WO2018031008A1

WO2018031008A1 - Soluble plug usable downhole

Info

Publication number: WO2018031008A1
Application number: PCT/US2016/046272
Authority: WO
Inventors: JR. James Dan VICK
Original assignee: Halliburton Energy Services Inc
Current assignee: Halliburton Energy Services Inc
Priority date: 2016-08-10
Filing date: 2016-08-10
Publication date: 2018-02-15
Anticipated expiration: 2019-02-10
Also published as: SA519400840B1; MY193988A; AU2016418517A1; GB2566408B; GB2566408A; AU2016418517B2; GB202105062D0; NO20240932A1; GB2591687B; US20210222507A1; NO20190016A1; GB2591687A

Abstract

Soluble plugs are usable downhole to block fluid flow, but dissolve in response to contact with fluid to allow fluid flow. Some aspects can involve a plug assembly including a housing and a plug. The housing can be positioned in a flow path in a wellbore. The plug can be positioned in an inner area of the housing for preventing fluid flow between a first part of the flow path and a second part of the flow path. The plug can include a solid material for at least partially dissolving in response to contact with a fluid to allow fluid flow between the first part and the second part.

Description

SOLUBLE PLUG USABLE DOWNHOLE Technical Field

[0001] The present disclosure relates generally to controlling fluid flow downhole, and more particularly (although not necessarily exclusively), to plugs for use in wellbores.

Background

[0002] A well system, such as an oil or gas well for extracting hydrocarbon fluids from a subterranean formation, can use a pump-out plug. The pump-out plug can be positioned in a tubing string within a wellbore to prevent fluid flow between an upper portion of the tubing string and a lower portion of the tubing string. The pump-out plug can respond to a threshold amount of pressure by moving to a second position and can interfere with wellbore activities. For example, a pump-out plug can respond to a threshold amount of pressure by moving to the bottom of the wellbore and interfering with drilling. In another example, the pump-out plug can move to a second position that is between the tubing string and a production zone and interfere with the flow of production fluid.

Brief Description of the Drawings

[0003] FIG. 1 is a cross-sectional diagram of an example of a wellbore with a plug assembly using a soluble plug made of a solid material according to one aspect of the present disclosure.

[0004] FIG. 2 is a cross-sectional diagram of an example of a plug assembly for use in a wellbore with a soluble plug made of a solid material according to one aspect of the present disclosure.

[0005] FIG. 3 is a cross-sectional diagram of an example of the plug assembly in FIG.

2 in which the solid material is partially dissolved according to one aspect of the present disclosure.

[0006] FIG. 4 is a cross-sectional diagram of an example of the plug assembly in FIG.

2 after the solid material is dissolved according to one aspect of the present disclosure.

[0007] FIG. 5 is a cross-sectional diagram of an example of a plug assembly with dividers according to one aspect of the present disclosure. [0008] FIG. 6 is a cross-sectional diagram of an example of a plug assembly with dividers and a penetrating sleeve according to one aspect of the present disclosure.

[0009] FIG. 7 is a cross-sectional diagram of an example of a plug assembly with a coating according to one aspect of the present disclosure.

[0010] FIG. 8 is a cross-sectional diagram of an example of a plug assembly with a soluble plug made of solid material fluidly sealing an opening in a housing of the plug assembly according to one aspect of the present disclosure.

[0011] FIG. 9 is a flow chart of an example of a process for using a plug assembly with a soluble plug made of solid material according to one aspect of the present disclosure.

Detailed Description

[0012] Certain aspects and features relate to a soluble plug made from solid material for use with wellbore activities. The soluble plug can be positioned in a wellbore to fluidly separate two parts of a flow path. The solid material can dissolve in response to contact with a specific fluid to allow fluid flow between the two parts of the flow path.

[0013] During various stages of a well system (e.g., pre-completion or post completion), it can be beneficial to temporarily plug a wellbore. For example, a completed wellbore can be plugged so that wellbore activities above the plug do not effect an area of the wellbore below the plug. In some aspects, the soluble plug can be positioned within a tubing string in the wellbore to fluidly separate two parts of a flow path. And, after a period of time, the soluble plug can be dissolved to reform the flow path. For example, the soluble plug can be positioned in a production tubing to fluidly separate a production zone from a wellhead. The soluble plug can prevent production fluid from flowing towards the surface. Then, the solid material can be exposed to a fluid such that the soluble plug dissolves and creates a flow path between the production zone and the wellhead.

