Patent Publication Number: US-2023144758-A1

Title: Downhole inflow control

Description:
TECHNICAL FIELD 
     This disclosure relates to downhole inflow control, and in particular, downhole automatic water shut off. 
     BACKGROUND 
     Premature water breakthrough in hydrocarbon production from reservoirs can be a major challenge in oil and gas operations. Water production from sections, for example, along horizontal wells can be due to reservoir heterogeneity and can adversely impact hydrocarbon recovery, well life, and well economics. Inflow control devices are typically used to control water production from hydrocarbon reservoirs. 
     SUMMARY 
     This disclosure describes technologies relating to downhole inflow control, and in particular, downhole automatic water reduction and shut off. Certain aspects of the subject matter described can be implemented as an apparatus. The apparatus includes a funnel, a core, a first coating, a second coating, and a third coating. The funnel includes multiple inlet ports. The funnel includes an outlet port. The core is disposed within the funnel. The core defines a first outer diameter. The outlet port has an inner diameter that is less than the first outer diameter of the core. The first coating is disposed on and surrounds an outer surface of the core. The first coating defines a second outer diameter. The first coating is configured to dissolve at a first dissolution rate in response to being exposed to water or a fluid including water. The second coating is disposed on and surrounds an outer surface of the first coating. The second coating defines a third outer diameter. The second coating is configured to dissolve at a second dissolution rate different from the first dissolution rate in response to being exposed to water or a fluid including water. The third coating is disposed on and surrounds an outer surface of the second coating. The third coating defines a fourth outer diameter. The third coating is configured to dissolve in response to being exposed to a hydrocarbon or a fluid including a hydrocarbon. The third coating can be configured to be resistant to dissolving in response to being exposed to water. 
     This, and other aspects, can include one or more of the following features. In some implementations, the second dissolution rate of the second coating is less than the first dissolution rate of the first coating. In some implementations, the first coating has a first thickness, and the second coating has a second thickness. In some implementations, a difference between the first thickness of the first coating and the second thickness of the second coating is less than 0.1 centimeters. In some implementations, the third coating has a third thickness. In some implementations, a difference between the third thickness of the third coating and the first thickness of the first coating is less than 0.1 centimeters. In some implementations, the third thickness of the third coating is in a range of from about 50% to about 100% of the first thickness of the first coating. In some implementations, the funnel includes a first end, a second end, and a wall that spans from the first end to the second end. In some implementations, the wall defines a longitudinal axis through the first end and the second end. In some implementations, the wall has a first cross-sectional area at the first end and a second cross-sectional area at the second end. In some implementations, the first cross-sectional are and the second cross-sectional area are perpendicular to the longitudinal axis. In some implementations, the first cross-sectional area is greater than the second cross-sectional area. In some implementations, the core coated with the first coating, the second coating, and the third coating is disposed between the first end and the second end of the funnel. In some implementations, a first inlet port of the multiple inlet ports is disposed on the first end of the funnel. In some implementations, the outlet port is disposed on the second end of the funnel. In some implementations, a second inlet port of the multiple inlet ports is disposed on the wall of the funnel at a first distance from the first end along the longitudinal axis. In some implementations, the wall has a third cross-sectional area at the first distance. In some implementations, the third cross-sectional area is perpendicular to the longitudinal axis. In some implementations, the third cross-sectional area has an inner diameter that is less than the third outer diameter and greater than the second outer diameter. In some implementations, a third inlet port of the multiple ports is disposed on the wall of the funnel at a second distance from the first end along the longitudinal axis. In some implementations, the wall has a fourth cross-sectional area at the second distance. In some implementations, the fourth cross-sectional area is perpendicular to the longitudinal axis. In some implementations, the fourth cross-sectional area has an inner diameter that is less than the second outer diameter and greater than the first outer diameter. 
     Certain aspects of the subject matter described can be implemented as a system. The system includes a tubular disposed within a wellbore formed in a subterranean formation. The system includes an inflow control device disposed on the tubular. The inflow control device is configured to control flow of wellbore fluid from the wellbore and into the tubular. The inflow control device includes a funnel, a core, a first coating, a second coating, and a third coating. The funnel includes multiple inlet ports. The funnel includes an outlet port. The core is disposed within the funnel. The core defines a first outer diameter. The outlet port has an inner diameter that is less than the first outer diameter of the core. The first coating is disposed on and surrounds an outer surface of the core. The first coating defines a second outer diameter. The first coating is configured to dissolve at a first dissolution rate in response to being exposed to water or a fluid including water. The second coating is disposed on and surrounds an outer surface of the first coating. The second coating defines a third outer diameter. The second coating is configured to dissolve at a second dissolution rate different from the first dissolution rate in response to being exposed to water or a fluid including water. The third coating is disposed on and surrounds an outer surface of the second coating. The third coating defines a fourth outer diameter. The third coating is configured to dissolve in response to being exposed to a hydrocarbon or a fluid including a hydrocarbon. The third coating can be configured to be resistant to dissolving in response to being exposed to water. 
