Apparatus and method for reducing water production from a hydrocarbon producing well

Abstract

A filtering apparatus for use in a hydrocarbon producing well for reducing water production therein includes a filtering medium treated with a relative permeability modifier such that the relative permeability modifier reduces the permeability of the filtering medium if the relative permeability modifier contacts water production. The relative permeability modifier may be used to treat a metal portion of the filtering medium in the case of a wire wrap screen or a wire mesh screen or may be use treat a metal portion or the prepacked component of a prepacked screen. The relative permeability modifier may be a polymer of at least one hydrophilic monomer and at least one hydrophobically modified hydrophilic monomer, a hydrophobically modified polymer, a hydrophobically modified water-soluble polymer, hydrophobically modified copolymers thereof or the like.

Description

TECHNICAL FIELD OF THE INVENTION

This invention relates, in general, to reducing water production from a hydrocarbon producing well and, in particular, to treating a filtering medium with a relative permeability modifier to reduce the permeability of the filtering medium upon contact with water production.

BACKGROUND OF THE INVENTION

Without limiting the scope of the present invention, its background will be described with reference to a subterranean hydrocarbon bearing formation that produces water, as an example.

The production of water from subterranean hydrocarbon bearing formations constitutes a major problem and expense in the production of the hydrocarbons. While hydrocarbon producing wells are usually completed in hydrocarbon producing formations, when the formations contain layers of water and hydrocarbons or when there are water producing zones near the hydrocarbon producing formations, the higher mobility of the water often allows the water to flow into the wellbores which penetrate the hydrocarbon producing formations by way of natural fractures or high permeability streaks. In the production of such wells, the ratio of water to hydrocarbons recovered often becomes so high that the cost of producing the water, separating it from the hydrocarbons and disposing of it represents a significant economic loss.

In order to reduce the production of undesired water from hydrocarbon producing formations, attempts have been made to use aqueous polymer solutions containing cross-linking agents. These aqueous polymer solutions have been pumped into the hydrocarbon producing formations so that they enter water zones within and adjacent to the formations and cross-link therein. The cross-linking of the polymer solutions causes them to form stiff gels which aid in stopping or reducing the flow of the undesired water. While such aqueous polymer solutions have achieved some degree of success, it has been found that they are not suitable for formation treatments unless the polymer solution can be placed solely in the offending water producing zone or zones. If a polymer solution is allowed to gel within a hydrocarbon producing zone, the cross-linked polymer gel will reduce or stop the flow of hydrocarbons in addition to the flow of water. The selected placement of a polymer solution in a producing formation requires expensive, time-consuming zonal isolation placement technology. In addition, even when a polymer solution is properly placed in a water producing zone, the cross-linked gels often do not remain stable in the zone due to thermal degradation or differences in the adsorption characteristics of the polymer and associated cross-linker.

More recently, chemicals referred to as relative permeability modifiers have been utilized to decrease the production of water with hydrocarbons. That is, water permeability modifying chemicals, such as polyacrylamide, have been introduced into formations producing hydrocarbon and water so that the chemicals attach to adsorption sites on surfaces within the porosity of the formations. The presence of the chemicals in the formations has the effect of reducing the flow of water through the treated formation while having a minimal affect on the flow of hydrocarbons therethrough. The use of water permeability modifying chemicals to decrease the production of water is considerably less expensive than other techniques such as the above described technique of blocking the flow of water with cross-linked polymers and does not require expensive zonal isolation procedures. It has been found, however, that the use of such hydrophilic water permeability modifying chemicals has resulted in only small reductions in water production and in some cases an unacceptable level of reduction in hydrocarbon production.

Therefore, a need has arisen for an apparatus and method for reducing water production from a hydrocarbon producing well. A need has also arisen for such an apparatus and method that reduces the water production without unacceptably reducing the production of hydrocarbons. Further, need has arisen for such an apparatus and method that reduces the water production without the need for intervention.

SUMMARY OF THE INVENTION

The present invention disclosed herein comprises an apparatus and method for reducing water production from a hydrocarbon producing well. The apparatus and method of the present invention are capable of achieving this reduction in water production without unacceptably reducing the production of hydrocarbons and without the need for intervention.

