Patent Application
20200291740
The present disclosure relates to systems and method of cementing a wellbore.
When drilling a wellbore that penetrates one or more subterranean earth formations, it may be advantageous or necessary to create a hardened plug in the borehole. Such plugs are used for abandonment of the well, wellbore isolation, wellbore stability, or kickoff procedures. There are a number of systems used to create the hardened plug.
For example, a cement plug may be set in a borehole by pumping a volume of spacer fluid compatible with the drilling mud and cement slurry into the workstring. Then, a predetermined volume of cement slurry is pumped behind the spacer fluid. The cement slurry travels down the workstring and exits into the wellbore to form a plug.
After the cement slurry has been pumped into the wellbore in sufficient quantities to form the plug, a portion of the workstring surrounded by cement, referred to as a sacrificial tail pipe is typically detached from the rest of the workstring and left in the wellbore. The disclosure below provides an additional apparatus and method capable of forming a cement plug in a wellbore.
In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals, respectively. Figures are not necessarily drawn to scale. Certain features of the apparatus or methods disclosed herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness.
Unless otherwise specified, any use of any form of the terms “connect,” “engage,” “couple,” “attach,” or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described unless specifically stated. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”. Reference to up or down will be made for purposes of description with “up,” “upper,” “upward,” or “upstream” meaning toward the surface of the wellbore and with “down,” “lower,” “downward,” or “downstream” meaning toward the terminal end of the well, regardless of the wellbore orientation.
The present disclosure provides a downhole tool comprising a diversion and movable isolation tool (“DMIT”) and disconnect tool, useful for, among other things, creating a cement plug in an open or cased well. In the present disclosure, the structure of the DMIT and disconnect tool are first described in detail. Next, the manner in which the disconnect tool disconnects from a workstring is described in detail. Finally, a method of using the DMIT and the disconnect tool to create a cement plug are described in detail.
Referring now to
The DMIT 100 comprises a body 104 having a body bore 106 and a plurality of radial ports 108 therethrough. Body 104 may have threaded upper end 107 to connect the DMIT to other tools or tubulars. In the embodiment shown body 104 is threadedly connected at a lower end thereof to a nose 110 comprising a nose seat 112. The nose 110 further comprises a nose bore 114 in selective fluid communication with the body bore 106, depending upon whether an obturator is seated against nose seat 112. As used herein, an obturator is a device configured to plug the flow of fluid through the nose 110. For example, the obturator may be a drop ball sized to engage nose seat 112 and plug the flow of fluid through the nose 110.
The body 104 and the nose 110 cooperate to provide a first flow path that allows fluid to pass through the DMIT 100 through the body bore 106 and the nose bore 114. However, when an obturator is successfully introduced into sealing engagement with the nose seat 112, fluid is restricted from flowing downwardly in the above-described first flow path, but instead, fluid introduced into the body bore 106 may pass out of the body bore 106 through the radial ports 108, which can be referred to as a second flow path.
The DMIT 100 also comprises at least one fluid isolator assembly (“FIA”) 116, and preferably at least two FIAs 116. The current embodiment shows four FIAs but it is understood that more or fewer than four can be included. The FIA 116 comprises a plurality of generally stacked flexible segments 118 and retainer rings 120. The stacked flexible segments 118 are sandwiched between two retainer rings 120. As shown in
In the embodiment shown, the FIA 116 comprises six stacked flexible segments 118 and a backstop ring 138.
The backstop ring 138 may be made of a material substantially similar to that of segments 118. It will be appreciated that any of the components of the DMIT 100 may be constructed of materials and/or combinations of materials chosen to achieve desired mechanical properties, such as, but not limited to, stiffness, elasticity, hardness (for example, as related to the possible need to drill out certain components of a DMIT 100), and resistance to wear and/or tearing. In some embodiments, the body 104 and/or nose 110 may comprise fiberglass and/or aluminum, the retainer rings 120 may comprise aluminum, and/or the segments 118 and/or the backstop ring 138 may comprise rubber. Spacers 126 are positioned between the intermediate stacks of flexible segments. The retainer rings 120 on the uppermost stacked flexible segments are captured between an exterior shoulder 122 of the body 104 and a spacer 126. A lock ring 124 engages the exterior of the body 104 below the lowermost retainer ring 120. Most generally, the FIA 116 can be provided with an overall diameter suitable for contacting an interior surface of a wellbore and/or a tubular of a wellbore. The FIA 116 thus may be configured to contact the surface of an uncased wellbore or the interior surface of casing 62 in a wellbore 64.
