Patent Application
20150198006
None.
1. Technical Field
The present invention relates to equipment and methods used in subterranean wells and, more particularly, to an expandable tie back seal.
2. Background Art
Wellbores are typically formed by drilling and thereafter lining a borehole with steel pipe called casing. The casing provides support to the wellbore and facilitates the isolation of certain areas of the wellbore adjacent hydrocarbon bearing formations. The casing typically extends down the wellbore from the surface of the well and the annular area between the outside of the casing and the borehole in the earth is filled with cement to permanently set the casing in the wellbore.
As the wellbore is drilled to a new depth, additional strings of pipe are run into the well to that depth, whereby the upper portion of the string of pipe or liner is overlapping the lower portion of the casing. The liner string is then fixed or hung in the wellbore, usually by some mechanical slip means, well known in the art.
In some instances, wells are completed with the remote perforating of liner to provide a fluid path for hydrocarbons to enter the wellbore where they flow into a screened portion of another smaller tubular or production tubing. In these instances, the wellbore around the tubing is isolated with packers to close the annular area and urge the hydrocarbons into the production tubing. In other completions, the last string of liner extending into the wellbore is itself pre-slotted or perforated to receive and carry hydrocarbons upwards in the wellbore. In these instances, production tubing is usually connected to the to of the liner to serve as a conduit to the surface of the well. In this manner, the liner is “tied back” to the surface of the well.
In order to complete these types of wells, the production tubing is inserted in the top of a liner in a sealing relationship, usually accomplished by the use of a polished bore receptacle in the liner top. A polished bore receptacle has a smooth cylindrical inner bore designed to receive and seal a tubular having a seal assembly on its lower end. The polished bore receptacle and seal assembly combination allows the production tubing to be “stung” into the liner in a sealing relationship and be selectively removed there from. As used herein, the term “polished bore receptacle” refers to a device used to locate and seal a first tubular in a second tubular.
Well-known technology permits wellbore tubular members to be expanded in situ. In addition to simply enlarging a tubular, the technology permits the physical attachment of a smaller tubular to a larger tubular by increasing the outer diameter of a smaller tubular with radial force from within. The expansion can be accomplished by a mandrel or a cone-shaped member urged through the tubular to be expanded or by an expander tool run in on a tubular string. For an example of an expander tool see: U.S. Pat. No. 7,779,910, issued Aug. 24, 2010 to Watson, entitled “Expansion Cone For Expandable Liner Hanger”, which is incorporated herein by reference for all purposes. Additionally, the term “expander tool” is used herein to refer to any member that used to expand a tubular, such as the roller expander tool, a cone member, hydraulic pressure or any other type of expansion member used in the oil and gas industry.
Tie back seals typically incorporate elastomers at the seal interface. Caustic fluids, high temperatures and high pressures encountered downhole often precipitate degradation of elastomeric seals. Degraded seals can develop leaks that can be costly to an operation whether left in place or replaced. When left in place, the quality of a production stream can suffer. When replaced, the cost of equipment and labor as well as costs of lost production, during replacement down-time, will accumulate. Accordingly, there is a need in the art for a highly durable tie back seal without elastomers that provides a reliable seal.
Embodiments of the present invention generally relate to methods and apparatus for completing a well. Particularly, the invention relates to a system of completing a wellbore through the expansion of tubular. More particularly, embodiments of the present invention relate to a tie back seal system, wherein the first tubular contains a polished bore receptacle configured to seal with the second tubular, thereby providing a sealed connection therebetween.
Disclosed herein is a tie back seal system. The system includes tubular members receptive for forming a tie back seal assembly therein. The tie back seal assembly includes two telescoping tubular with the overlapping slip fit portions, at least one which is made from plastically deformable metallic material. The interior tubular having radially extending annular protrusions thereon, which when the tubular are plastically deformed to form a tie back seal, the protrusions engage the interior of the outer tubular to improve the sealing and durability of the seal system.