[0014] In some aspects, the solid material can include a metal, plastic, rubber, or a combination thereof that dissolves in response to contact with a specific fluid. For example, the solid material can be a magnesium alloy that dissolves in response to contact with water. In another example, the solid material can be aluminum and can dissolve in response to contact with an acid. In other examples, the solid material can be a plastic polymer such as, polyglycolic acid ("PGA"), polyactic acid ("PLA"), poly-3-hydroxybutyrate ("PHBV"), and thermoplastic polyurethane ("TPU"), or a rubber such as an acrylic rubber, or a rubber modified in styrene. In still other examples, the solid material can be an asphalt compound or paraffin wax. Descriptions of components as dissolving, as used herein, can include the components dissociating, eroding, melting, or disbanding. In additional or alternative aspects, the solid material can dissolve in response to an acidity of the fluid, a temperature of the fluid, or a chemical composition of the fluid. In some aspects, the solid material can be a rigid dissolvable material such that it can hold its shape and can be dissolved in response to contact with a fluid. In some examples, the solid material can be a composite material such as concrete, but is not a granular mixture such as a sand and salt mixture.

[0015] In additional or alternative aspects, a section of the solid material can extend radially from the plug and hold the plug in position. For example, the section extending from the plug can be positioned in a groove in a surrounding housing (e.g., a tubing string) and the solid material can be rigid enough such that the plug is held in position.

[0016] In some aspects, the two parts of the flow path can be in an inner area of a tubing string. For example, a tubing string can be positioned in a wellbore and define a flow path between a downhole portion of the tubing string and a near-surface portion of the tubing string. The soluble plug can be positioned in the inner area of the tubing string to fluidly seal the downhole portion from the near-surface portion.

[0017] In additional or alternative aspects, one part of the flow path can be an inner area of a tubing string and the other part can be an external area to the tubing string. For example, a tubing string positioned in a wellbore can have an opening in the tubing string defining a flow path between the inner area and the external area. The soluble plug can be positioned in the opening or with respect to the opening to fluidly seal the inner area of the tubing string from the external area. In some aspects, the soluble plug can be a sleeve positioned in the inner area or the external area to cover the opening. In additional or alternative aspects, the soluble plug can be positioned in the opening.

[0018] In some aspects, the soluble plug can be part of a plug assembly that can be positioned in the inner area of a tubing string, around the exterior of a tubing string, or between two segments of a tubing string. In additional or alternative aspects, the plug assembly can be placed directly in a wellbore to fluidly separate two portions of the wellbore. A plug assembly can include a housing with shearable pins to hold the soluble plug in position. In some aspects, the shearable pins can respond to a threshold amount of pressure by shearing and allowing the soluble plug to move. The soluble plug can move to another position in the housing or can move to a position external to the housing. In additional or alternative aspects, the plug assembly can include dividers to fluidly seal the soluble plug from the fluid that dissolves the solid material. The dividers can be made of a soluble material (e.g., natural rubber) such that the dividers dissolve in response to the specific fluid or to another fluid. Additionally or alternatively, an element in the plug assembly can penetrate a divider in response to a threshold amount of pressure, electric signal, or another stimulus.

[0019] In some aspects, positioning the soluble plug in a wellbore can create a barrier. Barriers are either physical or operational elements incorporated into a wellbore that isolate pressures and prevent movement of fluids within the wellbore. Some barriers are used temporarily to facilitate various well construction processes. The use of barriers can be regulated by organizations including the Bureau of Safety and Environmental Enforcement ("BSEE"). For example, a BSEE regulation states that before a well operator removes a blowout preventer, a wellbore is to have two barriers in place. The soluble plug can be a physical barrier by isolating pressures and preventing movement of fluids within the wellbore.

[0020] These illustrative examples are given to introduce the reader to the general subject matter discussed here and are not intended to limit the scope of the disclosed concepts. The following sections describe various additional features and examples with reference to the drawings in which like numerals indicate like elements, and directional descriptions are used to describe the illustrative aspects but, like the illustrative aspects, should not be used to limit the present disclosure.

