Patent Publication Number: US-8528640-B2

Title: Wellbore flow control devices using filter media containing particulate additives in a foam material

Description:
BACKGROUND OF THE DISCLOSURE 
     1. Field of the Disclosure 
     The disclosure relates generally to apparatus and methods for controlling and filtering fluid flow into a wellbore. 
     2. Description of the Related Art 
     Hydrocarbons such as oil and gas are recovered from a subterranean formation using a wellbore drilled into the formation. Such wells are typically completed by placing a casing along the wellbore length and perforating the casing adjacent each such production zone to extract the formation fluids (such as hydrocarbons) into the wellbore. The casing may include a filtering mechanism or device that removes contaminants from fluid which flows through the perforations. Filtering devices often have complex assembly structure and may require frequent maintenance and/or replacement due to clogging and breakdown of such devices due to the relatively harsh environment downhole. Servicing a downhole filter device may cause significant downtime for a wellbore, reducing productivity. 
     The present disclosure addresses at least some of these prior art needs. 
     SUMMARY OF THE DISCLOSURE 
     In aspects, the present disclosure provides an apparatus methods for controlling flow of formation fluids into a wellbore. 
     In one aspect a fluid flow device is provided that in one embodiment may include a substantially permeable member made by combining a particulate additive with one or more materials that when processed by themselves form a substantially impermeable mass. 
     In another aspect, a method for making a fluid communication device is provided that in one embodiment may include; providing one or more materials that when processed will provide a substantially non-permeable mass; providing a particulate additive; combining the particulate additive with the one or more materials to form a substantially permeable member. In another aspect, the method may further include placing the substantially permeable member adjacent a tubular member having fluid flow passages therein to form a screen that inhibits particles above a selected size in a fluid from flowing from the substantially permeable member into the tubular member. 
     Examples of the more important features of the disclosure have been summarized rather broadly in order that detailed description thereof that follows may be better understood, and in order that the contributions to the art may be appreciated. There are, of course, additional features of the disclosure that will be described hereinafter and which will form the subject of the claims appended hereto. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The advantages and further aspects of the disclosure will be readily appreciated by those of ordinary skill in the art as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference characters generally designate like or similar elements throughout the several figures of the drawing and wherein: 
         FIG. 1  is a schematic elevation view of an exemplary multi-zonal wellbore and production assembly which incorporates a fluid control system in accordance with one embodiment of the present disclosure; 
         FIG. 2  is a sectional side view of an exemplary fluid flow device (or flow control device) that includes a filtration device in accordance with one embodiment of the present disclosure; 
         FIG. 3  is a view of an exemplary foam mass including cells and cell walls in accordance with one embodiment of the present disclosure; 
         FIG. 4  is a view of an exemplary body formed from a foam mass including fluid communication paths within the body in accordance with one embodiment of the present disclosure; 
         FIG. 5  is a sectional side view of an exemplary filtration device including a standoff member and a body formed from a foam mass in accordance with one embodiment of the present disclosure; 
         FIG. 6  is a sectional side view of an exemplary filtration device including a body formed from a foam mass, where the body is located outside a tubular structure, in accordance with one embodiment of the present disclosure; 
         FIG. 7  is a sectional side view of an exemplary filtration device including a body formed from a foam mass, where the body is located inside a tubular structure, in accordance with one embodiment of the present disclosure; and 
         FIG. 8  is a schematic view of an exemplary wellbore and fluid flow control plugs as a part of a production assembly in accordance with one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The present disclosure relates to devices and methods for controlling fluid production at a hydrocarbon producing well. The present disclosure is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the present disclosure with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein. 
