Ram block inner seal assembly and seal therefore

Abstract

In one aspect there is provided a ram block inner seal assembly comprising a core member having a top face, a bottom face, a front face, a rear face, and two side faces. A connector portion connects the top and bottom faces. A peripheral member surrounds the front, rear and side faces. The core member further comprises a peripheral groove on at least the front and side faces, the peripheral groove having a cross-sectional profile. The peripheral member further comprises an energizing section that has a cross-sectional profile which substantially matches the cross-sectional profile of the peripheral groove.

Claims

1. A ram block inner seal assembly, for use with a blowout preventer (BOP) having a single pair of opposing ram blocks to facilitate sealing of a wellbore, the ram block inner seal assembly comprising: a core member (20) having a top face (20t), a bottom face (20b), a front face (20f), a rear face (20r), two side faces (20s), and a single, solid connector portion (24) connecting said top face (20t) and bottom face (20b); and a peripheral member (30) that surrounds substantially all of the front face (20f), the rear face (20r) and the two side faces (20s); wherein the peripheral member (30) is comprised of a suitable material to provide the ram block inner seal assembly (10) with sufficient wellbore sealing characteristics to enable sealing of the BOP against typical wellbore pressures when said ram block inner seal assembly (10) is used with said BOP; wherein a single pair of core members (20) can be placed within said single pair of opposing ram blocks; and wherein, when said BOP is actuated, said single pair of core members (20) cooperate to enable said sealing of the BOP.

2. The ram block inner seal assembly of claim 1 wherein the peripheral member (30) is elastomeric.

3. The ram block inner seal assembly of claim 1 wherein the core member (20) further comprises a peripheral groove (22) on said front face (20f) and said side faces (20s); and wherein said peripheral groove (22) has a semi-circular cross-sectional profile (22p), a maximum depth (D); and wherein the maximum depth (D) of said groove (22) is the radius of the semicircle.

4. The ram block inner seal assembly of claim 3 wherein the peripheral member (30) further comprises an energizing section (32) that: (i) extends radially inward from said front face (30f) and side faces (30s) at least partially towards a centre point of peripheral member (30), and (ii) has a cross-sectional profile (32p) that substantially matches the semi-circular cross-sectional profile (22p) of the peripheral groove (22).

5. The ram block inner seal assembly of claim 4 wherein the energizing section (32) further comprises an energizing axis (A) which runs between front face (30f) and rear face (30r).

6. A ram block inner seal assembly comprising: a core member (20) having a top face (20t), a bottom face (20b), a front face (20f), a rear face (20r), two side faces (20s), and a single, solid connector portion (24) connecting said top face (20t) and bottom face (20b); and an elastomeric peripheral member (30) that surrounds substantially all of the front face (20f), the rear face (20r) and the two side faces (20s); wherein the core member (20) further comprises a peripheral groove (22) on said front face (20f) and said side faces (20s), said peripheral groove (22) having a semi-circular cross-sectional profile (22p) and a maximum depth (D); wherein the maximum depth (D) of said groove (22) is the radius of the semicircle and wherein the peripheral member (30) further comprises an energizing section (32) having a cross-sectional profile (32p) that substantially matches the semi-circular cross-sectional profile (22p) of the peripheral groove (22).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Referring to the drawings, several aspects of the present invention are illustrated by way of example, and not by way of limitation, in detail in the figures, wherein:

(2) FIG. 1a is an exploded perspective view of a PRIOR ART pipe ram;

(3) FIG. 1b is an exploded, sectioned perspective view of the PRIOR ART pipe ram of FIG. 1a, taken along line 1-1;

(4) FIG. 1c is an exploded perspective view of a PRIOR ART blind ram;

(5) FIG. 2a is a perspective view of a PRIOR ART pipe ram inner seal;

(6) FIG. 2b is an exploded perspective view of the PRIOR ART pipe ram inner seal of FIG. 2a;

(7) FIG. 2c is an exploded, sectioned perspective view of the PRIOR ART pipe ram inner seal of FIG. 2a, taken along line 2-2 in FIG. 2b;

(8) FIG. 2d is a perspective view of a PRIOR ART blind ram inner seal;

(9) FIG. 3a is an exploded top perspective view of one embodiment of a ram block inner seal assembly of the present invention;

(10) FIG. 3b is an exploded bottom perspective view of the ram block inner seal assembly of the embodiment of FIG. 3a;

(11) FIG. 3c is an exploded, sectioned, top perspective view of the ram block inner seal assembly of the embodiment of FIG. 3a, taken along lines 3-3 and 4-4 in FIG. 3a;

(12) FIG. 3d is an exploded, sectioned, top perspective view of the ram block inner seal assembly of the embodiment of FIG. 3a, taken along line 5-5;

(13) FIG. 3e is a perspective view of the ram block inner seal assembly of the embodiment of FIG. 3a;