     This, and other aspects, can include one or more of the following features. In some implementations, the second dissolution rate of the second coating is less than the first dissolution rate of the first coating. In some implementations, the first coating has a first thickness, and the second coating has a second thickness. In some implementations, a difference between the first thickness of the first coating and the second thickness of the second coating is less than 0.1 centimeters. In some implementations, the third coating has a third thickness. In some implementations, a difference between the third thickness of the third coating and the first thickness of the first coating is less than 0.1 centimeters. In some implementations, the third thickness of the third coating is in a range of from about 50% to about 100% of the first thickness of the first coating. In some implementations, the funnel includes a first end, a second end, and a wall that spans from the first end to the second end. In some implementations, the wall defines a longitudinal axis through the first end and the second end. In some implementations, the wall has a first cross-sectional area at the first end and a second cross-sectional area at the second end. In some implementations, the first cross-sectional are and the second cross-sectional area are perpendicular to the longitudinal axis. In some implementations, the first cross-sectional area is greater than the second cross-sectional area. In some implementations, the core coated with the first coating, the second coating, and the third coating is disposed between the first end and the second end of the funnel. In some implementations, a first inlet port of the multiple inlet ports is disposed on the first end of the funnel. In some implementations, the outlet port is disposed on the second end of the funnel. In some implementations, a second inlet port of the multiple inlet ports is disposed on the wall of the funnel at a first distance from the first end along the longitudinal axis. In some implementations, the wall has a third cross-sectional area at the first distance. In some implementations, the third cross-sectional area is perpendicular to the longitudinal axis. In some implementations, the third cross-sectional area has an inner diameter that is less than the third outer diameter and greater than the second outer diameter. In some implementations, a third inlet port of the multiple ports is disposed on the wall of the funnel at a second distance from the first end along the longitudinal axis. In some implementations, the wall has a fourth cross-sectional area at the second distance. In some implementations, the fourth cross-sectional area is perpendicular to the longitudinal axis. In some implementations, the fourth cross-sectional area has an inner diameter that is less than the second outer diameter and greater than the first outer diameter. 
     Certain aspects of the subject matter described can be implemented as a method. An apparatus is disposed within a wellbore formed in a subterranean formation. The apparatus includes a funnel, a core, a first coating, a second coating, and a third coating. The funnel includes multiple inlet ports. The funnel includes an outlet port. The core is disposed within the funnel. The core defines a first outer diameter. The outlet port has an inner diameter that is less than the first outer diameter of the core. The first coating is disposed on and surrounds an outer surface of the core. The first coating defines a second outer diameter. The first coating is configured to dissolve at a first dissolution rate in response to being exposed to water or a fluid including water. The second coating is disposed on and surrounds an outer surface of the first coating. The second coating defines a third outer diameter. The second coating is configured to dissolve at a second dissolution rate different from the first dissolution rate in response to being exposed to water or a fluid including water. The third coating is disposed on and surrounds an outer surface of the second coating. The third coating defines a fourth outer diameter. The third coating is configured to dissolve in response to being exposed to a hydrocarbon or a fluid including a hydrocarbon. The third coating can be configured to be resistant to dissolving in response to being exposed to water. Wellbore fluid from the subterranean formation is received by the multiple inlet ports of the funnel. The wellbore fluid includes a hydrocarbon and water. The wellbore fluid is directed to the core by the funnel. The third coating is contacted with the hydrocarbon of the wellbore fluid to dissolve the third coating. In response to dissolving the third coating, the ball is moved toward the outlet port and the second coating is exposed to the wellbore fluid. The second coating is contacted with the water of the wellbore fluid to dissolve the second coating. In response to dissolving the second coating, fluid communication between a first portion of the inlet ports and the outlet port is obstructed by the core with the second and third coatings dissolved, such that fluid flow through the apparatus and out of the outlet port decreases. The first coating is contacted with the water of the wellbore fluid to dissolve the first coating. In response to dissolving the first coating, fluid communication between a remaining portion of the inlet ports and the outlet port is obstructed by the core with the first, second, and third coatings dissolved, such that the fluid flow through the apparatus and out of the outlet port is prevented. 
