RING SAFETY VALVE FOR A BOREHOLE

Abstract

An annular safety valve (16) that can be positioned in a borehole (12) may include a housing (105, 406) having an opening (104, 411) extending through the housing (105, 406) to allow pressure to be transmitted between a first annular zone (18) of the borehole (12) below the annular safety valve (16) and a second annular zone (20) of the borehole (12) above the annular safety valve (16). The housing (105, 406) may define the opening (104, 411) by a seat face (126, 410). A valve (102, 408) may extend through the opening (104, 411). A groove (112) may at least partially surround the seat face (126) in order to maintain a shape of the seat face (126) in response to an increase in pressure in the first zone (18) of the borehole (12).The shape of the seat face (126) can correspond to a surface of the valve (102) intended to prevent pressure from being transmitted between the first annular zone (18) of the borehole (12) and the second annular zone (18) of the borehole (12) when the annular safety valve (16) is in the closed position.

Description

Title of the invention: RING SAFETY VALVE FOR A BOREHOLE technical field

[0001] The present invention relates generally to an annular safety valve (ASV) that can be positioned at the bottom of a well in a borehole, and more particularly (but not necessarily exclusively), to an ASP comprising a groove positioned around an orifice or one of the ASP. Context

[0002] A VSA can be part of a completion column that can be positioned at the bottom of a wellbore. The VSA can operate between an open and a closed position. The VSA can include a housing having one or more openings for gas injection. The VSA can further include a valve positioned in the opening. A surface area of ​​the valve can close or seal tightly against a seat of the opening in the closed position. In the open position, the valve may not close or seal tightly against the opening so that, under normal gas injection conditions, the VSA allows the gas injection to move beyond the VSA. In some VSA designs, for example, designs in which the VSA has a narrow or thin wall cross-section, the openings in the housing (or orifices) can occupy a significant portion of the wall cross-section.This can lead to high stress on the section containing the openings. The internal pressure trapped below the VSA can create circumferential stress in the wall section as the parts attempt to expand due to this internal pressure. This expansion can cause deformation of the openings and, consequently, of the seat face. The shape of the openings can indeed change from round to oval, which can prevent the valve(s) from sealing properly against the seat surrounding the opening, causing the VSA to leak at higher pressures because the seat no longer matches the valve geometry. Brief description of the drawings

[0003] Fig. 1 is a schematic illustration of a well system comprising a VSA positioned in a borehole, according to one aspect of the present invention.

[0004] The [Fig.2] is a cross-sectional side view of part of a VSA, according to one aspect of the present invention.

[0005] [Fig.3A] is a perspective view of a portion of the VSA of [Fig.2], according to one aspect of the present invention.

[0006] [Fig.3B] is an enlarged perspective view of a portion of the VSA shown in [Fig.3A], according to one aspect of the present invention.

[0007] Fig. 4 is a top view of a portion of the VSA of figures 3A, 3B, according to one aspect of the present invention.

[0008] Fig. 5 is a cross-sectional side view of part of a VSA, according to one aspect of the present invention. Detailed description

[0009] Certain aspects and features of the present invention relate to a VSA that can be positioned in the wellbore. The VSA can be part of a completion column that can be positioned at the bottom of a wellbore. The VSA can operate between an open and a closed position. The VSA can include a housing having one or more openings for gas injection. The VSA can further include a valve positioned in the opening. A surface area of ​​the valve can close or seal tightly against a seat of the opening in the closed position. The VSA can be actuated in the closed position in response to an emergency situation in order to contain the pressure of the injected gas within the annular space of the wellbore for safety reasons. In the closed position, the VSA traps the injection gas pressure in the annular space below the VSA.In the open position, the valve may not close or seal tightly against the opening, so that under normal gas injection conditions, the VSA allows gas injection through the annular space to move beyond the VSA. The position of the VSA valves can be controlled by means of an actuator located inside the VSA that can move the valve (or a set of valves) away from a seat (i.e., move the valve sealing face away from the housing seat) surrounding the opening to position the VSA in the open position. The actuator may be coupled to a control line. The actuator can also move the valve (or a set of valves) on the seat to position the VSA in the closed position. To close the VSA, the pressure in the control line can be vented, and the pressure of a spring can push the valve(s) back (i.e.,the sealing face of the valve) on the seat, thus moving the VSA into the closed position and trapping the pressure of the annular space below the VSA. When the VSA is in the closed position and the pressure is trapped below the valves, the housing can be subjected to tubing pressure and an axial load on the valves.

