In the oil and gas industry, some techniques for exploring and/or extracting hydrocarbons from the earth include operations that are to be performed by a well tool located downhole in a wellbore and that require application of a deployment or activating force only when the well tool is located at a target position downhole. Examples include, but are not limited to, actuated deployment of sensors in the wellbore, forced engagement of sensors with subterranean formations, locking or anchoring downhole the well tool in a desired downhole location, diverting fluid flow (for example by actuated movement of diverter sleeves), activating downhole power storage, and releasing downhole sensors.
For this purpose, well tools often include remotely controllable actuators incorporated in the tool and configured for actuating downhole deployment of the tool. Operator control over activation and/or deactivation of the downhole actuator at an operator-selected time and/or at a target position along the wellbore is achieved by the provision of a control channel between the downhole tool and the surface. In some cases, downhole actuators are electrically powered by electrical conductors ran downhole from the surface and/or by downhole storage devices. In some instances, the actuators are hydraulically powered by means of an electrically controlled and powered pump in a liquid-filled sealed fluid circuit (e.g., containing hydraulic oil as actuating medium). Electrical conductors may in such cases again be run downhole to the pump for powering the hydraulic circuit. Electrical conductors and electronic components of some downhole actuators can display sub-optimal performance and/or reliability in particularly harsh downhole conditions, for example at high ambient temperatures. Actuators in high temperature optical fiber applications, for example, can typically be exposed to downhole conditions in which the tool electronics can be prone to failure or non-responsiveness.
Some embodiments of the disclosure are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which:
The following detailed description refers to the accompanying drawings that depict various details of examples selected to show how aspects of this disclosure may be practiced. The discussion addresses various examples of the disclosure at least partially in reference to these drawings, and describes the depicted embodiments in sufficient detail to enable those skilled in the art to practice the subject matter disclosed herein. Many other embodiments may be utilized for practicing the disclosure other than the illustrative examples discussed herein, and structural and operational changes in addition to the alternatives specifically discussed herein may be made without departing from the scope of the disclosure.
In this description, references to “one embodiment” or “an embodiment,” or to “one example” or “an example,” are not intended necessarily to refer to the same embodiment or example; however, neither are such embodiments mutually exclusive, unless so stated or as will be readily apparent to those of ordinary skill in the art having the benefit of this disclosure. Thus, a variety of combinations and/or integrations of the embodiments and examples described herein may be included, as well as further embodiments and examples as defined within the scope of all claims based on this disclosure, and all legal equivalents of such claims.
One aspect of the disclosure comprises a single-use pressure-controlled actuator for downhole well tools or mechanisms. The actuator may be configured for activation/deactivation control and actuation by agency of wellbore fluid pressure exclusively (e.g., by pressure levels of drilling fluid or drilling mud in the wellbore). The actuator may thus be particularly useful in downhole applications where power and/or control cables are not readily or reliably conveyable to a downhole location, but where mechanical actuation is nevertheless required for specific tasks. The actuator may be configured for activation by increasing wellbore fluid pressure above a predetermined threshold level.
In some embodiments, the actuator comprises a plunger displaceably mounted on a sealed cylinder body, with a non-reclosable frangible device closing off wellbore fluid access to an interior of the cylinder body, the frangible device being configured for automatic failure in response to exposure of wellbore fluid pressures exceeding a predetermined activation threshold, thereafter to allow flow of wellbore fluid into the cylinder body for causing actuated movement of the plunger by hydraulic action of the wellbore fluid. In some embodiments, the actuator may further comprise a deactivation mechanism for pressure-controlled deactivation of the actuator subsequent to pressure-triggered activation. The deactivation mechanism may comprise a second non-reclosable frangible device sealingly closing off wellbore fluid access to a compression chamber within the cylinder body, the second frangible device being configured for automatic failure in response to exposure to wellbore fluid pressures exceeding a predefined deactivation threshold, thereafter to allow equalization of fluid pressures across a plunger head within the cylinder body.
In
The housing 103 in this example embodiment comprises a cylinder broadly similar in construction to a pressure vessel, having a circular cylindrical cylinder wall 104 of substantially constant thickness. The cylinder wall 104 defines a hollow interior defining a cylinder volume 109. In this example embodiment, the cylinder volume 109 is a generally circular cylindrical space extending along a longitudinal axis 124 of the housing 103. The cylinder wall 104 may be of sheet metal, in this example embodiment being of mild steel.
The housing 103 defines a deployment or activation port 133 that comprises an opening extending through the cylinder wall 104 at one of its ends, thereby providing a fluid passage or fluid conduit to that, when unoccluded, establishes a flow connection between the interior cylinder volume 109 and the exterior of the housing 103. The housing 103 forms part of a housing assembly that also includes a non-reclosable frangible closure device in the example form of an activation rupture disc 136 sealingly mounted in the activation port 133. As will be described in greater detail below, the activation rupture disc 136 is operable between (a) an initial intact condition or closed state (shown in
The rupture disc 136 is in this example embodiment a commercially available rupture disc, but may in other embodiments be custom manufactured specifically for the disclosed applications. Commercially available rupture discs (also known as a burst discs, bursting discs, or burst diaphragms), are non-re-closing pressure relief devices that, in most uses, protect a pressure vessel, equipment or system from over-pressurization or potentially damaging vacuum conditions. Rupture discs are typically sacrificial parts, because of their one-time-use time use membrane that fails at a predetermined differential pressure across the device. The membrane is usually made of metal, but nearly any material (or different materials and layers) can be used to suit a particular application. Rupture discs provide substantially instant response (within milliseconds) to system pressure, but once the disc has ruptured, it will not reseal. Although commonly manufactured in disc form, and employed has such in the example embodiments described herein as such, the devices are also available as rectangular panels.
In this example embodiment, the activation rupture disc 136 is removably and replaceably mounted on the housing 103. Removable and replaceable mounting is effected by complementary screw threads on a radially outer periphery of the rupture disc and on a radially inner periphery of the activation port 133, respectively. The housing 103 thus provides a mounting formation for removable and replaceable semi-permanent mounting of the activation rupture disc 136, the port 133 this example being a circular cylindrical screw-threaded passage or conduit extending through the cylinder wall 104.