       FIG. 1  shows a side view of an exemplary wellbore  100  that has been drilled through the earth  112  and into a pair of formations  114  and  116  from which it is desired to produce hydrocarbons. The wellbore  110  is cased by metal casing, as is known in the art, and a number of perforations  118  penetrate and extend into the formations  114  and  116  so that production fluids may flow from the formations  114  and  116  into the wellbore  110 . The wellbore  110  has a deviated, or substantially horizontal leg  119 . The wellbore  10  has a late-stage production assembly, generally indicated at  120 , disposed therein by a tubing string  122  that extends downwardly from a wellhead  124  at the surface  126  of the wellbore  100 . The production assembly  120  defines an internal axial flowbore  128  along its length. An annulus  30  is defined between the production assembly  120  and the wellbore casing. The production assembly  120  has a deviated, generally horizontal portion  132  that extends along the leg  119  of the wellbore  100 . Production devices  134  are positioned at selected locations along the production assembly  120 . Optionally, each production device  134  may be isolated within the wellbore  100  by a pair of packer devices  136 . Although only three production devices  134  are shown in  FIG. 1 , there may be a large number of such production devices arranged in a serial fashion along the horizontal portion  132 . 
     Each production device  134  features a production control device  138  used to govern one or more aspects of flow of one or more fluids into the production assembly  120 . As used herein, the term “fluid” or “fluids” includes liquids, gases, hydrocarbons, multi-phase fluids, mixtures of two of more fluids, water, brine, engineered fluids such as drilling mud, fluids injected from the surface such as water, and naturally occurring fluids such as oil and gas. Additionally, references to water should be construed to also include water-based fluids; e.g., brine or salt water. In accordance with embodiments of the present disclosure, the production control device  138  may have a number of alternative constructions that ensure controlled fluid flow therethrough. In an aspect, the production devices  34  may be wellbore filtration devices, such as sand filtration screens. Further, the illustrated production devices  134  may utilize filtration media, materials, and bodies, as discussed with respect to  FIGS. 2-8  of the present disclosure. As described herein, the devices discussed with respect to  FIGS. 1-8  may be referred to as fluid control or fluid filtering devices. 
       FIG. 2  is an illustration of an exemplary flow device  200  (also referred to as the “fluid flow device” or “production control” device) made according to one embodiment of the disclosure that may be placed in a wellbore. The flow device  200  is placed within a formation from which it is desired to produce hydrocarbons. The depicted flow device  200  is a side sectional view with a portion of the device structure removed to show the device&#39;s components. The wellbore is cased by metal casing and cement, and a number of perforations and flow passages enable production fluids to flow from the formation into the wellbore. The filtration device  200  may provide fluid communication paths and filtering mechanisms to remove unwanted solids and particulates from the production fluids. The depicted flow device  200  includes a filter member or body  202  which includes a substantially permeable foam mass configured to allow fluid flow into a tubing string, made according to one embodiment of the disclosure. 
     The exemplary flow device  200  also includes a tubular member  204 , which provides a flow passage for the production fluid to the wellbore surface. In addition, a shroud member  206  may be positioned outside of the filter member  202 . A standoff member  208  may be provided between the tubular member  204  and the filter body  202 . The standoff member  208  may be arranged to provide structural support while also providing spacing between the filter body  202  and the tubular member  204 , thereby reducing restrictions on the fluid flow into the tubular member  204 . In some embodiments, the standoff member  208  may be referred to as a drainage assembly. The shroud member  206  may include passages  210 , wherein the passages  210  may have tortuous fluid flow paths configured to remove larger particles from the production fluid prior to it entering the filtration device  200 . Further, the shroud member  206  may provide protection from wear and tear on the filter member  202  and the flow device  200 . The tubular member  204  includes passages  212  allow the production fluid to enter into the tubular member  204  and thus into the wellbore. In one aspect, the production fluid may flow along an axis  214 , toward the surface of the wellbore. The filter member  202  may be formed from one or more materials or components, such as a polymeric foam, which create cells and cell walls in the body. The cell-based structure of the foam enables the filter body  202  to have a light weight and low density, reducing overall weight of the device while retaining a durable and effective fluid filter structure. For example, two chemical components or materials, which when or processed form a closed cell foam, may be used to form the foam mass. A closed cell foam is a foam with a cell structure that is substantially impermeable to fluid flow through the foam. Therefore, a foam mass composed of closed cell foam is substantially impermeable. As depicted, however, a particulate additive may be added to one or more of the components prior to formation of the foam mass to create fluid communication paths between closed cells and across the resulting mass or body. The additive causes formation of openings in the cell walls, therefore enabling passage of a fluid between the cells. Accordingly, the components that originally may be used to form a substantially non-permeable foam mass are altered by the addition of the particulate additive to form a substantially permeable member or foam mass. In an embodiment, the filter member  202  may be formed by any suitable polymeric material, such as polyurethane, epoxy, fluorinated polymer and other polymers and their blends. 
