A method and a well device for temporary well isolation during a well completion phase

Abstract

The invention is a method for temporary well isolation during a well completion phase, wherein the method comprises the steps of: running a production tubing (12) with at least one glass disc (20) installed, through a wellhead (10) and into a reservoir (16) in a subterrain formation (18), wherein the glass disc (20) is run in a completion fluid that is heavier than the reservoir pressure, wherein the pressure above and below the glass disc (20) is kept equal during the run in state, setting a production packer (14) and pressure test against the glass disc (20), circulating in a lighter fluid or gas to lighten a column on an upper side of the glass disc (20), characterized by creating an underbalanced pressure on the upper side of the glass disc (20), sufficient to force the glass disc (20) against a glass disc break mechanism (22) disposed on said upper side of the glass disc (20), and shatter the glass disc (20) to open the well and allowing flow in the production tubing (12).

Description

[0001] A method and a well device for temporary well isolation during a well completion phase

[0002] Field of the invention

[0003] The present invention relates to a method and a well device for temporary well isolation during a well completion phase.

[0004] Typical activities are pressure test and packer setting.

[0005] Background of the invention

[0006] In different types of well operations, it is a need for well tool devices providing a temporary isolation of a tubing or casing string during well completion activities. A common solution is a frangible glass plug or disc configured to break at a given differential pressure across the plug, in example 5 000 psi. In example if there are a hydrostatic pressure on both sides of the plug i.e., 3000 psi, the differential pressure is zero across the plug. If pressure at wellhead / surface is increased by i.e., 5 000 psi, the pressure above the plug will be 8 000 psi, and the differential pressure across the plug will be 5 000 psi, at this point the plug will activate and open.

[0007] Typical for activation of barrier valves / plugs is that they will activate on overbalanced pressure.

[0008] International patent application published as WO2020 / 197413 beonging to the applicant, defines a plug breaking mechanism with a plug disposed inside a housing and axially slidable within a limited interval inside the housing, a seal ring inside the housing between the plug and the housing, axially slidable between a first position and a second position and sealing between the plug and the housing, the seal ring having a seal ring uphole pisten area exposed to the pressure above the plug, and shear elements with a given shear value preventing axial movement of the seal ring inside the housing prior to shearing the shear element, and breaking members physically separated from the plug with the seal ring in its first position and exposed to the plug with the seal ring in its second position, wherein biasing members are acting on said seal ring in an uphole direction, urging the seal ring in the uphole direction.

[0009] US2017 / 0321518A1 describes a well tool device with a housing and a through bore. A frangible obstruction device is provided inside the longitudinal bore, where through fluid flow is prevented due to the frangible obstruction device. The frangible obstruction device includes a through opening. The well tool device further includes an actuation device extending fluidtight at least into the through opening. The actuation device includes an actuation tool connection interface and a disintegration device. The disintegration device is configured to be at least partially moved into the frangible obstruction device and thereby provide disintegration of the frangible obstruction device, hence allowing fluid flow through the between the first end and the second end of the through bore.

[0010] Objects of the present invention

[0011] According to the invention, the glass disc is activated and crushed first with an underbalance on the upper side of the glass disc, whereas traditionally another tool with the same function is activated on an overbalance on the upper side. With the present invention, there is no need to consider pressure cycles on the upper side of the glass disc when installing the lower or upper completion of the well. The operator can pressure test against the glass disc without risk of activating the shear function on the glass disc.

[0012] The glass disc will be run as a part of the completion in a completion fluid that is heavier than the reservoir pressure. When the completion is installed and tested and ready to open the well for production, lighter fluid or gas is circulated in to lighten the column on the upper side of the glass disc. When the differential pressure (the underbalance) is large enough to reach the predetermined shear pressure for activation of the glass break mechanism, the glass disc breaks and the well starts to flow and produce.

[0013] Hence, it is an object to provide an improved method and well device for temporary well isolation during a well completion phase.