The plunger 106 comprises a plunger head 118 sealingly located in the cylinder volume 109 for hydraulically actuated axial displacement along the cylinder volume 109. In this example embodiment, the plunger head 118 is a disc-shaped element oriented perpendicularly relative to the cylinder axis 124. A radially outer periphery of the plunger head 118 is in sliding sealed engagement with an inner cylindrical surface of the cylinder wall 104 by means of a seal 130 (e.g., comprising an O-ring) in contact with the inner diameter of the cylinder wall 104.
The plunger head 118 thus sealingly separates the cylinder volume 109 into two distinct but complementary volumes whose capacities are complementarily or sympathetically variable in response to axial movement of the plunger head 118. In this example embodiment, the complementarily variable volumes that together make up the cylinder volume 109 are identified as an activation chamber 112 and a compression chamber 115. These chambers are here distinguished by the fact that the activation port 133 provides a flow connection (when the activation rupture disc 136 is omitted or has ruptured, thus being in its opened state) between the exterior of the housing 103 and the activation chamber 112. Note that, in this example embodiment, location of the activation port 133 on an end wall of the housing 103 ensures that the activation port 133 is in flow connection with the activation chamber 112, regardless of the axial position of plunger head 118.
In contrast, the compression chamber 115 is in this example embodiment not in fluid communication with any flow passage or opening of that connects it to the exterior of the housing 103, thus being in permanent fluid isolation.
A force transmission component or working member connected to the plunger head 118 is in this example embodiment provided by a plunger rod 121 that extends axially along the compression chamber 115 and through a complementary opening in a corresponding end wall of the housing 103, projecting from the end of housing 103. An outer end of the plunger rod 121 is thus, in use, exposed to ambient drilling fluid 204. A fluid seal 127 is provided at the end wall opening through which the plunger rod 121 extends, to sealingly engage with the periphery of the plunger rod 121 and prevent fluid flow into or out of the compression chamber 115 through the end wall.
In an initial dormant condition (in which the actuator 100 is to be conveyed downhole for in situ deployment), the cylinder volume 109 is filled with a compressible fluid. In some embodiments, the compression chamber 115 and/or the activation chamber 112 may contain air. In other embodiments, the chambers of the cylinder volume 109 may be filled with an inert or noncorrosive gas, thereby to promote reliability and longevity of components exposed thereto, such as the seals and the interior surfaces of the housing 103. In this example embodiment, the activation chamber 112 and the compression chamber 115 are each initially charged with nitrogen. Although the chambers 112, 115 are in the described example embodiment pressurized at more or less equal to atmospheric pressure, higher initial gas pressures may in other embodiments be employed. A benefit of initially charging both of these volumes with gas at atmospheric pressure is that there is no net hydraulic force on the plunger 106 when the actuator 100 is located above ground, at atmospheric pressure.
Pressure-controlled activation of the actuator 100 to cause hydraulic actuation of the plunger 106 (in this example embodiment to deploy the plunger rod 121) will now be described with reference to
As mentioned above, the actuator 100 is moved into position in the downhole environment in an initial dormant condition (shown in
When, however, ambient fluid pressure exceeds a predetermined activation threshold, the activation rupture disc 136 fails automatically, causing hydraulically actuated deployment of the plunger rod 121, as will be described below. Note that elevation of the drilling fluid pressure to exceed the activation threshold may be effected in some instances by locating of the actuator 100 is at a fixed downhole position, and thereafter ramping up the ambient fluid pressure bias via an operator-controlled wellbore pressure control system (such as that provided, for example, by a wellbore pumping system as described with reference to
In
In this example embodiment, an axial direction (i.e., aligned with the axis 124) extending from the activation chamber 112 towards the compression chamber 115 is thus the activation direction or the deployment direction of the plunger 106, with the opposite axial direction being referred to herein as the deactivation direction or the retraction direction.
Note that the sealed compression chamber 115 and the gas held captive therein serves as a cushioning mechanism that resists maximal axial displacement of the plunger 106 in the activation direction, thereby to limit the likelihood of dynamic metal-on-metal contact between the plunger head 118 and the end wall of the housing 103. It will be appreciated that, after failure of the activation rupture disc 136, the plunger 106 will automatically seek an equilibrium position in which gas pressure in the compression chamber 115 is more or less equal to the ambient fluid pressure. Although axial momentum of the plunger rod 121 during equalization may carry the plunger head 118 somewhat beyond the particular equilibrium position for the operative drilling fluid pressure, the compressible nature of the gas in the compression chamber (together with the fact that the compression chamber 115 is a sealed volume) causes the plunger head 118 to settle in the equilibrium position in a resiliently damped oscillatory movement. In other words, the sealed and gas-filled compression chamber provides an air cushion for stopping hydraulically actuated axial movement of the plunger 106 in an damped oscillatory fashion.
In some embodiments, the actuator 100 can have a cushioning mechanism that includes a damping system instead of or in addition to the air cushion provided by the compression chamber 115, as described above. A damping fluid (e.g., gas in the compression chamber 115 or a noncompressible fluid such as hydraulic oil in a pressure-connected damping volume), may in such instances be forced through a restricted orifice in response to actuated movement of the plunger 106 in the activation direction, thus damping axial movement of the plunger 106, shock absorber-fashion.
As mentioned above, the actuator 100 can form part of a downhole tool, an example embodiment of which (indicated by reference number 200) is partially shown in
Returning now to the example embodiment of
In some methods of using the actuator 100, the tool 200 may be returned to the surface subsequent to activation of the actuator 100 and associated deployment of the tool 200. In such cases, ambient fluid pressure will progressively decrease as the tool 200 is raised towards the surface, with fluid pressure at the surface approaching atmospheric pressure. It will be appreciated that exposure of the actuator 100, while in its activated condition (i.e., in which the activation rupture disc 136 has failed), to ambient fluid pressures which are more or less at atmospheric levels will cause the plunger 106 to seek a hydrostatic equilibrium position which corresponds more or less to its initial dormant position (
The actuator 100 is broadly similar in construction to the actuator 100 of
The deactivation port 303 is this example embodiment located at or adjacent an end of the housing 103 furthest from the activation chamber 112, being shaped and positioned such that it leads into only the compression chamber 115 (and not into the activation chamber 112), regardless of the axial position of the plunger head 118 between its opposite extremes. The deactivation port 303, when it is not closed off by a closure device, thus defines a fluid connection between the compression chamber 115 and ambient drilling fluid 204 exterior to the housing 103.