[0021] FIG. 1 is a cross-sectional diagram of a well assembly 100 with a wellbore 102 and a plug assembly 112. The wellbore 102 extends through various earth strata. The wellbore 102 has a substantially vertical section 104 and a substantially horizontal section 106. The substantially vertical section 104 and the substantially horizontal section 106 can include a casing string 108 cemented at an upper segment of the substantially vertical section 104. [0022] A tubing string 110 extends from the surface within wellbore 102. The tubing string 110 can provide a flow path between a portion of the wellbore 102 and the surface. The wellbore 102 can be at any point in the life cycle of a wellbore (e.g., pre-completion, during completion, or production). A plug assembly 112 can be included between an upper portion 114 of the tubing string 110 and a lower portion 116 of the tubing string 110. The plug assembly 112 can include a soluble plug made of solid material for preventing fluid flow through the flow path. For example, the plug assembly 112 can prevent fluid flow between the upper portion 114 and the lower portion 116. The plug assembly 112 can be positioned in the wellbore such that the plug assembly 112 is a physical barrier. In additional or alternative examples, the plug assembly 112 can prevent fluid flow between an inner area 118 of the tubing string 110 and an external area 120 of the tubing string.

[0023] At least some of the soluble plug can dissolve in response to a fluid making contact with the solid material to allow fluid flow through the flow path. In some aspects, the solid material can respond to a fluid naturally present in the well assembly 100 (e.g., water or production fluid). In additional or alternative aspects, the fluid can be introduced to the well assembly 100 (e.g., an acid). The fluid can contact the solid material while the soluble plug is coupled to the plug assembly 112. In additional or alternative aspects, the soluble plug can respond to a threshold amount of pressure by moving to a second position. For example, the soluble plug can move to a second position within the inner area 118 or can move to the external area 120. In some aspects, the solid material can be exposed to a fluid after the soluble plug has moved to the second position.

[0024] Although FIG. 1 depicts a plug assembly 112 positioned along a tubing string

110, a plug assembly can be used separate from a tubing string in a wellbore. For example, the plug assembly 112 can be positioned within a wellbore and can include packers coupled to an exterior surface of the plug assembly 112 to prevent a fluid flow around the plug assembly 112. In additional or alternative aspects, a plug assembly can be positioned external to a tubing string and can prevent a flow path between two portions of a wellbore. In alternative aspects, a plug assembly can be included in an inner area of the a tubing string or as component of a tubing string.

[0025] In some aspects, the plug assembly 112 can be used with other well tools in various well assemblies. For example, a plug assembly can be positioned in a simpler wellbore, such as a wellbore having only a substantially vertical section. In additional or alternative examples, a plug assembly can be positioned in an open-hole environment or in a cased well. In additional or alternative aspects, a plug assembly can be positioned in a substantially vertical section of a wellbore. In some aspects, a wellbore can include more than one plug assembly.

[0026] The plug assembly 112 can have many, various forms. FIG. 2 is a cross- sectional diagram of the plug assembly 112 according to one example. The plug assembly 112 includes a soluble plug 206 made of a solid material and a housing. The housing includes an upper housing 202 coupled to a lower housing 204. The upper housing 202 and the lower housing 204 define an inner area with an upper portion 212a and a lower portion 212b. The soluble plug 206 is positioned within the inner area between the upper portion 212a and the lower portion 212b. The soluble plug 206 is shaped such that a section of the soluble plug 206 extends into a groove between the upper housing 202 and the lower housing 204. The section holds the soluble plug 206 in position to allow O-rings 210 to fluidly seal the upper portion 212a from the lower portion 212b. In additional or alternative aspects, a soluble plug can fluidly seal a flow path without O-rings.

[0027] Although the solid material in FIG. 2 is depicted as a metal, the solid material can be any rigid dissolvable material such that the section of the soluble plug 206 that extends into the groove is strong enough to hold the soluble plug 206 in position. In some examples, the solid material can be a composite material, but is not a sand and salt mixture.

[0028] Although FIG. 2 depicts the upper housing 202 as being partially surrounded by the lower housing 204, other implementations are possible. For example, the lower housing 204 can be partially surrounded by the upper housing 202. In some alternative aspects, a plug assembly can include a single housing. Although FIG. 2 depicts the upper housing 202 and lower housing 204 as cylindrical, a housing of any shape can be used. Furthermore, descriptions of components as upper or lower used herein are intended to denote a component relative to other components in a plug assembly and are not intended to imply that a particular orientation is required.

[0029] The solid material can partially dissolve in response to contact with a specific fluid. The solid material in FIG. 2 is depicted as a metal, but the solid material can include a metal, plastic, rubber, or a combination thereof that dissolves in response to contact with the fluid. In some examples, the solid material is not sand or a sand and salt mixture. The fluid can dissolve the solid material based on the acidity of the fluid, temperature of the fluid, the chemical composition of the fluid, or another characteristic of the fluid.