In one aspect, the present invention is directed to a filtering apparatus that comprises a filtering medium treated with a relative permeability modifier that reduces the permeability of the filtering medium if the relative permeability modifier contacts water production. In one embodiment, the filtering medium is a sand control screen such as a wire wrap sand control screen, a prepacked sand control screen, a wire mesh sand control screen or the like. In any of these examples, the relative permeability modifier may be used to treat a metal portion of the filtering medium. Alternatively or additionally, in the case of a prepacked sand control screen, the relative permeability modifier may be used to treat the prepacked material of the sand control screen.

In one embodiment of the present invention, the relative permeability modifier used to treat the filtering medium is selected from the group consisting of a polymer of at least one hydrophilic monomer and at least one hydrophobically modified hydrophilic monomer, a hydrophobically modified polymer, a hydrophobically modified water-soluble polymer and hydrophobically modified copolymers thereof. For example, the relative permeability modifier may be selected from the group consisting of a polymer of at least one of acrylamide, 2-acrylamido-2-methyl propane sulfonic acid, N,N-dimethylacrylamide, vinyl pyrrolidone, dimethylaminoethyl methacrylate, acrylic acid, dimethylaminopropylmethacrylamide, trimethylammoniumethyl methacrylate chloride, methacrylamide, and hydroxyethyl acrylate combined with at least one of alkyl acrylates, alkyl methacrylates, alkyl acrylamides, alkyl methacrylamides, alkyl dimethylammoniumethyl methacrylate bromide, alkyl dimethylammoniumethyl methacrylate chloride, alkyl dimethylammoniumethyl methacrylate iodide, alkyl dimethylammonium propylmethacrylamide bromide, alkyl dimethylammonium propylmethacrylamide chloride and alkyl dimethylammonium propylmethacrylamide iodide. As another example, the relative permeability modifier may be selected from the group consisting of hydrophobically modified polydimethylaminoethyl methacrylate, hydrophobically modified polyacrylamide and hydrophobically modified copolymers of dimethylaminoethyl methacrylate and vinyl pyrollidone.

In another aspect, the present invention is directed to a method for reducing water production in a hydrocarbon producing well. The method includes treating a filtering medium with a relative permeability modifier, disposing the filtering medium proximate a production zone of the well, producing fluids from the production zone and reducing the permeability of the filtering medium if the relative permeability modifier contacts water production.

In a further aspect, the present invention is directed to a completion system for use in a hydrocarbon producing well having multiple production zones. The completion system comprises a production tubing string extending along a substantial length of the well and an isolation and filtration subassembly disposed proximate each of the production zones. Each isolation and filtration subassembly is operably associated with the production tubing string such that fluid from the respective production zones is produced through one of the isolation and filtration subassemblies into the production tubing string. In addition, each isolation and filtration subassembly provides substantial zonal isolation of the respective production zones. The isolation and filtration subassemblies include at least one filtering medium treated with a relative permeability modifier such that the relative permeability modifier reduces the permeability of the associated filtering medium if the associated filtering medium contacts water production, thereby reducing the production of water from the associated production zone.

BRIEF DESCRIPTION OF THE DRAWINGS

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:

FIG. 1 is a schematic illustration of an offshore oil and gas platform operating a completion system for reducing water production from a hydrocarbon producing well of the present invention;

FIG. 2 is partial cut away view of an apparatus for reducing water production from a hydrocarbon producing well of the present invention;

FIG. 3 is partial cut away view of an apparatus for reducing water production from a hydrocarbon producing well of the present invention;

FIG. 4 is partial cut away view of an apparatus for reducing water production from a hydrocarbon producing well of the present invention;

FIG. 5 is a schematic illustration of a completion system for reducing water production from a cased hydrocarbon producing well of the present invention; and

FIG. 6 is a schematic illustration of a completion system for reducing water production from a horizontal, open hole hydrocarbon producing well of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

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 FIG. 1, a completion system for reducing water production from a hydrocarbon producing well is being installed from an offshore oil and gas platform that is schematically illustrated and generally designated 10. A semi-submersible platform 12 is centered over a submerged oil and gas formation 14 located below sea floor 16. A subsea conduit 18 extends from deck 20 of platform 12 to wellhead installation 22 including blowout preventers 24. Platform 12 has a hoisting apparatus 26 and a derrick 28 for raising and lowering pipe strings such as production tubing string 30.