The actuator 100 of
The deactivation disc 306 is in this example embodiment a rupture disc similar to the activation disc 136, but has a different pressure rating. The pressure rating of a rupture disc is in this embodiment substantially equal to a maximum indicated pressure differential across it which the rupture disc can bear without failing. In the example embodiment of
In operation, hydraulically actuated, pressure-controlled deployment of the actuator 100, when located at a target downhole position, is achieved by performing the operations described above with reference to the actuator 100 of
The operator thereafter has the option of deactivating the actuator 100 by controlling increase of ambient drilling fluid pressure. When the ambient drilling fluid pressure is ramped up above the higher one of the drilling fluid pressure thresholds (also referred to herein as the deactivation pressure), the deactivation disc 306 fails, so that a rupture 404 (
Note that deactivation of the actuator 100 in this manner can cause at least partial retraction of the plunger 106 due to hydraulic action whereby the plunger 106 finds an equilibrium position in which fluid pressures in the activation chamber 112 and the compression chamber 115 are equalized, both being substantially equal to ambient fluid pressure values. The equilibrium position of the free-floating plunger 106 will automatically move away from the compression chamber 115, in a deactivation direction opposite to the activation direction, in response to subsequent decreases in ambient drilling fluid pressures. Pressure decreases to cause retraction of the plunger 106 (i.e., movement thereof in the deactivation direction) may be effected by operator-control of wellbore pressure, and/or may in some instances result at least in part from uphole movement of the actuator 100.
In some embodiments, the actuator 100 may include a return mechanism configured to automatically cause substantially reliable return of the plunger 106 to its dormant position subsequent to deactivation of the actuator 100. One example embodiment of an apparatus that includes such a return mechanism is shown in
In the example embodiment of
Operation of the actuator 100, in use, is schematically illustrated in
After locating the actuator 100 at a target position downhole and subsequently ramping up the drilling fluid pressure above the lower threshold value (or, instead, upon lowering the actuator 100 to a target depth corresponding to the lower threshold pressure) the activation disc 136 ruptures, causing pressure equalization between the activation chamber 112 and the ambient drilling fluid 204. The increased fluid pressure in the activation chamber 112 causes deployment by hydraulically actuated displacement of the plunger 106 for increased extension of the plunger rod 121 from the housing 103 (
When the deployed actuator 100 is to be retrieved or retracted, the operator can remotely trigger deactivation of the actuator 100 and automated retraction of the plunger rod 121 by increasing drilling fluid pressure to exceed the corresponding deactivation pressure at the downhole location of the actuator 100. As before, such above-threshold ambient fluid pressure conditions result in failure of the deactivation disc 306, exposing the compression chamber 115 to ambient fluid pressure conditions. Because the activation chamber 112 and the compression chamber 115 are now in fluid communication via the ambient drilling fluid 204, fluid pressures in the respective chambers equalize, so that there is substantially no net hydraulic force exerted on the plunger 106. The actuator 100 is thus deactivated.
The compression spring 505, however, continues to bias the plunger 106 to exert an axially retractive bias on the plunger 106, but the biasing force is no longer opposed by the hydraulic/pneumatic forces caused by a pressure differential across the activation chamber 112 and the compression chamber 115. The compression spring 505 therefore causes automatic retraction of the plunger 106 subsequent to failure of the deactivation disc 306, as shown schematically in
As mentioned previously, the activation disc 136 and/or the deactivation disc 306 may in some embodiments be configured for removable and replaceable mounting on the housing 103. A drilling tool system of which the actuator 100 forms part may further include a plurality of rupture discs having a variety of respective pressure ratings. Such a set of rupture discs may be of modular construction, in that each rupture disc may be mountable on either one of the ports 133, 303. Any of the rupture discs may thus be selected by an operator to serve either as the activation disc 136 or as the deactivation disc 306. A method of deploying a downhole tool can in such instances include selecting a particular activation rupture disc 136 and/or a particular deactivation disc 306 from a plurality of interchangeably mountable rupture discs having different threshold pressure values (which may be expressed as respective pressure differentials) at which the respective rupture disc is designed to fail. The provision of a plurality of such modularly interchangeable removable and replaceable rupture discs allows an operator to configure a particular actuator 100 on-site for deployment at an operator-selected trigger pressure or target depth, and/or to configure the actuator 100 for pressure-activated retraction at an operator-selected deactivation pressure.
A further benefit of removable and replaceable connection of the rupture discs 136, 306 to the housing 103 is that the actuator 100 is thus repeatedly reusable subject to replacement of failed rupture discs between successive deployments. The actuator 100 of
Limitation mechanisms may be provided for limiting axial displacement of the plunger 106 to a particular axial range. A mechanical stop may, for example, be provided for limiting plunger movement during deployment. An example of such a mechanical stop can be seen in a double acting actuator 100 forming part of a tool 600 illustrated in
Note that operation of the shoulder 660 causes the plunger head 118 to stop short of the axial position it would otherwise have assumed for drilling fluid pressures greater than that at which the plunger rod 121 reaches the shoulder 660. As a result, the sealed volume defined by the compression chamber 115 has a greater capacity and concomitantly a lower pressure than would otherwise have been the case at such drilling fluid pressure levels. Thus limiting the gas pressure level in the compression chamber 115 translates to a relative increase in the pressure differential across the deactivation disc 306 for a given pressure beyond the deployment stroke limit, when compared to an otherwise identical device without the shoulder 660.
As can be seen from the above description, the actuator 100 of
Note that the physical properties of the compression spring 505 are selected such that the magnitude of the bias is, on the one hand, weak enough to allow more or less full deployment of the plunger rod 121, while, on the other hand, being strong enough to ensure reliable and full retraction of the plunger 106 under the urging of the compression spring 505, overcoming residual forces resistive to the axial retraction—such as friction forces on the seals 127, 130 and damping effects that may be caused by forced expulsion of drilling fluid 204 from the activation chamber 112. It will be appreciated that the magnitudes of the above-discussed forces relevant to selection of the physical properties of the compression spring 505 may, for identical actuators 100, differ in magnitude at different ambient drilling fluid pressures. The method may thus include fitting different actuators 100 that are intended for deployment at different trigger pressures with differently rated compression springs 505.
