Patent Application
20090159292
The present invention relates generally to the field of conveying equipment into wells, and more particularly to transporting equipment through an open end of a well that may contain pressure, while maintaining a pressure barrier at all times.
Underground formations may exist at substantial elevated pressures posing challenges during exploration and production. In many instances, the pressures are great enough to produce an elevated pressure differential at a wellhead relative to ambient pressure. Failure to control such pressure differentials could result in an undesirable situation referred to as a blowout—an uncontrolled flow of reservoir fluids into the wellbore, and sometimes catastrophically to the surface.
Typically, a wellhead fixture including a pressure controller is mounted on the upper of the well to isolate wellbore pressures from an ambient pressure. During exploration and production, however, there remains a need to install and/or remove down-hole devices from the well. For example, logging tools designed to evaluate a formation and/or well conditions are inserted into the well, lowered to various depths as may be required during exploration, and later removed from the well, without jeopardizing crew, equipment, or production of the well. Presently, transfer of such logging tools through an open of a well under pressure can be accomplished using a pressure-controlling wellhead fixture configured to allow for transfer of the logging tool while maintaining a pressure barrier at the wellhead. One such class of fixtures is known generally as Christmas trees, including a configuration of valves and access fittings. Another such class of wellhead fixtures is known generally as blowout preventors (BOPs). Either class of wellhead fixtures can be configured with facilities to enable safe access for well intervention apertures. For example, BOPs can include an open channel with one or more reversibly sealable elements configured to open to allow passage of the logging tool, drill string, or thrust tube and closing thereafter to form a pressure barrier.
At least one such process of putting drill pipe or other down-hole devices into a well under pressure with BOPs maintaining a pressure barrier is referred to as snubbing. If the well has been closed with a so-called ram-type BOP, larger diameter features of the down-hole devices, such as tools or joints will not pass by the closed ram element. To keep the well closed another ram-type BOP or an annular BOP is included in series. The first ram element must be opened manually, then the down-hole device lowered until the larger diameter feature is just below the ram element, and then closing the first ram element again. The second ram element is then opened allowing the larger diameter element to pass. This procedure is repeated whenever a larger diameter feature, such as a tool or tool joint must pass by a ram-type BOP. Exercising such care in dealing with larger diameter features by snubbing is generally a time consuming proposition.
If only an annular BOP has been closed rather than the ram-type BOP, the drill pipe or other down-hole device may be slowly and carefully lowered into the wellbore, since the annular BOP opens slightly to permit the larger diameter feature to pass through. In snubbing operations, the pressure in the wellbore acting on the cross-sectional area of the tubular element (i.e., down-hole device) can exert sufficient force to overcome the weight of a drill string, so the string must be pushed (or “snubbed”) back into the wellbore. Such thrust can be provided by a coil tubing unit pushing to a proximal end of a tool or axial array of tools within the wellbore. Such an axial array of tools is referred to as a tool string.
Applying down-hole axial thrust to such an elongated tool or string of tools generally requires the use of a rig or derrick providing lateral support to the tool or string of tools suspended above the wellhead fixture. Such strings are typically assembled vertically above a wellhead fixture before insertion, requiring tall rigs. The rig itself is constructed above the open end of the wellhead fixture and directed along the wellbore axis and may extend from 10 to 100 feet or more, depending upon the length of the tool or tool string. An array of multiple interconnected tools is referred to as a tool string. Such strings are typically assembled vertically above a wellhead fixture before insertion, requiring tall rigs. Unfortunately, construction of such a rig or derrick adds to time and complexity on-site during any such deployment and extraction procedure. The rigs must be provided, constructed, used, deconstructed and removed. Such on-site access time can be quite expensive, particularly for offshore applications, thus any procedures leading to delay, such as snubbing and rig construction, are highly undesirable.