[0014] Summary of the invention

[0015] According to a first aspect of the invention, a method for temporary well isolation during a well completion phase is provided, wherein the method comprises the steps: running a production tubing with at least one glass disc installed, through a wellhead and into a reservoir in a subterrain formation, wherein the glass disc is run in a completion fluid that is heavier than the reservoir pressure, wherein the pressure above and below the glass disc is kept equal during the run in state, setting a production packer and pressure test against the glass disc, circulating in a lighter fluid or gas to lighten a column on an upper side of the glass disc, thus creating an underbalanced pressure on the upper side of the glass disc, sufficient to force the glass disc against a glass disc break mechanism disposed on said upper side of the glass disc, and shatter the glass disc to open the well and allowing flow in the production tubing.

[0016] The glass disc is arranged for axial displacement in the production tubing and to be forced against breaking pins 23 in the glass disc break mechanism, when the underbalanced pressure is large enough.

[0017] The glass disc glass break mechanism can be activated by a shear pressure acting on the glass disc break mechanism.

[0018] The step of circulating in lighter fluid or gas can comprise displacing fluid above the glass disc through a circulation sleeve above the production packer or gas lift through gas mandrels.

[0019] The glass disc can be arranged to shatter when the underbalance pressure reaches a predetermined shear pressure, for instance 206,8bar (3000psi).

[0020] According to a second aspect of the invention, a well tool device for temporary well isolation during a well completion phase is provided, comprising a tubular arranged for assembly in a production tubing, said tubular further comprises a glass disc and a glass disc break mechanism disposed within a through running boring, wherein the glass disc break mechanism is installed above in the tubular and on an upper side of the glass disc, and the glass disc is arranged to be forced against the glass disc break mechanism by an underbalanced pressure created on said upper side of the glass disc, wherein the glass disc 20 is arranged for axial displacement in the through running boring 24 of the tubular 12a and to be forced against crush elements 23 in the glass disc break mechanism 22, when the underbalanced pressure is large enough.

[0021] The glass disc can be a solid and disintegratable disc or plug made of brittle glass. The glass disc break mechanism can in one embodiment comprise one or more pins 23 protruding axially in the through running boring of the tubular, or one or more pins 23 mounted inside the tubular, and which are protruding inwardly in the through running boring, wherein the underbalanced pressure forces the glass disc against the pins 23 to shatter the glass disc.

[0022] The glass disc break mechanism can in another embodiment comprise a load ring supporting the glass disc, said load ring is axially movable within the through running boring between a first position in where the glass disc is with a distance to a breaking pin and a second position in where the glass disc is forced against the breaking pin.

[0023] The load ring can be resting on a shear ring with an annular shear lip to prevent axial movement in the first position until the shear lip is subjected to a force higher than a predetermined force, wherein the annular shear lip of the shear ring extends radially inward in the through running boring, and the breaking pin is resting on the shear ring, and said breaking pin is accommodated in a pocket on an outside of the load ring.

[0024] Description of the figures

[0025] Embodiments of the present invention will now be described, by way of example only, with reference to the following figures, wherein:

[0026] Figure 1 shows an overview of a well with a production tubing installed.

[0027] Figure 2 shows a well tool device according to the invention.

[0028] Fig. 3a-3d show operation sequence in the method according to the invention.

[0029] Fig. 4 illustrates in isometric view, a glass disc 20 with an overlying glass disc break mechanism 22.

[0030] Fig. 5 illustrates a vertical cross section of an embodiment of the invention with the arrangement of Fig. 4 installed.

[0031] Description of preferred embodiments of the invention

[0032] Underbalance and Overbalance Pressure

[0033] Overbalance Pressure:

[0034] If hydrostatic pressure in a well is higher than the reservoir pressure, the difference is called overbalance pressure, or simply overbalance. Underbalance Pressure:

[0035] If reservoir pressure is more than hydrostatic pressure, the difference is called underbalance.

[0036] Conversion

[0037] 3,000psi - 206,8bar

[0038] 6,000psi - 413,7bar 10,000psi - 689,5bar 15,000psi - 1034,2bar

[0039] The invention is disclosed and shown in the drawings in a basically vertical well.

