent the flow of particulate materials of a predetermined size from passing therethrough.
Fluid collection subassembly 184 of sand control screen assembly 170 also includes instrumentation and communication systems that allow information relating to the adjacent formation to be obtained and transmitted to the surface substantially in real time as desired. As illustrated, one of the perforated tubular 186 has been replaced with an electronics package 190 that includes one or more sensors. The sensors may be any one or more of the following types of sensors, including pressure sensors, temperature sensors, piezoelectric acoustic sensors, flow meters for determining flow rate, accelerometers, resistivity sensors for determining water content, velocity sensors, weight sensors or any other sensor that measures a fluid property or physical parameter downhole. As used herein, the term sensor shall include any of these sensors as well as any other types of sensors that are used in downhole environments and the equivalents to these sensors. For example, a fiber optic distributed temperature sensor 192 is depicted as being wrapped around one of the perforated tubular 186. The sensors may include or be associated with a microprocessor to allow manipulation and interpretation of the sensor data and for processing instructions. Likewise, the sensors may be coupled to a memory which provides for storing information for later batch processing or batch transmission, if desired. Importantly, this combination of components provides for localized control and operation of other downhole components such as an actuator which may be associated with a flow control device, a safety device or other actuatable downhole device. Alternatively or additionally, the sensor data may be digitally encoded and sent to the surface using electrical, optical, acoustic, electromagnetic or other telemetry techniques.
Even though the sand control screen assemblies of the present have been described as having a fluid collection assembly that channels fluids into a fluid collecting annular chamber or manifold prior to entry into the internal flow path of the base pipe, those skilled in the art will recognize that other types of fluid collection techniques could alternatively be used. For example, as best seen in
In a manner similar to that described above, sand control screen assembly 200 is run downhole with swellable material layer 208 in its unexpanded configuration. Upon contact with the activation fluid, such as a hydrocarbon fluid, water or gas as described herein, swellable material layer 208 is radially expanded, as best seen in
Even though the sand control screen assembly 200 has been described as having fluid inlets 210 formed in the shape of a “T”, those skilled in the art will recognize that other fluid inlets having other shapes could alternatively be used and would be considered within the scope of the present invention. For example, as best seen in
Even though the sand control screen assemblies 200, 220, 240, 260 have been described as having fluid inlets that radially outward shift in a piston-like manner, those skilled in the art will recognize that other techniques may be used to radially extend fluid inlets which would be considered within the scope of the present invention. For example, as best seen in
Referring next to
Each fluid inlet 320 also includes a fluid flow control device 328 that is disposed within discharge tube 326. Depending upon the desired operation, fluid flow control device 328 may take a variety of forms. For example, it may be desirable to temporarily prevent fluid flow through fluid inlets 320. In this case, fluid flow control device 328 may be a dissolvable, removable or shearable plug formed from sand, salt, wax, aluminum, zinc or the like or may be a pressure activated device such as burst disk. As another example, it may be desirable to prevent fluid loss into the formation during high pressure operations internal to sand control screen assembly 310 in which case, fluid flow control device 328 may be a one-way valve or a check valve. In a further example, it may be desirable to control the rate of production into sand control screen assembly 310 in which case, fluid flow control device 328 may be an inflow control device such as a nozzle, a flow tube, an orifice or other flow restrictor. As yet another example, it may be desirable to control the type of fluid entering sand control screen assembly 310 in which case, fluid flow control device 328 may be a production control device such as a valve that closes responsive to contact with an undesired fluid, such as water. Such valves may be actuated by a swellable material including those discussed above, organic fibers, an osmotic cell or the like.
Referring next to
Disposed between base pipe 332 and sleeve 334 is a pair of fluid flow control devices 350, 352. As described above, depending upon the desired operation, fluid flow control devices 350, 352 may take a variety of forms including in any combination of dissolvable, removable or shearable plugs, a burst disk, a one-way valve, a check valve, a nozzle, a flow tube, an orifice or other flow restrictor, a valve that closes responsive to contact with an undesired fluid and the like. In certain embodiments, sleeve 334 is removable by mechanical or chemical means such that the operation of fluid flow control devices 350, 352 can be disabled if desired.
Referring to
In addition to providing a path for formation fluids to enter internal flow path, sand control screen assembly 360 provides support to formation to prevent formation collapse. Specifically, the shape and configuration of screen sections 372 makes the outer surface of sand control screen assembly 360 particularly compliant which improves the contact between sand control screen assembly 360 and the formation upon radial expansion of swellable material layer 368.
Referring to
While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments.
This is a divisional application of co-pending application Ser. No. 12/201,468, entitled Sand Control Screen Assembly and Method for Use of Same, filed Aug. 29, 2008.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12201468 | Aug 2008 | US |
| Child | 12888590 | US |