(14) FIG. 3f is a sectioned perspective view of the ram block inner seal assembly of the embodiment of FIG. 3a, taken along line 6-6 in FIG. 3e;

(15) FIG. 3g is a sectioned perspective view of the ram block inner seal assembly of the embodiment of FIG. 3a, taken along line 7-7 in FIG. 3e;

(16) FIG. 4a is an exploded top perspective view of another embodiment of a ram block inner seal assembly of the present invention;

(17) FIG. 4b is an exploded bottom perspective view of the ram block inner seal assembly of the embodiment of FIG. 4a;

(18) FIG. 5a is an exploded perspective view of yet another embodiment of a ram block inner seal assembly of the present invention; and

(19) FIG. 5B is an exploded, sectioned perspective view of the ram block inner seal assembly of the embodiment of FIG. 5a, taken along line 8-8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(20) The following description is of preferred embodiments by way of example only and without limitation to the combination of features necessary for carrying the invention into effect. Reference is to be had to the Figures in which identical reference numbers identify similar components. The drawing figures are not necessarily to scale and certain features are shown in schematic or diagrammatic form in the interest of clarity and conciseness.

(21) A first embodiment of the ram block inner seal assembly 10 of the present invention is shown in FIGS. 3a-3g and comprises a core member 20 and a peripheral member 30 that surrounds the core member 20. The core member 20 is preferably a substantially solid member made from metal, steel or any other suitable material that provides adequate strength, durability and rigidity to support the various loads that may be encountered by the assembly 10 during operation in a blowout preventer (BOP). The peripheral member 30 is preferably elastomeric and made from natural rubber, polyisoprene, polybutadiene, polyisobutylene, polyurethane, or other suitable material to provide the desired sealing and energizing characteristics typically associated with rubber blocks in conventional inner seals, so as to enable the ram block inner seal assembly 10 to facilitate or enable sealing of the BOP against common or typical wellbore pressures; e.g. by sealing around a section of tubing, and/or by sealing against a second, opposingly oriented ram block inner seal assembly. More preferably, peripheral member 30 is a substantially band- or ribbon-like member that surrounds the periphery of the core member 20, as further described below.

(22) The core member 20 preferably comprises a top face 20t, a bottom face 20b, a front face 20f, a rear face 20r, and two side faces 20s (see FIGS. 3a and 3b). The core member 20 preferably also comprises a peripheral groove 22 on the front and side faces 20f, 20s, and a connector portion 24 connecting said top face 20t and bottom face 20b (see FIGS. 3c and 3d). More preferably, the connector portion 24 is a solid, or substantially solid, central mass portion comprising the bulk of the core member 20. Advantageously, a solid or substantially solid core member 20, with only a peripheral groove 22 on the front and side faces 20f, 20s, strengthens the assembly 10, allows it to withstand higher wellbore pressures, increases cycle life, and reduces the amount of expensive rubber or elastomeric material required to manufacture an assembly 10.

(23) The peripheral groove 22 is preferably defined by groove edges 23 on the front and side faces 20f, 20s. Even more preferably, the peripheral groove 22 has a cross-sectional profile 22p, e.g. a semicircular cross-section profile 22p wherein the maximum depth D of the groove 22 is then the radius of the semicircle (see FIG. 3d). It should be noted that a groove 22 with a different cross-sectional profile 22p (e.g. a square or rectangular cross-sectional profile between groove edges 23, or a squircle or rounded-rectangle cross-sectional profile) will also work; see, for example, the embodiment of FIGS. 5a-5b. Even more preferably, the core member 20, along with the peripheral groove 22 and groove edges 23, is machined from a solid piece of metal or steel (e.g. via CNC machining).

(24) The elastomeric, peripheral member 30 preferably surrounds all, or substantially all, of the front, rear and side faces 20f, 20r, 20s of the core member 20 in a close-fitting arrangement (as shown in the Figures). As such, the elastomeric, peripheral member 30 will likewise further comprise a front face 30f, rear face 30r and side faces 30s. Preferably, the elastomeric, peripheral member 30 further comprises an enlarged or thickened energizing section or energization pathway 32 that: (i) extends radially inward from said front face 30f and side faces 30s, partially towards a centre point of peripheral member 30, and (ii) has a cross-sectional profile 32p that substantially matches the cross-sectional profile 22p of the groove 22 of the core member 20. More preferably, energizing section 32 further comprises an energizing axis A which runs between front face 30f and rear face 30r, along one or both side faces 30s. When assembled into the assembly 10 energizing axis A is then positioned substantially within groove 23 along the core member's side faces 20s and between top and bottom faces 20t, 20b, substantially co-planar therewith (see FIGS. 3c-3d).