[0040] Hence, the terms “upper”, “upstream”, “overlying”, “upwards”, “above”, etc., relates to what is shown in fig. 1. In a horizontal well similar terms have the same meaning, but in a horizontal direction towards the wellhead.

[0041] Fig. 1 shows an overview of a well. During completion, a production tubing 12 is installed between a wellhead 10 on the seafloor and a reservoir 16 in a subterrain formation 18. Production packers 14 are installed between the production tubing 12 and the subterrain formation 18.

[0042] A glass disc 20 and a glass disc break mechanism 22 is installed in a tubular 12a of the production tubing 12. As seen in fig. 2, the glass disc break mechanism 22 is arranged in a through running boring 24 in the tubular 12a and on an above or upper side of the glass disc 20, i.e., in the part of the tubular 12a closest to the wellhead 10. Hence, the glass disc 20 is installed below the glass disc break mechanism 22.

[0043] The glass disc 20 is a solid glass disc, such as a disintegratable disc or plug, for instance made of brittle glass, so it can be shattered by the glass disc break mechanism 22.

[0044] The glass disc 20 is arranged to be forced against the glass disc break mechanism 22 by an underbalanced pressure created on the upper side of the glass disc 20, i.e. the pressure below the glass disc is greater than the pressure above. The operational process steps shall be explained later. Hence, the glass disc 20 is arranged for axial displacement in the through running boring 24 of the tubular 12a and to be forced against for instance breaking pins or crush elements 23 in the glass disc break mechanism 22, when the underbalanced pressure is large enough.

[0045] The glass disc break mechanism 22 can in a first embodiment comprise one or more crush elements I breaking pins 23 protruding axially in the through running boring 24 of the tubular 12a, or one or more crush elements I breaking pins 23 mounted inside the through running boring 24 of the tubular 12a, and which are protruding inwardly in the through running boring.

[0046] The glass disc break mechanism 22 can in an embodiment comprise a load ring 25 supporting the upper face of the glass disc 20, wherein the load ring 25 is axially movable within the through running boring 24 between a first position in where the glass disc 20 is with a distance to a breaking pin 23 and a second position in where the glass disc 20 is forced against the breaking pin 23.

[0047] Said load ring 25 is in an embodiment shown in Figs. 4 and 5 arrangedresting on a shear ring 26 with an annular shear lip 261 to prevent axial movement in the first position until the shear lip 261 is subjected to a force higher than a predetermined force, created by the underbalanced pressure. The annular shear lip 261 of the shear ring 26 extends radially inward in the through running boring 24. The breaking pin 23 is arrangedresting on the shear ring 26, and the breaking pin 23 can be accommodated in a pocket 251 on an outside of the load ring 25.

[0048] Fig. 4 illustrates in isometric view, a glass disc 20 with an overlying glass disc break mechanism 22. The overlying glass disc break mechanism 22 embodiment comprises crush elements 23 in pockets 251 in a load ring 25 underlying a shear ring lip 261 of a shear ring.

[0049] Fig. 5 illustrates a vertical cross section of an embodiment of the invention with the arrangement of Fig. 4 installed. It is arranged so as for when the pressure from below makes the shear lip break, the glass element will be pushed upwardly onto the crush element 23 which damages the breakable plug glass disc sufficiently to shatter due to the pressure and the tubular 12a will be opened.

[0050] Fig. 3a-3d show operation sequence of the method according to the invention. Fig. 3a shows run-in-hole state with the glass disc 20. Same pressure above and below the glass disc 20, for instance 10,000psi. The glass disc 20 is run as part of the completion in a completion fluid that is heavier than the reservoir pressure.

[0051] Setting production packer 14 and pressure test against the glass disc 20 is illustrated in fig. 3b, for instance by applying 5,000psi.

[0052] Thereafter a lighter fluid or gas is circulated to lighten a column on an upper side of the glass disc 20, as seen in fig. 3c, thus creating an underbalanced pressure on the upper side of the glass disc 20. When the underbalanced pressure is sufficiently large enough it will force the glass disc 20 against the glass disc break mechanism 22 arranged on said upper side of the glass disc 20, thus shattering the glass disc 20 and opening the well and allowing flow in the production tubing 12, as seen in fig. 3d.