Some variations to the above-described example actuators will now be briefly discussed with reference to example actuators forming part of the respective example downhole tools illustrated in
Some embodiments may provide for an actuator 100 in which the deployment stroke comprises retraction of the plunger rod 121 into the housing 103. Such arrangements may be used in applications where the plunger 106 is configured for exerting a pulling force on a deployment mechanism of a downhole tool of which of the actuator 100 forms part, to cause actuated deployment of a locking member of the tool. Example embodiments of such pull-action actuators 100 are illustrated in
As can be seen, for example, in
Note that, in the actuator 100 of
The actuator 100 can be used many different applications where downhole exertion of an actuating force is required on a single-use basis. Example applications include: deployment of anchoring mechanisms for positioning sensors in a wellbore (see, for example,
A benefit of the example actuators 100 is that its mechanism of deployment and retraction is robust and reliable, even in harsh downhole environments. Because the activation and deployment mechanisms of the actuator 100 is wireless and is exclusively mechanical/hydraulic, not being dependent on any electronic control circuitry or electrical power, the actuator 100 is largely resistant to high temperatures. This allows for reliable use of the actuator 100 in-temperature environments where electronics have a high risk of failure. The actuator 100 is particularly compatible with high temperature optical fiber applications and instrumented wells were activation is required only once.
The example actuator 100 is furthermore of simple construction, allowing for cost effective manufacture with high reliability. Cost-effectiveness of the actuator 100 is enhanced in embodiments where the rupture discs are removably and replaceably connectable to the housing 103, allowing for multiple repeat uses of the actuator 100.
In
The sensor tool 600 comprises a rigid frame 630 in the example form of a base plate on which a sensor pad 636 and the housing 103 of the actuator 100 are fixedly mounted. When the sensor tool 600 is locked in position (as shown in
As mentioned, a mechanical coupling or link may be provided between the casing 612 and the formation 118 (e.g., by filling with settable cementitious material, such as concrete, the annular cavity between the outer diameter of the casing 612 and the co-axial borehole wall 618, and allowing the material to set). Seismic activity in the formation is thus transferred to the casing 612 via an encapsulating concrete jacket. The anchoring mechanism 606, in turn, serves to link the tool 600 to the casing 612 by physical contact, and to provide a mechanical or seismic coupling between the frame 630 and the casing 612, allowing the transfer of seismic waves or vibration experienced by the casing 612 to the frame 630. The sensor pad 636 is, in its turn, mounted to the frame 630 for substantially lossless (or low-loss) transmission of seismic signals from the frame to the sensor pad 636 in this example embodiment, the frame 630 may be a steel structure of one-piece construction, for example being formed from steel plate. The sensor pad 636 is rigidly mounted on the frame 630, for example being welded or bolted to the frame to promote effective transmission of seismic signals from the frame to the sensor pad 636. Activation of the anchoring mechanism 606 therefore effectively couples or link the sensor pad 636 mechanically to the formation 118, with seismic tremors or other seismic activity transmitted via the formation 118 being transmitted to the casing via the intermediate cement jacket, from the casing to the anchoring mechanism, from the anchoring mechanism to the frame 630, and from the frame to the sensor pad 636.
The anchoring mechanism 606 in this example embodiment comprises a mechanical linkage 642 which is, at one end thereof, pivotally connected to the plunger rod 121 of the actuator 100. The other end of the linkage 642 is connected to the frame at an anchor point provided by an anchor 648 such as to allow only pivoting about the anchor 648 as the single degree of movement relative to the frame 630, preventing relative translation between the linkage component connected thereto and the frame 630.
Operation of the anchoring mechanism 606 will now be described in greater detail with reference to
The linkage 642 of the anchoring mechanism 606 is in this example embodiment has two link members consisting of rigid elongated metal bars providing a proximal link 707 closest to the actuator 100, and a distal link 714 furthest from the actuator 100. The actuator 100 is oriented in this example embodiment such that its longitudinal axis 124 is parallel to a longitudinal axis of the borehole, but is laterally offset relative thereto, due to location of the tool 600 in the annular cavity between the casing 612 and the borehole wall 618. Is A proximal end of the proximal link 707 (i.e., the end of the proximal link 707 closest to the actuator 100) is connected end-to-end to the end of the plunger rod 121 that projects from the housing 103, to provide an actuated joint 721 that allows pivotal movement of the proximal link 707 about the actuated joint 721. The distal end of the proximal link 707 is, in turn, connected end-to-end to the proximal end of the distal link 714, defining an expansion joint 728 about which both of the links 707, 714 are pivotable.
Similarly, the distal link 714 is pivotally connected to the proximal link 707 at the expansion joint 728 and is pivotally connected to the anchor 648 at its distal end, defining a fixed anchored joint 735 about which the distal link 714 is pivotally displaceable. It will thus be seen that the anchoring mechanism 606 is of jackknife construction, with the actuated joint 721 having a fixed radial position relative to the borehole 624 (i.e., an a radial direction indicated by arrows 748 in
The tool 600 is initially lowered into the annular cavity between the outer diameter of the casing 612 and the inner diameter of the borehole wall 618 while the tool 600 is in its initial dormant condition (
When the ambient drilling fluid exceeds ambient drilling fluid conditions corresponding to the trigger pressure of the activation disc 136, the activation disc 136 ruptures, automatically resulting in hydraulically actuated axial displacement of the plunger rod 121 in the activation direction 742 (
The continuously urged physical contact between the anchoring mechanism and the relevant cavity wall physically couples the tool 600 to the borehole wall 618 and/or the casing 612 so as to establish a mechanical or vibratory pathway between the borehole wall 618 and the tool 600. Such a physical coupling to the borehole wall 618 promotes accurate and sensitive exposure of the sensor tool 600 to seismic activity in the relevant Earth formation. Note that the mechanical or vibratory pathway between the point of contact (in this example the expansion joint 728) of the anchoring mechanism and the actuator housing 103 comprises an uninterrupted series of rigid components, in this example being metal components. The anchoring mechanism 606 is, in this example embodiment, configured to transmit seismic waves experienced at the borehole wall 618 to the frame 630 not only via the actuator housing 103, but also via the anchor 648.