A wellbore 32 extends through the various earth strata including formation 14. A casing 34 is cemented within wellbore 32 by cement 36. Production tubing 30 includes various tools such as a plurality of isolation and filtration subassemblies that are disposed proximate formation 14 and divide formation 14 into a plurality of isolated or substantially isolated production zones. As illustrated, production zone 38 is defined by annular barriers 40, 42 and screen assembly 44, production zone 46 is defined by annular barriers 42, 48 and screen assembly 50 and production zone 52 is defined by annular barriers 48, 54 and screen assembly 56. Once production commences from formation 14, fluid may be produced into production zone 38 via perforations 58, into production zone 46 via perforations 60 and into production zone 52 via perforations 62.

As explained in more detail below, the completion system of the present invention is capable of reducing water production, including any water produced with hydrocarbons from formation 14 such as salt water and brines, without reducing the production of hydrocarbons and without the need for intervention. Specifically, screen assemblies 44, 50, 56 have each been treated with a relative permeability modifier that reduces the permeability of a screen assembly 44, 50, 56 if that screen assembly 44, 50, 56 contacts water production. Importantly, the relative permeability modifier used in the present invention is substantially inert to hydrocarbons such that the permeability of a screen assembly 44, 50, 56 is not adversely affected by hydrocarbon production. In addition, the action of the relative permeability modifier is initiated by contact with water production, thereby not requiring intervention by field personnel.

Even though FIG. 1 depicts a vertical well, it should be understood by those skilled in the art that the completion system of the present invention is equally well-suited for use in deviated wells, inclined wells or horizontal wells. Also, even though FIG. 1 depicts an offshore operation, it should be noted by one skilled in the art that the completion system of the present invention is equally well-suited for use in onshore operations. Further, even though FIG. 1 depicts three production zones, it should be understood by those skilled in the art that the completion system of the present invention is equally well-suited for use with any number of production zones whether those production zones are adjacent to one another and sharing a common annular barrier, as depicted, or separated from one another.

Referring now to FIG. 2, therein is depicted a partial cut away view of a screen assembly for reducing water production from a hydrocarbon producing well of the present invention that is generally designated 100. Screen assembly 100 includes a base pipe 102 that has a plurality of openings 104 that allow the flow of production fluids into the production tubing. The exact number, size and shape of openings 104 are not critical to the present invention, so long as sufficient area is provided for fluid production and the integrity of base pipe 102 is maintained. Spaced around base pipe 102 is a plurality of ribs 106. Ribs 106 are generally symmetrically distributed about the axis of base pipe 102. Ribs 106 are depicted as having a cylindrical cross section, however, it should be understood by one skilled in the art that ribs 106 may alternatively have a rectangular or triangular cross section or other suitable geometry. Additionally, it should be understood by one skilled in the art that the exact number of ribs 106 will be dependent upon the diameter of base pipe 102 as well as other design characteristics that are well known in the art.

Wrapped around ribs 106 is a screen wire 108. Screen wire 108 forms a plurality of turns, such as turn 110, turn 112 and turn 114. Between each of the turns is a gap through which formation fluids flow. The number of turns and the gap between the turns are determined based upon the characteristics of the formation from which fluid is being produced and the amount expansion experienced by the selected relative permeability modifier. Together, ribs 106 and screen wire 108 may form a screen jacket which is attached to base pipe 102 by welding or other suitable techniques. As will be recognized by those skilled in the art, screen assembly 100 may typically be used in sand control operations wherein particulate materials such as sand are produced during the production of hydrocarbons from the well. Screen assembly 100 of the present invention, however, is not only suitable for sand control operations but is alternatively or additionally suitable for reducing water production from the well. Specifically, as explained in more detail below, screen wire 108 has been treated with a relative permeability modifier which expands when it comes in contact with water. As such, the gaps between the turns of screen wire 108 are reduced or eliminated when the relative permeability modifier is exposed to water which reduces the permeability of screen assembly 100 and, in some embodiments, can effectively shut off production from screen assembly 100.

Referring now to FIG. 3, therein is depicted a partial cut away view of a screen assembly for reducing water production from a hydrocarbon producing well of the present invention that is generally designated 120. Screen assembly 120 includes a base pipe 122 that has a plurality of openings 124 which allow the flow of production fluids into the production tubing. The exact number, size and shape of openings 124 are not critical to the present invention, so long as sufficient area is provided for fluid production and the integrity of base pipe 120 is maintained.

