WOUND COMPOSITE CORE FOR MOLDED COMPONENTS

Abstract

An apparatus and a technique related to a composite member of two different composite materials is disclosed. Aspects include a technique which may include forming a first portion using a first composite material and forming a second portion molding a second composite material over the first portion. Aspects further include a millable frac or bridge plug may be created.

Claims

1. A component on a composite bridge plug used for plugging a wellbore, the component comprising: a first member comprising a first composite material; and a second member comprising a second composite material, wherein the first composite material is different from the second composite material.

2. The component of claim 1, wherein the first composite material comprises a wound composite material.

3. The component of claim 2, wherein the second composite material comprises a molded composite material.

4. The component of claim 3, wherein the first member forms a core of the component.

5. The component of claim 3, wherein the first member forms an outer portion of the component.

6. The component of claim 3, wherein the second member forms a core of the component.

7. The component of claim 3, wherein the second member forms an outer portion of the component and is molded over the first member.

8. The component of claim 7, wherein the first member has a substantially cylindrical shape.

9. A method of forming a composite bridge plug comprising: forming a first composite member, the first composite member comprising a first composite material forming a core; and forming a second composite member about the core, the second composite member comprising a second composite material, wherein the first composite material is different than the second composite material.

10. The method of claim 9, wherein the first composite material comprises a wound composite.

11. The method of claim 10, wherein the wound composite comprises at least one of a filament wound composite and a convolute wound composite.

12. The method of claim 9, wherein the first composite material comprises a molded composite.

13. The method of claim 9, wherein the second composite material comprises a molded composite.

14. The method of claim 9, wherein the step of forming the second composite member comprises molding the second composite material onto the first composite member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood; however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein.

[0008] FIG. 1 illustrates a wound composite part around a mandrel, according to an aspect of this disclosure;

[0009] FIG. 2 illustrates the wound composite part shown in FIG. 1 positioned within a mold in a first position, according to an aspect of this disclosure;

[0010] FIG. 3 illustrates the would composite part shown in FIG. 1 positioned within a mold in a second position, according to an aspect of this disclosure;

[0011] FIG. 4 illustrates a wound composite with a molded outer shell, according to an aspect of this disclosure; and

[0012] FIG. 5 illustrates a composite plug lower cone, according to an aspect of this disclosure.

DESCRIPTION OF THE INVENTION

[0013] In the following description, numerous details are set forth to provide an understanding of some aspects of the present disclosure. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described aspects may be possible.

[0014] Certain terminology is used in the description for convenience only and is not limiting. The words “top”, “bottom”, “above,” and “below” designate directions in the drawings to which reference is made. The term “substantially” is intended to mean considerable in extent or largely but not necessarily wholly that which is specified. The terminology includes the above-listed words, derivatives thereof and words of similar import.

[0015] Typically, when designing a frac or bridge plug component, one selects a material based on a desired functionality. However, some components could benefit from the advantages provided by both a molded phenolic and a wound composite. Making components out of both materials could increase functionality and/or decrease cost. Table 1 below lists some examples of possible advantages and disadvantages of the wound composites and molded fiber phenolic materials.

[0016] In conventional systems, frac or bridge plug components that are small in overall volume, require complex geometries or features, and/or do not have a functional requirement for high hoop strength, are typically made of molded composite. Components that are large in overall volume, have simple geometries, and/or in which have a functional requirement for a high hoop strength, are typically made of wound composite and machined to a final shape.

[0017] Complex components of millable frac plugs, in which a large hoop strength is desired, are typically made out of a wound composite and machined to final form. This can be problematic for complex components at a production scale due to the cost of machining complex geometries. If the component was molded, the production price of that component would be mostly independent of geometric complexity. For many components, molded phenolic does not have the hoop strength desired for particular applications, preventing these parts from being molded to final form.

[0018] Aspects described herein include a manufacturing method to enable a composite frac plug component to be formed out of both molded fiber phenolic and wound composite. Benefits of the composite frac plug include providing 1.) a low volumetric cost of wound composite and a low manufacturing cost of molded phenolic, and 2.) a high hoop strength of wound composite and high bearing/shear strength of molded composite. A performance benefit of both materials may be achieved without negatively affecting part cost.

[0019] The composite frac plug component may include a core of wound composite, which provides the frac plug component with the strength advantages of a wound composite. One aspect may include winding a composite cylinder that provides structural strength with minimal machining or surface features desired. The wound cylinder could make up the bulk of the volume, thereby reducing molded material costs. A phenolic shell may be molded over the wound cylinder to achieve a net-shape part. The molded material may be used to add complex features. In conventional systems, these features may have been machined otherwise. Additionally, the molded material may provide bearing and shear strength not achieved with the wound material alone.

[0020] FIGS. 1 through 5 illustrate several steps for manufacturing a composite frac plug having both molded fiber phenolic material and a wound composite. FIG. 1 illustrates a winding process, which includes winding a composite material about a winding mandrel 5 to form a wound composite member 10. In an aspect, the winding process may include a conventional filament or convolute-wound process. The winding mandrel 5 rotates about an axis A. In an aspect, axis A extends through a center of the mandrel 5. The composite member 10 may include a minimal number of features, and may primarily form a cylindrical tube-like structure.

[0021] FIG. 2 illustrates the wound composite member 10 positioned within a two piece mold 20. The two piece mold 20 may include an upper mold 22 and a lower mold 24. The two piece mold 20 is in an open position, whereby the upper mold 22 is spaced apart from the lower mold 24. Each of the upper and lower molds 22 and 24 may include a molded composite preform 30 within.

[0022] FIG. 3 illustrates the two piece mold 20 in a closed position, whereby the upper mold 22 and the lower mold 24 are compressed towards each other. During compression, the wound composite member 10 may be fully encapsulated by the molded composite material 30.

[0023] FIG. 4 illustrates a final composite frac plug 40 comprising the wound composite member 10 at its core and the molded composite material 30 formed about the wound composite member 10. The resulting composite frac plug 40 may be predominantly made of wound composite by volume. The raw composite material is generally cheaper than molded phenolic, which makes the resulting composite frac plug 40 cheaper to manufacture. The composite frac plug 40 retains an overall hoop strength similar to that of a part made of wound composite. Furthermore, complex geometries may be molded onto the final shape of the frac plug 40, allowing difficult-to-machine features to be added. This results in a frac plug 40 that is cheaper to manufacture at the production scale.

[0024] FIG. 5 illustrates an example of a feature molded onto the frac plug 40, according to an aspect of this disclosure. A complex geometry that may be molded to the final shape and that also has a high hoop strength may include, for example, a lower cone 100 of a composite frac/bridge plug. The composite plug lower cone 100 may comprise a hybrid composite material with filament or convolute-wound core 102 with a molded composite shell 104.

[0025] These specific embodiments described above are for illustrative purposes and are not intended to limit the scope of the disclosure as otherwise described and claimed herein. Modification and variations from the described embodiments exist. The scope of the invention is defined by the appended claims.