MULTI-STAGE SEAL FOR WELL FRACTURING
A fracturing system including a ring gasket disposed between a fracturing tree and a wellhead component is provided. In one embodiment, the ring gasket includes multiple sealing stages that seal against grooves in the fracturing tree and the wellhead component. The ring gasket may also include one or more recesses between the sealing stages. In some embodiments, the ring gasket has a configuration that reduces gasket setting load and increases flange separation load compared to other gaskets used in fracturing operations. And in some embodiments, the system enables monitoring of gasket sealing integrity, even during fracturing operations. Additional systems, devices, and methods are also disclosed.
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This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the presently described embodiments. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present embodiments. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In order to meet consumer and industrial demand for natural resources, companies often invest significant amounts of time and money in finding and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired subterranean resource such as oil or natural gas is discovered, drilling and production systems are often used to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource. Further, such systems generally include a wellhead assembly through which the resource is extracted. These wellhead assemblies may include a wide variety of components, such as various casings, valves, fluid conduits, and the like, that aid drilling or extraction operations.
Additionally, such wellhead assemblies may use a fracturing tree and other components to fracture a well and enhance production. As will be appreciated, resources such as oil and natural gas are generally extracted from fissures or other cavities formed in various subterranean rock formations or strata. To facilitate extraction of such resources, a well may be subjected to a fracturing process that creates one or more man-made fractures in a rock formation. This helps couple pre-existing fissures and cavities, allowing oil, gas, or the like to flow into the wellbore. Such fracturing processes typically include injecting a fracturing fluid—often a mixture including sand and water—into the well to increase the well's pressure and form the man-made fractures.
Certain aspects of some embodiments disclosed herein are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below.
Embodiments of the present disclosure generally relate to well fracturing operations. In some embodiments, a fracturing tree and a wellhead component (e.g., a tubing spool) are joined via a flanged connection that includes a ring gasket with multiple sealing stages. In one embodiment, the ring gasket includes at least one recess in the body of the ring gasket between the sealing stages to decrease gasket setting load and increase flange separation load of the fracturing tree and the wellhead component. Additionally, some embodiments include a test port connected to a sealing groove in which the ring gasket is disposed, enabling the sealing integrity of the ring gasket to be monitored during fracturing.
Various refinements of the features noted above may exist in relation to various aspects of the present embodiments. Further features may also be incorporated in these various aspects. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above-described aspects of the present disclosure alone or in any combination. Again, the brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of some embodiments without limitation to the claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects, and advantages of certain embodiments will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
One or more specific embodiments of the present disclosure will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, any use of “top,” “bottom,” “above,” “below,” other directional terms, and variations of these terms is made for convenience, but does not require any particular orientation of the components.
Turning now to the drawings, a resource extraction system 10 is illustrated in
A production tree 18 is connected to the wellhead assembly 16 (e.g., to a tubing spool) and facilitates extraction of the natural resource from the well 12. In some instances, and to further facilitate production, a fracturing tree 20 may be connected to the wellhead assembly 16. By injecting a fracturing fluid into the well 12 via the fracturing tree 20, the system 10 increases the number or size of fractures in a resource-bearing rock formation (or strata) to enhance recovery of the desired resource.
A particular arrangement 24 of a fracturing tree 20 connected to a wellhead assembly 16 is depicted in
The connection of the fracturing tree 20 to the component 30 may be referred to as a fracturing connection. And in the present depiction, the fracturing tree 20 and the component 30 include respective flanges 32 and 34 (depicted as ring joint type flanges) joined together with fasteners 36 (such as nuts with studs of a studded flange 34), though other fasteners or manners of connecting the tree 20 and the component 30 could instead be used. Consequently, in those embodiments having such flanges, this connection between the fracturing tree 20 and the component 30 may also be referred to as a flanged connection. In at least some embodiments, the flanges 32 and 34 conform to Advanced Petroleum Institute (API) Specification 6A (i.e., the flanges 32 and 34 are API flanges). And in at least some of these embodiments the flanges 32 and 34 conform to the specifications of 6BX flanges in API Specification 6A (i.e., the flanges 32 and 34 are 6BX flanges).