Positioned around base pipe 122 is a fluid-porous, particulate restricting, metal filter having a plurality of layers of a wire mesh that are sintered or diffusion bonded together to form a porous wire mesh screen 126. As should be understood by those skilled in the art, screen 126 allows fluid flow therethrough but prevent the flow of particulate materials of a predetermined size from passing therethrough. The layers of wire mesh may include drain layers that have a mesh size that is larger than the mesh size of the filter layers. For example, a drain layer may preferably be positioned as the outermost layer and the innermost layer of wire mesh screen 126 with the filter layer or layers positioned therebetween.

Positioned around screen 126 is a screen wrapper 128 that has a plurality of openings 130 which allow the flow of production fluids therethrough. The exact number, size and shape of openings 130 is not critical to the present invention, so long as sufficient area is provided for fluid production and the integrity of screen wrapper 128 is maintained. Typically, various sections of screen 126 and screen wrapper 128 are manufactured together as a unit by, for example, sintering or diffusion bonding a number layers of wire mesh that form screen 126 together with screen wrapper 128, then rolling the unit into a tubular configuration. The two ends of the tubular unit are then seam welded together. Several tubular units of the screen and screen wrapper combination may then be placed over each joint of base pipe 122 and secured thereto by welding or other suitable technique.

As with screen assembly 100, screen assembly 120 of the present invention is not only suitable for sand control operations but is alternatively or additionally suitable for reducing water production from the well. Specifically, as explained in more detail below, wire mesh screen 126 has been treated with a relative permeability modifier which expands when it comes in contact with water. As such, when wire mesh screen 126 is exposed to water, the permeability of screen assembly 120 is reduced and in some embodiments, production through screen assembly 120 can be effectively shut off.

Referring now to FIG. 4, therein is depicted a partial cut away view of a screen assembly for reducing water production from a hydrocarbon producing well of the present invention that is generally designated 140. Screen assembly 140 includes a base pipe 142 that has a plurality of openings 144 that allow the flow of production fluids into the production tubing. The exact number, size and shape of openings 144 are not critical to the present invention, so long as sufficient area is provided for fluid production and the integrity of base pipe 142 is maintained. Spaced around base pipe 142 is a plurality of ribs 146. Ribs 146 are generally symmetrically distributed about the axis of base pipe 142. Ribs 146 are depicted as having a cylindrical cross section, however, it should be understood by one skilled in the art that ribs 146 may alternatively have a rectangular or triangular cross section or other suitable geometry. Additionally, it should be understood by one skilled in the art that the exact number of ribs 146 will be dependent upon the diameter of base pipe 142 as well as other design characteristics that are well known in the art.

Wrapped around ribs 146 is a screen wire 148. Screen wire 148 forms a plurality of turns, such as turn 150, turn 152 and turn 154. Between each of the turns is a gap through which formation fluids flow. The number of turns and the gap between the turns are determined based upon the characteristics of the formation from which fluid is being produced as well as other factors known to those skilled in the art. Positioned around screen wire 148 is a prepack sand 156 that may be a baked-resin of sand, gravel, engineered proppants or other pack material that is highly permeable to the flow of hydrocarbon fluids but blocks the flow of the particulates carried in the hydrocarbon fluids. As should be understood by one skilled in the art, the thickness of the layer of prepack sand 156 and the size of the sand forming the layer of prepack sand 156 is determined based upon the characteristic of the particular implementation.

A plurality of ribs 158 is disposed within the exterior portion of the layer of prepack sand 156. Ribs 158 are generally symmetrically distributed about the axis of base pipe 142. Ribs 158 are depicted as having a cylindrical cross section, however, it should be understood by one skilled in the art that ribs 158 may alternatively have a rectangular or triangular cross section or other suitable geometry. Additionally, it should be understood by one skilled in the art that the exact number of ribs 158 will be dependent upon the diameter of base pipe 142 as well as other design characteristics that are well known in the art.

Wrapped around ribs 156 is a screen wire 160. Screen wire 160 forms a plurality of turns, such as turn 162, turn 164 and turn 166. Between each of the turns is a gap through which formation fluids flow. The number of turns and the gap between the turns are determined based upon the characteristics of the formation from which fluid is being produced as well as other factor known to those skilled in the art. Together, ribs 146, screen wire 148, prepacked sand 156, ribs 158 and screen wire 160 may form a screen jacket which is attached to base pipe 142 by welding or other suitable techniques.