     This, and other aspects, can include one or more of the following features. In some implementations, the second dissolution rate of the second coating is less than the first dissolution rate of the first coating. In some implementations, the first coating has a first thickness, and the second coating has a second thickness. In some implementations, a difference between the first thickness of the first coating and the second thickness of the second coating is less than 0.1 centimeters. In some implementations, the third coating has a third thickness. In some implementations, a difference between the third thickness of the third coating and the first thickness of the first coating is less than 0.1 centimeters. In some implementations, the third thickness of the third coating is in a range of from about 50% to about 100% of the first thickness of the first coating. In some implementations, the funnel includes a first end, a second end, and a wall that spans from the first end to the second end. In some implementations, the wall defines a longitudinal axis through the first end and the second end. In some implementations, the wall has a first cross-sectional area at the first end and a second cross-sectional area at the second end. In some implementations, the first cross-sectional are and the second cross-sectional area are perpendicular to the longitudinal axis. In some implementations, the first cross-sectional area is greater than the second cross-sectional area. In some implementations, the core coated with the first coating, the second coating, and the third coating is disposed between the first end and the second end of the funnel. In some implementations, a first inlet port of the multiple inlet ports is disposed on the first end of the funnel. In some implementations, the outlet port is disposed on the second end of the funnel. In some implementations, a second inlet port of the multiple inlet ports is disposed on the wall of the funnel at a first distance from the first end along the longitudinal axis. In some implementations, the wall has a third cross-sectional area at the first distance. In some implementations, the third cross-sectional area is perpendicular to the longitudinal axis. In some implementations, the third cross-sectional area has an inner diameter that is less than the third outer diameter and greater than the second outer diameter, such that a center of the core with the second and third coatings dissolved is disposed between the second inlet port and the outlet port, thereby obstructing fluid communication between the first portion of the inlet ports and the outlet port. In some implementations, a third inlet port of the multiple ports is disposed on the wall of the funnel at a second distance from the first end along the longitudinal axis. In some implementations, the wall has a fourth cross-sectional area at the second distance. In some implementations, the fourth cross-sectional area is perpendicular to the longitudinal axis. In some implementations, the fourth cross-sectional area has an inner diameter that is less than the second outer diameter and greater than the first outer diameter, such that the center of the core with the first, second, and third coatings dissolved is disposed between the third inlet port and the outlet port, thereby obstructing fluid communication between the inlet ports and the outlet port, such that fluid flow through the apparatus and out of the outlet port is prevented. 
     The details of one or more implementations of the subject matter of this disclosure are set forth in the accompanying drawings and the description. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG.  1 A  is a schematic diagram of an example well. 
         FIG.  1 B  is a schematic diagram of an inflow control device installed in the well of  FIG.  1 A . 
         FIG.  2 A  is a side cross-sectional view of an inflow control device that can be installed in the well of  FIG.  1 A . 
         FIG.  2 B  is a cross-sectional view of a coated core that can be disposed within the inflow control device of  FIG.  2 A . 
         FIG.  2 C  is a side cross-sectional view of the inflow control device of  FIG.  2 A , in which a core coating has dissolved. 
         FIG.  2 D  is a side cross-sectional view of the inflow control device of  FIG.  2 C , in which a core coating has dissolved. 
         FIG.  2 E  is a side cross-sectional view of the inflow control device of  FIG.  2 D , in which a core coating has dissolved. 
         FIG.  3    is a top cross-sectional view of an inflow control device that can be installed in the well of  FIG.  1 A . 
         FIG.  4    is a flow chart of a method for controlling flow of wellbore fluid, for example, in the well of  FIG.  1 A . 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure describes an autonomous inflow control device (ICD) that can successfully perform water shut off without depending on viscosity or density differences between oil and water phases. The ICD includes a funnel with multiple inlet ports, for example, on the top and on the sides. The funnel also includes an outlet port located near the tapered end of the funnel, such that a general fluid flow direction is toward the tapered end. The ICD includes a core disposed within the funnel, and the core is coated with multiple layers of chemicals. The core can be, for example, a non-dissolvable core, and the layers of coating are such that the core and the layers of coating together are in the form of a ball. Each layer is dissolvable based on exposure to certain fluids, such as oil and/or water. As the layers dissolve, the ball&#39;s outer diameter decreases and the overall direction of fluid flow pushes the ball towards the tapered end of the funnel. Eventually, once all the coated layers have dissolved, the core shuts off the fluid connection between the inlet ports and the outlet port, effectively shutting off fluid flow through the ICD. For example, as the coated layers dissolve, the force generated by the flow of fluids through the funnel pushes the core (which can be non-dissolvable) towards the tapered end of the funnel, and the core will then restrict the flow of fluid out of the outlet, thereby restricting, and if required, shutoff, the fluid flow from the larger end to the tapered end of the funnel. 