Note further that hydraulic actuation of the anchoring mechanism 606, to provide a persistent physical coupling, is not limited to the initial deployment of the anchoring mechanism into contact with the borehole wall 618, but comprises continuous application of force by the actuator on the anchoring mechanism 606, to continuously press the anchoring mechanism 606 into contact with the borehole wall 618. The construction of the actuator 100, as described previously, allows utilization of the pressurized wellbore fluid for hydraulically forcing the anchoring mechanism 606 continuously into contact with the borehole wall 618.
In this deployed condition, the expansion joint 728 of the anchoring mechanism 606 is continuously forced radially outwardly against the borehole wall 618, causing corresponding radially inward bearing of the frame 630 against the outer cylindrical sidewall. While surface of the casing 612. Axial displacement of the tool 600 along the annular cavity between the casing 612 and the borehole wall while the anchoring mechanism 606 is in the activated condition, is resisted by axially acting friction caused by the a radial contact or bracing force exerted via the anchoring mechanism 606 and acting perpendicularly to the outer surface of the casing 612 and the co-axial cylindrical borehole wall 618. In this manner, the anchoring mechanism 606 serves to secure or anchor the tool 600 in position while it is in the activated condition. It will be appreciated that the radial lodging forces (which result in frictional resistance to axial displacement of the tool 600) is caused by hydraulic actuation of the plunger 106 through hydraulic action of the ambient drilling fluid 204 with which the cavity between the casing 612 and the borehole wall 618 is filled.
In some example embodiments, a method of installing the sensor tool 600 in a target position along the borehole 624 may comprise inserting the tool 600 into the annular cavity between the casing 612 and the borehole wall 618, and moving the tool 600 axially along the annular cavity until it reaches a desired target position. After deployment of the anchoring mechanism 606 at the target position (e.g. by ramping up drilling fluid pressure levels above the predefined trigger pressure, or in response to the drilling fluid 204 reaching pressure levels corresponding more or less to the target depth) the annular cavity at and adjacent to the target position at which the tool 600 is located may then be filled with a settable fluid material, in this example embodiment being filled with concrete. Once the concrete has set, the tool 600 is permanently held captive in the target position by the ambient concrete.
In other embodiments, however, the sensor tool 600 may be located only temporarily at a particular target position, and may selectively be released after axial anchoring thereof into position by the anchoring mechanism, to allow retrieval or further axial displacement under operator control. Release or retraction of the anchoring mechanism 606 can selectively be effected by an operator by controlled increase of ambient drilling fluid conditions to a level greater than the deactivation pressure of the deactivation disc 306. Exposure of the actuator 100 to such above-threshold drilling fluid conditions automatically results, in this example embodiment in rupture of the deactivation disc 306, in this example embodiment, causing automatic retraction of the plunger rod 121 into the housing 103 under the urging of the spring 505, resulting in displacement of the expansion joint 728 radially inwardly (see, for example
An example embodiment of a drilling installation in which one or more of the sensor tools 600 is in this example embodiment applied is illustrated schematically in
In an upper part of the borehole 624 (further referred to as the casing section), a circular cylindrical bore of the wellbore 800 is defined by a tubular steel casing 612 located co-axially in a widened top section of the borehole wall 618, so that the inner diameter of the wellbore 800 in the casing section is lined by the casing 612. The casing 612 may have perforations along certain parts of its length, to allow ingress of hydrocarbons in liquid form into the wellbore 800, through the casing 612.
An assembly of logging while drilling (LWD) tools is may be integrated into a bottom-hole assembly (BHA) 826 near the bit 814. As the bit 814 extends the borehole 624 through the formations 818, LWD tools collect measurements relating to various formation properties as well as the tool orientation and various other drilling conditions. The LWD tools may take the form of a drill collar, i.e., a thick-wall led tubular that provides weight and rigidity to aid the drilling process. A telemetry sub may be included to transfer images and measurement data to a surface receiver and to receive commands from the surface. In some embodiments, the telemetry sub does not communicate with the surface, but rather stores logging data for later retrieval at the surface when the logging assembly is recovered.
The wellbore 800 of
The circumferential arrangement of sensor tools 600 about a central longitudinal axis of the borehole 624 is substantially rotationally symmetrical, by which is meant that the arrangement of tools 600, when the wellbore is viewed in an axial direction, is substantially identical to their arrangement when rotated through an angle of 360°/n (where n is a an integer representing the number of tools 600 in a cross-section of the installation at the relevant depth). In the illustrated example of
It will be appreciated that such rotationally symmetrical arrangement of the tools 600 about the casing 612 will result in automatic centering of the casing 612 in the borehole 624, if equal radially inward wedging forces are exerted by all of the tools 600 located at the same depth. Based on the previously described configuration of the respective actuators 100 of the tools 600, it will be understood that any two of the actuators 100 exposed to identical ambient drilling fluid pressures will exert identical wedging forces pushing radially outwardly against the borehole wall 618 and pushing radially inwardly against the casing 612. This is because the wedging force of each tool 600 is caused by actuation of the plunger 106 through hydraulic action of the drilling fluid 204.
A method of deploying or installing the array of sensor tools 600 can in such cases comprise positioning each of the sensor tools 600 in a desired target position, and thereafter increasing pressure levels in the drilling fluid 204 located in the annular cavity around the casing 612 to above-threshold levels for the respective actuators 100. When the activation threshold is exceeded, the respective rupture discs 136 fail, causing deployment of the respective anchoring mechanisms 606. Note that, in some embodiments, tools 600 deployed at different depths may be provided with rupture discs 136 whose pressure rating is selected so that all of the tools 600 of the array have the same threshold pressure for triggering deployment. In other embodiments, each tool 600 may be customized to have a trigger pressure that corresponds to a particular depth at which it is to be deployed. Such a tool 600 can be placed into position around the casing 612 by lowering it downwards along the annular cavity until it reaches the target depth, at which point the tool 600 automatically deploys and is wedged in place.