[0030] For example, FIG. 3 depicts the plug assembly 112 in FIG. 2 with a section of the soluble plug 206 partially dissolved. The section of the soluble plug 206 extending into the groove between the upper housing 202 and the lower housing 204 can prevent the soluble plug 206 from moving. The O-rings 210 can fluidly seal the flow path between the upper portion 212a of the inner area from the lower portion 212b of the inner area. In additional or alternative examples, a section of the soluble plug 206 closer to the lower portion 212b can be partially dissolved in response to the solid material being contacted by the fluid. In some aspects, the section of the soluble plug 206 extending into the groove can partially dissolve and can allow the soluble plug 206 to move to a second position. The second position can be in the plug assembly 112 or external to the plug assembly 112. The second position can have a concentration of the fluid such that the solid material dissolves.

[0031] The fluid (e.g., water or production fluid) can be naturally present in an environment of the plug assembly 112 and can gradually dissolve the solid material. Additionally or alternatively, the fluid (e.g., an acid) can be introduced into the environment of the plug assembly 112 and can cause the soluble plug 206 to rapidly dissolve.

[0032] FIG. 4 depicts the plug assembly 112 in FIG. 2 with the soluble plug 206 in FIG.

2 dissolved. Fluid flow can pass through the inner area of upper housing 202 and lower housing 204 forming a flow path between the upper portion 212a and the lower portion 212b. In some aspects, the plug assembly 112 can be part of a well assembly and a flow path can form to allow a production fluid flow from a production zone to the wellhead. In some aspects, the O-rings 210 can also be dissolvable.

[0033] A plug assembly according to various aspects can take other forms. For example, FIG. 5 is a cross-sectional diagram of an example of a plug assembly 500 with dividers 514a-b. The plug assembly 500 includes an upper housing 502 coupled to a lower housing 504. The upper housing 502 and the lower housing 504 define an inner area with an upper portion 512a and a lower portion 512b. The soluble plug 506 is positioned within the inner area between the upper portion 512a and the lower portion 512b. Shear pins 508 hold the soluble plug 506 in position to allow O-rings 510 to fluidly seal the upper portion 512a from the lower portion 512b. In some aspects, the plug assembly 500 can be part of a tubing string or positioned in a tubing string. In additional or alternative aspects, the plug assembly 500 can be positioned in a wellbore and can include packers coupled to the exterior surface of the upper housing 502 or lower housing 504 to prevent a fluid flow around the plug assembly 500.

[0034] The solid material can partially dissolve in response to contact with a fluid to allow fluid flow between the upper portion 512a and the lower portion 512b. Although the solid material in FIG. 5 is depicted as a metal, the solid material can be a metal, plastic, rubber, or combination thereof. Divider 514a is coupled to the upper housing 502 to fluidly seal the soluble plug 506 from the upper portion 512a of the inner area. Divider 514b is coupled to the lower housing 504 to fluidly seal the soluble plug 506 from the lower portion 512b of the inner area. Each divider 514a-b also traps an inert fluid 516 between the divider 514a-b and the soluble plug 506. The inert fluid 516 can be any substance that can contact the solid material without causing the solid material to dissolve. In some aspects, the inert fluid 516 can be a substance that repels the fluid. For example, the inert fluid can be oil and the fluid can be water, such that the oil repels the water.

[0035] In some aspects, a threshold amount of pressure applied to a divider 514a-b can cause an opening to form in the divider to allow the soluble plug 506 to be exposed to the fluid. In additional or alternative aspects, the divider 514a-b can be made of a flexible material (e.g., rubber) to allow the divider 514a-b to bend under pressure. In some aspects, the dividers 514a-b can be soluble so that the dividers 514a-b dissolve and expose the soluble plug 506 to the fluid. For example, the dividers 514a-b can be made of natural rubber and dissolve in response to production fluid.

[0036] In some examples, the shear pins 508 can shear in response to a threshold amount of pressure prior to the divider 514a-b to allow the soluble plug 506 to be exposed to the fluid. The shear pins 508 can shear to allow the soluble plug 506 to pierce the divider 514a-b. Additionally or alternatively, the soluble plug 506 can move to a second position. A soluble plug can move to a second position in the wellbore that exposes the solid material to the fluid. The shear pins 508 and O-rings 510 can also be made of a dissolvable material.

