RIGLESS DRILLING AND WELLHEAD INSTALLATION

Abstract

The present invention relates to methods and systems for establishing a well foundation as well as for drilling and installation of a surface casing without any use of a drilling rig.

Claims

1. A method for installation of a surface casing using a vessel, the method comprising: preparing a well casing assembly comprising a high pressure housing (HPH), an HPH running tool, a cement stinger, an HPH side entry sub, and an HPH lifting sub into one unit onshore or on the vessel; connecting a hose from the vessel to the side entry sub of the surface casing assembly; dispatching the well casing assembly from the vessel; lowering the well casing assembly by means of a crane or winch on the vessel; stabbing the well casing assembly into a low pressure housing and running the well casing assembly into a borehole supported by a wire; latching and locking the HPH of the surface casing assembly into the low pressure housing; cementing the surface casing in place by pumping cement from the vessel, through the hose, into the side entry sub, through the HPH running tool and down and out of the cement stinger; releasing the HPH running tool; and pulling out of the borehole together with the lifting sub, the side entry sub and the cement stinger by using the hoisting means on the vessel.

2. The method for installation of the surface casing using the vessel of claim 1, wherein the well casing assembly is a surface casing assembly comprising the HPH and a surface casing or a conductor assembly comprising the low pressure housing and outer conductor piping.

3. The method for installation of the surface casing using the vessel of claim 1, wherein cement returns are coming back out through a check valve of the surface casing, along an outside of the surface casing assembly, and finally the cement returns go out through ports in the low pressure housing.

4. The method for installation of the surface casing using the vessel of claim 1, further comprising: circulating a fluid through the low pressure housing.

5. The method for installation of the surface casing using the vessel of claim 4, wherein the circulating of the fluid through the low pressure housing is performed by a pump on the vessel or on a seabed.

6. The method for installation of the surface casing using the vessel of claim 4, wherein the fluid is seawater.

7. The method for installation of the surface casing using the vessel of claim 1, further comprising: causing the HPH to remain coupled to the low pressure housing and positioned to be coupled to a blowout preventer.

8. A system for installation of a surface casing using a vessel, the system comprising: a surface casing assembly comprising a high pressure housing (HPH), a surface casing, an HPH running tool, a cement stinger, an HPH side entry sub, and an HPH lifting sub, wherein the surface casing assembly is configured to be dispatched from the vessel and then lowered down on a wire of a crane on the vessel and is further configured to be stabbed into a subsea node with a low pressure housing and to be run into a borehole on the wire; and a hose from the vessel connected to the HPH side entry sub of the surface casing assembly; wherein the HPH of the surface casing assembly is configured to be locked into the low pressure housing; wherein the cement stinger is configured to cement the surface casing in place in the borehole by means of a pump configured to pump cement from the vessel, through the hose, into the HPH side entry sub and through the HPH running tool; and wherein the HPH running tool is configured to be released and pulled out of the borehole together with the lifting sub, the HPH side entry sub and the cement stinger by using the wire of the crane on the vessel.

9. The system for installation of the surface casing using the vessel of claim 8, wherein the surface casing assembly further comprises a surface casing or a conductor assembly comprising the low pressure housing and outer conductor piping.

10. The system for installation of the surface casing using the vessel of claim 8, further comprising: a check valve downstream of the cement stinger.

11. The system for installation of the surface casing using the vessel of claim 10, wherein the cement is configured to flow through the check valve and along an outside of the surface casing assembly.

12. The system for installation of the surface casing using the vessel of claim 11, further comprising: ports formed in the low pressure housing configured to permit flow of the cement after flowing through the check valve.

13. The system for installation of the surface casing using the vessel of claim 8, wherein the hose is configured to carry a fluid to be circulated through the low pressure housing.

14. The system for installation of the surface casing using the vessel of claim 13, wherein the fluid is seawater.

15. The system for installation of the surface casing using the vessel of claim 13, further comprising: a second pump positioned on a seabed to circulate the fluid.

16. The system for installation of the surface casing using the vessel of claim 8, wherein the surface casing assembly is assembled at an onshore location.

17. A system comprising: a high pressure housing (HPH); a surface casing coupled to the HPH; an HPH running tool coupled to the HPH; a cement stinger coupled to the HPH running tool and extending through at least part of the surface casing; an HPH side entry sub coupled to the HPH running tool; and an HPH lifting sub coupled to the HPH side entry sub; a hose from the vessel connected to the HPH side entry sub of the surface casing assembly; and a pump coupled to the hose; wherein the HPH is configured to be locked into a low pressure housing coupled to a borehole, the cement stinger is configured receive cement supplied by the pump, and the HPH running tool is configured to be released and pulled out of the borehole together with the lifting sub, the HPH side entry sub, and the cement stinger.