Once all of the tools 600 in the array have been deployed, the cumulative effect of the respective wedging forces exerted on the casing by the tools 600 will be to center the casing 612 in the casing section of the borehole 624, thus ensuring co-axial alignment of the casing 612 with the borehole 624. Each tool 600 is moreover firmly engaged both with the borehole wall 618 and with the casing 612, thus allowing reliable measurement by the respective sensor pads 636 of seismic activity to which it is exposed. In some embodiments, the annular cavity between the casing 612 and the borehole wall 618 can thereafter be filled with concrete which, once said, permanently installs of the deployed sensor tools 600 in position around the casing 612.
Note that the above-referenced described deployment and use of the array of sensor tools 600 in the casing section need not occur while the drill string 808 is located in the wellbore 800, as illustrated in
At various times during the drilling process, the drill string 808 may be removed from the borehole 624, as shown in
The example wireline logging sonde 909 may have pads and/or centralizing springs to maintain the sonde 909 near the central axis of the borehole 624, while the sonde 909 is stationary and/or while the sonde 909 is axially displaced along the borehole 624. In some embodiments, tools or anchoring mechanisms provided on the sonde 909 may be configured for pressure-controlled triggering and for drilling fluid actuation by incorporation of an actuator 100 similar or analogous to those described above. An example of such an automatically centering anchoring mechanism and/or tool can be seen with reference to
The logging sonde 909 can also include one or more tools configured for operation during forced engagement with the borehole wall 618. In the example embodiment of
In other embodiments (see, for instance, the example embodiment of
It should be appreciated that, although in this example embodiment, the use of a plurality of differently rated actuators 100 configured for staggered tool deployment is used together with a sensor tool 600, other embodiments may provide for similar or analogous multi-actuator staggered deployment in conjunction with downhole tools having different functions. Note that although the example embodiment discloses a pair of actuators 100 incorporated in a single seismic sensor tool 600, other embodiments provide for incorporation of three or more of actuators 100 in the tool 600.
Yet a further technique by which sensor tools and/or hydraulic actuators according to the disclosure can be employed in a downhole drilling environment is illustrated in
An uphole interface 1067 may be provided to exchange communications with the supervisory sub 1064 and receive data to be conveyed to the surface computer system 1066. Surface computer system 1066 is configured to communicate with supervisory sub 1064 to set logging parameters and collect logging information from the one or more logging tools 1065. Surface computer system 1066 is configured by software (shown in
Note that various modifications to above-described example actuators 100 and tools 600 can be made without departing from the scope of the disclosure. Some modifications and variations (which represent only a non-exhaustive selection of possible modifications and variations) will now be described with reference to
The actuator 100 of
In an initial dormant condition (
When the activation rupture disc 136 fails in response to ambient drilling fluid pressures exceeding its pressure rating, the tool 600 is automatically disposed to a deployed condition (
The anchoring mechanism 606 may in some embodiments comprise a mechanical advantage mechanism, being configured to translate displacement of an actuated member (here, the plunger 106) to displacement at least part of a coupling member (here, the expansion joint 728 provided together by the pivoted links 707) with mechanical advantage. Anchoring mechanisms 606 such as that shown in
The tool 600 remains in the deployed condition of
The frame 630 of the tool 600 is thereby wedged or anchored into position by a transverse anchoring or coupling force (F), resulting in axially acting frictional resistance to axial displacement by engagement of the plunger rod 121 and frame 630 with the casing 612. As is the case with the various example embodiments, the magnitude of frictional resistance to displacement of the tool 600 is proportional to the magnitude of the wedging force exerted against the casing 612 (and/or, in some embodiments, against the borehole wall 618).
When the activated tool 600 (
A sequence of pressure-activated hydraulically actuated deployment/retraction events performed by the tool 600 of
activation of the first actuator 100a at a lowermost threshold pressure (e.g., 30 bar in a first example, or, in a second example at much higher well pressures, 5 bar above default well pressure at the tool), triggered by automatic failure of the first activation rupture disc 136a, thereby to lock the tool 600 axially in place within the casing at the first measurement position, with continuous actuation of the transversely disposed plunger rod 121a through hydraulic action of the pressurized drilling fluid 204 ensuring solid contact between the tool 600 and the casing 612 for promoting effective measurement of seismic activity at the first measurement position by the sensor pad 636;
subsequent activation of the first actuator 100a at a lower intermediate threshold pressure (e.g., 35 bar in first example, or 10 bar above default well pressure in the second example), triggered by failure of the first deactivation disc 306a, allowing axial displacement of the tool 600 among the casing 612 to a second measurement position;
subsequent activation of the second actuator 100b at a higher intermediate threshold pressure (e.g., 40 bar in the first example, or 15 bar above default well pressure in the second example), triggered by automatic failure of the second deactivation disc 306b, thereby to lock the tool 600 axially in place within the casing at the second measurement position, with continuous actuation of the transversely disposed plunger rod 121b through hydraulic action of the pressurized drilling fluid 204 ensuring solid contact between the tool 600 and the casing 612, to promote effective measurement of seismic activity at the second measurement position by the sensor pad 636; and subsequent deactivation of the second actuator 100b at a uppermost threshold pressure (e.g., 45 bar in the first example, or 20 bar above the default well pressure in the second example), triggered by failure of the second deactivation disc 306b, thereby to allow further displacement or axial removal of the tool 600 from the casing 612.
Note that the housing 103a of the first actuator 100a has a configuration different from those of previously described embodiments in which the housing 103 is a hollow cylinder, the activation chamber 112 and the compression chamber 115 being axially aligned cylindrical cavities together constituting the cylinder volume 109. The activation chamber 112a and compression chamber 115a of the first housing 103a in
The anchoring mechanism 606 of
A longitudinal spacing between the cross pieces 1414, 1415 is thus variable in response to actuated movement of the plunger 106 in the housing 103. When the plunger 106 is in a fully extended position corresponding to the dormant condition of the anchoring mechanism 606, the links 1421 of each pair are longitudinally aligned, lying flat against the sides of the actuator housing 103, so that the width of the anchoring mechanism 606 (represented by the transverse spacing between the jackknife joints 1428) is more or less equal to the length of the crosspieces 1414, 1415, thus allowing operator-controlled movement of the anchoring mechanism 606 along the borehole 624.