(25) As such, in embodiments of the assembly 10 where the peripheral groove 22 has a semicircular cross-sectional profile 22p and a maximum depth D, then the energizing section 32 will have a corresponding semicircular cross-sectional profile 32p and a corresponding maximum thickness T to match the groove's depth D (see FIG. 3d). In other embodiments (not shown), the elastomeric, peripheral member 30 further comprises an enlarged or thickened energizing section or energization pathway 32 that extends radially inward from, not only the front face 30f and side faces 30s, but also the rear face 30r.

(26) The use of “top” and “bottom” are used herein as respective references to the orientation of the assembly 10 (and the core and peripheral members 20, 30) within a BOP positioned on a traditional substantially vertical well. The term “up” and “down” are then used with respect to the ground. More specifically, the term “up” may be used to describe a vector that is normal to the ground and away from the ground. More specifically, the term “down” may be used to describe a vector that is normal to the ground and pointing toward the ground. However, there may be uses of the present invention where the assembly 10 (and the core and peripheral members 20, 30) is used in different orientations, such as in a substantially horizontal orientation in a horizontal well drilling operation. In such a case, the term “down” is then used with respect to the downhole side of a BOP, while the term “up” is then used with respect to the opposite, uphole side of a BOP.

(27) Similarly, the use of “front” and “rear” are used herein as respective references to the orientation of the assembly 10 (and the core and peripheral members 20, 30) within a BOP. The term “front” and “rear” are then used with respect to the central axis of the BOP, wherein “front” is then used with respect to that part of the member 20,30 most proximate to the central axis of the BOP, while the term “rear” is then used with respect to the opposite side of the member 20,30 that is most distal to the central axis of a BOP. For example, the front face 20f of the core member 20 would be that face of the member 20 closest to the BOP's central axis, while the rear face 20r is then that face of the member 20 furthest away from the BOP's central axis. When the assembly 10 is placed in a ram block of a BOP and actuated to close, the “front” side of the assembly 10 is the side most proximate to the BOP's central axis and is the side that will typically close against the “front” side of an opposing inner seal assembly and any tubular that may be in the BOP.

(28) One way to manufacture the inner seal assembly 10 of the present invention is to machine the core member 20 from a solid piece of metal or steel (e.g. via CNC machining, as noted above), machine out the peripheral groove 22, position the core member 20 within a suitable mould, and then pour rubber or other elastomeric material within the mould so as to form the peripheral member 30 in place around the core 20. Alternatively, core member 20 may be cast, forged or moulded, using conventional techniques.

(29) When an embodiment of the ram block inner seal assembly 10 of the present invention is utilized in a ram block of a blowout preventer (BOP), and the ram block is actuated (i.e. moved towards the BOP's axial center line) and forced closed against an opposing ram block and any tubular that may be in the BOP (e.g. if the ram block is a pipe ram block), the elastomeric member 30 will become energized to generate a pressure tight seal across its front, rear and side faces 30f, 30r, 30s. Some of the force from the closure of the ram blocks will also energize any energizing section 32 that is along the front and side faces 30f, 30s. The energizing section 32 will then allow a greater amount of that force be transmitted (through peripheral member 30) towards the rear face 30r of the peripheral member 30 (as compared to embodiments without said energizing section 32), and then energize any outer seal that may be in the ram block positioned against the rear face 30r.

(30) Advantageously, the connector portion 24 of the core member 22 maintains a predetermined distance between the top face 20t and bottom face 20b, even during times when the inner seal assembly 10 is subject to the great forces used to energize the elastomeric, peripheral member 30 and generate a high pressure seal. Unlike the prior-art inner seal assemblies, where the metal plates “float” on the rubber block and where the generation of a high pressure seal and the force put into the rubber block spreads these metal plates apart and damages the ram block, the inner seal assembly 10 of the present invention does not have this defect. More advantageously, by limiting the elastomeric aspect of an inner seal assembly 10 to a peripheral member 30 (including any energizing section 32), the amount/volume of expensive rubber or elastomer required is significantly reduced as compared to prior-art inner seal assemblies. This very significantly reduces the cost associated with the manufacturing of such inner seal assemblies, since the elastomeric part is often much more expensive than any metal or steel used in the core member (or in the prior art metal plates).

(31) Even more advantageously, by utilizing a semi-circular cross-section for profiles 22p and 32p any energizing forces experienced by the assembly 10 during creation of a pressure seal are deflected away from groove edges 23 and, instead, directed along energizing axis A (between front 30f and rear 30r faces), thereby further reducing any stress on the groove edges 23 and directing such forces along axis A to the rear face 30f and any outer seal that may be adjacent such rear face 30f. Advantageously, this design significantly reduces and eliminates rubber or elastomer from extruding along vertical axis of the assembly 10, but instead flows along (horizontal) axis A to energize the any outer seals.

(32) Those of ordinary skill in the art will appreciate that various modifications to the invention as described herein will be possible without falling outside the scope of the invention. In the claims, the word “comprising” is used in its inclusive sense and does not exclude other elements being present. The indefinite article “a” before a claim feature does not exclude more than one of the features being present.