[0053] Displacement of fluid above the glass disc 20 to lighter fluid or gas in the well can be done through a circulation sleeve above the production packer 14 or gas lift through gas mandrels. The glass disc 20 will shatter when differential (underbalance) pressure reaches the predetermined shear pressure, in this case 3000psi.

Claims

Claims1. A method for temporary well isolation during a well completion phase, wherein the method comprises the steps: running a production tubing (12) with at least one glass disc (20) installed, through a wellhead (10) and into a reservoir (16) in a subterrain formation (18), wherein the glass disc (20) is run in a completion fluid that is heavier than the reservoir pressure, wherein the pressure above and below the glass disc (20) is kept equal during the run in state, setting a production packer (14) and pressure test against the glass disc (20), circulating in a lighter fluid or gas to lighten a column on an upper side of the glass disc (20), characterized by creating an underbalanced pressure on the upper side of the glass disc (20), sufficient to force the glass disc (20) against a glass disc break mechanism (22) disposed on said upper side of the glass disc (20), and shatter the glass disc (20) to open the well and allowing flow in the production tubing (12).

2. The method according to claim 1 , wherein the glass disc (20) is arranged for axial displacement in the production tubing (12) and to be forced against crush elements (23) in the glass disc break mechanism (22), when the underbalanced pressure is large enough.

3. The method according to claim 2, wherein the glass disc glass break mechanism (22) is activated by a shear pressure acting on the glass disc break mechanism (22).

4. The method according to claim 1 , wherein the step of circulating in lighter fluid or gas comprises displacing fluid above the glass disc (20) through a circulation sleeve (13) arranged above the production packer (14) or gas lift through gas mandrels (13').

5. The method according to claim 1 , wherein the glass disc (20) is arranged to shatter when the underbalance pressure reaches a predetermined shear pressure, for instance 206,8bar (3000psi).

6. A well tool device for temporary well isolation during a well completion phase, comprising a tubular (12a) arranged for assembly in a production tubing (12), said tubular (12a) further comprises a glass disc (20) and a glass disc break mechanism(22) disposed within a through running boring (24), characterized in that the glass disc break mechanism (22) is installed above in the tubular (12a) and on an upper side of the glass disc (20), and the glass disc (20) is arranged to be forced against the glass disc break mechanism (22) by an underbalanced pressure created on said upper side of the glass disc (20), wherein the glass disc (20) is arranged for axial displacement in the through running boring (24) of the tubular (12a) and to be forced against crush elements (23) of the glass disc break mechanism (22), when the underbalanced pressure is large enough.

7. The well tool device according to claim 6, wherein the glass disc (20) is a solid and disintegratable disc or plug made of brittle glass.

8. The well tool device according to claim 6, wherein the glass disc break mechanism (22) comprises said one or more crush elements (23) protruding axially in the through running boring (24) of the tubular (12a), or said one or more crush elements (23) mounted inside the tubular (12a), and which are protruding inwardly in the through running boring (24), wherein the underbalanced pressure forces the glass disc (20) against the crush elements (23) to break the glass disc (20).

9. The well tool device according to claim 6, wherein the glass disc break mechanism (22) comprises a load ring (25) supporting the glass disc (20), said load ring (25) is axially movable within the through running boring (24) between a first position (P1) in where the glass disc (20) is with a distance to said crush element(23) and a second position (P2) in where the glass disc (20) is forced against the crush element (23).

10. The well tool device according to claim 9, wherein said load ring (25) is resting on a shear ring (26) with an annular shear lip (261) to prevent axial movement in the first position until the shear lip (261) is subjected to a force higher than a predetermined force, wherein the annular shear lip(261) of the shear ring (26) extends radially inward in the through running boring (24), and the crush element (23) is resting on the shear ring (26), and said crush element (23) is accommodated in a pocket (251) on an outside of the load ring (25).

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