[0010] In certain aspects of the present invention, the VSA may include a groove (or recess) around at least a portion of an outside diameter of the VSA seat. The groove may provide an improved metal-on-metal gas-tight seal for the VSA. The groove may be drilled into the housing near the seat to prevent the seat to change shape due to the pressure below the VS A. Rather than no longer conforming to the valve geometry, the seat can retain its shape and close properly, regardless of the pressure below the VS A.

[0011] In certain aspects of the present invention, a seat insert can be positioned within the opening and seating region of a VSA. The seat insert can define a surface against which the valve of the VSA seals abuts when the VSA is in the closed position. The seat insert can be formed separately from the housing or can be formed as a single unit with the housing. The seat insert can move independently of the rest of the housing, so that the seat insert does not deform in response to the deformation of the rest of the housing. For example, the seat insert may not deform when the rest of the housing deforms in response to high pressure below the VSA.

[0012] Illustrative examples are given to introduce the reader to the subject matter discussed here and are not intended to limit the scope of the concepts described. The following describes various features and additional examples, but should not be used to limit the present invention.

[0013] Figure 1 is a schematic illustration of a well system 10 comprising a set of boreholes according to one aspect of the present invention. The well system 10 includes a borehole, which is a borehole 12 extending through a surface 14 and various soil layers. The well system 10 can be an onshore well system or a marine well system. A casing train 13 can be positioned in the borehole 12, and a casing train 15 can be positioned inside the casing train 13. The casing train 15 can be, for example, a completion column. The casing train 15 can include a VSA 16. The VSA 16 can provide a communication path in an annular zone between the casing train 15 and the casing train 13.The VSA 16 can have an open position to allow pressure to be transmitted between a first annular zone 18 of the borehole 12 (for example, an annular zone located between the casing train 13 and the casing train 15) below the VSA 16 and a second annular zone 20 of the borehole (for example, an annular zone between the casing train 13 and the casing train 15) above the VSA 16. The VSA 16 can have a closed position to prevent pressure from being transmitted between the first annular zone 18 of the borehole 12 below the VSA 16 and the second annular zone 20 of the borehole 12 above the VSA 16.

[0014] Figure 2 is a cross-sectional side view of part of a VSA 100 according to a example of the present invention. The VSA 100, which could, for example, be the VSA 16, comprises a valve 102 housed in an opening 104 of a casing 105. The VSA 100 is shown in a closed position in [Fig. 2]. As shown in the [Fig. 2] In the closed position, a sealing face 106 of the valve 102 interfaces (or comes into contact) with a seat 110 of the housing 105 such that the valve 102 is hermetically sealed against the seat 110 in order to trap the pressure of the injected gas in the annular space of the well below the closed VSA 100. In some aspects of the present invention, the VSA 100 also includes a groove or recess 112 that at least partially surrounds the seat 110 of the VSA. When the VSA 100 is in the closed position (as shown in [Fig. 2]), a pressure applied in the annular space below the VSA 100 does not pass through the opening 104, which is hermetically sealed by the valve 102 of the VSA 100.