Additional details about the fracturing connection of arrangement 24 are illustrated in the cross-section of
In one embodiment generally depicted in
As noted above, the flanges 32 and 34 of some embodiments are 6BX flanges. API Specification 6A also defines a class of BX gaskets, and states that only such BX gaskets shall be used with 6BX flanges. But contrary to this instruction, in at least some embodiments (including that illustrated in
The ring gasket 44 also includes a pressure port 70 extending axially through its body. With reference to
As depicted in
The test port 52 is connected to the region 74 by the conduit 50. And as noted before, the region 74 is connected to the region 72 by the pressure port 70. The isolation of pressure within the regions 72 and 74 from pressure about the fracturing tree 20 and the wellhead component 30 and from pressure within the bores 40 and 42 facilitates monitoring of the sealing integrity of the ring gasket 44 in one embodiment. In one instance, the test port 52 may be used before a fracturing operation to ensure proper setting and adequate sealing of the ring gasket 44. For example, in an embodiment in which the ring gasket 44 is intended to maintain sealing at both the outer and inner stages 56 and 58 once installed in the sealing grooves 46 and 48, the regions 72 and 74 may be pressurized via the test port 52 and conduit 50. If both stages 56 and 58 are properly sealing against the grooves 46 and 48, the regions 72 and 74 will maintain the applied pressure. If not, the regions 72 and 74 will lose pressure, indicating loss of sealing integrity. Such testing may, of course, be performed after a fracturing operation as well.
But in addition to testing before or after operation, certain embodiments also allow the pressure within the regions 72 and 74 to be monitored via the test port 52 during operation of the wellhead assembly. If the initial pressure in the regions 72 and 74 is between the environmental pressure outside the wellhead assembly and the pressure in the bores 40 and 42 in operation (e.g., the fracturing pressure in a fracturing operation), loss of sealing integrity of the ring gasket 44 will cause a change in the pressure in the regions 72 and 74. Particularly, loss of sealing integrity at inner sealing surfaces 64 or 66 will cause fluid from the bores 40 and 42 to leak into the regions 72 or 74, generally increasing the pressure in these regions. Alternatively, loss of sealing integrity at outer sealing surfaces 60 or 62 will result in leaking of fluid from the regions 72 or 74 to the exterior environment, generally decreasing the pressure in the regions 72 and 74. While loss of sealing integrity at both sealing stages of the ring gasket 44 may result in increasing or decreasing pressure within the regions 72 and 74 depending on the magnitude of failure at each stage of the ring gasket 44, the corresponding change in pressure can still be monitored and correlated to a loss of sealing integrity.
This capability of monitoring pressure and sealing integrity may be beneficial in a number of applications, including during well fracturing operations. One example of a method for performing fracturing operations is generally represented by block diagram 76 in
After the ring gasket is set, fracturing of the well may begin as indicated at block 82. It is noted that fracturing trees often experience significant vibration and bending moments as a result of receiving and transmitting high-pressure fracturing fluids into the well. Excessive forces on the fracturing tree could cause the ring gasket to lose sealing engagement at a sealing surface and result in leaking of fracturing fluid. But in accordance with the present technique, the sealing integrity of the ring gasket may be monitored (e.g., through the pressure monitoring described above) during fracturing of the well as indicated at block 84. A sudden pressure change detected within a region between the sealing stages of the ring gasket 44 (e.g., within the regions 72 or 74) may be indicative of loss of sealing integrity and the fracturing operation may be suspended (block 86) to reduce or prevent leaking of fluid at the ring gasket 44. In such an instance, further integrity testing may be performed after suspension of fracturing and suitable adjustments may be made by the operator. For instance, additional preload may be applied or the ring gasket may be replaced, if needed. In some cases, the loss of sealing integrity at one stage of the ring gasket 44 may be detected before loss of sealing integrity at the other stage of the ring gasket 44, which may allow the fracturing operation to be suspended before any leaking of fracturing fluid through the connection to the surrounding environment can occur. Of course, it will be appreciated that the fracturing operation may also be completed (i.e., also end at block 86) without loss of sealing integrity at the ring gasket 44.