     The subject matter described in this disclosure can be implemented in particular implementations, so as to realize one or more of the following advantages. By implementing several of the described ICDs at various points along a well, inflow of water can be controlled automatically across various producing locations in a well, regardless of heterogeneity. Inflow of water can be controlled and reduced without requiring well intervention, which can be costly and time-consuming. The ICDs described here can adjust inflow automatically without relying on changes in viscosity and/or density of the wellbore fluid that is being produced. Implementation of the subject matter described can increase lifespan of a production well and improve hydrocarbon recovery from a production well. Implementation of the subject matter described can avoid downtime associated with water shutoff techniques that implement dads or plug setting. Implementation of the subject matter described can reduce costs, for example, associated with delayed rigging activities for sidetracking, by eliminating the need for running production logging tools for the purpose of water shutoff intervention, by eliminating the need for well intervention operations for water shutoff, or a combination of these. Implementation of the subject matter described can conserve reservoir pressure (thereby maintaining hydrocarbon production and avoiding excessive pressure loss) and improve well operating efficiency by minimizing water cycling, which involves processing produced water and re-injecting the processed produced water back into the reservoir to boost pressure. The ICDs described here can, once activated, choke flow of fluid in a first direction (for example, from the formation and into a tubing) while allowing flow of fluid in a second direction (for example, from the tubing and to the formation). As such, the ICDs described here can successfully perform water shutoff from the formation while also allowing for injection of treatment fluids to the formation. 
       FIG.  1 A  depicts an example well  100  constructed in accordance with the concepts herein. The well  100  extends from the surface through the Earth to one more subterranean zones of interest  110  (one shown). The well  100  enables access to the subterranean zones of interest  110  to allow recovery (that is, production) of fluids to the surface and, in some implementations, additionally or alternatively allows fluids to be placed in the Earth. In some implementations, the subterranean zone  110  is a formation within the Earth defining a reservoir, but in other instances, the zone  110  can be multiple formations or a portion of a formation. The subterranean zone can include, for example, a formation, a portion of a formation, or multiple formations in a hydrocarbon-bearing reservoir from which recovery operations can be practiced to recover trapped hydrocarbons. In some implementations, the subterranean zone includes an underground formation of naturally fractured or porous rock containing hydrocarbons (for example, oil, gas, or both). In some implementations, the well can intersect other types of formations, including reservoirs that are not naturally fractured. The well  100  can be a vertical well or a deviated well with a wellbore deviated from vertical (for example, horizontal or slanted). The well  100  can include multiple bores forming a multilateral well (that is, a well having multiple lateral wells branching off another well or wells). 
     In some implementations, the well  100  is a gas well that is used in producing hydrocarbon gas (such as natural gas) from the subterranean zones of interest  110  to the surface. While termed a “gas well,” the well need not produce only dry gas, and may incidentally or in much smaller quantities, produce liquid including oil, water, or both. In some implementations, the well  100  is an oil well that is used in producing hydrocarbon liquid (such as crude oil) from the subterranean zones of interest  110  to the surface. While termed an “oil well,” the well not need produce only hydrocarbon liquid, and may incidentally or in much smaller quantities, produce gas, water, or both. In some implementations, the production from the well  100  can be multiphase in any ratio. In some implementations, the production from the well  100  can produce mostly or entirely liquid at certain times and mostly or entirely gas at other times. For example, in certain types of wells it is common to produce water for a period of time to gain access to the gas in the subterranean zone. The concepts herein, though, are not limited in applicability to gas wells, oil wells, or even production wells, and could be used in wells for producing other gas or liquid resources or could be used in injection wells, disposal wells, or other types of wells used in placing fluids into the Earth. 
     The wellbore of the well  100  is typically, although not necessarily, cylindrical. All or a portion of the wellbore is lined with a tubing, such as casing  112 . The casing  112  connects with a wellhead at the surface and extends downhole into the wellbore. The casing  112  operates to isolate the bore of the well  100 , defined in the cased portion of the well  100  by the inner bore  116  of the casing  112 , from the surrounding Earth. The casing  112  can be formed of a single continuous tubing or multiple lengths of tubing joined (for example, threadedly) end-to-end. In some implementations, the casing  112  is perforated in the subterranean zone of interest  110  to allow fluid communication between the subterranean zone of interest  110  and the bore  116  of the casing  112 . In some implementations, the casing  112  is omitted or ceases in the region of the subterranean zone of interest  110  (as shown in  FIG.  1 A ). This portion of the well  100  without casing is often referred to as “open hole.” As shown in  FIG.  1 A , the cased portion of the well  100  can cease at a casing shoe  114 . 