[0015] The groove 112 can isolate the seat 110 from the housing 105 against which the valve 102 rests or is hermetically protected from the influence of deformation in the housing 105 due to internal pressure below the VSA 100. Without the groove 112, increased pressure in the annular space below the VSA 100 can lead to circumferential stress in the housing 105 and cause uneven deformation of the housing 105 around the opening, which can also lead to uneven deformation of the seat 110. Uneven deformation of the seat 110 can cause the geometry of the seat 110 to no longer correspond to the geometry of the valve 102, in particular the sealing face 106 of the valve 102, so that the valve 102 does not seal tightly against the seat 110 in the closed position.The groove 112 can prevent uneven deformation of the seat 110 and ensure improved sealing between the valve 102 and the seat 110, even when increased pressure below the VSA could cause deformation of the housing 105. The groove 112, for example, can provide a space in which the housing 105 can deform without causing deformation of the shape of the seat 110. The groove 112 can be drilled, it can be 3D printed as part of the housing 105, it can be formed by spark erosion or by other suitable processes.

[0016] Figure 3A is a perspective view of a portion of the housing 105 of the VSA 100 shown in Figure 2. While Figure 3A represents two openings 104, 120 in the housing 105, more or fewer openings (and corresponding valves) can be used. The openings 104, 120 can be axial openings for gas injection according to an example of the present invention. The openings 104, 120 can also be called orifices. Figure 3B also shows an enlarged view of the openings 104, 120, the seats 110, 122 and the grooves 112, 124. The seats 110, 122 surround the openings 104, 120 to receive and seal tightly against the respective valves (not shown to facilitate visualization of the openings 104, 120 and the seats 110, 122) of the VSA 100. Grooves or recesses 112, 124 are positioned around the seats 110, 122.Although gorges 112, 124 are depicted as extending entirely around seats 110, 122 on the . In Figures 3A and 3B, in some examples, grooves 112 and 124 may only partially extend around seats 110 and 122. In some aspects, one or more grooves may extend at least partially around seats 110 and 122; for example, two grooves together may partially surround a seat. In some examples, grooves 112 and 124 may be formed by a trepanation process, although other suitable methods for creating grooves 112 and 124 may be used in other examples. Furthermore, although grooves 112 and 124 are shown to have a generally rectangular cross-section, in some examples, they may have a different cross-sectional shape.

[0017] As described above with regard to [Fig. 2], the grooves 112, 124 can separate a portion of the seats 110, 122 from the other parts of the housing 200. The separation between the seat 110, 122 and other parts of the housing 105 can allow the housing 105 to deform within the groove 112, 124 in response to pressure, without affecting the shape or size of the openings 104, 120 or the seats 110, 122. For example, the grooves 112, 124 can isolate a sealing face of the seats 110, 122, which contacts a valve (not shown) and seals tightly against it, from the influence of the rest of the housing 105 expanding due to the internal pressure of the tube or the annular pressure below the VSA 100. Thus, the grooves 112, 124 can give some flexibility to the respective seats 110, 122 and allow the parts of the respective seats 110, 122 which press tightly against the valves to retain their shapes.The seal between the valves and the respective seats 110, 122 can be improved and a gas leak between the valves and the respective seats 110, 122 when the VSA 100 is in the closed position can be reduced by fitting the grooves 112, 124.

[0018] Figure 4 is a top plan view of a portion of the housing 105 of Figures 2, 3A, and 3B, comprising the seat 110 surrounding the opening 104. The seat 110 includes a seat face 126 that contacts, interfaces, or hermetically seals with a surface of a valve (not shown to facilitate visualization of the opening 104, the seat 110, and the seat face 126) extending inside the housing 105. Figure 4 further shows the groove 112 extending around the seat 110, according to an embodiment of the present invention. The groove 112 may be a trepanned groove. The groove 112 can isolate the seat 110, including the seat face 126, from growth or deformation of a remaining part of the housing 105 when the housing 105 is subjected to internal pressure.In addition, the groove 112 can provide the seat face 126 with a degree of freedom or flexibility allowing the seat face 126 to maintain the same geometry as the surface of the valve which contacts, interfaces or presses against. hermetically against the seat face 126, thus maintaining a metal-on-metal seal between the seat face 126 and the high-pressure valve.