[0037] Although FIG. 5 depict two dividers 514a-b, any number of divider can be coupled to the upper housing 502, lower housing 504, or both. For example, a plug assembly can include a single divider coupled to the upper housing 502 for fluidly sealing the soluble plug 506 from the upper portion 512a. In other examples, a plug assembly can include several dividers that respond to different stimuli to allow a soluble plug to be exposed to the fluid.

[0038] FIG. 6 is a cross-sectional diagram of an example of a plug assembly 600 with dividers 614a-b and a penetrating sleeve 618 according to one aspect of the present disclosure. The plug assembly 600 includes an upper housing 602 coupled to a lower housing 604. The upper housing 602 and the lower housing 604 define an inner area with an upper portion 612a and a lower portion 612b. The soluble plug 606 is positioned within the inner area between the upper portion 612a and the lower portion 612b. The soluble plug 606 is shaped such that a section of the soluble plug 606 extends into a groove between the upper housing 602 and the lower housing 604. The section holds the soluble plug 606 in position to allow O-rings 610 to fluidly seal the upper portion 612a from the lower portion 612b. In some aspects, the plug assembly 600 can be part of a tubing string or positioned in a tubing string. In additional or alternative aspects, the plug assembly 600 can be positioned within a wellbore and can include packers coupled to the exterior surface of the upper housing 602 or lower housing 604 to prevent a fluid flow around the plug assembly 600.

[0039] The solid material of the soluble plug 606 can partially dissolve in response to contact with a fluid and can allow a fluid flow between the upper portion 612a and the lower portion 612b. Although the solid material in FIG. 6 is depicted as a metal, the solid material can be any rigid dissolvable material such that the section of the soluble plug 606 that extends into the groove is strong enough to hold the soluble plug 606 in position. In some examples, the solid material can be a composite material, but is not a sand and salt mixture. Dividers 614a-b trap an inert fluid 616 around the soluble plug 606 and fluidly seal the soluble plug 606 the upper portion 612a and lower portion 612b of the inner area. The penetrating sleeve 618 is positioned within the upper portion 612a and can respond to a threshold amount of pressure by penetrating the divider 614a. Penetrating the divider 614a can expose the solid material of the soluble plug 606 to the fluid.

[0040] Although FIG. 6 depicts the penetrating sleeve 618 in the upper portion 612a various implementations are possible for penetrating the dividers 614a-b. In some aspects, a penetrating sleeve can be positioned in the lower portion 612b or in both the upper portion 612a and the lower portion 612b. In additional or alternative aspects, a penetrating component is used rather than a penetrating sleeve. For example, a rod can be suspended in the plug assembly that penetrates a divider in response to a threshold amount of pressure. In some aspects, the rod can be made of the solid material or another dissolvable material. In additional or alternative examples, a signal sent from a device located in the wellbore or at the surface can cause penetration of a divider.

[0041] Although FIG. 6 depicts two dividers 614a-b trapping inert fluid 616 various implementations are possible for fluidly sealing a soluble plug. For example, multiple dividers can be used on the same side of the soluble plug. In some aspects, a pair of dividers can trap the fluid between the pair of dividers, such that if both dividers are penetrated the fluid can contact the solid material.

[0042] FIG. 7 is a cross-sectional diagram of an example of a plug assembly 700 with a coating 714 covering a surface of the solid material. The plug assembly 700 includes an upper housing 702 coupled to a lower housing 704. The upper housing 702 and the lower housing 704 define an inner area with an upper portion 712a and a lower portion 712b. The soluble plug 706 is positioned within the inner area between the upper portion 712a and the lower portion 712b. Shear pins 708 hold the soluble plug 706 in position to allow O- rings 710 to fluidly seal the upper portion 712a from the lower portion 712b. In some aspects, the plug assembly 700 can be part of a tubing string or positioned in a tubing string. In additional or alternative aspects, the plug assembly 700 can be positioned within a wellbore and can include packers coupled to the exterior surface of the upper housing 702 or lower housing 704 to prevent a fluid flow around the plug assembly 700.

[0043] The solid material of the soluble plug 706 can partially dissolve in response to contact with a fluid. A coating (e.g., rubber) 714 can be applied to a surface of the solid material to prevent the fluid from contacting the solid material. A section 716 of the surface of the solid material is uncoated and fluidly sealed from the fluid by the O-rings 710 while the soluble plug 706 is held in place by the shear pins 708. In some aspects, the shearing pins can respond to a threshold amount of pressure applied to the soluble plug 706 by shearing to allow the soluble plug 706 to move to a second position. While in the second position, the uncoated section 716 of the solid material can be exposed to the fluid and cause the solid material to dissolve.

