Patent Application
20210277735
The present invention is a tandem releasable bridge plug system and a method for setting such tandem releasable bridge plugs in a casing.
Retrievable bridge plugs or “RBP's” are well known in the well service industry. A retrievable bridge plug carried on a drill pipe string may be set by the following actions:
The drill pipe string rotational movements may be to the right or left and corresponding axial movements being up or down may be special designed. The deck crew will know the required steps for a particular connector or “running tool” and perform them sequentially on the deck on the drill pipe string “in blind”, by manipulating the drill pipe string topside. Such combinations of rotations and axial forces may be:
Other rotations and forces may be applicable and is subject to the tool designer's discretion.
An opposite sequence of the opposite steps may be used to retrieve the tool:
In the prior art U.S. Pat. No. 9,279,307, two consecutive plugs in a well are removed in one run. The plug of the prior art has no through bore, and a special axially arranged release tool is required below the upper plug, and this is required before setting. However the US patent is not enabled to set two plugs in one run.
In the prior art U.S. Pat. No. 4,928,762 to Mamke, “Retrievable bridge plug and packer”, he discloses a retrievable bridge plug and packer apparatus including a packer settable by right-hand rotation and vertical manipulation of the tool string, and a bridge plug also settable by right-hand rotation and vertical manipulation of the tool string. A disabling tool is provided to disable the packer during setting of the bridge plug so that the packer is not prematurely set. After setting of the bridge plug below a formation, the packer and disabling tool may be disengaged from the bridge plug. The disabling tool is disengaged so that the packer may be set above the formation. The packer may not be closed or disconnected from the drill pipe string. The packer is unset by pulling the tool string, and the packer and disabling tool may be reconnected to the bridge plug.
U.S. Pat. No. 5,020,597 to Braddick et al., “Arrangement and method for conducting substance and lock therefor” describes a cementing string for a liner, with upper and lower wiper plugs with external seals thereon releasably connected to the operating string. A lock arrangement prevents premature release of the upper and lower wiper by mechanical force, but is responsive to fluid pressure to first release the lower wiper prior to release of the upper wiper.
US patent application 2004/0050546 relates to an arrangement of sequentially configured packer J tools for one trip sequential setting of packer tools and for subsequent one trip sequential release of the tools.
U.S. Pat. No. 2,806,532 provides an improved method and apparatus for straddling casing perforations and for applying high pressures safely to the locations surrounding the casing perforations.
U.S. Pat. No. 4,794,989 discloses an apparatus for use in completing oil or gas wells having two or more perforated production zones which includes packers and assemblies for closing off the annular space between the tubing string and the well bore intermediate adjacent zones to isolate one from the other in order to produce from each individually.
US patent application 2004/0251024 describes a method for performing single trip perforation and packing operations via a downhole assembly in a cased well bore. The assembly is provided with an upper packer and a lower packer and has fluid communication established therethrough. The upper packer of the assembly is set to isolate a perforated production zone by introducing pressurized fluid through the assembly and against the casing below the lower packer of the assembly.
A first problem in the industry, since the lower plug is set by manipulating the drill pipe string through rotational left or right, and/or axial movements up or down, and if combining two similarly operated plugs, one may hardly control, upon manipulating the drill pipe string rotationally and axially, which plug does what. One solution may be to design the plugs with mutually excluding different setting and releasing mechanisms but this requires much special preparation of each tool and a large stock of tools with separate setting and release mechanisms. The result, in practice, is that one may only set one plug on one drill pipe string at a time, requiring a second run for setting the second plug. So setting the plug may take twice the time compared to removing them. Further, setting two plugs fast during an emergency is not possible with the prior art.
A second problem in the industry is, since it is only possible to set one plug in one run, one may only have the time required to set one plug in a safety disconnect plugging operation such as for disconnecting the upper part of the drill pipe string and hanging off the major part of the drill string in one plug in the borehole.
A third problem is that in order to use two plugs for search and location of a casing string leakage, one may run a lower plug on a first drill pipe string and then locate the lower bound of the leak, then run an upper plug on a second drill pipe string to locate the upper bound of the leak, and thus locate the location of the leak. Such a leak may be in a casing string of continuous even diameter, or it may be in a transition from one casing diameter to a liner diameter, i.e. for testing a liner hanger seal.