     As discussed below, the flow device  200  may have a number of alternative constructions that ensure controlled fluid flow therethrough. Various materials may be used to construct the components of the filtration device  200 , including metal alloys, steel, polymers, any suitable durable and strong material, or any combination thereof. As depicted herein, the illustrations shown in the figures are not to scale, and assemblies or individual components may vary in size and/or shape depending on desired filtering, flow, or other relevant characteristics. Further, some illustrations may not include certain components removed to improve clarity and detail of the elements being discussed. 
       FIG. 3  is a view of a portion of an exemplary permeable foam mass  300 , which is formed into a body of the filtration device. The illustration provides a magnified view of a foam structure, and the foam&#39;s cell structure. A polymeric foam may be mixed to form the permeable foam mass  300 . The permeable foam mass  300  may include cell walls  302  which form cells  304  that are open spaces filled with a gas or other fluid. For a permeable foam mass, the ratio of open cell ( 304 ) volume to cell wall ( 302 ) volume may vary, depending on the materials used and the desired filter properties such as permeability, weight, and durability. For example, the open cell to cell wall volume ratio may range from 8:1 to 1:1. 
     The components or materials used to form the permeable foam mass may be mixed with a particulate additive  306 , which creates fluid communication paths or openings  308 . The particulate additive  306  may be composed of any suitable inert material, including clay, mica, fine sand, salt dust, ground mineral dust, silica, carbonate, titania, glass fibers, carbon fibers, polymer fibers, polymer fibers, or ceramic fibers. In addition, nano-particles may be used as an additive, including, but not limited to, buckey balls, carbon nano tubes, or graphene platelets. The size and concentration of the particulate additive  306  may depend on the components used to form the cell structures as well as the ratio of open cells to cell walls. Other factors, including application specific needs, such as tensile strength requirements, size of particles to be filtered from the production fluid, and desired permeability of the body, may also influence the size and amount of particulate additives. In one embodiment, approximately 0.05% to 3% by weight of polymeric solids of a particulate additive may be added to the mixture of foam components. For example, about 1.5 grams of a particulate additive may be added during a mixing of a polymer, wherein the total weight of the polymeric solid is about 100 grams when dry. Therefore, the particulate additive is about 1.5% by weight of the solid polymer material. In addition, the particulate additive  306  may be approximately 0.01 to 0.5 millimeters in size or diameter. 