Further disclosed herein is a method of sealing a tie back to a tubular. The method includes: positioning a metal deformable tubular member of the tie back within an outer tubular member; expanding the deformable tubular in a radial direction to contact the outer tubular. The expanding step causing the protrusions to engage the outer tubular creating annular contact areas comprising plastic deformation of the interior all of outer tubular member.
Further disclosed herein is a tie back system and method wherein the axially spaced protrusions on the outer surface of interior tubular member that have a generally triangular-shaped cross section.
The drawings are incorporated into and form a part of the specification to illustrate at least one embodiment and example of the present invention. Together with the written description, the drawings serve to explain the principles of the invention. The drawing is only for the purpose of illustrating at least one preferred example of at least one embodiment of the invention and is not to be construed, as limiting the invention to only the illustrated and described example or examples. The various advantages and features of the various embodiments of the present invention will be apparent from a consideration of the drawing in which:
Embodiments of the present invention generally relate to methods and apparatus for completing a well. Particularly, the invention relates to a system of completing a wellbore through the expansion of one or more tubular members. More particularly, embodiments of the present invention relate to the concurrent expansion of a first and second tubular, wherein the first tubular contains a polished bore receptacle for forming a tie back seal, configured to sealingly receive a portion of the second tubular, thereby providing a sealable connection therebetween.
Referring more particularly to the drawings, wherein like reference characters are used throughout the various figures to refer to like or corresponding parts, there is shown in the figures, one embodiment of the tie back seal system of the present invention.
Turning first to
In this embodiment, the telescoped or overlapping portion of well tubing 5 comprises a de back seal mandrel 2. The telescoped or overlapping portion of well tubing 6 cot a tie back seal receptacle 1. The receptacle can be M the form or a polished bore receptacle. For descriptive purposes, the cone 3 of an expander tool is illustrated in
Tie back seal mandrel 2 comprises a tubular member made from deformable metallic material. Mandrel 2 has an outer diameter and wall thickness which when compared to the well tubing 5 is smaller and thinner, respectively. The wall thickness of the tie back receptacle 1 is thinner than the wall thickness of the well tubing 6.
According to a particular feature, the present invention uses a plurality of radially extending metallic protrusions or ridges 4 which are preferably integrally formed on the reduced diameter outer surface of the seal mandrel 2. These protrusions can be integrally formed on the tubular members, for example, by casting and/or machining. Ridges 4 are axially spaced apart a distance D. Ridges 4 are annular shaped in that they extend continuously around the circumference of the seal mandrel 2 outer surface. In other words, each protrusion is endless or ring shaped as contrasted with the spiral pattern with ends that is present in a threaded connection. As illustrated in detail in
As illustrated in diagram form in
The interaction between the protrusions 4 and interior wall surface of the tie back receptacle 14 can be altered by the selection of materials for the tubing sections. By forming the receptacle from relatively hard material and the mandrel with a lesser hardness, more deformation of the protrusions would be expected. The dimensions of the sections and cone can be selected to vary the expansion process and amount of deformation in the sealing area.
In another embodiment, the protrusions illustrated in
While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods also can “consist essentially of” or “consist of” the various components and steps. As used herein, the words “comprise,” “have,” “include,” and all grammatical variations thereof are each intended to have an open, non-limiting meaning that does not exclude additional elements or steps.
Therefore, the present inventions are well adapted to carry out the objects and attain the ends and advantages mentioned as well as those which are inherent therein. While the invention has been depicted, described, and is defined by reference to exemplary embodiments of the inventions, such a reference does not imply a limitation on the inventions, and no such limitation is to be inferred. The inventions are capable of considerable modification, alteration, and equivalents in form and function, as will occur to those ordinarily skilled in the pertinent arts and having the benefit of this disclosure. The depicted and described embodiments of the inventions are exemplary only, and are not exhaustive of the scope of the inventions. Consequently, the inventions are intended to be limited only by the spirit and scope of the appended claims, giving full cognizance to equivalents in all respects.
Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an”, as used in the claims, are defined herein to mean one or more than one of the element that it introduces. if there is any conflict in the usages of a word or term in this specification and one or more patent(s) or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2012/052721 | 8/28/2012 | WO | 00 | 2/27/2015 |