[0019] Figure 5 represents a portion of a VSA 400 according to an aspect of the present invention in which a seat insert 402 is provided around a seat 404 of the housing 406. A valve 408 of the VSA 400 includes a sealing face 412 that contacts, interfaces with, or hermetically seals against a seat face 410 of the seat insert 402. The seat insert 402 may be clamped into an opening or orifice 411 of the housing 406. In some aspects, the seat insert 402 may be pressed into the opening or orifice 411 of the housing 406. In some aspects, the seat insert 402 may be shrink-fitted into the opening or orifice 411 of the housing 406.The seat insert 402 may be made of the same material as the housing 406 or may be a different material, including, but not limited to, a metallic material, a polymer material, or another material suitable for sealing between the seat insert 402 and the sealing face 412 of the valve 408. In some aspects, the seat insert 402 may comprise an Inconel 718 alloy (UNS No. 7718) with a minimum yield strength of 125,000 lb / in² and a maximum hardness of 40 Rc, although other materials may be used. The seat insert 402 can extend over the opening 411. The seat insert 402 can be formed independently of the housing 406, so that the seat insert 402 can comprise a different material than the housing 406. For example, the housing 406 can comprise a material having a lower yield strength than the material constituting the seat insert 402.In certain aspects, the seat insert 402 can be adjusted by shrink fitting or cryogenically adjusted within the housing 406. In response to high pressure below the VSA 400, the housing 406 can deform while the seat insert 402 cannot deform, so that the valve 408 can continue to contact, interface with, or seal tightly against the seat face 410 of the seat insert 402. The seat insert 402 may not deform in response to deformation of the housing 406. By maintaining the shape of the seat insert 402 when the housing 406 deforms, the valve 408 can continue to contact, interface with, or seal tightly against the seat insert 402.Ensuring a constant seal between the seat insert 402 and the valve 408 can improve the functionality of the VSA 400 over time when the VSA 400 may undergo changes in the shape of its housing 406 under the effect of high pressure below the seat insert 402. In some aspects of the present invention, the seat insert 402 can be used with a groove surrounding the seat 404, or in other aspects (as shown in [Fig. 5]) the seat insert 402 can be used without a groove.

[0020] As used below, any reference to a series of examples should be understood as a reference to each of those examples in a disjunctive manner (for example, "Examples 1-4" should be understood as "Examples 1, 2, 3 or 4").

[0021] Example 1 is an annular safety valve that can be positioned in a borehole, the annular safety valve comprising: a housing having an opening extending through the housing to allow pressure to be transmitted between a first annular zone of the borehole below the annular safety valve and a second annular zone of the borehole above the annular safety valve, the housing defining the opening by a seat face; a flap extending through the opening;and a groove surrounding at least partially the seat face in order to maintain a shape of the seat face in response to an increase in pressure in the first annular zone of the borehole, the shape of the seat face corresponding to a surface of the valve intended to prevent pressure from being transmitted between the first annular zone of the borehole and the second annular zone of the borehole when the annular safety valve is in the closed position.

[0022] Example 2 is the annular safety valve of Example 1, further comprising: a second opening, the housing defining the second opening by a second seat face; a second valve extending through the second opening; and a second groove surrounding at least partially the second seat face in order to maintain a shape of the second seat face in response to an increase in pressure in the first annular zone of the borehole, the shape of the second seat face corresponding to a surface of the second valve intended to prevent pressure from being transmitted between the first annular zone of the borehole and the second annular zone of the borehole when the annular safety valve is in the closed position.

[0023] Example 3 is the annular safety valve of one or more examples 1 and 2, in which the groove completely surrounds the seat face.

[0024] Example 4 is the annular safety valve of one or more examples 1 to 3, in which the groove completely surrounds the seat face.