When, however, the activation rupture disc 136 fails due to above-threshold drilling fluid conditions, the plunger 106 is actuated by hydraulic action of the drilling fluid to retract the plunger 106 into the housing 103, thus moving the mobile crosspiece 1415 forcibly closer to the static crosspiece 1414, shortening the overall length of the anchoring mechanism 606. As a result, the links 1421 pivot outwards, causing radially outward movement of the jackknife joints 1428 for bracing against the borehole wall at diametrically opposite positions (
Note again that the deployed anchoring mechanism 606 provides a mechanical link or seismic pathway between the actuator housing 215 (and therefore to the sensor pad 636 incorporated in a sensor tool of which the anchoring mechanism 606 forms part). Seismic signals or waves arriving at the physical contact interface of the jackknife joint 1428 against the borehole wall 618 is transferable to the body of the tool by a rigid components comprising the link 1421, static crosspiece 1414, and link 1421, at least.
When the anchoring mechanism 606 is to be released, the drilling fluid pressure at the downhole position of the deployed anchoring mechanism 606 is raised above the threshold pressure of the deactivation disc 306. This results in exposure of the compression chamber 115 [to the ambient drilling fluid, resulting in equalization of the fluid pressures in the compression chamber 115 and the activation chamber 112, allowing axial movement of the plunger 106 back to its fully extended position under action of the compression spring 505 mounted in the compression chamber 115. The resulting increase in spacing between the crosspieces 1414, 1415 causes the links 1421 to pivot inwards, so that the jackknife joints 1428 are retracted radially inwards to once again lie flat against the actuator housing 103. The anchoring mechanism 606 is thus released from being anchored in a particular downhole position, to allow operator-controlled movement of the anchoring mechanism 606 (and therefore of a tool of which it might form part) along the borehole 624.
The actuator 100 of
In an initial dormant condition (
When the activation rupture disc 136 fails in response to ambient drilling fluid pressures exceeding its pressure rating, the tool 600 is automatically disposed to a deployed condition (
The anchoring mechanism 606 in this position provides a physical link between the actuator housing (and therefore to a sensor forming part of the tool via a tool frame to which the actuator housing is rigidly connected) and the borehole wall. This provides a seismic pathway for transmission of seismic activity, for example via the contact shoe 1612 and the wedging lever 1606. Effective transmission of seismic activity along the seismic pathway is promoted by contact between the wedging lever 1606 and the actuator housing 103 at the fulcrum 1609.
Note that the actuator 100 of the
The wedging lever 1709 of
When in the dormant condition (
Continued application of hydraulic actuating force on the plunger 106 by the ambient drilling fluid continuously exerts an actuating force on the wedging lever 1709 via the pull link 1727, ensuring that the anchoring mechanism 606 continuously lodges the tool of which it forms part firmly in position at a target location. Continuous application of such a contacting force with which the wall engaging portion of the anchoring mechanism 606 (here, the shoe 1612) is forced into contact with the wall also promotes reliable transmission of received seismic signals from the shoe 1612 to a sensor of the tool via a mechanical or seismic link defined at least in part by the shoe 1612, the wedging lever 1709, the fixed fulcrum 1718, and the frame 630.
As is the case with the example embodiment of
From the foregoing it can be seen that one aspect of the above-described example embodiments provides an apparatus comprising:
an actuator housing configured for incorporation in a tool to be located in a downhole environment exposed to ambient drilling fluid, the housing defining an activation chamber and a fluid passage connecting the activation chamber to an exterior of the housing;
an actuated member displaceably mounted on the housing and configured for hydraulically actuated movement in an activation direction relative to the housing in response to exposure of the activation chamber to pressurized ambient drilling fluid via the fluid passage; and
an activation chamber closure device obstructing the fluid passage and isolating the activation chamber from ambient drilling fluid exterior to the housing, the activation chamber closure device being configured for automatically opening in response to ambient drilling fluid conditions that exceed a predefined activation threshold, thereby to place the activation chamber in flow connection with ambient drilling fluid for actuation of the actuated member by hydraulic action of the drilling fluid. The activation chamber closure device is also referred to herein as the activation closure.
Opening of the activation chamber closure member may comprise rupture or failure of the closure member's structural integrity, thereby allowing fluid flow through a rupture or fissure in the closure member that is mounted in the fluid passage. The activation chamber closure device may thus be a frangible closure (e.g., a rupture disc) configured for automatic failure in response to exposure to ambient drilling fluid pressures exceeding an activation pressure corresponding to the activation threshold. The frangible closure and may be removably and replaceably mounted on the housing.
A hollow interior of the actuator housing and the actuated member may together define the activation chamber and a complementary compression chamber sealingly separated from the activation chamber, such that displacement of the actuated member in the activation direction corresponds to expansion of the activation chamber and simultaneous sympathetic compression of the compression chamber. The compression chamber may be a substantially sealed volume containing a compressible fluid. The compression chamber may be gas-filled, in some embodiments be filled with air, and in some embodiments being filled with a noncorrosive gas, such as nitrogen.
The apparatus may comprise a cushioning mechanism configured for exerting on the actuated member resistance to movement thereof in the activation direction, such that the resistance increases in magnitude with an increase in displacement of the actuated member in the activation direction. In some example embodiments, the cushioning mechanism may at least in part be provided by the compression chamber, in which pneumatic resistance to expansion of the activation chamber may automatically result from compression of gas in the compression chamber.
The actuator housing may define a deactivation passage connecting the compression chamber to the exterior of the housing. The apparatus main such case further comprise a compression chamber closure device (also referred to herein as the deactivation closure device) sealingly closing off the deactivation passage and being configured for automatically opening in response to ambient drilling fluid pressures that exceed a predefined deactivation threshold, which may be significantly higher than the activation threshold.
The apparatus may in some embodiments comprise a stopping mechanism configured for mechanically stopping movement of the actuated member in the activation direction beyond a predetermined deployment stroke limit.