Systems and processes are described for facilitating rapid transfer of down-hole devices through a pressure controlling wellhead fixture capping a well under pressure, without requiring a rig and without jeopardizing operators, equipment, or the well itself. An adaptive seal assembly is provided that is sized and shaped to accommodate down-hole devices of varying cross section. The assembly includes a housing with a mating flange for coupling the open end to a reversibly sealable wellhead fixture. One or more dynamic sealing elements are disposed between the housing and the down-hole device forming a pressure barrier between the well and ambient environment. Once the pressure barrier has been established, any reversible seals in the wellhead fixture can be opened, allowing for substantially unhindered transfer of the down-hole device in a preferred direction, either into or out of the well. Preferably, the dynamic seal element is configured to maintain a seal against varying cross section of the down-hole device as it is translated along axis.
One embodiment of the invention relates to a process for transferring a down-hole device across an open end of a well under pressure. The process includes attaching one end of an adaptive seal assembly to an open end of the well under pressure. The adaptive seal assembly is accessible at both ends and defines a passage therethrough. The down-hole device is positioned at least partially within the passage defined by the adaptive seal assembly. An interior region defined between an interior surface of a housing of the adaptive seal assembly and an adjacent periphery of the down-hole device is sealed. The seal provides a barrier isolating an elevated wellbore pressure within the well from an ambient pressure. An axial force is applied to a proximal end of the down-hole device, translating the down-hole device through the open end of the well under pressure. The seal between the housing and the down-hole device is automatically readjusted responsive to any cross sectional variations of the down-hole device. Readjustment of the seal maintains pressure isolation as the down-hole device is translated through the assembly.
Another embodiment of the invention relates to a system for transferring a down-hole device across an open end of a well under pressure. The system includes an adaptive seal assembly having a housing with an enclosed side wall open at both ends and defining a passage therethrough. The housing includes a mounting flange at one end, configured for securely mounting the adaptive seal assembly in relation to the open end of the well under pressure. At least one dynamic seal element is positioned within an interior region defined between an interior surface of the enclosed side wall and an adjacent periphery of the down-hole device. The dynamic seal element is configured to seal an elevated pressure in the wellbore with respect to ambient pressure. The assembly also includes an actuator configured to adjust the at least one dynamic seal element between open and closed configurations. A sealing engagement can be maintained by readjustment of the dynamic seal element allowing pressure isolation to be maintained as the down-hole device is translated through the assembly.
Yet another embodiment of the invention relates to a process for transferring a down-hole device across an open end of a well under pressure. The process includes at least one of robotically transferring the down-hole device between a storage location and the open end of the well under pressure and robotically positioning the down-hole device relative to the open end of the well under pressure.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.
An adaptive seal assembly including at least one dynamic seal is provided in a housing mountable to a wellhead fixture. The adaptive seal assembly includes facilities to vary an aperture of the dynamic seal to maintain a pressure along a wellbore side of the reversible seal including devices having variations in cross section when translated along a wellbore axis. The reversible seal is sized and shaped to accept any cross section of the down-hole device. Having sealed against wellbore pressure, safety sealing features provided by the wellhead fixture are necessary. Thus, insertion or extraction of the device can be accomplished rapidly, without the need for snubbing. Once transfer of the tool has been completed, the wellhead fixture can be re-sealed either against the device, a coil tube or drill string applying thrust to the device, or completely sealed, allowing the well to resume normal operations.
The dynamic seal includes an aperture than can be opened wide enough to allow the widest portion of a device to pass. Each tool of a tool string can be inserted individually with interconnections performed at the wellhead fixture. Accordingly, there is no need for a separate rig or derrick, since the tools are supported in the assembly. In some embodiments, support equipment can be provided to manipulate the tools and chamber, such as a crane or one or more robotic arms.
An exemplary embodiment of an adaptable seal assembly 25 is illustrated in
The adaptive seal assembly 25 includes an array of dynamic sealing elements 42a, 42b, 42c (generally 42). Each dynamic sealing element 42 of the array is disposed at a respective location along the wellbore axis. In some embodiments, the dynamic sealing elements 42 are annular structures including a central aperture centered along the wellbore axis. The dynamic sealing elements 42 are actuatable such that the dimensions of the internal aperture vary when actuated between open and closed positions. When a down-hole device such as a logging tool 46 is inserted within the central aperture of the dynamic sealing element 42, the dynamic sealing element 42 can be actuated to close against an external surface of the logging tool 46 forming a seal along a perimeter of an adjacent cross section of the tool 46.