[0025] Example 5 is the annular safety valve of one or more examples 1 to 4, further comprising at least two additional openings, each opening of the two additional openings being associated with a respective groove surrounding at least partially each of the at least two additional openings.

[0026] Example 6 is the annular safety valve of one or more examples 1 to 5, further comprising a seat insert positioned in the opening, the seat insert having a seat face to maintain a seat face shape in response to an increase in pressure in the first annular zone of the borehole, the shape of the seat face corresponding to a surface of the valve intended to prevent pressure from being transmitted between the first annular zone of the borehole and the second annular zone of the borehole when the annular safety valve is in the closed position in response to an increase in pressure in the first annular zone of the borehole.

[0027] Example 7 is an annular safety valve that can be positioned in a borehole, the annular safety valve comprising: a housing having an opening extending through the housing to allow pressure to be transmitted between a first annular zone of the borehole below the annular safety valve and a second annular zone of the borehole above the annular safety valve; and a flap extending through the opening; at least one of (a) a seat insert positioned in the opening, the seat insert having a sealing surface to maintain a shape of the sealing surface in response to an increase in pressure in the first annular zone of the borehole,(a) the shape of the sealing surface corresponding to a valve surface intended to prevent pressure transmission between the first annular zone of the borehole and the second annular zone of the borehole when the annular safety valve is in the closed position in response to a pressure increase in the first annular zone of the borehole, or (b) a groove at least partially surrounding the opening to maintain a shape of the seat face in response to a pressure increase in the first annular zone of the borehole, the shape of the seat face corresponding to a valve surface intended to prevent pressure transmission between the first annular zone of the borehole and the second annular zone of the borehole when the annular safety valve is in the closed position.

[0028] Example 8 is the annular safety valve of Example 7, further comprising: a second opening in the housing; a second valve extending through the second opening; and a second seat insert positioned in the second opening, the second seat insert having a second sealing surface to maintain a shape of the second seat face in response to an increase in pressure in the first annular zone of the borehole, the shape of the second sealing surface corresponding to a surface of the second valve intended to prevent pressure from being transmitted between the first annular zone of the borehole and the second annular zone of the borehole when the annular safety valve is in the closed position.

[0029] Example 9 is the annular safety valve of one or more examples 7 and 8, further comprising at least two additional openings, each opening of the two additional openings being associated with a respective seat insert extending inside each opening of at least two additional openings.

[0030] Example 10 is the annular safety valve of one or more examples 7 and 8, in which the housing comprises a first material and in which the seat insert comprises the first material.

[0031] Example 11 is the annular safety valve of one or more examples 7 to 10, in which the housing comprises a first material and in which the seat insert comprises a second material different from the first material.

[0032] Example 12 is the annular safety valve of Example 11, in which the first material has a lower yield strength than the second material.

[0033] Example 13 is the annular safety valve of one or more examples 7 to 12 in which the seat insert comprises a polymer material.

[0034] Example 14 is the annular safety valve of one or more examples 7 to 12, in which the seat insert comprises a metallic material.

[0035] Example 15 is the annular safety valve of one or more examples 7 to 14, in which the sealing surface of the seat insert is concave in shape and in which the surface of the valve is convex in shape.

[0036] Example 16 is the annular safety valve of one or more examples 7 to 15, further comprising a groove at least partially surrounding the opening to help maintain the shape of the sealing surface in response to an increase in pressure in the first annular zone of the borehole.