As will be recognized by those skilled in the art, screen assembly 140 may typically be used in sand control operations wherein particulate materials such as sand are produced during the production of hydrocarbons from the well. Screen assembly 140 of the present invention, however, is not only suitable for sand control operations but is alternatively or additionally suitable for reducing water production from the well. Specifically, as explained in more detail below, one or more of screen wire 148, prepacked sand 156 and screen wire 160 has been treated with a relative permeability modifier which expands when it comes in contact with water. As such, when a treated filtering medium is exposed to water, the permeability of screen assembly 140 is reduced and, in some embodiments, production through screen assembly 140 can be effectively shut off.

As previously alluded to, the filtering media 108, 126, 148, 156, 160 of the above described screen assemblies 100, 120, 140 may be treated with a relative permeability modifier such that the permeability of the screen assemblies 100, 120, 140 can be reduced if the filtering media 108, 126, 148, 156, 160 comes in contact with water. As an example, the relative permeability modifier may be comprised of a polymer made from a combination of at least one hydrophilic monomer and at least one hydrophobically modified hydrophilic monomer that attaches to the permeable sites on the filtering media 108, 126, 148, 156, 160. The presence of the polymer in the filtering media 108, 126, 148, 156, 160 reduces the flow of water therethrough.

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, dimethylaminopropylmethacrylamide, trimethylammoniumethyl methacrylate chloride, methacrylamide and hydroxyethyl acrylate. Of these, acrylamide, 2-acrylamido-2-methyl propane sulfonic acid, acrylic acid, dimethylaminoethyl methacrylate and vinyl pyrrolidone are preferred.

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. Of these, octadecyldimethylammoniumethyl methacrylate bromide, hexadecyldimethyl-ammoniumethyl methacrylate bromide, hexadecyldimethylammoniumpropyl methacrylamide bromide, 2-ethylhexyl methacrylate and hexadecyl methacrylamide are preferred.

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 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. Particularly suitable polymers having molecular weights and mole ratios in the ranges set forth above include, but are not limited to, an acrylamide/octadecyldimethylammoniumethyl methacrylate bromide copolymer, a dimethylaminoethyl methacrylate/hexadecyldimethylammoniumethyl methacrylate bromide copolymer, a dimethylaminoethyl methacrylate/vinyl pyrrolidone/hexadecyldimethylammoniumethyl methacrylate bromide terpolymer and an acrylamide/2-acrylamido-2-methyl propane sulfonic acid/2-ethylhexyl methacrylate terpolymer. Of these, an acrylamide/octadecyl dimethylammoniumethyl methacrylate bromide copolymer having a mole ratio of hydrophilic monomer to hydrophobically modified hydrophilic monomer of 96:4 is presently preferred.

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.

Referring next to FIG. 5, therein is depicted a completion system for reducing water production from a substantially vertical section of a hydrocarbon producing well of the present invention that is generally designated 200. Completion system 200 is disposed with cased wellbore 202 that traverses hydrocarbon bearing subterranean formation 204. Completion system 200 includes a production tubing 206 that extends from the surface to formation 204. Completion system 200 also includes a plurality of isolation and filtration subassemblies disposed proximate formation 204 dividing formation 204 into a plurality of isolated or substantially isolated production zones. As illustrated, production zone 208 is defined by annular barriers 210, 212 and screen assembly 214, production zone 216 is defined by annular barriers 212, 218 and screen assembly 220 and production zone 222 is defined by annular barriers 218, 224 and screen assembly 226. Fluid communication from formation 204 into production zones 208, 216, 222 is allowed, respectively, via perforations 228, 230, 232. In the illustrated embodiment, screen assemblies 214, 220, 226 may represent any of the screen assemblies discussed above or other suitable type of screen assembly wherein the filtering medium is treated with any of the relative permeability modifiers discussed above or other suitable relative permeability modifier. In the illustrated embodiment, annular barriers 210, 212, 218, 224 may represent any suitable annular flow restriction means commonly known in the art such as mechanical set packers, hydrostatic set packers, hydraulic set packers, differential set packers, inflation set packers, swelling elastomer set packers and the like.