Each of the dynamic seal elements 42 can be held in place with respect to the housing 34. For example, each of the dynamic seal elements can be supported by a respective dynamic seal support bracket 44a, 44b, 44c (generally 44) securely attached to the housing 34. The dynamic seal supporting brackets 44 maintain the relative axial positioning of the dynamic seal elements 42 while allowing the dynamic seal elements 42 to vary between open and closed positions.
In some embodiments, one or more of the dynamic seal elements 42 include a respective compliant seal 43 positioned along an internal perimeter of its respective central aperture. The compliant seal 43 is pinched between the perimeter of the internal aperture of the dynamic seal 42 and the adjacent exterior surface of the logging tool 46. For cylindrical applications, the compliant seal can include an annular structure formed of an elastomeric material extending for a restricted length along the wellbore axis. When the dynamic seal 42 is in a closed position, the compliant seal 43 forms a sufficient seal to maintain a pressure barrier between a wellbore pressure P1 along one side of the dynamic seal 42 and a different pressure along an opposite side of the dynamic seal 42, without requiring the dynamic seal to clamp hard against the external surface of the logging tool 46. Consequently, the logging tool 46 is slidable along the wellbore axis when a thrust is applied, while still maintaining a seal. One or more sealing members 49 can be included between one or more of the dynamic seal elements 42 and an adjacent surface of the housing 34 to maintain a pressure differential thereacross.
The dynamic seal elements 42 can be formed as a closed-loop kinematics mechanism having the following capabilities: (i) converts the area of a circle into a ring that has an outer diameter larger than the initial diameter of the circle, and (ii) modifies the inner radius of a cylindrical device enlarging or reducing its diameter. The closed-loop kinematics mechanism can be formed from a series of basic linkages that pivot with respect to each other. As one of the rigid linkages pivots with respect to the other, the other pairs of rigid linkages of the closed-loop mechanism similarly pivot. Operation of the dynamic seal elements 42 can be controlled by one or more of the shapes of the rigid linkages and the locations of the pivots. Such closed-loop mechanisms can be referred to as deployable structures, which are described in more detail in U.S. patent application Ser. No. 11/247,918, entitled “Mechanical crawler”, filed on Oct. 11, 2005, commonly owned and incorporated herein by reference in its entirety. Although the exemplary embodiments are directed to cylindrical applications, dynamic seal elements can be provided having internal apertures shaped to accommodate polygonal tools (e.g., rectangular), ellipsoidal tools, and complex-shaped tools having perimeters with a combination of linear and curvilinear shapes.
The adaptive seal assembly 25 includes at least one actuator 50 configured to actuate the actuatable dynamic seal elements 42 between open and closed positions. In the exemplary embodiment, the adaptive seal assembly 25 includes a single actuator 50, such as a rotary motor positioned at one end of an elongated drive shaft 52. An opposite end of the drive shaft 52 is retained in a bearing 54 allowing the drive shaft 52 to rotate when a torque is provided by the motor 50. A respective transmission 56a, 56bb, 56c (generally 56) is provided between the elongated drive shaft 52 and each of the dynamic seal elements 42. Each of the dynamic seal elements 42 can include a respective dynamic seal drive shaft 58a, 58b, 58c (generally 58) coupled to the respective transmission 56. Rotation of the elongated drive shaft 52 rotates the dynamic seal drive shaft 58 linked through the transmission 56 thereby actuating the respective dynamic seal element 42 between open and closed configurations depending upon direction of the rotation.