[0037] Example 17 is a downhole assembly that can be positioned in a well casing train of a borehole comprising: a completion column including an annular safety valve, in which the annular safety valve further comprises: a housing having a plurality of openings extending through the housing to allow pressure to be transmitted between a first annular zone of the borehole below the annular safety valve and a second annular zone of the borehole above the annular safety valve, a plurality of seat faces, each seat face of the plurality of seat faces defining an opening of the plurality of openings;a plurality of valves, each valve of the plurality of valves extending through a respective opening of the plurality of openings, wherein each valve of the plurality of valves has a surface that corresponds to a surface of each respective seat face intended to prevent pressure from being transmitted between the first annular zone of the borehole and the second annular zone of the borehole when the annular safety valve is in the closed position; and a plurality of grooves, each groove of the plurality of grooves extending at least partially around a respective seat face of the plurality; of seat faces in order to maintain a shape of the respective seat face in response to an increase in pressure in the first annular zone of the wellbore.

[0038] Example 18 is the well bottom set of Example 17, in which each of the grooves of the plurality of grooves extends entirely around the respective seat face of the plurality of seat faces.

[0039] Example 19 is a well bottom set of Example 17, in which at least one of the grooves of the plurality of grooves extends only partially around at least one respective seat face of the plurality of seat faces.

[0040] Example 20 is the well bottom set of Example 17, in which each of the grooves in the plurality of grooves is a trepanned groove.

[0041] The preceding description of certain embodiments, including the illustrated embodiments, has been provided solely for illustrative and descriptive purposes and is not intended to be exhaustive or to limit the invention to the precise forms described. Numerous modifications, adaptations, combinations, and uses thereof are possible without departing from the scope of the invention.

Claims

Demands

1. An annular safety valve (16) that can be positioned in a borehole (12), the annular safety valve (16) comprising: a housing (105) having an opening (104) extending through the housing (105) to allow pressure to be transmitted between a first annular zone (18) of the borehole (12) below the annular safety valve (16) and a second annular zone (20) of the borehole (12) above the annular safety valve (16), the housing (105) defining the opening (104) by a seat face (126); a flapper (102) extending through the opening (104);and a groove (112) surrounding at least partially the seat face (126) in order to maintain a shape of the seat face (126) in response to an increase in pressure in the first annular zone (18) of the borehole (12), wherein the shape of the seat face (126) corresponds to a surface of the valve (102) intended to prevent pressure from being transmitted between the first annular zone (18) of the borehole (12) and the second annular zone (20) of the borehole (12) when the annular safety valve (16) is in the closed position.;

2. A ring safety valve (16) according to claim 1, further comprising: a second opening (120), in which the housing (105) defines the second opening (120) by a second seat face; a second valve extending through the second opening (120); and a second groove (124) at least partially surrounding the second seat face to maintain a shape of the second seat face in response to a pressure increase in the first ring zone (18) of the borehole (12), in which the shape of the second seat face corresponds to a surface of the second valve intended to prevent pressure from being transmitted between the first ring zone (18) of the borehole (12) and the second ring zone (20) of the borehole (12) when the ring safety valve (16) is in the closed position.

3. Annular safety valve (16) according to claim 1, wherein the groove (112) surrounds the seat face (126) and wherein the groove is a trepanned groove.

4. Annular safety valve (16) according to claim 1, further comprising at least two additional openings, each opening of the two additional openings being associated with a respective groove (112) surrounding at least partially each of the at least two additional openings.

5. Annular safety valve (16) according to claim 1, further comprising a seat insert positioned in the opening, the seat insert having a seat face to maintain a shape of the seat face in response to a pressure increase in the first annular zone of the borehole, wherein the shape of the seat face corresponds to a surface of the valve intended to prevent pressure from being transmitted between the first annular zone of the borehole and the second annular zone of the borehole when the annular safety valve is in the closed position in response to a pressure increase in the first annular zone of the borehole.