[0044] In some aspects, the coating 714 can be made of a material that dissolves in response to contact with another fluid. For example, the plug assembly 700 can be in a wellbore with the soluble plug 706 made of a water soluble solid material (e.g., a magnesium alloy) and the coating 714 made of a non-water soluble material (e.g., aluminum). An acid can be introduced into plug assembly 700 to dissolve the coating 714, which can expose the solid material to water that can be naturally present in the wellbore.

[0045] FIG. 8 is a cross-sectional diagram of an example of a plug assembly 800 with a soluble plug 806 positioned with respect to an opening 804 in a housing 802. A flow path is formed between an inner area 810 of the housing 802 and an external area 812. The soluble plug 806 is coupled to the inner surface of the housing 802 by shear pins 808 such that the soluble plug 806 prevents fluid flow through the opening 804.

[0046] In FIG. 8, the soluble plug 806 is a sleeve positioned in a groove in an inner surface of the housing 802. In some aspects, the soluble plug 806 can extend into the inner area of the housing 802, extend into the opening 804, or both. In additional or alternative aspects, the soluble plug 806 can respond to a threshold amount of pressure by shearing the shear pins 808 and moving to a second position. In some aspects, the housing 802 is a tubing string for use in a wellbore. In additional or alternative aspects, the housing 802 can be positioned in an inner area of a tubing string or in line with a tubing string.

[0047] The soluble plug 806 can be made of a solid material that dissolves in response to contact with a specific fluid. The fluid can be introduced into the plug assembly 800 from the surface or can be naturally present in the wellbore. In some aspects, a coating can be applied to a section of the surface of the soluble plug 806 to protect the solid material from being exposed to the fluid. In additional or alternative aspects, dividers can be positioned in the plug assembly 800 to fluidly seal the soluble plug 806 from a part of the flow path that can contain the fluid. Once the soluble plug 806 is dissolved the flow path will reform between the inner area 810 and external area 812.

[0048] FIG. 9 is a flow chart of an example of a process for using a plug assembly with a soluble plug made of a solid material. The process can be used to plug a wellbore during drilling, completion, production, or abandonment and later unplug the wellbore. In some aspects, the process can create a physical barrier as recommended by the BSEE for some wellbore activities.

[0049] In block 902, a first part of a flow path in a wellbore is fluidly sealed from a second part of the flow path by a soluble plug formed of solid material. In some aspects, the soluble plug can be part of a plug assembly that includes a housing that defines a part of the flow path. The housing can be a tubing string and the soluble plug can fluidly separate two portions of the tubing string. For example, the soluble plug can be positioned within a well assembly with a production tubing extending from a wellhead to a production zone. The soluble plug can fluidly seal a flow path between the production zone and the wellhead. In additional or alternative aspects, an opening in the housing can define a flow path such that the first part is an inner area of the housing and the second part is an external area of the housing.

[0050] In some aspects, sealing the first part of the flow path from the second part can further include using shearable pins to hold the soluble plug in position. In additional or alternative aspects, O-rings can expand between the soluble plug and a housing to further seal the first part from the second part. In some aspects, the process further includes sealing the soluble plug from a part of the flow path to prevent exposure to a fluid. For example, a divider can be positioned in a part of the flow path to trap an inert fluid between the divider and the soluble plug. In additional or alternative examples, a section of the surface of the soluble plug can be coated in a substance that fluidly seals the section of the surface.

[0051] In block 904, the solid material is at least partially dissolved in response to contact with a fluid. The solid material can be a rigid dissolvable material that maintains its shape but dissolves in response to contact with the fluid. For example, the solid material can be a metal, plastic, or rubber that dissolves in response to the acidity of the fluid, a temperature of the fluid, or a chemical composition of the fluid. In some examples, the solid material is not sand or a sand and salt mixture.

[0052] In some aspects, the fluid is introduced into the plug assembly from the surface. For example, a well operator can introduce acid into the plug assembly to dissolve a soluble plug made of aluminum. In additional or alternative aspects, the fluid can be naturally present in the wellbore. In some examples, the soluble plug can move from the plug assembly to a segment of the wellbore with a concentration of the fluid.