18. The system of claim 17, wherein the HPH, the surface casing, the HPH running tool, the cement stinger, the HPH side entry sub, and the HPH lifting sub form a surface casing assembly.

19. The system of claim 17, further comprising: a check valve coupled to the surface casing, the check valve configured to permit flow of the cement out of the surface case.

20. The system of claim 19, further comprising: one or more ports formed in the low pressure housing configured to receive the cement after passing through the check valve.

Description

[0064] These and other aspects of the invention are apparent from and will be further elucidated, by way of example(s), with reference to the drawings, wherein:

[0065] FIG. 1-5 show a well hole drilling method according to the present invention.

[0066] FIG. 6-10 illustrate a casing running and cementing method according to the present invention.

[0067] A subsea node 1 is provided for the drilling method. The subsea node 1 forms an outer protective casing for the drilling equipment and will provide a means for anchoring drilling equipment and/or well foundation to the seabed. The subsea node 1 is typically completed with a wellhead assembly comprising an outer well housing or low pressure housing (LPH) 2 and an inner well housing or high pressure housing (not shown). The outer well housing 2 can be provided with an outer conductor piping 32. The subsea node 1 can be completed with the wellhead assembly prior to or after completion of the well drilling.

[0068] The subsea node 1 is preinstalled in a separate operation on a seabed 12. The completion of the subsea node 1 with the low pressure housing (LPH) 2 is often done onshore prior to any other offshore operation while the high pressure housing (not shown) is installed after drilling of the first section of the well.

[0069] It is possible to drill the first section of the well without BOP. However, when the well is approaching high pressure subterranean structures, a BOP has to be installed on the subsea node 1.

[0070] Drilling at first a part of a well 20 with a vessel 18 and without a BOP, will reduce the cost of each well by limiting the rig time for well drilling and simplify the structure requirement for this first drilling part. Thereafter a rig can arrive and install the BOP directly at a preinstalled wellhead. It is also a safe method as the vessel 18 doesn't need to be straight above the well centre and can easily escape in an event of release of shallow gas.

[0071] FIG. 1:

[0072] An onshore preassembled drilling assembly according to the present invention comprises a bottom hole assembly (BHA) 5. This BHA 5 can typically comprise a drill bit with stabilizers, a drilling motor, which can be, but is not limited to, for example a drilling motor 6, a kelly bushing adapter 3, a non-rotating or non-circular string or pipe 7, which can be, but is not limited to, for example one piece of a kelly string, a side entry sub 8 with a swivel and a lifting sub 9.

[0073] The drilling assembly is lifted into the sea and lowered down on a cable 11 of a vessel crane 19 into the subsea node 1 and the LPH 2. In this context, the cable 11 can be a cable, wire, rope or chain.

[0074] The BHA 5 is lowered into the subsea node 1 and the kelly bushing adapter 3 is locked to the subsea node 1. And more particularly, torque keys of the kelly bushing adapter 3 are aligned with the subsea node 1 and then the kelly bushing adapter 3 is locked to the low pressure housing or well housing 2 using a locking mechanism 4. When the kelly bushing adapter 3 is locked to the subsea node 1 and the bottom hole assembly 5, the bottom hole assembly 5 is prevented from rotational movement or moving sideways, but is allowed to move vertically.

[0075] The locking mechanism 4 can be any locking device that can be remotely operated or be configured to be operated by an ROV. The locking mechanism 4 lock the kelly bushing 3 to the subsea node 1 or well housing 2.

[0076] FIG. 2A-2B:

[0077] While the drilling assembly weight is set down, a fluid is pumped through a hose 10 into the side entry sub 8 down the kelly string or non-rotating drill string 7 in order to drive the drilling motor 6 that spins the drill bit. The fluid can be provided from the vessel 18 or a fluid reservoir on the sea bed. The drill bit of the BHA 5 can be driven hydraulically from a high volume pump (not shown) on the vessel 18 (FIG. 2A).

[0078] A pump 24 for drill cutting removal can be used for the circulation of the fluid. The pump can be positioned on the seabed 12 as shown in FIG. 2B.

[0079] The hose 10 can be, but is not limited to, for example a black eagle hose, a coil tubing or any flexible hosing. The fluid can be any drilling fluid.

[0080] The reactional force that is created between the bottom hole assembly (BHA) 5 and the seabed 12 under the ground will be absorbed by the kelly bushing adapter 3 and transferred via the low pressure housing (LPH) 2 to the subsea node 1.