Disconnect tool 200 may comprise a collet 211 with collet heads 212 at an upper end thereof.
Coupling 205 is connected to the DMIT by, for example, being threadedly connected to body 104 of the DMIT 100 and to collet 211. Coupling 205 is a generally tubular member with bore 208 that is sufficiently large to allow a drop ball 300 configured to engage with the nose 110 to pass therethrough. Collet 211 defines a bore 209 in which releasing sleeve 214 is positioned. Shear pins 217 connect releasing sleeve 214 to collet 211, and although in the embodiment shown coupling 205 connects DMIT 100 to disconnect tool 200, coupling 205 can be removed and the DMIT 100 connected directly to disconnect tool 200 as shown in
When sufficient force is exerted downward on the releasing sleeve 214, shear pins 217 will break allowing the releasing sleeve 214 to move downward. Collet housing 220 is connected to coupling 225 which is connected to workstring 230 thereabove. When upper collet housing 220 is pulled upwardly, collet housing 220 and the workstring 230 thereabove may be disconnected from DMIT 100.
Having described the components comprising the DMIT and disconnect tool provided by the present disclosure, the manner in which the disconnect tool operates is described in connection with
In some embodiments, the drop dart 400 may have wipers 404. Wipers 404 are biased outwardly so as to contact the inner surface of the workstring 230 and disconnect tool 200. Wiper 404 may act to clean the interior of workstring 230 and/or the disconnect tool 200 as the drop dart 400 moves downward. However, because wipers 404 are flexible, wipers 404 will not unduly restrict the downward movement of the drop dart 400.
DMIT 100 and disconnect tool 200 are connected to workstring 230 and lowered into well 60. Well 60 can be in varying stages of completion and can, for example, be cased or uncased. The disclosure herein described uses a cased wellbore. As DMIT 100 is lowered through wellbore 60, any fluid present in the well will be displaced upwardly through the interior of the DMIT 100 and either upward through the workstring 230 or outward through the radial ports 108 and into annulus 70. As DMIT 100 is lowered through wellbore 60 the operator can periodically circulate fluid to ensure that the wellbore is able to circulate, to clear the wellbore, or both.
Once DMIT 100 is placed in the desired location in wellbore 60, drop ball 300 may be dropped through the workstring 230 to engage nose 110 which redirects fluid outward through radial ports 108. Once drop ball 300 has engaged nose 110, fluid can be pumped through the workstring and out the radial ports 108.
Once a desired volume of fluid has been pumped through workstring 230, the drop dart 400 can be dropped through the workstring 230. The drop dart 400 can move through the workstring using the force of gravity or using hydraulic pressure of a fluid pumped behind the drop dart 400. The fluid may be water, or other fluid pumped ahead of cement, or may be the cement to form the cement plug.
Wiper 404 will wipe the inner surface of workstring 230 and disconnect tool 200 as it travels downwardly. Once the drop dart 400 engages the releasing sleeve 214, the disconnect tool 200 can be activated and workstring 230 separated from the disconnect tool 200 and the DMIT 100 in the manner previously described. Once the DMIT 100 and workstring 230 have been separated, cement may be displaced through workstring 230. Workstring 230 may be pulled upwardly simultaneously as cement is displaced therethrough. Once a desired amount of cement has been displaced, fluid may be pumped behind the cement, and the workstring 230 retrieved. The cement plug will be left in the well as shown in
One having skill in the art will appreciate that multiple DMITs, each connected to a disconnect tool 200 could be placed in series along a workstring to thereby form multiple plugs in a wellbore. The upper tool in a series would simply include tool diameters large enough for balls 300 and darts 400 to pass therethrough to the DMIT therebelow.
The particular embodiments disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. Therefore, the particular illustrative embodiments disclosed above may be altered or modified, and all such variations are considered within the scope and spirit of the present invention. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly defined.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US16/32054 | 5/12/2016 | WO | 00 |