[0053] In some aspects, the process further includes piercing a divider that fluidly seals the soluble plug from the fluid using a penetrating component. For example, the process can include activating a penetrating sleeve that responds that shifts to pierce the divider such that the soluble plug can be exposed to the fluid. In some aspects, the penetrating component can be activated in response to a threshold amount of pressure. In additional or alternative aspects, the penetrating component can be controlled by a signal sent from another device.

[0054] In block 906, a fluid flow is allowed between the first part and the second part. In some examples, the fluid flow can occur in response to the solid material being dissolved. In additional or alternative examples, the fluid flow can be allowed between the first part and second part in response to the soluble plug being moved to a second position.

[0055] In some aspects, a soluble plug usable downhole is provided according to one or more of the following examples:

[0056] Example #1: A plug assembly can include a housing and a plug. The housing can be positioned in a flow path in a wellbore. The plug can be positioned in a first portion in an inner area of the housing for preventing fluid flow between a first part of the flow path and a second part of the flow path. The plug can include a solid material for at least partially dissolving in response to contact with a fluid flow to allow the fluid flow between the first part and the second part.

[0057] Example #2: The plug assembly of Example #1 can further include a divider in the inner area of the housing. The divider can fluidly sealing the plug from at least one of the first part and the second part while the plug is in the inner area of the housing.

[0058] Example #3: The plug assembly of Example #2 can feature the divider including a natural rubber for retaining an inert fluid between the divider and the plug.

[0059] Example #4: The plug assembly of Example #2 can further include a sleeve in the inner area of the housing for responding to a threshold amount of pressure by penetrating the divider to allow the fluid to contact the solid material. [0060] Example #5: The plug assembly of Example #1 can further include a pin. The pin can couple the plug to the housing and respond to a threshold amount of pressure against the plug by shearing to allow the plug to move to a second position.

[0061] Example #6: The plug assembly of Example #5 can feature a first surface of the solid material coated with a substance for fluidly sealing the solid material from at least one of the first part or the second part while the plug is in the first position. And, further feature a second surface of the solid material that can be exposed to the fluid in the second position.

[0062] Example #7: The plug assembly of Example #1 can feature a section of the plug that extends into a groove in an inner surface of the housing. The section can prevent the plug from moving to a second position.

[0063] Example #8: The plug assembly of Example #1, can feature the first part of the flow path in the inner area of the housing, the second part of the flow path external to the housing, and the plug positioned to prevent the fluid flow through an opening in the housing.

[0064] Example #9: The plug assembly of Example #1, can feature the solid material as not a sand and salt mixture.

[0065] Example #10: The plug assembly of Example #1, can feature the plug assembly positioned within the wellbore to form a physical barrier.

[0066] Example #11: A well assembly can include production tubing, a housing, and a plug. The production tubing can extend from a wellhead to a production zone in a wellbore, and define a flow path. The housing can be positioned in the flow path. The plug can be positioned in an inner area of the housing for preventing production fluid from flowing from the production zone to the wellhead. The plug can include a solid material for at least partially dissolving in response to contact with a fluid to allow the production fluid to flow from the production zone to the wellhead.

[0067] Example #12: The well assembly of Example #11, can further feature a coating on a first surface of the solid material to fluidly seal the solid material from the fluid while the plug is in a first position. And, further feature a second surface that is exposable to the fluid while the plug is in a second position. [0068] Example #13: The well assembly of Example #12, can feature the first position is within the inner area of the housing, and the plug in the first position is for responding to a threshold amount of pressure by moving to the second position that is external to the inner area of the housing.

[0069] Example #14: The well assembly of Example #11, can feature the solid material including a magnesium alloy and the fluid including water.

[0070] Example #15: The well assembly of Example #11, can feature the solid material responding to at least one of an acidity of the fluid, a temperature of the fluid, or a chemical composition of the fluid.

[0071] Example #16: A method can include sealing a first part of a flow path in a wellbore from a second part of the flow path by a plug formed of a solid material. The method can also include at least partially dissolving the solid material in response to contact with a fluid. The method can further include allowing fluid flow between the first part and the second part.

[0072] Example #17: The method of Example #16, can feature sealing the first part of the flow path from the second part of the flow path using a divider to fluidly seal the plug from the first part. The method can further include trapping an inert fluid between the divider and the plug.

[0073] Example #18: The method of Example #17, can feature at least partially dissolving the solid material by penetrating the divider in response to a threshold amount of pressure in the wellbore.