     During formation of the cell walls  302  and cells  304 , the particulate additive  306  may occupy cell wall regions, wherein the particulate additive  306  may cause a fracture in the cell wall to enable formation of the openings  308 . Not all cell walls are occupied and/or fractured by the particulate additives  306 . The lack of particulate induced fracture is illustrated by a solid wall  310 . In such a case, the solid wall  310  provides strength for the cell structure of the permeable foam mass  300 . In one aspect, a wall thickness  312  may be substantially the same dimension as the particulate additive  306  diameter, enabling formation of the openings  308 . For example, the particulate additive  306  may be added to one or more foam mass components prior to mixing to form a foam mass. After mixing the components, the particulate additives  306  may cause openings to form in cell walls during cooling of the foam. Accordingly, the openings  308  enable fluid communication between cells of the mass. The openings may be formed during the mixing and formation of the foam mass or via a mechanical process, such as compression and expansion or forcing a fluid through the cells within the mass. The foam mass  300  created by this process may be described as substantially permeable, wherein the cell wall formations and fractures enable a selected amount of fluid to flow therethrough. Moreover, the structure provided by the cells and cell walls enables the foam mass  300  to retain desirable characteristics of a closed cell foam, such as compressive strength, rigidity, and durability, while also exhibiting the permeable characteristics of an open cell foam. Although the description provided above relates to two components that form an impermeable member and one particulate additive, one or more than one particulate additives may be combined with one or more or other materials to produce the filtration member or mass according to this disclosure. Further, in an aspect, the permeable member is a mass having an open volume to a solid volume ratio of about 4 to 1. In such a case, the open volume is a cavity that enables fluid flow and the solid volume is a foam or other structure that inhibits fluid flow. Moreover, after addition of the particulate additive, the permeable member is a mass having a mechanical strength that is up to about 20% less than the mechanical strength of the substantially impermeable mass prior to addition of the particles. 
     Referring to  FIG. 4 , the illustration provides a view of an exemplary body  400  of a permeable foam mass. In an aspect, the body  400  may be a sheet or layer that is wrapped around a tubular fluid communication structure. Cell walls  402  form a structure around cells  404 , which may be filled with fluids, such as gases or liquids that travel through the body  400 . The cell walls  402  may be formed by a chemical reaction between two or more components, thereby forming the cells  404 , which are open areas or regions filled with a gas, and the cell wall  402  structures. As depicted, a particulate additive  406  may be added to the components to cause formation of passages  408  to enable fluid communication between cells  404  and across the body  400 . The particulate additive  406  may be a plurality of granulate inert structures that range in size, causing fractures in the cell walls  402  during formation. For example, a fluid  410  may enter one side of the body  400 , travel through the passages  408 , and exit the body, as shown by arrow  412 . Accordingly, during a fluid filtering operation, a fluid may travel as shown by arrows  414  and  416  through the body  400 . 
       FIG. 5  is a sectional side view of an exemplary filtration device (or filtration member)  500 , which may be used in a wellbore as illustrated in  FIGS. 1 and 2 , To enhance clarity, the illustration includes only one half of the filtration device  500 . The filtration device  500  includes a filter member or filter body  502  formed from a permeable foam mass as described previously. The filtration device  500  may also include a tubular member or pipe  504 , which directs the production fluid to the wellbore surface. The fluid may flow from a formation, as shown by an arrow  506 , into the filter body  502 . The filter body  502  may be coupled to a standoff member  507 , which enables drainage and flow of the fluid between the filter body  502  and the tubular member  504 . The production fluid may flow  508  into the pipe  504  via passages  510 . In an embodiment, the filtration device  500  is a sand screen assembly used to remove solids and contaminants from production fluid prior to extraction. 
       FIG. 6  is a sectional side view of another exemplary filtration device  600 , as discussed with respect to  FIG. 5 . The illustration includes only one half of the filtration device  600  to enhance clarity. The filtration device  600  includes a filter body  602 , which is formed from a permeable foam mass. The filtration device  600  also includes a pipe  604 , which directs the production fluid to the wellbore surface. As depicted, the filter body  600  is a sheet or layer wrapped around the pipe  604 . The fluid may flow, as shown by an arrow  606 , into the filter body  602 . In addition, the production fluid may flow  608  into the pipe  604  via passages  610 . The filter body  602  may include components that are sufficiently rigid and strong to withstand direct impingement from large particles in the formation fluid. 
       FIG. 7  is a sectional side view of another exemplary filtration device  700 , as previously discussed with respect to  FIGS. 5 and 6 . The illustration includes only one half of the filtration device  700  to enhance clarity. The filtration device  700  includes a filter body  702 , which is formed from a permeable foam mass. The filtration device  700  also includes a pipe  704 , wherein the filter body  702  is located inside the pipe  704 . The production fluid may flow through pipe passages  706 , as shown by an arrow  708 , into the filter body  702 . The permeable mass within the body  702  enables fluid flow while filtering the fluid prior to flowing inside the body, as shown by an arrow  710 , prior to flowing axially to the surface. As depicted, the filter body  700  is a sheet or layer of permeable foam mass placed within the pipe  704 . 
     As discussed herein, the permeable foam mass may include a shape-conforming material. The types of materials that may be suitable for preparing the shape-conforming material may include any material that is able to withstand typical downhole conditions without undesired degradation. In non-limiting embodiments, such material may be prepared from a thermoplastic or thermoset medium. This medium may contain a number of additives and/or other formulation components that alter or modify the properties of the resulting shape-conforming material. For example, in some non-limiting embodiments the shape-conforming material may be either thermoplastic or thermoset in nature, and may be selected from a group consisting of polyurethanes, polystyrenes, polyethylenes, epoxies, rubbers, fluoroelastomers, nitriles, ethylene propylene diene monomers (EPDM), other polymers, combinations thereof, and the like. 
     In certain non-limiting embodiments the shape-conforming material may have a “shape memory” property. Therefore, the shape-conforming material may also be referred to as a shape memory material or component. As used herein, the term “shape memory” refers to the capacity of the material to be heated above the material&#39;s glass transition temperature, and then be compressed and cooled to a lower temperature while still retaining its compressed state. However, it may then be returned to its original shape and size, i.e., its pre-compressed state, by reheating close to or above its glass transition temperature. This subgroup, which may include certain syntactic and conventional foams, may be formulated to achieve a desired glass transition temperature for a given application. For instance, a foaming medium may be formulated to have a transition temperature just slightly below the anticipated downhole temperature at the depth at which it will be used, and the material then may be blown as a conventional foam or used as the matrix of a syntactic foam. 
     The initial (as-formed) shape of the shape-conforming material may vary, though an essentially cylindrical shape is usually well-suited to downhole wellbore deployment, as discussed herein. The shape-conforming material may also take the shape of a sheet or layer, as a component of a fluid or sand control apparatus. Concave ends, striated areas, etc., may also be included in the design to facilitate deployment, or to enhance the filtration characteristics of the layer, in cases where it is to serve a sand control purpose. 
     Referring to  FIG. 8 , the illustration shows an exemplary wellbore  800  where a plug composed of permeable foam mass may be utilized as part of a fluid production assembly. The schematic illustration has several elements of a production assembly removed to enhance clarity of the elements to be discussed. The wellbore  800  may be drilled through the earth to form a borehole including an upper region  802 , where a compacted plug  804  may be deployed. As depicted, the compacted plug  804  travels from a wellbore surface  806  downhole  808  to a selected location  810  within the wellbore. The compacted plug  804  is formed from a shape memory foam, which may be formed into the plug shape below a glass transition temperature of the shape-memory foam. The shape memory foam also includes the particulate additive, as described above, which cause the foam to be substantially permeable while also exhibiting shape memory characteristics. The compacted plug  804  may retain its compact shape while the plug is below the glass transition temperature. Once the plug reaches the selected location  810  downhole, exposure to a temperature at or above the glass transition temperature causes an expanded plug  812  to conform to formation walls  814 . Accordingly, formation fluid flow  816  is drawn to and through the permeable foam mass of the expanded plug  812 . The fluid then flows from the plug  812  toward the wellbore surface  806 , as shown by an arrow  818 . The expanded plug  812  may include or be coupled to a substantially non-permeable member  820 , thereby prevent fluid flow in a downhole region  822 . The substantially non-permeable member  820  may be a closed cell foam or other material with shape-memory properties as discussed above. The shape of the compacted ( 804 ) and expanded ( 812 ) plugs may be configured to adapt to the wellbore. For example, a cylindrical wellbore may require cylindrical plugs  804  and  812 . 
