Patent ID: 12252948

DETAILED DESCRIPTION

In the description that follows, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of the invention. In the following description, the terms “inwardly” and “outwardly” are directions toward and away from, respectively, the geometric axis of a referenced object. Where components of relatively well-known designs are employed, their structure and operation will not be described in detail.

In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments and examples described herein. However, those of ordinary skill in the art will understand the embodiments and examples described herein can be practiced without these specific details. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein.

The embodiments described herein generally relate to seal and clamping systems which can help prevent or reduce leaks from wellheads, especially gas leaks such as methane leaks. The embodiments herein are particularly relevant to preventing or reducing leaks form wells that use a Larkin-style wellhead or a wellhead similar in style.

Referring now toFIGS.1, there is shown a wellhead assembly10, which is a style sometimes called a Larkin-style wellhead. As illustrated, wellhead assembly10has a tubing head12coming up from below. Tubing head12defines a central head bore14. A stripper rubber16is inserted into central head bore14. Above stripper rubber16is a slip assembly18, generally comprising tubing slips20and slip bowl22. Above slip assembly18is a bottom packing ring24and a top packing ring28with a seal ring26sandwiched in-between. The slip assembly18, bottom packing ring24, seal ring26and top packing ring28are typically encased within stripper adapter30; though, in some embodiments top packing ring28may only be partially encased and extend out of stripper adapter30. At the top, is top nut (or top cap)32, which caps off stripper adapter30.

Looking closer at stripper adapter30, it has an upper end34, a lower end36, an outer adapter surface38and an inner adapter surface48. Outer adapter surface38extends from the upper end34to the lower end36. Outer adapter surface38has a first outward-projecting shoulder40located between the upper end34and lower end36so as to define an upward facing ledge42. As will be appreciated, shoulder40and its ledge42extend circumferentially around outer adapter surface38, which is generally cylindrical; though of course, having an outer diameter for its lower portion44that is greater than the outer diameter for its upper portion46.

Inner adapter surface48defines a central adapter bore50in which slip assembly18, bottom packing ring24, seal ring26and top packing ring28are contained. Additionally, these contained components along with top nut32define a smaller bore52within central adapter bore50. Smaller bore52extends down to central head bore14and allows positioning and operation of well components, such as a polished rod (not shown).

The upper end34is configured to mate with the top nut32such that a circumferential lip54of top nut32overlaps a first portion56of the outer adapter surface38at the upper end34. Additionally, lower end36is configured to mate with the tubing head12such that, at the lower end36, the stripper adapter30extends over the upper section58of the tubing head12so that the outer adapter surface38at the lower end36forms a second outward-projecting shoulder60so as to define a downward facing ledge62.

Unfortunately, even though seal ring64is often provided, it has been discovered that the overlap area66can be subject to leaks especially of light gases such as methane. In order to address this issue, the current disclosure provides for a seal/clamping assembly (sometimes referred to herein as “seal/clamping assembly”), which can prevent or at least reduce leakage at overlap area66.

Turning now toFIGS.2-7, a seal/clamping assembly100is illustrated. Assembly100is made up of three major systems: housing system200, sealing system300and a clamping system400.

Housing system200generally will comprise one or more components that form a housing that can surround a wellhead10at overlap area66. Typically, the housing system200will comprise two or more sections or portions that can be formed around wellhead10so as to be easily assembled in the field on an existing wellhead. Generally, housing system200will have a cylindrical form. For example, as can be most easily seen fromFIGS.4and5, housing system200can comprise two or more mating cylindrical portions, such as first cylindrical portion201and second cylindrical portion202. The cylindrical portions mate to form a cylinder, which in this embodiment is housing system200as a cylindrical housing.

As can be seen from the figures, each cylindrical portion has a first end203,204; a second end205,206; an inner curved surface207,208extending between the first end and the second end, and an outer curved surface209,210extending between the first end and the second end.

The inner curved surface207,208has an upper inner groove211,212at the first end, and a lower inner groove213,214at the second end. When first cylindrical portion201is mated with second cylindrical portion202, the upper inner grooves211,212of the cylindrical portions form a circumferentially-extending upper inner groove216and the lower inner grooves213,214of the cylindrical portions form a circumferentially-extending lower inner groove218. As will be understood, typically grooves216,218extend entirely around the inner surface of the mated portions of housing200.

The outer curved surface209,210has a plurality (typically at least three and generally four) outer grooves219,220longitudinally spaced apart on the outer curved surface209,210. When the first cylindrical portion201is mated with the second cylindrical portion202, the outer grooves form a series of spaced-apart circumferentially-extending outer grooves222, made up of four such grooves in the illustrated embodiment. As will be understood, typically grooves222extend entirely around the outer surface of the pated portions of housing200.