In some embodiments, the adaptive seal assembly 25 is automatically controllable. For example, a controller 62 provides commands to the actuator 50. One or more of the dynamic seal elements 42 can include a respective sensor 60a, 60b, 60c (generally 60). The sensors 60 are configured to provide an indication of the seal between the internal aperture of a respective dynamic seal element 42 and an adjacent external perimeter of the logging tool 46. In some embodiments, the sensor 60 can be a strain gauge provided within or along a surface of the compliant seal member 43. The strain gauge measures strain which is indicative of the seal with a greater strain indicating a tighter seal. One or more of the sensors 60 can be coupled to the controller 62. The controller 62 can be configured to operate in a feedback-loop control automatically adjusting the actuation of the one or more dynamic seal elements 42 as a function of input received from the sensors 60. The one or more actuators 50 and sensors 60 can be coupled to a remote controller 62 through a wire, an optical fiber, or a wave guide. In some embodiments, the one or more of the actuators 50 and sensors 60 can be coupled to the remote controller 62 via a wireless communications link. In some embodiments, the controller 62 is not remote, but provided within the housing 34 for a self-contained assembly 25.
An exemplary process 70 for transferring a down-hole device such as a logging tool through an open end of a well under pressure is illustrated in
The adaptable seal assembly includes one or more dynamic seal elements. At least one of the dynamic seal elements is adjusted to form a seal against an adjacent perimeter along an external surface of the end portion of the logging tool (76). The dynamic seal can be an annular device extending in a plane perpendicular to the wellbore access. Once a seal has been established, an elevated wellbore pressure is isolated from ambient pressure surrounding the wellhead fixture. Once such a pressure barrier has been established at the adaptive seal assembly, any reversible seals provided within the wellhead fixture can be opened providing access to the depths of the wellbore (77).
A thrust is applied to the logging tool urging it in a preferred direction along the wellbore axis. The thrust translates a substantial portion of the logging tool through the adaptable seal assembly (78). Preferably one or more of the dynamic seal elements are automatically adjustable or readjusted to maintain a seal against an external surface of varying cross-section of the logging tool as the tool is translated along the axis of the well (80). Preferably such readjustment of the dynamic seals is accomplished automatically such that the seal is adjusted to maintain a controlled pressure against the adjacent external surface of the logging tool. Such pressure can be regulated using a pressure sensor at the seal and a feedback controller configured to adjust the dynamic seal actuator according to the sensed pressure thereby maintaining a pressure within a preferred pressure range.
A more detailed view of an exemplary reversible seal 42′ of an exemplary adaptive sealing assembly 25′ is provided in the sectional view of
In the illustrative embodiment, the enclosed linkage 45 forms an annular structure disposed between an interior surface of a housing 34′ and an outer surface of a tool 46 positioned therein. An internal aperture of the annular enclosed mechanical linkage 45 is configured selectively to expand and contract when one or more of the double lever assemblies are manipulated. In the illustrative embodiment, an outer perimeter of the annular structure 45 remains in sealable contact with the inner wall of the housing 34′ while an inner perimeter of the annular structure 45 is allowed to vary between maximum and minimum diameters according to adjustment of the mechanical linkage. Thus, the annular structure 45, when engaging the tool 46 with its inner perimeter forms a seal between the inner wall of the housing 34′ and the outer surface of the tool 46. In some embodiments, a sealing member 43′ is inserted between the inner perimeter of the annular structure 45 and the outer surface of the tool 46. For example, an elastomeric material 43′ can be applied or fixed to the inner perimeter of the annular structure 45 such that when the inner perimeter is enclosed to engage the outer surface of the tool 46, the elastomeric material 43′ is entrapped between the inner perimeter and the tool 46 forming a fluid-tight seal. In some embodiments, the elastomeric material 43′ is segmented around the inner perimeter to provide a continuous seal when closed, but allowing substantial expansion without damage to the elastomeric material 43′. In some embodiments, the elastomeric material includes multiple layers of varying compliance.
A pressure sensor 60′ such as a strain gauge can be positioned between the inner perimeter and the outer surface of the tool 46 as shown. For example, the pressure sensor 60′ can be impregnated within the elastomeric material and configured to sense a strain indicative of the pressure exerted between the inner perimeter of the annular structure 45 when engaging the outer surface of the tool 46. Alternatively or in addition, the pressure sensor 60′ can be included between the outer perimeter of the annular structure 45 and the interior surface of the housing 34′, once again sensing pressure exerted when the reversible seal 42′ is adjusted to form a seal. One or more pressure sensors 60′ can be coupled to an external pressure monitor (not shown) providing the user with an indication of the pressure exerted. More preferably, the one or more pressure sensors 60′ can be connected to a controller in a feedback control loop configuration such that the controller adjusts the reversible seal 42′ in response to monitored output pressure provided by the pressure sensor 60′. The controller adjusts the inner perimeter of the reversible seal 42′ until a predetermined sealing pressure is obtained. Once the desired sealing pressure is obtained, further adjustment of the annular structure terminates.
In some embodiments, one or more sealing members 81 are provided along the outer edge of the annular structure 45 and the inner surface of the housing 34′. As shown, these may include one or more elastomeric seals, washers, or o-rings 81 disposed between the outer perimeter of the deployable structure 45 and a flange 44′ coupled to the inner wall of the housing 34′.
A planar view along the wellbore axis of an exemplary dynamic seal having an annular shape is illustrated in an open position in
As shown in
When closed, an internal perimeter of the dynamic seal 45 is urged against an adjacent external surface of the logging tool 46. Thus, the internal diameter of the closed dynamic seal ID2 is approximately equal to an external diameter of the logging tool 46. Preferably, the dynamic seal 45 extends within the plane perpendicular to the wellbore axis to occlude any opening between the logging tool 46 and the bracket 44′ or housing 34′. A cross-sectional side view is shown in
In some embodiments, the adaptive seal assembly is configured to apply a thrust to a down-hole device while also maintaining a peripheral seal about an outer surface of the down-hole device. One such class of adaptive seal assemblies providing an internal thrust capability is illustrated in
In the exemplary embodiment, the adaptive seal assembly 100 includes six dynamic sealing elements 104a through 104f (generally 104). Each of the dynamic seal elements 104 includes an annular structure having a central aperture through which the logging tool 46 can traverse. Each of the dynamic seal elements 104 is also configured to vary its internal aperture between open and closed positions. In an open position, the dynamic seal element 104 is open substantially such that the logging tool 46 can pass through its central aperture without any hindrance. In a closed position, the central aperture of the dynamic seal element 104 is urged against an adjacent outer surface of the logging tool 46 forming a seal thereabout. In at least some embodiments, each dynamic seal element 104 resides in a parallel plane, orthogonal to and spaced apart along a longitudinal axis of the logging tool 46. The dynamic seal element 104 can remain orthogonal to the longitudinal axis during transitions between open and closed positions. One or more actuators 106a through 106f (generally 106) are provided to independently adjust the dynamic seal elements 104 between open and closed positions.
To provide longitudinal thrust to the logging tool 46, one or more of the dynamic seal elements 104 is configured such that it is translatable along the longitudinal axis of the logging tool 46, at least when the dynamic seal element 104 is in a closed position. Travel distances of each of the dynamic seal elements 104 are generally limited by spacing of other adjacent dynamic seal elements 104. Preferably, the at least one of the dynamic seal elements being translated clamps to the tool, such that the tool is also translated by a corresponding distance.
The adaptive seal assembly 100 also includes one or more translation actuators 108a through 108f (generally 108). The exemplary embodiment includes eight such translation actuators, one for each of the eight dynamic seal elements 104. In some embodiments, each of the translation actuators 108 is configured to translate a respective one of the dynamic seal elements at limited distance ι along the longitudinal axis of the logging tool 46. Such translation can be provided by a rotating threaded shaft linked to a mounting bracket supporting the dynamic seal element 104. Preferably, the mounting bracket is slidable along the longitudinal axis of the logging tool 46. Rotation of the threaded shaft urges the respective mounting bracket in a longitudinal direction according to the direction of rotation of the shaft. Alternatively or in addition, one or more of the dynamic seal elements is bendable allowing a perimeter of the internal aperture to translate a limited distance along the longitudinal axis according to bending of the dynamic seal 104. As illustrated, a third dynamic seal element 104c is configured in a closed position and bent downward while adjacent dynamic seal 104d is in a closed position. By a sequencing of the reversible seal actuators 106 and the translation actuators 108, a controlled thrust can be applied to the logging tool 46.
An exemplary embodiment of a dynamic seal 104a is schematically illustrated in cross section in
The configuration of dynamic seal elements not involved in the particular step of the respective phase are illustrated in an open position, away from the logging tool 46. In some embodiments, one or more of these unused dynamic seal elements 104 can remain in a closed configuration without clamping the tool contributing to sealing against the logging tool while allowing translation of the tool. Sequencing of the dynamic seal elements 104 can be accomplished by a remote controller coupled to the actuators 106, 108 and preprogrammed with a preferred sequence. Thrust to the logging tool 46 can be provided in an opposite direction by essentially reversing the ordering of the phases. In some embodiments, other sequences of the dynamic seal elements can be used. Although six dynamic seal elements are provided in the illustrative embodiment, different numbers of dynamic seal elements can be provided to the same effect, with at least two elements to provide a step capability while maintaining a seal against the logging tool 46.
Another class of adaptive seal assemblies also including a thrust capability is illustrated in
In the exemplary embodiment, the adaptive seal assembly 120 includes eight dynamic sealing elements 124a through 124h (generally 124). Each of the dynamic seal elements 124 includes an annular structure having a central aperture dimensioned to accommodate passage therethrough of a maximum cross section of a logging tool 46 can traverse. Each of the dynamic seal elements 124 is also configured to vary its internal aperture between open and closed positions. In an open position, the dynamic seal element 124 spaced away from the logging tool 46 leaving an open space between the perimeter of the aperture and a tool 46 disposed therein. In a closed position, the central aperture of the dynamic seal element 124 is urged toward the outer surface of the logging tool 46 substantially closing any open space. In at least some embodiments, each dynamic seal element 124 resides in a parallel plane, orthogonal to and spaced apart along a longitudinal axis of the logging tool 46. The dynamic seal element 124 can remain orthogonal to the longitudinal axis during transitions between open and closed positions.
In some embodiments, a single actuator, such as a rotary motor 126 rotates an elongated drive shaft 128, held at an opposite end by a rotary bearing 130. The drive shaft 128 can be coupled to each of the dynamic seal elements 124 through a respective transmission, transferring motor torque to the dynamic seal element 124. Sequencing of the different dynamic seal elements 124 can be accomplished by an initial positioning, or keying of the dynamic seal elements 124 with respect to each other. As the motor is turned, the relative positioning of the dynamic seal elements is maintained. In other embodiments, more than one actuators are provided. For example, each dynamic seal element 124 can be configured with a respective actuator to independently adjust the dynamic seal elements 124 between open and closed positions. A controller can be used to provide a control signal to each of the dynamic seal elements 124, maintaining a relative positioning of the dynamic seal elements throughout the phase sequence.
In some embodiments, the assembly 120 also includes an elongated, flexible tubular membrane 132 disposed between the logging tool 46 and the internal apertures of the dynamic seal elements 124. Preferably, the tubular membrane 132 is attached to each of the dynamic seal elements 124, such that the membrane flexes with opening and closing of the dynamic seal elements 124. With such a configuration, thrust can be generated in the logging tool 46 by expanding and contracting each of the dynamic seal elements 124 according to a controlled sequence of expansions and contractions. In some embodiments, the sequence of expansions and contractions form an undulating wave directed along the wellbore axis. When a fluid 134 is trapped between the tubular membrane 132 and the outer surface of the logging tool 46, the annular wave entrapping a portion of the fluid pushes against the fluid trapped therein, causing the logging tool 46 to be displaced along the wellbore axis, in the direction of the traveling wave according to thin film fluid mechanics. The first three dynamic seal elements 124a, 124b, 124c are sequenced to form a wave entrapping fluid 134 in a pocket formed in the tubular membrane 132. Exemplary devices are described in U.S. patent application Ser. No. 11/247,918, entitled “Mechanical crawler”, filed on Oct. 11, 2005.