While the aspects of the present disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. But it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.
1. A well-fracturing system comprising:
- a wellhead component including a sealing groove;
- a fracturing tree coupled to the wellhead component such that the sealing groove of the wellhead component is aligned with an additional sealing groove of the fracturing tree; and
- a ring gasket disposed between the wellhead component and the fracturing tree within the sealing groove and the additional sealing groove, wherein the ring gasket is a multi-stage sealing gasket including: a first sealing stage in the form of an outer end of the multi-stage sealing gasket having surfaces that seal against the sealing groove and the additional sealing groove, respectively; a second sealing stage in the form of an inner end of the multi-stage sealing gasket having surfaces that seal against the sealing groove and the additional sealing groove, respectively; and a recess in a surface of the multi-stage sealing gasket between the first and second sealing stages.
2. The well-fracturing system of claim 1, wherein the wellhead component includes a test port that enables testing of pressure within the sealing groove.
3. The well-fracturing system of claim 2, including a pressure port through the multi-stage sealing gasket, wherein the pressure port fluidly connects a region in the sealing groove between the multi-stage sealing gasket and the wellhead component with another region in the additional sealing groove between the multi-stage sealing gasket and the fracturing tree to enable testing of pressure within both regions via the test port.
4. The well-fracturing system of claim 2, wherein the wellhead component and the fracturing tree are coupled together via a flanged connection.
5. The well-fracturing system of claim 4, wherein the test port is in a flange of the wellhead component and is fluidly connected to the sealing groove.
6. The well-fracturing system of claim 5, wherein the flange of the wellhead component is an API flange.
7. The well-fracturing system of claim 6, wherein the flange of the wellhead component is a 6BX flange.
8. The well-fracturing system of claim 7, wherein the ring gasket has a lower gasket setting load than a BX ring gasket.
9. The well-fracturing system of claim 1, wherein the recess in the surface of the multi-stage sealing gasket includes a first recess between surfaces of the first and second sealing stages that seal against the sealing groove of the wellhead component and a second recess between surfaces of the first and second sealing stages that seal against the additional sealing groove of the fracturing tree.
10. The well-fracturing system of claim 1, wherein the ring gasket is a stainless steel ring gasket.
11. The well-fracturing system of claim 1, wherein pressure within the recess of the multi-stage sealing gasket during fracturing is less than bore pressure within the wellhead component and greater than environmental pressure outside of the wellhead component.
12. A well-fracturing system comprising:
- a wellhead component including a 6BX flange;
- a fracturing tree connected to the 6BX flange; and
- a non-BX ring gasket disposed in sealing grooves of the 6BX flange and the fracturing tree.
13. The well-fracturing system of claim 12, comprising a test port fluidly connected to at least one of the sealing grooves of the 6BX flange or the fracturing tree.
14. The well-fracturing system of claim 12, wherein the non-BX ring gasket includes a pair of opposing recesses between inner sealing surfaces of the non-BX ring gasket and outer sealing surfaces of the non-BX ring gasket.
15. The well-fracturing system of claim 12, wherein the wellhead component includes a tubing spool.
16. A well-fracturing method comprising:
- beginning fracturing of a well using a fracturing tree coupled to a wellhead assembly; and
- monitoring, via pressure testing, sealing integrity of a gasket between the fracturing tree and the wellhead assembly during the fracturing of the well.
17. The well-fracturing method of claim 16, wherein monitoring the sealing integrity of the gasket includes monitoring pressure within a recess in which the gasket is disposed.
18. The well-fracturing method of claim 17, wherein monitoring the pressure within the recess includes monitoring the pressure within a region between two sealing stages of the gasket in the recess.
19. The well-fracturing method of claim 16, comprising detecting, via the monitoring of the sealing integrity of the gasket, a loss of preload on the gasket during fracturing of the well.
20. The well-fracturing method of claim 19, stopping fracturing of the well in response to the detected loss of preload on the gasket.
International Classification: E21B 43/26 (20060101); E21B 47/06 (20060101); E21B 33/03 (20060101);