In use, the cylindrical portions mate around a portion of the outer adapter surface and an upper section of the tubing head so that the circumferentially-extending upper inner groove216is above the outward-projecting shoulder40and the circumferentially-extending lower inner grove218is below the second outward projection shoulder60.

As will be realized from the above and the figures, the cylindrical portions have mating sides223,224. In some embodiments, at least one of the mating sides has a notch226(seeFIG.8), which can be at the first end and/or second end. The notch226facilitates separation of the cylindrical portions. For example, as chisel can be used at notch226to separate the cylindrical portions.

As most easily seen fromFIGS.3and7, seal system300provides plastic or rubber sealing gaskets to prevent leakage through the seal/clamping assembly. Seal ring300can comprise an upper seal ring302, a lower seal ring304, and a plurality of longitudinal gaskets306.

In use, seal system300is positioned such that the upper seal ring302is in the circumferentially-extending upper inner groove216, the lower seal ring304is in the circumferentially-extending lower inner groove218, and the longitudinal gaskets306are positioned between the cylindrical portions; Thus, in use, the longitudinal gaskets306extend longitudinally between the upper seal ring302and lower seal ring304. As will be realized, there typically will be one longitudinal gasket per pair of mating sides for the cylindrical portions. Thus, if two cylindrical portions are used (as illustrated), then there are two pairs of mating sides and two gaskets would be used.

As will be realized from the above disclosure andFIG.3, in use upper seal ring302will be positioned above the outward-projecting shoulder40, and lower seal ring304will be positioned below the second outward projection shoulder60.

As most easily seen fromFIGS.2,3and6, clamping system400provides for a secure clamping of housing system200and seal system300in place to ensure a fluid-tight seal is made with wellhead10and between the components of the housing system200and the seal system300. Generally, in any embodiment, the clamping system400should be considered to so secure the housing system200and seal system300to the wellhead10.

In the embodiment illustrated, clamping system400comprises a plurality of clamps410. While two or more clamps can be used, typically at least three clamps will be used, and more typically four or more clamps will be used. Each of the clamps410is positioned in a respective circumferentially-extending outer groove of the series of spaced-apart circumferentially-extending outer grooves222, so as to hold the cylindrical portions of the housing system in matting position about the wellhead assembly10, ensure sealing contact of the mating sides with gasket306, and to ensure sealing contact of the upper seal ring302and lower seal ring304with the wellhead assembly10.

For example, each of the clamps410may comprise a first saddle412, a second saddle414and a connection assembly, such as connecting bolts and nuts416along with tubes422,432or426,436or other suitable connection assembly. First saddle412has a first arched member418, which is configured to mate into groove222. At a first end420of first arched member418there is a first tube422, and at a second end424of the first arched member418there is a second tube426. Likewise, for second saddle414, there is second arch member428(configured to mate into groove222), and at a first end430of second arched member428there is a first tube432, and at a second end434of the second arched member428there is a second tube436.

In use, the connecting bolts and nuts416are used to connect the first saddle412to the second saddle414by passing the bolts through the tubes. Thus, a bolt416extends through the first tube422attached to the first arched member418and through the first tube432attached to the second arched member428. Likewise, another bolt416extends through the second tube426attached to the first arched member418and through the second tube436attached to the second arched member428. Once in place, the bolts can be secured by the nuts to a suitable tension.

The seal/clamping systems of this disclosure can be further understood by the following numbered embodiments.

Embodiment 1: a seal and clamping system for a wellhead assembly, wherein the wellhead assembly is of the type comprising:a top cap having a lower circumferential lip;a tubing head defining a central head bore, the tubing head having an upper section and lower section;a stripper adapter, the stripper adapter having;an upper end;a lower end;an outer adapter surface extending from the upper end to the lower end, wherein the outer adapter surface has a first outward-projecting shoulder between the upper end and lower end so as to define an upward facing ledge; andan inner adapter surface defining a central adapter bore, andwherein the upper end is configured to mate with the top cap such that the circumferential lip overlaps a first portion of the outer adapter surface at the upper end, and the lower end is configured to mate with the tubing head such that at the lower end the stripper adapter extends over the upper section of the tubing head so that the outer adapter surface at the lower end forms a second outward-projecting shoulder so as to define an downward facing ledge; andwherein the seal/clamping assembly comprises:a housing having:a first end configured to seal to the outer adapter surface above the first outward-projecting shoulder;a second end configured to seal to the tubing head below the second outward-projecting shoulder;an inner curved surface extending between the first end and the second end; andan outer curved surface extending between the first end and the second end; anda clamping system configured to hold the housing in position about the wellhead assembly so as to ensure sealing contact at the upper end and lower end with the wellhead assembly.