The apparatus may further comprise a deactivation mechanism configured for, subsequent to opening of the activation chamber closure device, automatically displacing the actuated member in a deactivation direction, opposite to the activation direction, in response to the establishment of a flow connection between the compression chamber and ambient drilling fluid. The deactivation mechanism may comprise a bias mechanism configured for urging the actuated member in the deactivation direction. The bias mechanism may in some embodiments comprise an elastically deformable spring element operatively connected to the actuated member and configured for exerting on the actuated member a bias force that increases in magnitude with an increase in displacement thereof in the activation direction. The spring element may comprise a resiliently compressible spring located in the compression chamber and configured for lengthwise compression in response to movement of the actuated member in the activation direction.
Another aspect of the disclosure, as exemplified by the described example embodiments, includes a system comprising:
an actuator mechanism configured for incorporation in a tool to be employed in a downhole drilling environment in which the actuator mechanism is exposed to ambient drilling fluid, the actuator mechanism comprising a housing and an actuated member that is mounted on the housing and that is configured for hydraulically actuated movement relative to the housing in response to establishment of a flow connection, via an activation conduit defined by the housing, between ambient drilling fluid and an activation volume defined by the housing; and
a plurality of different activation closure devices configured for interchangeable, removable and replaceable mounting on the actuator mechanism, each activation closure device being configured for, when mounted on the actuator mechanism, substantially closing off the activation conduit at below-threshold drilling fluid pressures, and for automatically switching, in response to ambient drilling fluid pressures greater than a corresponding activation threshold, to an opened state in which the activation volume is in flow connection with ambient drilling fluid via the activation conduit.
Two or more of the plurality of different activation closure devices have different respective activation thresholds, allowing operator modification of an operative activation threshold for the actuator mechanism by removal of one activation closure device from the actuating mechanism and replacement thereof by another activation closure device having a different corresponding activation threshold. A single actuator mechanism is thus customizable by an operator for deployment in a range of different applications in which different activation threshold pressures are to apply.
The plurality of different activation closure devices may be of modular construction, having similar respective mounting formations for cooperation with a complementary mounting formation provided by the actuator mechanism. Defined differently, the actuator mechanism and a plurality of the closure devices may provide a modular system allowing for on-site customization or reconfiguration of different actuator mechanisms to have different respective activating pressure thresholds.
In some embodiments, the actuating mechanism may further be configured for automatic deactivation, subsequent to switching of the activation closure device to the opened state, in response to establishment of a flow connection between the ambient drilling fluid and a deactivation volume of the actuator mechanism via a deactivation conduit defined by the actuator mechanism. In such cases, the system may further comprise a plurality of different deactivation closure devices configured for interchangeable, removable and replaceable mounting on the actuator mechanism, each deactivation closure device being configured for, when mounted on the actuator mechanism, substantially closing off the deactivation volume at below deactivation-threshold drilling fluid pressures, and for automatically switching, in response to ambient drilling fluid pressures greater than a corresponding deactivation threshold, to an opened state in which the deactivation volume is in flow connection with ambient drilling fluid via the deactivation conduit.
Note that, in some embodiments, the closure devices and the actuating mechanism may be configured such that the plurality of deactivation closure devices and the plurality of activation closure devices are nonoverlapping sets, with each activation device being mountable in association with only one of the activation conduit on the deactivation conduit. In other embodiments, each closure device may be configured for interchangeable mounting on the actuator mechanism, to serve either as a activation closure device or as a deactivation closure device. In such cases, the plurality of deactivation closure devices and the plurality of activation closure devices may be overlapping sets, in some embodiments being fully overlapping sets provided by a single group of closure devices. Respective mounting formations provided by the actuator mechanism to receive closure devices for the activation conduit and the deactivation conduit respectively may in other words be compatible with the plurality of deactivation closure devices and the plurality of activation closure devices.
Another aspect of the disclosed embodiments includes a method comprising:
providing an actuator mechanism at a downhole location such that the actuator mechanism is exposed to ambient wellbore fluid, the actuator mechanism comprising
a housing that defines an activation volume and an activation conduit leading into the activation volume,
an actuated member mounted on the housing and configured for hydraulically actuated movement relative to the housing in response to flow of wellbore fluid into the activation volume, and
an activation closure member mounted on the housing to isolate the activation volume from the ambient wellbore fluid by closing off the activation conduit, the activation closure member being configured to open the activation conduit in response to wellbore fluid pressures exceeding a predetermined activation threshold level; and
causing wellbore pressure levels at the actuator mechanism exceed the activation threshold level, thereby to cause automatic opening of the activation conduit by the activation closure member, resulting in hydraulically actuation of the actuated member by action of the wellbore fluid.
As discussed previously, above-threshold wellbore fluid pressure levels at the actuator mechanism may be caused by controlled increase of ambient pressure levels at a given downhole location, and/or may in some embodiments be caused by displacing the actuator mechanism along the wellbore to a particular downhole location at which the ambient fluid pressure levels exceed the activation threshold.
In some embodiments, the actuator mechanism may further define a deactivation volume and a deactivation conduit leading into the deactivation volume, with the actuator mechanism further comprising a deactivation closure member mounted on the housing to isolate the deactivation volume from the ambient wellbore fluid by closing off the deactivation conduit. The method may in such cases further comprise causing wellbore pressure levels at the actuator mechanism to exceed a predetermined deactivation threshold level, thereby triggering automatic opening of the deactivation conduit by the deactivation closure device, to cause the activation of the actuator mechanism.
The method may further comprise the operation of retooling the actuator mechanism after an activation/deactivation cycle, for example by removing the previously installed activation closure device and/or deactivation closure device, and mounting a replacement activation closure device and/or a replacement deactivation closure device on the housing. In some embodiments, the method may comprise operator-controlled modification of the actuator mechanism to have an operator-selected activation pressure threshold and/or deactivation pressure threshold. This may in some example embodiments comprise selecting from a plurality of different closure devices respective closure devices having pressure ratings corresponding to the selected activation pressure threshold and/or deactivation pressure threshold, and mounting the selected closure device(s) on the housing in association respectively with the activation conduit and/or the deactivation conduit. In some example embodiments, each closure device comprises a non-reclosable rupture discs having a predetermined pressure rating.
In the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.
Filing Document | Filing Date | Country | Kind |
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PCT/US15/17734 | 2/26/2015 | WO | 00 |