     A production tubing  116  can be installed in the casing  112 . The production tubing  116  can extend into the open hole portion of the well  100 . The production tubing  116  can be secured by a packer  118 . While  FIG.  1 A  depicts four packers  118 , the well  100  can include fewer or more packers depending, for example, on the length of the production tubing  116 . Each packer  118  surrounds the production tubing  116 , centers the production tubing  116  within the wellbore of the well  100 , and stabilizes the production tubing  116  during well operations. The well  100  can include an ICD  200 . The ICD  200  can, for example, control the flow of fluids from the wellbore and into the production tubing  116 . While  FIG.  1 A  depicts five ICDs  200  distributed along the production tubing  116 , the well  100  can include fewer or more ICDs depending, for example, on the length of the production tubing  116 , characteristics of the well  100  along the length of the production tubing  116 , or a combination of both. 
       FIG.  1 B  depicts the ICD  200  installed in a sleeve  120  that surrounds the production tubing  116 . As shown in  FIG.  1 B , the ICD  200  can be disposed within an annulus of the sleeve  120 . The dotted arrows in  FIG.  1 B  depict a general direction of fluid flow from the wellbore, through the sleeve  120  and ICD  200 , and into the production tubing  116 . Wellbore fluid from the wellbore can flow into the sleeve  120 , for example, through perforations defined on an outer surface of the sleeve  120 . The wellbore fluid then flows through the annulus of the sleeve  120  and into the ICD  200 . The ICD  200  can be disposed within the annulus of the sleeve  120 , such that any wellbore fluid that flows from the wellbore and enters the sleeve  120  must flow into the ICD  200  without bypassing the ICD  200 . In some configurations, the wellbore fluid freely enters the ICD  200  and exits the ICD  200  and continues to flow through the sleeve  120  and eventually into the production tubing  116 . In some configurations, the wellbore fluid is slowed down by an obstruction implemented by the ICD  200  to reduce flow of the wellbore fluid exiting the ICD  200  and into the production tubing  116 . In some configurations, flow through the ICD  200  is blocked, such that no fluid exits the ICD  200  and enters the production tubing  116 . 
       FIG.  2 A  is a side cross-sectional view of the ICD  200  that can be installed in the well  100 . The ICD  200  includes a funnel  201  that includes multiple inlet ports, labeled as  203  followed by a letter (for example,  203   a ). The funnel  201  includes an outlet port  205 . The ICD  200  includes a core  207  with a first coating  209   a  disposed on and surrounding an outer surface of the core  207 . A second coating  209   b  is disposed on and surrounds an outer surface of the first coating  209   c . A third coating  209   c  is disposed on and surrounds an outer surface of the second coating  209   b.    
     The outlet port  205  has an inner diameter. The outlet port  205  is smaller than the core  207  (even with all of the coatings  209   a ,  209   b ,  209   c  dissolved), such that the core  207  cannot pass through the outlet port  205 . The ICD  200  is installed in a configuration such that fluid can flow through the ICD  200  in a general direction toward the tapered end of the funnel  201  (that is, toward the outlet port  205 ). Therefore, during operation, the general direction of the fluid flow through the ICD  200  biases the core  207  toward the outlet port  205 . 
     The first, innermost coating  209   a  can be disposed directly on the outer surface of the core  207 . The first, innermost coating  209   a  is configured to dissolve and/or erode in response to being exposed to water or a fluid including water (such as completion fluid). For example, the first, innermost coating  209   a  is configured to dissolve and/or erode in response to being exposed to a fluid including hydrocarbons and water associated with high water cut (such as water cut greater than 50%). For example, the dissolution rate of the first coating  209   a  in response to being exposed to water or a fluid including water (such as completion fluid) can be about 0.1 millimeters per month (mm/mo) in relation to thickness reduction of the first coating  209   a . The first coating  209   a  can include, for example, salt-based compounds designed to dissolve in water at a desired dissolution rate. In some cases, the first coating  209   a  includes polyvinyl alcohol. The first coating  209   a  can also include an additive and/or a filler. 