In operation, completion system 200 allows for the production of hydrocarbons from formation 204 into production tubing 206 from each of the production zones 208, 216, 222. In the event that water production occurs from formation 204 into one of the production zones 208, 216, 222, the screen assembly associated with that production zone will have a reduced permeability. For example, if water encroachment occurs from the lower end of formation 204, the produced water will first enter production zone 222. When the relative permeability modifier treating the filter medium of screen assembly 226 is contacted by the water, the relative permeability modifier swells to reduce the permeability of screen assembly 226, which reduces and, in some embodiments, eliminates water production into production tubing 206 through screen assembly 226. In this example, the hydrocarbon production into production zones 208, 216 is not affected by the water production into production zone 222 and the resulting permeability reduction of screen assembly 226. Over time as the water encroachment continues, water production may commence in production zone 216. When the relative permeability modifier treating the filter medium of screen assembly 220 is contacted by the water, the relative permeability modifier swells to reduce the permeability of screen assembly 220, which reduces and, in some embodiments, eliminates water production into production tubing 206 through screen assembly 220. In the illustrated embodiment, the hydrocarbon production into production zone 208 and any other production zone uphole of production zone 208 are not affected by the water production into production zone 216 and the resulting permeability reduction of screen assembly 220.

This process may continue as the water progressively encroaches into the upper production zones of the well, however, the water being produced into production tubing 206 is minimized as the water production in each successively encountered production zone is reduced or eliminated. As should be recognized by those skilled in the art, the greater the number of production zones in a well using the completion system of the present invention, the greater the control over the hydrocarbon to water production ratio. In addition, it should be noted by those skilled in the art that complete zonal isolation is not required with the present invention, rather, in certain embodiments, annular barriers 210, 212, 218, 224 need only to provide a suitable restriction or substantial isolation. For example, as long as suitable friction is created to fluid flow from one zone to the next due to a long distance, a small annular size or the like, water production into production tubing 206 will be suitably minimized. Likewise, if the various zones have been gravel packed, the particulate material that forms the gravel pack can provide such friction against inter-zonal fluid flow.

Also, it should be apparent to those skilled in the art that the use of directional terms such as top, bottom, above, below, upper, lower, upward, downward, etc. are used in relation to the illustrative embodiments as they are depicted in the figures, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure. As such, it is to be understood that the downhole components described herein may be operated in vertical, horizontal, inverted or inclined orientations without deviating from the principles of the present invention.

For example, as best seen in FIG. 6, therein is depicted a completion system for reducing water production from a substantially horizontal section of a hydrocarbon producing well of the present invention that is generally designated 240. Completion system 240 is disposed within an open hole wellbore 242 that traverses hydrocarbon bearing subterranean formation 244. Completion system 240 includes an production tubing 246 that extends from the surface to formation 244. Completion system 240 also includes a plurality of isolation and filtration subassemblies disposed proximate formation 244 dividing formation 244 into a plurality of isolated or substantially isolated production zones. As illustrated, production zone 248 is defined by annular barriers 250, 252 and screen assembly 254, production zone 256 is defined by annular barriers 252, 258 and screen assembly 260 and production zone 262 is defined by annular barriers 258, 264 and screen assembly 266. Screen assemblies 254, 260, 266 may represent any of the screen assemblies discussed above or other suitable type of screen assembly and preferably represent expandable screen assemblies that are expanded downhole into contact with the borehole, as illustrated. In addition, regardless of the type of screen assembly, the filtering medium associated with screen assemblies 254, 260, 266 is treated with any of the relative permeability modifier discussed above or other suitable relative permeability modifier. In the illustrated embodiment, annular barriers 250, 252, 258, 264 may represent any suitable annular flow restriction means commonly known in the art such as mechanical set packers, hydrostatic set packers, hydraulic set packers, differential set packers, inflation set packers, swelling elastomer set packers and the like.

In operation, completion system 240 allows for the production of hydrocarbons from formation 244 into production tubing 246 from each of the production zones 248, 256, 252. In the event that water production occurs from formation 244 into one of the production zones 248, 256, 262, the screen assembly associated with that production zone will have a reduced permeability. For example, if water production occurs from production zone 256, when the relative permeability modifier treating the filter medium of screen assembly 260 is contacted by the water, the relative permeability modifier swells to reduce the permeability of screen assembly 260, which reduces and, in some embodiments, eliminates water production into production tubing 246 through screen assembly 260. Likewise, if water production from production zone 248 occurs, when the relative permeability modifier treating the filter medium of screen assembly 254 is contacted by the water, the relative permeability modifier swells to reduce the permeability of screen assembly 254, which reduces and, in some embodiments, eliminates water production into production tubing 246 through screen assembly 254. Further, if water production from production zone 262 occurs, when the relative permeability modifier treating the filter medium of screen assembly 266 is contacted by the water, the relative permeability modifier swells to reduce the permeability of screen assembly 266, which reduces and, in some embodiments, eliminates water production into production tubing 246 through screen assembly 266.

