KOBE SUB, WELLBORE TUBING STRING APPARATUS AND METHOD
To address concerns of kobe plug cap portions being inadvertently removed, for example, by abutment with strings or tools passing thereby, a shielding structure may be employed to protect the cap against inadvertent removal. The port opening tool useful with the kobe plug is selected to overcome the shielding structure to open the kobe plug. To address concerns of a portion of the kobe plug becoming loose in the tubing string inner bore, a capturing mechanism may be provided that captures the cap portion after it is removed to open the kobe plug and prevented the cap portion from becoming loose in the inner bore of the tubing string.
1 . A kobe sub comprising: a tubular body connectable into a wellbore tubing string, the tubular body including a wall including an outer surface and an inner surface defining an inner bore and a port through the wall; a kobe plug installed in the port with a cap portion accessible in the inner bore, a base mounted in the port and connected to the cap portion, a channel extending through the base and closed by the cap portion; and a shielding structure in the inner bore to shield the cap portion from protruding into the inner bore.
2 . The kobe sub of claim 1 wherein the shielding structure includes a shielding wall extending alongside the cap portion.
3 . The kobe sub of claim 2 wherein the shielding wall is a sidewall of a slot formed in the wall inner surface.
4 . The kobe sub of claim 3 wherein the sidewall defines a slot depth and the slot depth is greater than the height of the cap portion such that the cap portion is fully recessed in the slot.
5 . The kobe sub of claim 3 wherein the slot includes a return overlying a portion of the cap portion.
6 . The kobe sub of claim 2 wherein the shielding wall includes an extension of the wall inner surface overlying a portion of the cap portion.
7 . The kobe sub of claim 1 wherein the shielding structure is a sleeve installed in the inner bore and positioned to overlie at least a portion of the cap portion.
8 . The kobe sub of claim 7 wherein the sleeve is moveable to abut against the cap portion to remove the cap portion from a sealing position on the base.
9 . The kobe sub of claim 7 wherein the sleeve includes a shoulder against which a port opening tool pushes to move the sleeve.
10 . The kobe sub of claim 9 wherein the shoulder is a ball seat and the port opening tool is a plug sized to land and seal in the ball seat.
11 . The kobe sub of claim 1 further comprising a cap portion capturing mechanism to capture the cap portion from becoming loose in the inner bore after the cap portion is removed from the base.
12 . The kobe sub of claim 11 wherein the cap portion capturing mechanism pushes the cap portion outwardly through the channel toward the outer surface.
13 . The kobe sub of claim 11 wherein the cap portion capturing mechanism stores the cap portion in the sub.
14 . The kobe sub of claim 1 wherein the shielding structure is a sleeve installed in the inner bore and positioned to overlie at least a portion of the cap portion and the cap portion capturing mechanism is a cavity in the sleeve that retains the cap portion after the cap portion is removed from the base.
15 . The kobe sub of claim 1 wherein the shielding structure is a slot formed in the wall inner surface and the cap portion capturing mechanism includes a return overlying a portion of the cap portion to prevent the cap portion from passing out of the slot after it is removed from the base.
16 . The kobe sub of claim 1 further comprising a flow limiting device in the channel for at least restricting flow through the channel and for providing a delay before the port becomes fully open to fluid flow.
17 . The kobe sub of claim 15 wherein the flow limiting device is removed by erosion.
18 . A method for forming a fluid channel through a tubing string wall, the method comprising: installing a tubing string in a wellbore, the tubing string including a tubular wall including an outer surface and an inner surface defining an open inner bore and a port through the wall; a kobe plug installed in the port with a cap portion accessible in the inner bore, a base mounted in the port and connected to the cap portion, a channel extending through the base and closed by the cap portion; and a shielding structure in the inner bore to shield the cap portion from protruding into the inner bore; introducing a port opening tool into the inner bore; manipulating the tool to overcome the shielding structure; and removing the cap portion to open the channel and form the fluid channel though the tubing string wall.
19 . The method of claim 18 wherein the shielding structure includes a shielding wall extending alongside the cap portion and manipulating the tool includes reaching past the shielding wall to remove the cap portion.
20 . The method of claim 19 wherein the shielding wall is a sidewall of a slot formed in the inner surface and manipulating the tool includes reaching into the slot to remove the cap portion.
21 . The method of claim 18 wherein the shielding structure is a sleeve installed in the inner bore and positioned to overlie at least a portion of the cap portion and manipulating the tool includes moving the sleeve.