Embodiment 2: the seal and clamping system of embodiment 1, wherein the seal and clamping system further comprises a seal system having an upper seal ring which seals the first end of the housing to the outer adapter surface, and a lower seal ring which seals the second end of the housing to the tubing head.

Embodiment 3: the seal and clamping system of either embodiment 1 or 2, wherein the housing comprises at least two mating portions which mate to form the housing.

Embodiment 4: the seal and clamping system of any of embodiments 1 to 3, wherein the mating portions have mating sides, and at least one of the mating sides has a notch, which facilitates separation of the cylindrical portions.

Embodiment 5: the seal and clamping system of either embodiment 3 or 4, wherein each mating portion has an upper inner groove at the first end of the inner curved surface, and a lower inner groove at the second end of the inner curved surface, and wherein when the cylindrical portions are mated, the upper inner grooves of the cylindrical portions form a circumferentially-extending upper inner groove and the lower inner grooves of the cylindrical portions form a circumferentially-extending lower inner groove.

Embodiment 6: the seal and clamping system of embodiment 5, wherein the mating portions of the housing are configured to mate around the wellhead assembly, and when the seal/clamping assembly is so mated, the mating portions mate around the second portion of the outer adapter surface and an upper section of the tubing head so that the circumferentially-extending upper inner groove is above the first outward-projecting shoulder, and the circumferentially-extending lower inner grove is below the second outward projection shoulder.

Embodiment 7: the seal and clamping system of embodiment 6, wherein the seal and clamping system further comprises a seal system having an upper seal ring, a lower seal ring and a plurality of longitudinal gaskets extending between the upper seal ring and lower seal ring; and wherein when the mating portions are mated the seal/clamping assembly is positioned such that the upper seal ring is in the upper inner groove, the lower seal ring is in the lower inner groove, and the longitudinal gaskets are positioned between the mating portions.

Embodiment 8: the seal and clamping system of any of embodiments 1 to 7, wherein the outer curved surface of the housing comprises a plurality of grooves spaced longitudinally apart on the outer curved surface, and wherein when the mating portions are mated, the outer grooves form a series of spaced-apart circumferentially-extending outer grooves and wherein the clamping system is configured to mate with the series of spaced-apart circumferentially-extending outer grooves so as to hold the housing in mating position and in sealing contact with the wellhead assembly.

Embodiment 9: the seal and clamping system of embodiment 8, wherein the clamping system comprises a plurality of clamps with each one of the clamps corresponding to a respective one of the circumferentially-extending outer grooves.

Embodiment 10: the seal and clamping system of embodiment 9, wherein each of the clamps comprise:a first saddle having a first arched member which mates into a first portion of one of the circumferentially-extending outer grooves;a second saddle having a second arched member, which mates into a second portion of the one of the circumferentially-extending outer grooves; anda connector which connects the first saddle to the second saddle.

Embodiment 11: the seal and clamping system of embodiment 10, wherein:the first saddle further comprises a first tube at a first end of the first arched member and a second tube at a second end of the first arched member;the second saddle further comprises a first tube at a first end of the second arched member and a second tube at a second end of the second arched member; andthe connector comprises a first bolt and a second bolt for joining the first arched member to the second arched member wherein, when so joined, the first bolt extends through the first tube of the first arched member and the first tube of the second arched member, and the second bolt extends through the second tube of the first arched member and the second tube of the second arched member.

Embodiment 12: the seal and clamping system of embodiment 11, wherein the clamping system comprises at least three clamps and there are at least three circumferentially-extending outer grooves.

Embodiment 13: the seal and clamping system of embodiment 11, wherein the clamping system comprises at least four clamps and there are at least four circumferentially-extending outer grooves.

The above elements of the seal/clamping system as well as others can be seen with reference to the figures. From the above description and figures, it will be seen that the present invention is well adapted to carry out the ends and advantages mentioned, as well as those inherent therein. While the presently preferred embodiment of the apparatus has been shown for the purposes of this disclosure, those skilled in the art may make numerous changes in the arrangement and construction of parts. All of such changes are encompassed within the scope and spirit of the appended claims.

Therefore, the present systems and methods are well adapted to attain the ends and advantages mentioned, as well as those that are inherent therein. The particular examples disclosed above are illustrative only, as the present systems and methods may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative examples disclosed above may be altered or modified, and all such variations are considered within the scope and spirit of the present treatment additives and methods. While the systems and methods are described in terms of “comprising,” “containing,” “having,” or “including” various components or steps, the compositions and methods can also, in some examples, “consist essentially of” or “consist of” the various components and steps. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee.