Patent Application
20240044227
The present disclosure relates generally to downhole equipment for hydrocarbon wells. More particularly, the present disclosure pertains to a method and apparatus for removing debris from a wellbore.
Hydrocarbon fluids such as oil and natural gas are produced from a subterranean geologic formation referred to as a reservoir, by drilling a wellbore that penetrates the hydrocarbon-bearing formation. After drilling, a casing can be lowered into the wellbore and various downhole operations can be performed and equipment placed to ready the well for production of oil or gas. In many wells, cleanout operations must be performed to remove sand and debris, which may accumulate as a result of well completion or production, to enable optimal production.
Known techniques for removing debris employ fluid circulation through either a venturi-style fluid suction device or actual circulation of either fluid or gas from the surface, or a combination of both techniques. However, these techniques and fluids are expensive and can add operational and safety risk. Debris removal systems that do not rely on fluid circulation also are known. Referred to as “sand pumps,’ these systems are mechanically operated in vertical or near-vertical wells to clean out debris through reciprocation of the work string or tubing. In such systems, rotation can be combined with reciprocation to help break up hard debris, but only reciprocation of the work string moves the fluid in the wellbore. More specifically, reciprocation of the work string (which carries the debris cleanout tools) moves the static fluid in the wellbore, creating a swabbing action that draws debris into a cavity or container where it is captured. The workstring can then be lifted from the wellbore so that the debris cavity can be retrieved and emptied. Although such systems are effective in a vertical section of the well, once the cleanout tool reaches a horizontal section, it begins to experience friction and non-optimal depth placement. Accordingly, such sand pumps are ineffective to remove debris from non-vertical wells.
In one aspect, a tool for cleaning debris from a wellbore comprises a rotational portion and a stationary portion. The rotational portion is configured to be coupled to a workstring disposed in the wellbore such that rotation of the workstring rotates the rotational portion. The stationary portion at least partially surrounds the rotational portion. The stationary portion is configured to remain stationary when the rotational portion and the workstring are rotated. The rotational portion and the stationary portion are shaped and configured such that, when the workstring is at least partially disposed in well fluid present in the wellbore, rotation of the rotational portion causes movement of well fluid such that well fluid flows into the workstring, thereby carrying debris from the wellbore into the workstring.
In another aspect, a system for cleaning debris from a wellbore includes an upper workstring portion, a lower workstring portion, and a fluid moving tool coupled between the upper and lower workstring portions. The fluid moving tool includes a rotational portion and a stationary portion. Rotation of the upper workstring portion causes rotation of the rotational portion. The rotational portion and the stationary portion are shaped and configured such that, when the lower workstring portion is at least partially disposed in well fluid, rotation of the rotational portion causes movement of the well fluid such that well fluid flows in the lower workstring portion, thereby carrying debris from the wellbore into the lower workstring portion.
In another aspect, a method of removing debris from a wellbore includes connecting a fluid moving tool to a workstring, the fluid moving tool including a rotational portion that rotates when the workstring is rotated. The method further includes running the workstring into a wellbore in which fluid is present. The method further includes moving the fluid into a lower end of the workstring by rotating the workstring to rotate the rotational portion of the fluid moving tool.
Certain embodiments of the invention are described with reference to the accompanying drawings, where like reference numerals denote like elements. It should be understood, however, that the accompanying drawings illustrate only the various implementations described herein and are not meant to limit the scope of the various technologies described herein. Various embodiments of the current invention are shown and described in the accompanying drawings of which:
The headings provided herein are for convenience only and do not necessarily affect the scope of the meaning of what is claimed in the present disclosure.
Various examples and embodiments of the present disclosure will now be described. The following description provides specific details for a thorough understanding and enabling description of these examples. One of ordinary skill in the relevant art will understand, however, that one or more embodiment described herein may be practiced without many of these details. Likewise, one skilled in the relevant art will also understand that one or more embodiments of the present disclosure can include other features and/or functions not described in detail herein. Additionally, some well-known structure or functions may not be shown or described in detail below, so as to avoid unnecessarily obscuring the relevant description.
Certain terms are used throughout the following description to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.
In the following discussion, any reference to up or down in the description is made for purposes of clarity, with “up”, “upper”, “upwardly”, or “upstream” meaning toward the surface of the borehole and with “down”, “lower”, “downwardly”, “downhole”, or “downstream” meaning toward the terminal end of the borehole, regardless of the borehole orientation. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship.
The term “debris” as used herein refers to any solid or accumulation of material that hinders optimum production of a well, such as sand, scale, metal shavings, junk, etc.
The systems and techniques that are described herein for removing debris from a wellbore convert rotational torque applied to a workstring into a downhole fluid pumping action that can be used to remove debris from the wellbore. The pumping action draws fluid that is present in the wellbore into the end of the workstring, carrying debris along with the fluid flow. The workstring is coupled to a fluid moving tool that operates through rotation of the workstring to pull fluid and debris from the wellbore into an inner volume (or cavity) within the workstring where the debris can be retained. The workstring (or tubing) may be rotated by a power source that, in some embodiments, can be located at the surface of the wellbore. The rotational power source can be, for example, a power swivel, top drive drilling rig or a rotary (i.e., a rig used to power rotary drilling of a wellbore). The fluid moving tool can be, for example, a progressive cavity pump that uses mechanical rotation as a power to create movement of static wellbore fluid. By using surface rotation of the workstring to move static fluid in the wellbore and capture debris, the need to pump circulating fluids into the wellbore to perform cleanout operations may be eliminated. This can significantly increase the efficiency of wellbore cleanout and reduce the costs associated therewith.
In operation, the workstring that the fluid moving tool is coupled to is lowered into a wellbore where well fluid is present in the wellbore. The fluid moving tool includes a rotational portion that rotates within a stationary portion. Rotation of the rotor within the stationary portion forces well fluid to move through the fluid moving tool, which carries debris from the wellbore into the workstring.
In various embodiments, the stationary portion can include a stationary elastomeric sleeve that is sized to create a series of cavities with the rotational portion to form a progressive cavity pump. In embodiments, the stationary portion can be held in place and prevented from rotating by anchors, such as drag blocks, gripping arms, abrasive material or the like, that contact the casing of the wellbore and prevent the stationary portion from rotating inside of the wellbore casing when the workstring is rotated.
In various embodiments, the length and volume of the lower portion of the workstring forms a cavity to hold the debris with one or more filters or screen filtering the debris from the well fluid. The systems may include check valves or other flow restriction devices at the bottom of the workstring to prevent the debris from falling out of the cavity when the workstring is pulled from the wellbore for debris retrieval. In other embodiments, the debris can be removed to pumping the debris through the workstring up to the surface. Filters or screens can be employed to restrict the size of debris particles or pieces that can enter the fluid moving tool to thereby reduce friction and extend the service life of the fluid moving tool.
The system can include other tools or devices that are positioned below the fluid moving tool and, in some embodiments, near the bottom of the workstring to assist in filtering, capturing and storing debris for retrieval at the surface. The distance between such tools or devices and the fluid moving tool can be relatively short (e.g., 30 feet as an example) or very long (e.g., thousands of feet). These tools or devices can include back check ball valves, finger baskets, flapper valves, darts, etc. that prevent the debris from falling out of the workstring when the workstring is pulled form the wellbore after cleanout operations have been completed.
In operation, as the workstring is rotated, it may also be translated within the wellbore (e.g., lowered) to engage debris. The fluid motion created by the fluid moving tool draws debris into the end of the workstring for collection and capture in the debris cavity. In embodiments the debris cavity can be a section of the workstring that provides a volume for collecting the debris.
In various embodiments, the section of the workstring that is further in the wellbore than the fluid moving tool is coupled to the fluid moving tool such that it rotates in conjunction with the upper section of the workstring using the same rotation power source. In such embodiments, the torque and resulting rotation above and below the fluid moving tool is transmitted directly through or otherwise coupled with the fluid moving tool's rotational portion. Rotation of the full length of the workstring may enable tools or devices at the lower end of the workstring to drill into or otherwise break up debris. Such tools or devices can include a drill bit, mill, notch collar, rotary shoe, or other similar devices or combinations of devices that include sharpened teeth or edges that are configured to break and move debris. Rotation of the workstring may also provide the benefit of breaking sliding friction forces between the workstring and the casing, thus assisting with deeper penetration into horizontal sections of the wellbore. In various embodiments, clutches and other mechanical or hydraulic systems can be incorporated in the system to transmit rotation to the end of the workstring to help break up debris or to reduce friction between the workstring and the casing. Rotation of the workstring may also allow for more reliable retrieval of the workstring from the wellbore.
Fluids present in the wellbore during the cleanout operation can be expelled or returned from the workstring into the wellbore at or above the fluid moving tool. In other embodiments, the fluid instead can be pumped to the surface while carrying the suspended debris in a slurry-like mixture.
The rate of rotation of the workstring and the rotational portion of the fluid moving tool may be variable. The velocity of the fluid in the system can vary and generally will depend on the configuration of the fluid moving tool and the speed of the rotation of the workstring and the rotational portion of the fluid moving tool. In various embodiments, during use, the workstring and the rotational portion of the fluid moving tool are rotated at a rate of about 60-150 revolutions per minute.
Turning now to
The cleanout assembly 102 includes a fluid moving tool 108 and a portion of workstring 101 defining a debris chamber or cavity 110. The fluid moving tool 108 includes a rotational portion 112 coupled to the workstring 101 such that the rotational portion 112 rotates with the workstring as described in more detail herein and as illustrated by arrows 124 in
In various embodiments, the fluid moving tool 108 also includes a stationary portion 114. The stationary portion 114 is configured as a tube inside of which the rotational portion 112 is at least partially disposed. In various embodiments, the rotational portion 112 and the stationary portion 114 together form a progressive cavity pump to create movement of well fluid in the wellbore. In such embodiments, as shown in
The workstring 101 is coupled at its upper end (i.e., the end nearer the wellbore opening) to a rotational power source 120 that may be located at the surface 122 of the wellbore 104, such as a power swivel, top drive drilling rig, a rotary, or a fluid-driven motor, for example. In other embodiments, the workstring 101 can be rotated with a rotating power source that is located downhole. The direction of rotation of the workstring 101 and rotational portion 112 is denoted in
In some embodiments, anchors 116 are coupled to the cylindrical body 114b of the stationary portion 114. The anchors 116 are configured to contact the casing 118 of the wellbore 104 to prevent rotation of the stationary portion 114. The anchors 116 ensure that the stationary portion 114 remains stationary when the rotational portion 112 is rotated with the workstring 101.
The fluid moving tool 108 also includes bearings 125 to provide smooth rotation of the rotational portion 112 relative to the stationary portion 114. The fluid moving tool 108 may further include upper and lower seals 126 coupled to the stationary portion 114 and contacting the rotational portion 112 to seal about the rotational portion 112.
As the rotational portion 112 rotates with the stationary portion 114, fluid is pumped form the lower portion of the workstring 101 (i.e., the portion that is further from the wellbore opening) through the fluid moving tool 108, toward the surface of the wellbore. The fluid flows from the lower portion of the workstring 101 through one or more apertures 127 in the rotational portion to enter the space between the rotational portion 112 and the stationary portion 114. The rotational portion 112 can include any number of apertures 127 (e.g., one aperture, two apertures, three apertures, etc.). The rotation of the rotational portion 112, and pumping of fluid through the fluid moving tool 108, pulls fluid through the lower portion of the workstring 101 toward the fluid moving tool 108. As a result, fluid is pulled into the downstream opening of the workstring 101, carrying debris 136 from the wellbore along with it. The debris 136 is filtered by the debris filter 138 such that the debris 136 is retained in the debris chamber 110.
The rotational portion 112 may further include upper apertures 128 through which, after passing through the cavities 115, the fluid passes from the space between the rotational component 112 and the stationary component 114 into an inner bore of the rotational component 112. The rotational portion 112 may further include fluid exit ports 129 to allow fluid flow 132 to exit the rotational portion 112 and return to the wellbore 104 during the cleanout operation.
In the embodiment shown, the system 100 includes a tool 134 at the lower end of the workstring 101 to assist with breaking up debris 136 in the wellbore 104. The tool 134 can include one or more sharpened edges or sharpened teeth 134a configured to break up the debris 136. For example, the tool 134 may be a mill, a drill bit, workover bit, rotary shoe or other suitable tool that can break up debris 136. The system 100 may also include a mule shoe or other device at the end of the workstring 101 that allows the passage of fluid therethrough. When the workstring 101 is rotated, the tool 134 breaks up debris 136 and the fluid moving tool 102 creates the fluid flow 132 which carries the debris 136 into the end of the workstring 101 where it may be collected in the lower workstring portion 110.
A debris filter 138 is positioned in the lower workstring portion below the fluid moving tool 108 to form a debris chamber 110 in the lower workstring portion. The debris filter 138 prevents debris particles that are larger than a specified size from entering the fluid moving tool 108. In such an embodiment, the debris 136 may be removed form the debris chamber 110 by pulling the workstring 101 from the wellbore 104 an emptying the debris chamber 110. In addition to capturing debris 136 in the debris chamber 110, the debris filter 138 also restricts the entry of debris particles into the fluid moving tool 108. This may reduce wear of the fluid moving tool 108 and increase its service life.
In other embodiments, the system 100 does not include a debris filter and the debris is pumped to the surface for removal. This may be appropriate for implementations in which the debris in the wellbore is generally of a smaller size. Such embodiments are described further below.
In the embodiment shown in
In the embodiment of
In any of the embodiments described herein, during operation of the fluid moving tool, a reverse circulation of fluid (i.e., fluid introduced into the wellbore from the surface) may be introduced into the annulus between the casing 118 and the workstring 101 to work in conjunction with the fluid moving tool to further enhance the flow of well fluid in the wellbore and removal of debris from the wellbore.
In addition to the rotor 206, the rotational portion 202 further includes a first shaft 210-1 coupled to a first end of the rotor 206 and a second shaft 210-2 coupled to a second opposite end of the rotor 206. The shafts 210-1, 210-2 are configured to rotate with the rotor 206 during operation and can be coupled to the rotor 206 in any appropriate way (e.g., threaded connection, press-fit, welded connection, etc.) In some embodiments, one or both of the shafts 210-1, 210-2 may be joined to the rotor 206 using a keyed or faceted joint to prevent relative rotation between the rotor 206 and the shafts 210-1 and 210-2.
The rotational portion 202 further includes a first coupler 212-1 and a second coupler 212-2 engaged with the first shaft 210-1 and the second shaft 210-2, respectively. The couplers 212-1, 212-2 are configured to join the rotational portion 202 to the workstring (e.g., workstring 101). The couplers 212-1, 212-2 are configured to rotate with the rotor 206 and the shafts 210-1, 210-2 during operation and can be coupled to the shafts 210-1, 210-2 in any appropriate way (e.g., threaded connection, press-fit, welded connection, etc.). In some embodiments, one or both of the coupler 212-1, 212-2 may be joined to the respective shaft 210-1, 210-2 using a keyed or faceted joint to prevent relative rotation between the rotor 206 and the shafts 210-1, 210-2.
In some embodiments, the shafts 210-1, 210-2 may be configured to flex during operation to allow for misalignment of the rotor 206 and the couplers 212-1, 212-2 (or the workstring). In some embodiments, the shafts 210-1, 210-2 includes reduced diameter portions to provide this flexibility. Additionally, or alternatively, the shafts 210-1, 210-2 can be constructed of a material that has a stiffness that is sufficiently low to allow flexing of the shafts 210-1, 210-2.
In addition to the stator 208, the stationary portion 204 includes a first housing 216-1 coupled to a first end of the stator 208 and a second housing 216-2 coupled to a second end of the stator 208. Each housing 216-1, 216-2 may include one or more bodies coupled together to form the housing 216. The first housing 216-1 at least partially surrounds the first shaft 210-1 and the first coupler 212-1. The second housing 216-2 at least partially surrounds the second shaft 210-1 and the second coupler 212-1. A first annular space 218-1 is defined between the first housing 216-1 and the first shaft 210-1. A second annular space 218-2 is formed between the second housing 216-2 and the second shaft 210-2.
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In another aspect, a method of removing debris from a wellbore includes connecting a fluid moving tool to a workstring. The fluid moving tool may be, for example, according to any of the embodiments described herein and include a rotational portion that rotates when the workstring is rotated. The method further includes running the workstring into a wellbore in which fluid is present. The method further includes moving the fluid into a lower end of the workstring by rotating the workstring to rotate the rotational portion of the fluid moving tool. In various embodiments, the method further comprises capturing wellbore debris carried in the moving fluid in a debris chamber in the workstring. The method may further include recirculating the moving fluid by expelling the moving fluid from the workstring through a fluid exit port located at or above the fluid moving tool. In some embodiments, the method further comprises pumping the fluid to the surface of the wellbore with the debris suspended in the fluid in a slurry-like mixture. In some embodiments, the method further includes providing a debris breakup device proximate a lower end of the workstring such that rotation of the workstring rotates the debris breakup device to break up accumulated debris in the wellbore.
For the purpose of promoting an understanding of the principles of the invention, referenced has been made to the embodiments illustrated in the drawings, and specified language has bene used to describe these embodiments. However, no limitation of the scope of the invention is intended by this specific language, and the invention should be construed to encompass all embodiments that would normally occur to one of ordinary skill in the art. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments unless states otherwise. The terminology used herein is for the purposed of describing the particular embodiments and is not intended to be limiting of exemplary embodiments of the invention.
The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. Numerous modifications and adaptations will be readily apparent to those of ordinary skill in this art without departing from the scope of the invention as defined by the following claims. Therefore, the scope of the invention is not confined by the detailed description of the invention but is defined by the following claims.
This application is a divisional of U.S. patent application Ser. No. 16/591,076, which was filed on Oct. 2, 2019, which claims priority to U.S. Provisional Patent Application No. 62/740,031, filed Oct. 2, 2018, the entirety of which is hereby incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62740031 | Oct 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16591076 | Oct 2019 | US |
| Child | 18379030 | US |