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In some embodiments, the robotic system 250 is positioned in relation to a stowed tool 252 and a user access aperture 256 of the adaptive seal assembly 254 such that the grasper 262 is moveable between the stowed tool 252 and the assembly 254 without having to relocate the base unit 258. The robotic system 250 includes sufficient degrees of freedom to allow the grasper 262 to access the stowed tool 252 and translate the stowed tool 252 to a position above the user access aperture 256 of the assembly 254. In some embodiments, the robotic system 250 is also capable of lowering the tool 252 into an internal cavity of the assembly 254 and into a wellhead fixture 36 as shown. The tools 252 can be stowed on the bed of a tool delivery vehicle such as a truck or rail vehicle as shown. Such precise robotic manipulation of tools 252 and/or assemblies 254 with respect to the wellhead fixtures 36 reduces the time and complexity associated with inserting and extracting tools from a well under pressure.
In some embodiments, the pick-and-place robotic system 250 includes a vertical mast 266 coupled at one end to the base unit 258 and at an opposite end to one end of an arm 260. The vertical mast 266 can be angled in some embodiments. Alternatively or in addition, the vertical mast can include an extendable portion allowing the mast to extend and contract along an axis of the mast. A first joint 268a is attached between the vertical mast 266 and the arm 260 allowing relative movement between the arm 260 and the vertical mast 266. The arm 260 includes a boom 270 coupled at one end to the first joint 268a and at an opposite end to a second joint 268b. A third joint 268c can be coupled between the second joint 268b and the grasper unit 262. Preferably, at least one of the base unit 258 and the vertical mast 262 is able to rotate with respect to the other.
In some embodiments, the robotic system includes a seven degrees-of-freedom (DOF) similar to that of a human arm. Such a configuration provides mobility for the robotic system 250 to grasp items such as tools 252 and/or adaptive seal assemblies 254 from different angles or directions. More or less degrees of freedom can be provided in various embodiments of the robotic system 250.
In some embodiments, a robotic system 251 includes a selective compliant assembly robot arm (SCARA). Such a SCARA configuration can provide a four-axis robot arm able to move to any XYZ coordinate within a work envelope. The fourth axis of motion is a wrist allowing a rotation of a grasper about the arm. Such a configuration can be accomplished with three parallel axis rotary joints. Vertical motion can be provided at an independent linear axis at the wrist or in the base of the robotic system 250. SCARA robots 251 are particularly useful in situations in which a final movement is to insert a grasped part using a single vertical move. Thus, the SCARA robot 251 is advantageous for many types of pick-and-place assembly applications, particularly those in which an elongated item is placed within a hole without binding.
During an insertion procedure, the coiled tubing thrust unit 308 provides a thrust directed away from the coiled tubing reel 302. The thrust unit 308 extracts a length of coiled tubing 304 from the reel and directs it upward at a slope and through a bend 310 into vertical alignment above the tool 40a. The tool 40a can be at least partially positioned within a wellhead fixture 36 as illustrated. Thrust applied by the coiled tubing thrust unit 308 extracts greater lengths of coiled tubing 304 from the coiled tubing reel 302, forcing it around the bend 310 and directing it downward into the well. The wellhead fixture 36 can include seals adapted to seal against the coiled tubing allowing the coiled tubing to thrust the tool 40a further down-hole while maintaining pressure differential within the well. Also illustrated is a robotic system 250 adjacent to the wellhead fixture 36 that can be used in combination with the rigless coiled tubing system 299. The robotic system 250 is shown grasping a second instrument 40b in anticipation for positioning it above an open end of the wellhead fixture 36 once the first instrument has been inserted. The end of the coiled tubing 304 coupled to the first tool 40a can be disconnected once the first tool 40a is sufficiently inserted into the open end of the wellhead fixture 36, and reconnected to a proximal end of the second tool 40b. The process can be repeated as necessary for additional tools of a tool array.
An alternative embodiment of a coiled tubing deployment system 299′ is illustrated in
While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.
