LINER FOR A WELLBORE

Abstract

A liner for a wellbore having a sidewall in which one or more nozzles are formed is described, wherein the one or more nozzles are plugged by temporary plugs. Also described is a method of completing an open hole well that penetrates a subterranean formation in which a liner having a sidewall in which one or more nozzles are formed, wherein the one or more nozzles are plugged by temporary plugs, is deployed in the well such that the nozzles communicate with the formation.

Claims

1. Liner for a wellbore having a sidewall in which one or more nozzles are formed, wherein the one or more nozzles are plugged by temporary plugs.

2. The liner according to claim 1 wherein the temporary plugs are removable by using a plugging medium that dissolves upon exposure to elevated temperature and/or an activation fluid, preferably an aqueous fluid.

3. The liner according to claim 1 wherein the temporary plugs are mechanical plugs that are removable by application of pressure cycles.

4. The liner according to claim 1 which comprises a liner top packer which isolates the liner top such that during operation all fluid flow is through the nozzles.

5. The liner according to claim 1 which comprises a liner shoe and a liner shoe shut off device, wherein the liner shoe shut off device allows circulation during displacement operations and subsequently isolates the liner shoe.

6. The liner according to claim 5 wherein the liner shoe shut off device can be shut by electronics activated by timer, RFID, pressure or flow.

7. The liner according to claim 5 wherein the liner shoe shut off device can be shut by mechanical means using pressure, actuation dart/ball or a combination of both.

8. A method of completing an open hole well that penetrates a subterranean formation in which a liner having a sidewall in which one or more nozzles are formed, wherein the one or more nozzles are plugged by temporary plugs, is deployed in the well such that the nozzles communicate with the formation.

9. The method according to claim 8 wherein a liner shoe shut off valve is deployed to allow initial fluid displacement through the liner with plugged nozzles.

10. The method according to claim 8 wherein after positioning of the liner the temporary plugs are removed from the nozzles.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be described with reference to the accompanying drawings of which:

[0020] FIG. 1 shows a Base Case Well Design with standard nozzles in liner;

[0021] FIG. 2 shows a Base Case Well Design showing displacement string required for displacing from non-aqueous fluid to aqueous fluid.

[0022] FIG. 3 shows the progression of design from base case (left embodiment) to embodiments according to the present invention (middle and right embodiment).

DETAILED DESCRIPTION OF THE INVENTION

[0023] The invention relates to the field of oil well drilling and more particularly to oil well completion and liners for achieving such a completion. The process in which the inventive liner can be advantageously used preferably involves providing a pre-punctured liner having plugged nozzles extending through the punctured holes. Once the liner is positioned, the temporary plugs allow for displacement of the wellbore from non-aqueous fluid to aqueous fluid. Thereafter the plugs are removed from the nozzles to provide unobstructed production and injection flow.

[0024] The present invention thus teaches in a preferred embodiment a method of completing an open hole well that penetrates a subterranean formation to control the production of oil from and injecting acidizing fluid to the formation. The well is provided with nozzles that extend through the liner and communicate with the formation. The nozzles provide negligible pressure drop in a steady state production scenario while in a transient high rate injection scenario sufficient pressure drop is achieved to allow for even distribution of injection fluids. Temporary plugs are located in the nozzle throat such that initially the nozzles act as a blank piece of pipe. A liner shoe shut off valve is deployed to allow initial fluid displacement through the liner with plugged nozzles. The liner with temporary plugs is deployed in the well in a non-aqueous fluid. The temporary plugs in conjunction with other components allow for displacement of non-aqueous fluids through the casing/liner during deployment to assist with reaching final placement depth. Once the liner is positioned, the temporary plugs allow for displacement of the wellbore from non-aqueous fluid to aqueous fluid. Thereafter, the temporary plugs are removed from the nozzles to provide unobstructed production and injection flow paths to the formation and unobstructed internals of the casing/liner for future intervention. Temporary plugs may be removed by a variety of intervention free methods such as: temperature dissolved materials, aqueous fluid dissolved materials, pressure actuated valves. Subsequent to the aqueous fluid displacement operations, a shut off valve isolates the shoe and ensures all future production and injection fluids pass through the nozzles once the temporary plugging mechanism is removed. A delayed actuated liner top packer is set once the aqueous fluid displacement operation is complete.

[0025] Current methods for displacing the pre-drilled liner from non-aqueous to aqueous fluid typically require deployment of a work string following deployment of the pre-drilled liner to final position. Such methods require significant operational time to manage the work string within the drilling rig structure and for physical deployment.

[0026] Pre-drilling of the liner is well specific and performed such that it provides negligible pressure drop in a steady state production scenario while in a transient high rate injection scenario sufficient pressure drop is achieved to allow for even distribution of injection fluids.

[0027] Alternate methods for the same displacement operation are to deploy the work string as an inner string within the pre-drilled liner. This method is not applicable in extended reach applications due to the higher weight of the liner negating ability to deploy to final position through increased drag.

[0028] The method according to the present invention enables displacement operation to take place through the pre-drilled liner without a subsequent work string deployment run nor the use of an inner string.

[0029] Preferred components that make this method achievable are described below:

[0030] Liner top packer with delayed activation (until after aqueous fluid displaced). Once set, this packer isolates the liner top ensuring all fluid flow is through the nozzles.

[0031] Liner shoe shut off device that allows circulation during displacement operations and subsequently isolates the shoe for the life of the well. Once isolated all fluid flow is through the nozzles. Device can be actuated shut by electronics activated by timer, RFID, pressure or flow. Alternatively a device that is shut by mechanical means using pressure, actuation dart/ball or combination of both.

[0032] Temporary plugged nozzles which are removed once the aqueous fluid displacement operations are completed. Temporary plugs can be removed by using a plugging medium that is dissolved with time and exposure to temperature and/or an activation fluid (typically an aqueous fluid) or a mechanical plug that is removed by application of pressure cycles. Temporary plugs must be designed to withstand differential pressure generated by the displacement operations across the device and provide sufficient time delay before removal to complete same.

[0033] A number of different temporary plugs may be utilized to execute the stated method.

[0034] Temporary plugs can be removed by using a plugging medium that is dissolved with time and exposure to temperature and/or an activation fluid (typically an aqueous fluid) or a mechanical plug that is removed by application of pressure cycles. Plugs would be required to withstand suitable differential pressure to allow displacement of the non-aqueous fluid with aqueous fluid at high rate. If temperature or activation fluid dissolution method is utilised, sufficient delay is required to enable deployment of the liner in an extended reach application.

[0035] The method described provides significant operational time and cost savings over the historical method. In addition the method described allows the pre-drilled liner to be washed, floated and/or reamed to total depth in extended reach applications. The nature of the temporary plugging of the nozzles in conjunction with the shut off shoe and liner top may also allow for the liner to be utilised as a tested barrier for upper completion operations.