A main object of the present invention is to disclose a tandem releasable bridge plug system and a method for setting such tandem releasable bridge plugs. The method of the invention is as follows: a method of setting a tandem releasable bridge plug system in a casing (0), comprising the steps of:
The plug system used in the above method is a tandem releasable bridge plug system arranged for setting a in a casing (0),
The first problem of setting two plugs in one run is thus solved by the invention. This reduces the setting time for two plugs by about 50%. Time is costly both from an economical and a safety view; a drilling rig and particularly a marine drilling platform has high day rates. Time may costly from a safety point of view if the two plugs are to set fast in order to remedy an undesired state of the well. The invention has several further significant advantages.
The second problem of not being able to set two plugs during a safety disconnect operation is solved by the invention. First, if the lower plug is set, optionally with a hang-off drill string below, then the most imperative problem is solved, the well is plugged by one plug, and one may leave the well in an emergency by disconnecting from the well. If time allows after setting the first, lower plug, one may further quickly set the upper plug as a backup to further reduce the risk of blow out, and then disconnect and prepare to leave the well.
The third problem of not being able to conduct a single run pressure testing for leak location in a casing string is solved.
The attached figures illustrate some embodiments of the claimed invention.
The invention will in the following be described and embodiments of the invention will be explained with reference to the accompanying drawings.
The invention is a method of setting a tandem releasable bridge plug system in a casing (0). The method comprises, in its minimum, broadest definition, the steps of:
After the above steps one may pull out the drill pipe string (4) from the well or not, depending on the subsequent operation to be made on the well.
The disconnectable connectors (2U, 2L) are both usually named “running and retrieving tool” of which an upper half, the upper sleeve portions, please see
The lower bridge plug (1L) is set according to the above described steps under the background art. A problem is how to set the lower bridge plug (1L) without setting or releasing the similarly operated upper bridge plug (1U), then release the upper bridge plug (1U) from the lower bridge plug (1L), and first now enabling the mechanism for initiating and conducting setting and release of the upper bridge plug (1U). In this way the tandem plugs (1L, 1U) may be set on one and the same run.
Before the upper plug (1U) is enabled, the lower plug (1L) may be repositioned until its operational required slip holding force and sealing property against the inner casing wall (0i) is met. After the upper plug (1U) is enabled, the lower plug (1L) may thereafter in practice only be reconnected, released and retrieved, preferably together with the upper plug (1U). We therefore do not show the release sequence because it is understandable as an inverse sequence when the setting sequence herein is explained.
Initially disabled upper plug:
The initially disabled upper bridge plug (1U) and its disconnectable connector (2U) are, before and during run-in and setting of the lower bridge plug (1L), temporarily disabled from being settable by any rotational and axial movements by the lock (5). In effect, as seen from the lower plug's (1L) side, except for the drag blocks (12U) of the upper bridge plug (1U), the upper plug (1U) just forms a passive part of the drill pipe string (4). Thus the deck crew may control the lower bridge plug (1L) as if it were the only bridge plug on the drill pipe string (4) until the lower bridge plug (1L) is set, disconnected, and the upper bridge plug (1U) is enabled.
In an embodiment of the invention, the initial disabling of the upper bridge plug (1U) is made by a ball seat axial sleeve (52) arranged in a collet sleeve (53) constituting the lock (5) of the connector (2U), please see
In an embodiment of the invention the ball (51) and the ball seat axial sleeve, hereafter called the first ball sleeve (52), may be transported by the pressure through the central bore and eventually be caught in a ball catcher (31) at the lower end of the upper retrievable bridge plug (1U). It is undesirable that the ball and sleeve shall drop freely into the casing below the upper plug (1U) as it would interfere with the lower plug (1L) on attempting reconnecting for retrieval and also create other problems. The relative shear pressure of the first seat sleeve (52) is in an embodiment set to 69 Bar (1000 psi).
When the release tool section (2U) lock mechanism is enabled to collapse, and the connector's J-slot mechanism to be enabled to prepare for contract, rotate in a given direction to release, an upper plug (1U) initiation and setting sequence may be activated.