6. An annular safety valve (16) that can be positioned in a borehole, the annular safety valve comprising: a housing having an opening defined by a seat face (410), the opening extending through the housing to allow pressure to be transmitted between a first annular zone (18) of the borehole (12) below the annular safety valve and a second annular zone (20) of the borehole (12) above the annular safety valve (16); and a flapper (408) extending through the opening;and at least one of (a) a seat insert (402) positioned in the opening (411), the seat insert (402) having a sealing surface to maintain a shape of the sealing surface in response to an increase in pressure in the first annular zone (18) of the borehole (12), in which the shape of the sealing surface corresponds to a surface of the valve (408) intended to prevent pressure from being transmitted between the first annular zone (18) of the borehole (12) and the second annular zone (20) of the borehole (12) when the annular safety valve (16) is in the closed position in response to an increase in pressure in the first annular zone (18) of the borehole (12), or (b) a groove (112) at least partially surrounding the opening (104) to maintain a shape of the seat face; (126) in response to an increase in pressure in the first annular zone (18) of the borehole (12), the shape of the seat face (126) corresponding to a surface of the valve (102) intended to prevent pressure from being transmitted between the first annular zone (18) of the borehole (12) and the second annular zone (20) of the borehole (12) when the annular safety valve is in the closed position.

7. Annular safety valve (16) according to claim 6, further comprising: a second opening (120) in the housing (105); a second valve extending through the second opening (120); and a second seat insert positioned in the second opening (120), the second seat insert having a second sealing surface to maintain a shape of the second sealing surface in response to a pressure increase in the first annular zone (18) of the borehole (12), wherein the shape of the second sealing surface corresponds to a surface of the second valve intended to prevent pressure from being transmitted between the first annular zone (18) of the borehole (12) and the second annular zone (20) of the borehole (12) when the annular safety valve (16) is in the closed position.

8. A ring safety valve (16) according to claim 6, wherein the seat face (410) of the seat insert (402) is concave in shape and wherein the surface of the valve (408) is convex in shape, and wherein the ring safety valve (16) further comprises at least two additional openings, each opening of the two additional openings being associated with a respective seat insert extending inside each opening of the at least two additional openings.

9. Annular safety valve (16) according to claim 6, wherein the housing (105) comprises a first material and wherein the seat insert (402) comprises the first material.

10. Annular safety valve (16) according to claim 6, wherein the housing (105) comprises a first material and wherein the seat insert (402) comprises a second material which is different from the first material, and wherein the first material has a lower yield strength than the second material.

11. Ring safety valve (16) according to claim 6, wherein the seat insert (402) comprises at least one of a polymer material or a metallic material.

12. Ring safety valve (16) according to claim 6, wherein the ring safety valve (16) comprises both the seat insert (402) positioned in the opening (104, 411) and the groove (112) surrounding at least partially the opening (104, 411).

13. Downhole assembly capable of being positioned inside a casing train (13) of a borehole (12) comprising: a completion column including an annular safety valve (16), in which the annular safety valve (16) further comprises: a housing (105, 406) having a plurality of openings extending through the housing (105, 406) to permit pressure to be transmitted between a first annular zone (18) of the borehole (12) below the annular safety valve (16) and a second annular zone (20) of the borehole (12) above the annular safety valve (16), a plurality of seat faces, each seat face of the plurality of seat faces defining an opening of the plurality of openings;a plurality of valves, each valve of the plurality of valves extending through a respective opening of the plurality of openings, wherein each valve of the plurality of valves has a surface that corresponds to a surface of each respective seat face intended to prevent pressure from being transmitted between the first annular zone (18) of the borehole (12) and the second annular zone (20) of the borehole (12) when the annular safety valve (16) is in the closed position; and a plurality of grooves, each groove of the plurality of grooves extending at least partially around a respective seat face of the plurality of seat faces in order to maintain a shape of the respective seat face in response to an increase in pressure in the first annular zone (18) of the borehole (12).

14. A well bottom assembly according to claim 13, wherein each of the grooves in the plurality of grooves either (a) extends entirely around the respective seat face of the plurality of

15. seat faces either (b) only partially extends around the respective seat face of the plurality of seat faces. Well bottom assembly according to claim 13, wherein each of the grooves of the plurality of grooves is a trepanned groove.

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