[0081] Drill cuttings returns are escaping through cement return ports on the LPH 2 with or without a drill cutting disposal pump system 24.

[0082] FIG. 3:

[0083] Once the total depth is reached, the drilling assembly will be pulled back using the cable 11 of the hoisting mechanism 19 on the vessel 18. The hoisting mechanism can be a crane or winch.

[0084] When the drilling motor 6 reaches the kelly bushing adapter 3, or any other catch device if used, the kelly bushing adapter 3 will be unlocked by opening the locking mechanism 4.

[0085] FIG. 4:

[0086] When the kelly bushing adapter 3 is unsecured, the whole drilling assembly will be pulled up. On FIG. 4, the kelly bushing adapter 3 is attached to the bottom hole assembly 5. When the locking mechanism 4 is unlocked, the kelly bushing adapter 3 is released from the subsea node 1 or the well housing 2.

[0087] However, in another embodiment, the kelly bushing adapter 3 can be part of the subsea node assembly. In this embodiment, the kelly bushing adapter 3 will remain on the seabed when the locking mechanism 4 is unlocked, while the bottom hole assembly is raised to the vessel.

[0088] FIG. 5:

[0089] The whole drilling assembly is then pulled to the water surface by pulling back on the cable 11 leaving the drilled well hole/borehole 20 ready for running a surface casing assembly.

[0090] FIG. 6:

[0091] The surface casing assembly is usually prepared onshore into one unit and comprises: a high pressure housing (HPH) 13 and a surface casing 21 with a check valve 22, a HPH running tool 15, a cement stinger 14, a side entry sub 16 with a swivel and a lifting sub 17.

[0092] The hose 10 from the vessel 18 is connected to the side entry sub 16.

[0093] The whole surface casing assembly is dispatched from the vessel 18 and lowered down on the wire 11 of the vessel crane 19.

[0094] FIG. 7A-7B:

[0095] The surface casing assembly is stabbed into the LPH 2 and run in the hole 20 on the wire 11. Finally, the HPH 13 latches and locks into the LPH 2.

[0096] Under the running-in step, circulation of seawater or other suitable fluid in the well hole 20 can be done using a pump on the vessel 18 (FIG. 7A), down the hose 10, through the side entry sub 16 and through the HPH running tool 15.

[0097] Alternatively, the pump 24 on the seabed can be used for the circulation of the seawater or the suitable fluid through the well hole 20 (FIG. 7B).

[0098] FIG. 8:

[0099] The surface casing 21 is cemented in place by pumping cement from the vessel 18, through the hose 10, into the side entry sub 16, through the HPH running tool 15 and down the cement stinger 14.

[0100] Cement returns are coming back out through the check valve 22, along outside of the surface casing assembly, and finally the cement returns are flown out through the ports in the LPH 2.

[0101] FIG. 9:

[0102] The HPH running tool 15 is released and then pulled out of the hole 20 together with the lifting sub 17, the side entry sub 16 and the cement stinger 14 using the vessel crane wire 11.

[0103] FIG. 10:

[0104] Left on the seabed 12 is a well 20 ready for a floating drilling unit to latch a BOP on to the HPH or wellhead 13.

[0105] Finally, the vessel 18 can move to a next well to be made.

[0106] It is not compulsory to remove the complete bottom hole assembly 5 from the well 20. In some situations, parts of or the complete bottom hole assembly is sacrificed in the well. In these situations, the cable 11 between the bottom hole assembly 5 and the vessel 18 is cut and the vessel can prepare to drill a new well and/or move to a new location.

[0107] In some occasions, a special kelly bushing has to be made if a kelly bushing, that is longer than what the vessel 18 can handle, is needed. Separate pipe sections or lengths can thus be connected together at or on the vessel 18, for example while running all this into the sea. For about a 50 meters hole, potentially a one piece pipe can be used, as mentioned before.

[0108] Depending on the length, the surface casing can be deployed as one assembly, if not it can be made up on the vessel 18 and then run into the sea, similar to what is done on a drilling rig.

[0109] The weight on the drill bit can be adjusted by a hive compensated crane on the vessel 18. This means that the crane 19 can have some hive compensating equipment thereon.

[0110] The total string weight should be configured to give sufficient weight to the bit in order to be able to carry on and/or fulfil the operations.

[0111] If the string is not very long, the whole string can be made up onshore and deployed straight from the back deck of the vessel 18 by the crane 19.

[0112] If a deeper hole is required, the string can be built of joints in the vessel moon pool. Thus, some handling equipment should be provided by the subsea contractor.

[0113] Additional modifications, alterations and adaptations of the present invention will suggest themselves to those skilled in the art without departing from the scope of the invention as defined in the following patent claims.