Oil and gas operations in both on shore and offshore locations requires maintaining proper separation of regions, fluids, and pressures at precise times. Wellbores are difficult to access, rendering this seemingly simple task difficult. There are many applications that benefit from proper barriers in the wellbore. Dissolvable materials have enabled removal of barriers in the right conditions without requiring active participation by an operator at the surface. There exists in the industry a continuing need for barriers that perform their tasks for a certain time and that are cost-effective.
Embodiments of the present disclosure are directed to a barrier assembly including a generally cylindrical housing having an interior bore through the housing, a small inner diameter region in the interior bore defining a narrowest portion of the housing, and a shoulder transverse to an axis of the housing, the axis being generally parallel with the generally cylindrical housing. The barrier assembly also includes a barrier unit receptacle defined by the shoulder and the housing, and a barrier unit. The barrier unit includes a shroud having a generally cylindrical main body defining a central bore through the shroud. The shroud is carried by the barrier unit receptacle. The barrier unit also includes a plug having a generally cylindrical body and a head. The generally cylindrical main body is axially coextensive with the shroud and is located within the central bore through the shroud. The head protrudes from the central bore through the shroud. The shroud is secured to the housing, and the plug is secured to the shroud. One or more of the shroud and the plug is made of a dissolvable material.
Further embodiments of the present disclosure are directed to a method including providing a barrier assembly in a wellbore that includes a housing having a primary axis and a passageway therethrough and being generally aligned with the primary axis. The passageway has a shoulder that is transverse to the primary axis. The barrier assembly also includes a shroud in the housing contacting the shoulder. The shroud has a central bore and a plug in the central bore of the shroud. The plug has a head that protrudes from the shroud at a lower end. The shroud and plug are dissolvable. The method also includes positioning the barrier assembly in the wellbore where the shroud and plug form a fluid barrier that persists until the shroud and/or plug dissolves sufficiently to release from the housing.
Still further embodiments of the present disclosure are directed to a system for establishing a barrier in a wellbore. The system includes a plug having a generally cylindrical body and a head, and the head is wider than the body. The system also includes a shroud around the body of the plug with the head protruding from the shroud. At least one of the plug and shroud is made of a dissolvable material. The system also includes a housing having a passageway through the housing having a narrowest region and a shoulder below the narrowest region, the housing having a shoulder configured to receive the shroud. The housing is located in the wellbore to establish a fluid barrier using the shroud and plug. When the dissolvable material dissolves the fluid barrier is terminated. Various other features of the present disclosure are described below.
The barrier assembly 100 includes a housing 102 that is a generally cylindrical member having a cylindrical outer surface and a central bore. The housing 102 defines a central axis running through the housing 102. The housing 102 has an outer diameter 104 that is a suitable size to fit into the wellbore. The housing 102 has a small inner diameter 106 that defines the narrowest point through the housing 102. The dimensions of the barrier assembly 100 and its various components can vary for a given installation. The small inner diameter 106 is small only in the sense that it is the narrowest path through the housing 102. The barrier assembly 100 and indeed the small inner diameter 106 may be as large as necessary and suitable. The housing 102 also includes a seat 108 above the small inner diameter 106. The seat 108 can be used with a ball (not shown) such as a frac ball that can be pumped down to the barrier assembly 100 after installation, or the barrier assembly 100 can be run in hole with the ball in place. Above the seat 108 are inner threads 110 that can provide an attachment mechanism for a tool that runs the barrier assembly 100 into the hole.
At a region below the small inner diameter 106 is a shoulder 114 that defines a larger diameter region at a lower portion of the housing 102 that receives a shroud 120 and a plug 140. The shroud 120 and plug 140 together are referred to as a barrier unit. The shroud 120, plug 140, and barrier unit will be described in greater detail below. The larger diameter region at the lower portion of the housing 102 is a barrier unit receptacle 119. The housing 102 also includes outer threads 116 that may be used to attach the barrier assembly 100 to a tubular or other structure in the wellbore. The housing 102 also has a set screw 118 that penetrates horizontally through the housing 102 and into the shroud 120 to at least temporarily hold the shroud 120 in place relative to the housing 102. The housing 102 is made of steel or any other suitable non-dissolvable material and as such will persist in the wellbore after other components may have dissolved. In some embodiments the housing 102 can also be made of a dissolvable material.
Each of the shroud 120 and plug 140 may be made of a dissolvable material such as a magnesium-based material. Any suitable dissolvable material may be used, provided the material has the desired strength and dissolution rates for a given application. In some embodiments one of the plug 140 and shroud 120 is dissolvable and the other is not. The barrier assembly 100 therefore can be run in hole and will provide separation between a region above the barrier assembly 100 and below for a desired time based on the material characteristics and then the plug 140 and/or shroud 120 dissolves. Once the plug 140 and/or shroud 120 dissolve the barrier assembly 100 ceases to function as a barrier and instead allows fluid communication through the barrier assembly 100.
In some embodiments the shear screws 152 are shearable with sufficient pressure above or below the barrier assembly 100. The pressure may be intentionally applied with a pump at a desired time that will break the shear screws 152 leaving the plug 140 unatttached, thereby allowing fluid through the barrier assembly 100 without having to wait for full dissolution of the plug 140 and/or shroud 120. Even after the plug 140 is released the shroud 120 and/or plug 140 will dissolve, rendering the effective diameter of the barrier assembly 100 larger than immediately after releasing the plug 140.
In other embodiments the catcher 162 is not directly coupled to the barrier assembly 160 and can instead be found as part of another piece of equipment in the wellbore located in a position to operate the same way as shown and described in
In other embodiments the pump 170 can be in the wellbore separate from the barrier assembly 170, but other than that difference can operate as described with respect to
The foregoing disclosure hereby enables a person of ordinary skill in the art to make and use the disclosed systems without undue experimentation. Certain examples are given to for purposes of explanation and are not given in a limiting manner.
This application claims priority to U.S. Provisional Patent Application No. 63/180,167 filed Apr. 27, 2021 entitled “DOWNHOLE ASSEMBLY WITH DISSOLVING PLUG AND MILL-OUT I.D.” which is incorporated herein by reference in its entirety.
Number | Date | Country | |
---|---|---|---|
63180167 | Dec 2021 | US |