     When shape-memory foam is used as a filtration device or media for downhole sand control applications, it is preferred that the filtration device remains in a compressed state during run-in until it reaches to the desired downhole location. Usually, downhole tools traveling from surface to the desired downhole location take hours or days. When the temperature is high enough during run-in, the heat might be sufficient to trigger expansion of the filtration devices made from the shape-memory polyurethane foam. To avoid undesired early expansion during run-in, delaying methods may or must be taking into consideration. In one specific, but non-limiting embodiment, poly(vinyl alcohol) (PVA) film is used to wrap or cover the outside surface of filtration devices made from shape-memory polyurethane foam to prevent expansion during run-in. Once filtration devices are in place in downhole for a given amount of time at given temperature, the PVA film is capable of being dissolved in the water, emulsions or other downhole fluids and, after such exposure, the shape-memory filtration devices can expand and totally conform to the bore hole. In another alternate, but non-restrictive specific embodiment, the filtration devices made from the shape-memory polyurethane foam may be coated with a thermally fluid-degradable rigid plastic such as polyester polyurethane plastic and polyester plastic. The term “thermally fluid-degradable plastic” is meant to describe any rigid solid polymer film, coating or covering that is degradable when it is subjected to a fluid, e.g. water or hydrocarbon or combination thereof and heat. The covering is formulated to be degradable within a particular temperature range to meet the required application or downhole temperature at the required period of time (e.g. hours or days) during run-in. The thickness of delay covering and the type of degradable plastics may be selected to be able to keep filtration devices of shape-memory polyurethane foam from expansion during run-in. Once the filtration device is in place downhole for a given amount of time at temperature, these degradable plastics decompose allowing the filtration devices to expand to the inner wall of bore hole. In other words, the covering that inhibits or prevents the shape-memory porous material from returning to its expanded position or being prematurely deployed may be removed by dissolving, e.g. in an aqueous or hydrocarbon fluid, or by thermal degradation or hydrolysis, with or without the application of heat, in another non-limiting example, destruction of the cross-links between polymer chains of the material that makes up the covering. 
     As shown in the upper region  802 , the shape-memory material has the compressed, run-in, compacted plug  804  form factor. After a sufficient amount heating at or above the glass transition temperature, the shape-memory permeable plug  804  expands from the run-in or compacted position to the expanded or set form  812  having an expanded thickness. In so doing, the shape-memory material of the expanded plug  812  engages with the formation walls  814 , and, thus, prevents the production of undesirable solids from the formation, allows only hydrocarbon fluids flow through the expanded plug  812 . 
     Further, when it is described herein that the filtration device  804  or plugs  812  “conforms” to the wellbore or “plugs” the wellbore, what is meant is that the shape-memory porous material expands or deploys to fill the available space up to the wellbore wall. The wellbore wall will limit the final, expanded shape of the shape-memory porous material and thus may not permit it to expand to its original, expanded position or shape. In this way however, the expanded or deployed shape-memory material as a component of the plug ( 804  and  812 ), being porous, remain in its plugged position in the wellbore and thus will permit hydrocarbons to flow from a subterranean formation into the wellbore, but will prevent or inhibit solids of particular sizes from entering the wellbore. This is because solids larger than certain sizes will generally be too large to pass through the open cells of the porous material. The type, amount and sizes of the additive particulates may be chosen to determine the size of the particles that will be inhibited from passing through the open cell porous material. 
     While the foregoing disclosure is directed to certain disclosed embodiments and methods, various modifications will be apparent to those skilled in the art. It is intended that all modifications that fall within the scopes of the claims relating to this disclosure be deemed as part of the foregoing disclosure. The abstract provided herein is to conform to certain regulations and it should not be used to limit the scope of the disclosure herein or any corresponding claims.