22 . The method of claim 21 wherein moving the sleeve causes the sleeve to abut against the cap portion and shear the cap portion from the base.
23 . The method of claim 18 wherein manipulating the tool includes manipulating a string on which the tool is carried.
24 . The method of claim 18 wherein manipulating the tool includes landing the tool against the shielding structure and applying a pressure driven force to overcome the shielding structure.
25 . The method of claim 18 further comprising capturing the cap portion such that the cap portion is prevented from becoming loose in the inner bore.
26 . The method of claim 25 wherein capturing the cap portion includes collecting the cap portion in the tool.
27 . The method of claim 25 wherein capturing includes storing the cap portion in the tubing string.
28 . The method of claim 25 wherein capturing includes pushing the cap portion out through the channel away from the inner bore.
29 . The method of claim 18 further comprising manipulating the tool to open a second kobe plug axially spaced from the kobe plug to form a second fluid channel through the tubing string wall.
30 . The method of claim 29 wherein the tool moves from the kobe plug to the second kobe plug while moving along the tubing string.
31 . The method of claim 29 further comprising delaying a full opening of the channel until after the tool has opened both the kobe plug and the second kobe plug.
32 . A tubing string system for installation in a wellbore comprising: a tubular body including a tubular wall with an outer surface and an inner surface defining an inner bore and a port through the tubular wall; a kobe plug installed in the port with a cap portion accessible in the inner bore, a base mounted in the port and connected to the cap portion, a channel extending through the base and closed by the cap portion; a shielding structure in the inner bore to shield the cap portion from protruding into the inner bore; and a port opening tool for overcoming the shielding structure and removing the cap portion from the base.
33 . The tubing string system of claim 32 wherein the shielding structure includes a shielding wall extending alongside the cap portion and the port opening tool includes a structure for reaching past the shielding wall to remove the cap portion.
34 . The tubing string system of claim 33 wherein the shielding wall is a sidewall of a slot formed in the wall inner surface and the port opening tool includes a structure for reaching into the slot to remove the cap portion.
35 . The tubing string system of claim 34 wherein the sidewall defines a slot depth and the slot depth is greater than the height of the cap portion such that the cap portion is fully recessed in the slot.
36 . The tubing string system of claim 34 wherein the slot includes a return overlying a portion of the cap portion and the port opening tool includes a structure for reaching past the return and into the slot to remove the cap portion.
37 . The tubing string system of claim 33 wherein the shielding wall includes an extension of the wall inner surface overlying a portion of the cap portion and the port opening tool includes a structure for reaching past the extension to remove the cap portion.
38 . The tubing string system of claim 32 wherein the shielding structure is a sleeve installed in the inner bore and positioned to overlie at least a portion of the cap portion and the port opening tool includes a structure for moving the sleeve to remove the cap portion.
39 . The tubing string system of claim 32 wherein the port opening tool is carried on a string.
40 . The tubing string system of claim 32 wherein the port opening tool is conveyed by fluid pressure.
41 . The tubing string system of claim 32 wherein the port opening tool is a plug and the sleeve includes a seat for retaining the plug such that a pressure driven force is generated to move the sleeve.
42 . The tubing string system of claim 32 further comprising a flow limiting device in the channel for at least restricting flow through the channel and for providing a delay before the port becomes fully open to fluid flow.
43 . The tubing string system of claim 42 wherein the flow limiting device is removed by erosion.
44 . The tubing string system of claim 32 further comprising a cap portion capturing mechanism to capture the cap portion from becoming loose in the inner bore after the cap portion is removed from the base.
45 . The tubing string system of claim 44 wherein the cap portion capturing mechanism pushes the cap portion outwardly through the channel toward the outer surface.
46 . The tubing string system of claim 44 wherein the cap portion capturing mechanism stores the cap portion in the sub.
47 . The tubing string system of claim 44 wherein the cap portion capturing mechanism collects the cap portion in the port opening tool.
48 . The tubing string system of claim 32 further comprising a second kobe plug axially spaced along the tubing string from the kobe sub and a second shielding structure for the second kobe plug; and the port opening tool also is operable to overcome the second shielding structure to open the kobe plug.
49 . The tubing string system of claim 32 wherein the kobe plug is one in a series of kobe plugs spaced axially along the tubing string, the series of kobe plugs being configured to be acted upon by the port opening tool in sequence in one operation.
50 - 119 . (canceled)