The operation of each of the screen assembly 254, 260, 266 is independent of the others which allows for significant control over the hydrocarbon to water production ratio. As such, the hydrocarbon production into a production zone which is not producing water is not affected by the water production into one of the other production zones and the resulting permeability reduction of the screen assembly in that production zone. Also, the greater the number of isolated production zones in the well using the completion system of the present invention, the greater the control over the hydrocarbon to water production ratio. In addition, the operation of each of the screen assembly 254, 260, 266 is in response to contact with the water production and does not require intervention by field personnel. In addition, it should be noted by those skilled in the art that a complete fluid seal is not required, rather, in certain embodiments, the annular barriers need only to provide a suitable restriction or substantial isolation to inter-zonal fluid flow.

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.

Claims

1. A filtering apparatus for use in a hydrocarbon producing well, the filtering apparatus comprising:

a filtering medium treated with a relative permeability modifier; and

wherein the relative permeability modifier reduces the permeability of the filtering medium if the relative permeability modifier contacts water production.

2. The filtering apparatus as recited in claim 1 wherein the filtering medium is a sand control screen selected from the group consisting of a wire wrap screen, a prepacked screen and a wire mesh screen.

3. The filtering apparatus as recited in claim 1 wherein the relative permeability modifier is used to treat at least one of a metal portion of the filtering medium and a prepacked component of the filtering medium.

4. The filtering apparatus as recited in claim 1 wherein the relative permeability modifier is selected from the group consisting of a polymer of at least one hydrophilic monomer and at least one hydrophobically modified hydrophilic monomer, a hydrophobically modified polymer, a hydrophobically modified water-soluble polymer and hydrophobically modified copolymers thereof.

5. The filtering apparatus as recited in claim 1 wherein the relative permeability modifier is selected from the group consisting of a polymer of at least one of acrylamide, 2-acrylamido-2-methyl propane sulfonic acid, N,N-dimethylacrylamide, vinyl pyrrolidone, dimethylaminoethyl methacrylate, acrylic acid, dimethylaminopropylmethacrylamide, trimethylammoniumethyl methacrylate chloride, methacrylamide, and hydroxyethyl acrylate combined with at least one of alkyl acrylates, alkyl methacrylates, alkyl acrylamides, alkyl methacrylamides, alkyl dimethylammoniumethyl methacrylate bromide, alkyl dimethylammoniumethyl methacrylate chloride, alkyl dimethylammoniumethyl methacrylate iodide, alkyl dimethylammonium propylmethacrylamide bromide, alkyl dimethylammonium propylmethacrylamide chloride and alkyl dimethylammonium propylmethacrylamide iodide.

6. The filtering apparatus as recited in claim 1 wherein the relative permeability modifier is selected from the group consisting of hydrophobically modified polydimethylaminoethyl methacrylate, hydrophobically modified polyacrylamide and hydrophobically modified copolymers of dimethylaminoethyl methacrylate and vinyl pyrollidone.

7. A method for reducing water production in a hydrocarbon producing well, the method comprising the steps of:

treating a filtering medium with a relative permeability modifier;

disposing the filtering medium proximate a production zone of the well;

producing fluids from the production zone; and

reducing the permeability of the filtering medium if the relative permeability modifier contacts water production.

8. The method as recited in claim 7 wherein the step of treating a filtering medium with a relative permeability modifier further comprises treating a sand control screen.

9. The method as recited in claim 7 wherein the step of treating a filtering medium with a relative permeability modifier further comprises treating at least one of a metal portion of the filtering medium and a prepacked component of the filtering medium.

10. The method as recited in claim 7 wherein the step of treating a filtering medium with a relative permeability modifier further comprises treating the filter medium with a relative permeability modifier selected from the group consisting of a polymer of at least one hydrophilic monomer and at least one hydrophobically modified hydrophilic monomer, a hydrophobically modified polymer, a hydrophobically modified water-soluble polymer and hydrophobically modified copolymers thereof.