     The second, intermediate coating  209   b  can be disposed directly on an outer surface of the first, innermost coating  209   a . The second, intermediate coating  209   b  is configured to dissolve and/or erode in response to being exposed to water or a fluid including water. For example, the second, intermediate coating  209   b  is configured to dissolve and/or erode in response to being exposed to a fluid including hydrocarbons and water associated with low water cut (such as water cut greater than 30% and less than 50%). The dissolution rate of the second coating  209   b  is different from the dissolution rate of the first coating  209   a . In some implementations, the dissolution rate of the second coating  209   b  is less than the dissolution rate of the first coating  209   a . For example, the dissolution rate of the second coating  209   b  in response to being exposed to water can be about 0.01 mm/mo in relation to thickness reduction of the second coating  209   b . The second coating  209   b  can include, for example, salt-based compounds designed to dissolve in water at a desired dissolution rate. In some implementations, the second coating  209   b  includes a matrix embedded with a water-soluble material. In such implementations, in response to being exposed to water, the water-soluble material dissolves, leaving a porous matrix that can erode away. In some implementations, the second coating  209   b  includes a resin that dissolves in water. The second coating  209   b  can also include an additive and/or a filler. 
     The third, outermost coating  209   c  can be disposed directly on an outer surface of the second, intermediate coating  209   b . The third, outermost coating  209   c  is configured to stay intact in response to being exposed to water or a fluid including water (for example, insoluble in water) and to dissolve in response to being exposed to a hydrocarbon (for example, oil). For example, the third coating  209   c  dissolves completely in response to being exposed to a hydrocarbon within a matter of hours. The third coating  209   c  can include, for example, a non-polar compound. In some implementations, the third coating  209   c  includes a solid resin made of a highly chlorinated alpha-olefinic polymer which is insoluble in water and soluble in oil. In some implementations, the third coating  209   c  includes a solid non-polar polymer, such as polyisoprene or polybutadiene. The third coating  209   c  can also include an additive and/or a filler. 
     The funnel  201  and the core  207  are made of a material that is resistant to degradation, dissolution, and/or reacting with wellbore fluids in downhole well conditions. For example, the funnel  201  and the core  207  can be made of a material that does not react with water and hydrocarbons. The funnel  201  can be made of a material that is resistant to corrosion and erosion, for example, a corrosion- and erosion-resistant metal. For example, the funnel  201  is made of Inconel. The core  207  can be made of a material that is resistant to corrosion, for example, a corrosion-resistant metal. For example, the core  207  can be made of Inconel or Teflon. 
     The funnel  201  can include a first end  201   a , a second end  201   b , and a wall  201   c  that spans from the first end  201   a  to the second end  201   b . The core  207  is disposed between the first end  201   a  and the second end  201   b  of the funnel  201 . The wall  201   c  can define a longitudinal axis  201   d  through the first end  201   a  and the second end  201   b . In some implementations, the wall  201   c  has a longitudinal length (between the first end  201   a  and the second end  201   b ) in a range of from about 2 centimeters (cm) to about 4 cm. The wall  201   c  can have a first cross-sectional area c 1  at the first end  201   a  and a second cross-sectional area c 2  at the second end  201   b . The first cross-sectional area c 1  and the second cross-sectional area c 2  are perpendicular to the longitudinal axis  201   d . The first cross-sectional area c 1  is greater than the second cross-sectional area c 2 . In some implementations, the first cross-sectional area c 1  has an inner diameter of about 1 cm. In some implementations, the second cross-sectional area c 2  has an inner diameter of about 0.2 cm. 
     In some implementations, the outlet port  205  is disposed at the tapered end (second end  201   b ) of the funnel  201 . In some implementations, a first inlet port  203   a  is disposed at the first end  201   a  of the funnel  201 . In some implementations, a second inlet port  203   b  is disposed on the wall  201   c  of the funnel  201  at a first distance from the first end  201   a  along the longitudinal axis  201   d . The wall  201   c  can have a third cross-sectional area c 3  at the first distance, and the third cross-sectional area c 3  can be perpendicular to the longitudinal axis  201   d . In some implementations, a third inlet port  203   c  is disposed on the wall  201   c  of the funnel  201  at a second distance from the first end  201   a  along the longitudinal axis  201   d . The wall  201   c  can have a fourth cross-sectional area c 4  at the second distance, and the fourth cross-sectional area c 4  can be perpendicular to the longitudinal axis  201   d.    
       FIG.  2 B  shows a cross-sectional view of the core  207  and the coatings  209   a ,  209   b ,  209   c  surrounding the core  207 . The core  207  defines a first outer diameter OD 1 . The first outer diameter OD 1  is less than the inner diameter of the outlet port  205  ( FIG.  2 A ). In some implementations, the first outer diameter OD 1  is in a range of from about 0.3 cm to about 0.5 cm. The first coating  209   a  defines a second outer diameter OD 2 . The second coating  209   b  defines a third outer diameter OD 3 . The third coating  209   c  defines a fourth outer diameter OD 4 . 