In an embodiment of the invention the released down going seat sleeve (52) will bring along with it a second seat sleeve (55), please see between the upper plug's (1U) drag block unit (12U) and the slip unit (14U) in
In an embodiment of the invention, after enabling the upper plug's (1U) release tool (2U), it is further enabled for the drill string (4) with the release tool (2U), please see
In the above, the lower and upper plugs (2L, 2U) are connected and are separated by any distance, at minimum only separated by the lower connector (2L), preferably also with the ball catcher. In an embodiment of the invention, it is advantageous to use an intermediate drill pipe string (3) below the upper plug (1U) and above the lower connector (2L) connected to the lower plug (1L). The length of the intermediate drill pipe string (3) should only be limited to an embodiment of the invention wherein it corresponds to have a length slightly less than the distance between the lower plug setting target depth (dL) for the lower plug (1L) and the upper plug setting target depth (dU) for the upper plug (2U). This in order for allowing for disconnecting from the lower plug (1L) before placing and setting the upper plug (1U). If they were still mechanically connected one could not rotate and move the upper drill pipe string (4) from topsides without affecting the lower plug (10. A significant advantage of having an intermediate string (3) length of almost the depth difference between lower and upper plugs' (1L, 1U9 setting target depths (dL, dU) becomes evident if the target depth difference is large: Given a lower target depth (dL) of, say 5000 m, and upper target depth (dU) of 1000 m, one would then have to run in lower plug (1L), then 4000 m of intermediate string (3), then upper plug (1U), and 1000 m of drill pipe string (4), in order to reach lower target depth. It would then be an operational advantage that when lower plug (1L) is set, the lower disconnectable connector (2L) is released, then the upper plug (1U) is near below its upper target depth (dU) and is rapidly set upon pulling out a short distance, and then, after testing for pressure integrity, one may pull out the relatively short, here 1000 m of drill pipe string (4) only. Thus the two purely setting related operations are conducted consecutively. Those are embodiments of the invention and may be varied with respect to relative lengths.
Free Upper Plug:
In an embodiment of the invention, the upper plug (1U) with its below mounted intermediate drill pipe string (3) is released from the lower plug (1L), and the upper plug (1U) may be enabled, not earlier. After the upper plug is enabled and also free from the lower plug (1L), and any drill pipe string manipulation with rotation or axial movement, will not affect the lower plug. The upper plug may now be set and pressure tested, and if necessary, released and repositioned for further testing until satisfactory, and then disconnected.
In an embodiment of the invention, there is arranged a ball and seat catcher (31) below the upper plug (1U) and above the lower connector (2L). The ball and seat catcher is provided with lateral bypass channels for maintaining fluid communication through to and including the lower connector (2L).
Testing Lower Plug from Below:
In an embodiment of the invention, after setting, and before shutting the lower plug by shutting the ball valve (18L) of the lower plug (1U), one may set the lower packer (16L), and then conduct pressure integrity testing of the sealing effect of the lower plug's (1L) packer (16L) from below by pressurizing the drill pipe string (4) topsides. If the pressure integrity test is not OK, resetting the lower plug (1L) is feasible and a new test may be run until the pressure integrity test from below is OK.
Testing Lower Plug from Above:
In a further embodiment of the above, after shutting the lower plug (1L) and having disconnected the lower connector (2L) from the lower plug (1L), one may conduct pressure integrity testing the lower plug (1L) from above by setting pressure through the drill pipe string (4).
Testing Upper Plug from Below:
In an embodiment of the invention, one may test the upper plug from below by the following steps: after setting, before shutting the upper plug (1U), setting its packer (16U), and then conduct pressure integrity testing for verifying the sealing effect of the upper plug's (1U) packer (16U) from the casing space below the upper plug (1U), but above the lower plug (1L), by pressurizing the drill pipe string (4) topsides. This pressure test should preferably not be run simultaneously with the “from above” pressure test of the lower plug (1L) described above, because, in case of a failed test, one would not know which of the lower and upper packers (16L, 16U) having a leakage.
Testing Upper Plug from Dbove:
Similar to above, in a further embodiment of the invention, one may test the pressure integrity of the upper plug (1U) from above by, after shutting the upper plug (1U) and disconnecting the drill pipe string (4), pressure integrity testing the upper plug (1U) from above by setting pressure through the drill pipe string (4) and the upper connector (2U).
The lower plug (1L) is, except for the absence of the lock mechanism (5) with its ball seat sleeve (52), the spline sleeve (53) and the second shear seat (55), and the ball catcher (31), of similar construction to the upper plug (1U) with regard to drag blocks (12L), slips (14L), and packer (16L).
If the casing to be plugged is of even diameter the upper and lower plugs (1U, 1L) are of the same diameter. In an embodiment the lower plug (1L) may be of a lower diameter than the upper plug (1U), e.g. if the lower plug (1L) shall be set in a liner below a liner hanger in a casing (0).
| Number | Date | Country | Kind |
|---|---|---|---|
| 20161455 | Sep 2016 | NO | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/NO2017/050223 | 9/13/2017 | WO | 00 |