11. The method as recited in claim 7 wherein the step of treating a filtering medium with a relative permeability modifier further comprises treating the filter medium with a relative permeability modifier selected from the group consisting of a polymer of at least one of acrylamide, 2-acrylamido-2-methyl propane sulfonic acid, N,N-dimethylacrylamide, vinyl pyrrolidone, dimethylaminoethyl methacrylate, acrylic acid, dimethylaminopropylmethacrylamide, trimethylammoniumethyl methacrylate chloride, methacrylamide, and hydroxyethyl acrylate combined with at least one of alkyl acrylates, alkyl methacrylates, alkyl acrylamides, alkyl methacrylamides, alkyl dimethylammoniumethyl methacrylate bromide, alkyl dimethylammoniumethyl methacrylate chloride, alkyl dimethylammoniumethyl methacrylate iodide, alkyl dimethylammonium propylmethacrylamide bromide, alkyl dimethylammonium propylmethacrylamide chloride and alkyl dimethylammonium propylmethacrylamide iodide.

12. The method as recited in claim 7 wherein the step of treating a filtering medium with a relative permeability modifier further comprises treating the filter medium with a relative permeability modifier selected from the group consisting of hydrophobically modified polydimethylaminoethyl methacrylate, hydrophobically modified polyacrylamide and hydrophobically modified copolymers of dimethylaminoethyl methacrylate and vinyl pyrollidone.

13. A completion system for use in a hydrocarbon producing well having multiple production zones, the completion system comprising:

a production tubing string extending along a substantial length of the well;

an isolation and filtration subassembly disposed proximate each of the production zones, each isolation and filtration subassembly operably associated with the production tubing string such that fluid from the respective production zones is produced through one of the isolation and filtration subassemblies into the production tubing string, each isolation and filtration subassembly providing at least substantial zonal isolation of one of the production zones; and

wherein at least one of the isolation and filtration subassemblies includes at least one filtering medium treated with a relative permeability modifier such that the relative permeability modifier reduces the permeability of the associated filtering medium if the associated filtering medium contacts water production, thereby reducing the production of water from the associated production zone.

14. The completion system as recited in claim 13 wherein each isolation and filtration subassembly further comprise a pair of annular barriers and a sand control screen.

15. The completion system as recited in claim 14 wherein the annular barriers are selected from the group consisting of mechanical set packers, hydrostatic set packers, hydraulic set packers, differential set packers, inflation set packers and swelling elastomer set packers.

16. The completion system as recited in claim 13 wherein the relative permeability modifier is used to treat at least one of a metal portion of the filtering medium and a prepacked component of the filtering medium.

17. The completion system as recited in claim 13 wherein each isolation and filtration subassembly provides zonal isolation of one of the production zones.

18. The completion system as recited in claim 13 wherein the relative permeability modifier is selected from the group consisting of a polymer of at least one hydrophilic monomer and at least one hydrophobically modified hydrophilic monomer, a hydrophobically modified polymer, a hydrophobically modified water-soluble polymer and hydrophobically modified copolymers thereof.

19. The completion system as recited in claim 13 wherein the relative permeability modifier is selected from the group consisting of a polymer of at least one of acrylamide, 2-acrylamido-2-methyl propane sulfonic acid, N,N-dimethylacrylamide, vinyl pyrrolidone, dimethylaminoethyl methacrylate, acrylic acid, dimethylaminopropylmethacrylamide, trimethylammoniumethyl methacrylate chloride, methacrylamide, and hydroxyethyl acrylate combined with at least one of alkyl acrylates, alkyl methacrylates, alkyl acrylamides, alkyl methacrylamides, alkyl dimethylammoniumethyl methacrylate bromide, alkyl dimethylammoniumethyl methacrylate chloride, alkyl dimethylammoniumethyl methacrylate iodide, alkyl dimethylammonium propylmethacrylamide bromide, alkyl dimethylammonium propylmethacrylamide chloride and alkyl dimethylammonium propylmethacrylamide iodide.

20. The completion system as recited in claim 13 wherein the relative permeability modifier is selected from the group consisting of hydrophobically modified polydimethylaminoethyl methacrylate, hydrophobically modified polyacrylamide and hydrophobically modified copolymers of dimethylaminoethyl methacrylate and vinyl pyrollidone.