     The first coating  209   a  has a first thickness (half of the difference between the second outer diameter OD 2  and the first outer diameter OA). In some implementations, the first thickness of the first coating  209   a  is in a range of from about 0.2 cm to about 0.3 cm. The second coating  209   b  has a second thickness (half of the difference between the third outer diameter OD 3  and the second outer diameter OD 2 ). In some implementations, the second thickness of the second coating  209   b  is in a range of from about 0.2 cm to about 0.3 cm. The third coating  209   c  has a third thickness (half of the difference between the fourth outer diameter OD 4  and the third outer diameter OD 3 ). In some implementations, the third thickness of the third coating  209   c  is in a range of from about 0.1 cm to about 0.2 cm. 
     In some implementations, the first thickness of the first coating  209   a  and the second thickness of the second coating  209   b  are substantially the same. In some implementations, a difference between the first thickness of the first coating  209   a  and the second thickness of the second coating  209   b  is less than 0.1 centimeters. In some implementations, the third thickness of the third coating  209   c  is substantially the same as the first thickness of the first coating  209   a  or the second thickness of the second coating  209   b . In some implementations, the third thickness of the third coating  209   c  is less than the first thickness of the first coating  209   a . In some implementations, the third thickness of the third coating  209   c  is less than the second thickness of the second coating  209   b . In some implementations, a difference between the first thickness of the first coating  209   a  and the third thickness of the third coating  209   c  is less than 0.1 centimeters. In some implementations, the third thickness of the third coating  209   c  is in a range of from about 50% to about 100% of the first thickness of the first coating  209   a.    
       FIG.  2 C  is a side cross-sectional view of the ICD  200  in which the third coating  209   c  has dissolved due to exposure to a hydrocarbon (for example, oil). Dissolution of the third coating  209   c  results in a reduction of the outer diameter of the coated core. The general direction of fluid flow through the ICD  200  causes the coated core to move toward the outlet port  205  as the outer diameter of the coated core decreases. 
       FIG.  2 D  is a side cross-sectional view of the ICD  200  in which the second coating  209   b  has dissolved due to exposure to water. The third coating  209   c  has previously dissolved ( FIG.  2 C ). In some implementations, the third cross-sectional area c 3  (associated with the second inlet port  203   b ) has an inner diameter that is less than the third outer diameter OD 3  (associated with the second coating  209   b ) and greater than the second outer diameter OD 2  (associated with the first coating  209   a ). In this instance, a center of the core  207  is between the second inlet port  203   b  and the outlet port  205 , and the core  207  obstructs fluid communication between a portion of the inlet ports (for example, the first inlet port  203   a  and the second inlet port  203   b ) and the outlet port  205 , such that fluid flow through the ICD  200  and out of the outlet port  205  decreases. 
       FIG.  2 E  is a side cross-sectional view of the ICD  200  in which the first coating  209   a  has dissolved due to exposure to water. The second coating  209   b  and the third coating  209   c  have previously dissolved ( FIG.  2 D ). Therefore, the core  207  is uncoated in this instance. In some implementations, the fourth cross-sectional area c 4  (associated with the third inlet port  203   c ) has an inner diameter that is less than the second outer diameter OD 2  (associated with the first coating  209   a ) and greater than the first outer diameter OD 1  (associated with the core  207  itself). The core  207  can form a seal with the inner wall of the funnel  201 . In this instance, the center of the core  207  is between the third inlet port  203   c  and the outlet port  205 , and the core  207  obstructs fluid communication between all of the inlet ports (for example, the first inlet port  203   a , the second inlet port  203   b , and the third inlet port  203   c ) and the outlet port  205 , such that fluid flow through the ICD  200  and out of the outlet port  205  is prevented. That is, fluid does not flow from the wellbore and into the production tubing  116  through the ICD  200  in this configuration. 
       FIG.  3    is a top cross-sectional view of an ICD  300  that is substantially similar to the ICD  200 . The ICD  300  includes a funnel  301  that has an elliptic cross-sectional area at its first end, in contrast to the circular cross-sectional area that funnel  201  of ICD  200 . In such implementations, an inlet port at the first end of the funnel  301  can be omitted because of the flow areas on opposing sides of the core  307 . As the coatings ( 309   a ,  309   b ,  309   c ) surrounding the core  307  dissolve due to exposure to wellbore fluids, the core  307  travels toward the tapered end (outlet port) of the funnel  301 , and the flow areas on opposing sides of the core  307  decrease in size, effectively decreasing the flow rate at which fluid flows through the ICD  300  and out of the outlet port. The cross-sectional area of the funnel  301  becomes gradually more circular approaching the second end of the funnel  301 , and the cross-sectional area of the funnel  301  can be completely circular at the second end of the funnel  301  to match the cross-sectional shape of the core  307 . Therefore, the core  307  can create a seal with the inner wall of the funnel  301  once all of its coatings have dissolved, such that flow through the ICD  300  and out of the outlet port is prevented. In sum, the ICD  300  can perform similarly as ICD  200 . 