[0074] Example #19: The method of Example #16, can feature sealing the first part of the flow path from the second part of the flow path by positioning the plug in an inner area of a housing in the wellbore. The method can further feature dissolving the solid material by moving the plug to a second position.

[0075] Example #20: The method of Example #16, can feature sealing the first part of the flow path from the second part of the flow path by preventing the fluid flow through an opening in a housing positioned in the wellbore such that the first part of the flow path is in an inner area of the housing and the second part of the flow path is external to the housing. [0076] The foregoing description of certain examples, including illustrated examples, has been presented only for the purpose of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Numerous modifications, adaptations, and uses thereof will be apparent to those skilled in the art without departing from the scope of the disclosure.

Claims

Claims What is claimed is:

1. A plug assembly comprising:

a housing positionable in a flow path in a wellbore; and

a plug positionable in a first position in an inner area of the housing for preventing fluid flow between a first part of the flow path and a second part of the flow path, the plug comprising a solid material for at least partially dissolving in response to contact with a fluid to allow the fluid flow between the first part and the second part.

2. The plug assembly of claim 1, further comprising a divider in the inner area of the housing for fluidly sealing the plug from at least one of the first part and the second part while the plug is in the inner area of the housing.

3. The plug assembly of claim 2, wherein the divider comprises a natural rubber for retaining an inert fluid between the divider and the plug.

4. The plug assembly of claim 2, further comprising a sleeve within the inner area of the housing for responding to a threshold amount of pressure by penetrating the divider to allow the fluid to contact the solid material.

5. The plug assembly of claim 1, further comprising a pin coupling the plug to the housing and for responding to a threshold amount of pressure against the plug by shearing to allow the plug to move to a second position.

6. The plug assembly of claim 5, wherein a first surface of the solid material is coated with a substance for fluidly sealing the solid material from at least one of the first part or the second part while the plug is in the first position, and a second surface of the solid material is exposable to the fluid in the second position.

7. The plug assembly of claim 1, wherein a section of the plug extends into a groove in an inner surface of the housing for preventing the plug from moving to a second position.

8. The plug assembly of claim 1, wherein the first part of the flow path is in the inner area of the housing, the second part of the flow path is external to the housing, and the plug is positionable to prevent the fluid flow through an opening in the housing.

9. The plug assembly of claim 1, wherein the solid material is not a sand and salt mixture.

10. The plug assembly of claim 1, wherein the plug assembly is positionable within the wellbore to form a physical barrier.

11. A well assembly comprising:

production tubing for extending from a wellhead to a production zone in a wellbore, and for defining a flow path;

a housing positionable in the flow path; and

a plug positionable in an inner area of the housing for preventing production fluid from flowing from the production zone to the wellhead, the plug comprising a solid material for at least partially dissolving in response to contact with a fluid to allow the production fluid to flow from the production zone to the wellhead.

12. The well assembly of claim 11, further comprising a coating on a first surface of the solid material to fluidly seal the solid material from the fluid while the plug is in a first position, and a second surface that is exposable to the fluid while the plug is in a second position.

13. The well assembly of claim 12, wherein the first position is within the inner area of the housing, and the plug in the first position is for responding to a threshold amount of pressure by moving to the second position that is external to the inner area of the housing.

14. The well assembly of claim 11, wherein the solid material comprises a magnesium alloy and the fluid comprises water.

15. The well assembly of claim 11, wherein the solid material responds to at least one of an acidity of the fluid, a temperature of the fluid, or a chemical composition of the fluid.

16. A method comprising:

sealing a first part of a flow path in a wellbore from a second part of the flow path by a plug formed of a solid material;

at least partially dissolving the solid material in response to contact with a fluid; and allowing fluid flow between the first part and the second part.

17. The method of claim 16, wherein sealing the first part of the flow path from the second part of the flow path comprises using a divider to fluidly seal the plug from the first part, the method further comprising:

trapping an inert fluid between the divider and the plug.

18. The method of claim 17, wherein at least partially dissolving the solid material further comprises penetrating the divider in response to a threshold amount of pressure in the wellbore.

19. The method of claim 16, wherein sealing the first part of the flow path from the second part of the flow path comprises positioning the plug in an inner area of a housing in the wellbore, and wherein dissolving the solid material further comprises moving the plug to a second position.

20. The method of claim 16, wherein sealing the first part of the flow path from the second part of the flow path further comprises preventing the fluid flow through an opening in a housing positioned in the wellbore such that the first part of the flow path is in an inner area of the housing and the second part of the flow path is external to the housing.