       FIG.  4    is a flow chart of a method  400  for controlling flow of wellbore fluid, for example, in the well of  FIG.  1 A . The ICD  200  or  300  can be used for implementing method  400 . For simplicity and clarity, method  400  is described in relation to the ICD  200 , but the method  400  can also be implemented using the ICD  300 . At block  402 , the ICD  200  is disposed within a wellbore formed in a subterranean formation (for example, the wellbore of the well  100  of  FIG.  1 A ). At block  404 , wellbore fluid is received by the inlet ports (for example, inlet ports  203   a ,  203   b , and  203   c ) of the funnel  201 . As mentioned previously, the wellbore fluid includes a hydrocarbon (such as oil) and water. At block  406 , the funnel  201  directs the wellbore fluid to the core  207 . At block  408 , the third coating  209   c  is contacted with the hydrocarbon of the wellbore fluid to dissolve the third coating  209   c . In response to dissolving the third coating  209   c  at block  408 , the core  207  (with the third coating  209   c  dissolved) is moved toward the outlet port  205  (for example, by the wellbore fluid flowing through the ICD  200 ), and the second coating  209   b  is exposed to the wellbore fluid at block  410 . At block  412 , the second coating  209   b  is contacted with the water of the wellbore fluid to dissolve the second coating  209   b . In response to dissolving the second coating  209   b  at block  412 , fluid communication between a first portion of the inlet ports  203  (for example, the first inlet port  203   a  and the second inlet port  203   b ) and the outlet port  205  is obstructed by the core  207  (with the second coating  209   b  and the third coating  209   c  dissolved) at block  414 , such that fluid flow through the ICD  200  and out of the outlet port  205  decreases. At block  416 , the first coating  209   a  is contacted with the water of the wellbore fluid to dissolve the first coating  209   a . In response to dissolving the first coating  209   a  at block  416 , fluid communication between a remaining portion of the inlet ports  203  (for example, the first inlet port  203   a , the second inlet port  203   b , and the third inlet port  203   c ) and the outlet port  205  is obstructed by the core  207  (with the first coating  209   a , the second coating  209   b , and the third coating  209   c  dissolved) at block  418 , such that fluid flow through the ICD  200  and out of the outlet port  205  is prevented. 
     While this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features that may be specific to particular implementations. Certain features that are described in this specification in the context of separate implementations can also be implemented, in combination, in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations, separately, or in any sub-combination. Moreover, although previously described features may be described as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can, in some cases, be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination. 
     As used in this disclosure, the terms “a,” “an,” or “the” are used to include one or more than one unless the context clearly dictates otherwise. The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. The statement “at least one of A and B” has the same meaning as “A, B, or A and B.” In addition, it is to be understood that the phraseology or terminology employed in this disclosure, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section. 
     As used in this disclosure, the term “about” or “approximately” can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range. 
     As used in this disclosure, the term “substantially” refers to a majority of, or mostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more. 
     Values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of “0.1% to about 5%” or “0.1% to 5%” should be interpreted to include about 0.1% to about 5%, as well as the individual values (for example, 1%, 2%, 3%, and 4%) and the sub-ranges (for example, 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The statement “X to Y” has the same meaning as “about X to about Y,” unless indicated otherwise. Likewise, the statement “X, Y, or Z” has the same meaning as “about X, about Y, or about Z,” unless indicated otherwise. 
     Particular implementations of the subject matter have been described. Other implementations, alterations, and permutations of the described implementations are within the scope of the following claims as will be apparent to those skilled in the art. While operations are depicted in the drawings or claims in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed (some operations may be considered optional), to achieve desirable results. In certain circumstances, multitasking or parallel processing (or a combination of multitasking and parallel processing) may be advantageous and performed as deemed appropriate. 
     Moreover, the separation or integration of various system modules and components in the previously described implementations should not be understood as requiring such separation or integration in all implementations, and it should be understood that the described components and systems can generally be integrated together or packaged into multiple products. 
     Accordingly, the previously described example implementations do not define or constrain the present disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of the present disclosure.