P/00/01 1 Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Flow-actuated actuator and method The following statement is a full description of this invention, including the best method of performing it known to us: FLOW-ACTUATED ACTUATOR AND METHOD BACKGROUND [0001] Downhole system operators are always receptive to new methods and devices to permit actuation of tools located downhole within a downhole system. Increasing flow rates of fluid pumped from surface can and has been harnessed as a method to permit actuation of a number of different types of devices in the downhole environment. In such methods downhole actuators typically use reduced diameter elements that resist fluid flow resulting in actuation forces that are proportional to the flow rate. While these work well for their intended purpose, the reduced diameter elements can limit other operations simply due to diametrical patency. Commonly then such actuators must be removed from the downhole system to allow full bore access. Devices and methods that permit actuation based on flow while not incurring the drawback noted would be well received in the art. BRIEF DESCRIPTION [0001A] The invention provides a method of actuating a tubular, comprising: flowing fluid through a housing defining a full bore radial dimension; flowing fluid through the tubular positioned within the housing; moving a flow resistor positioned downstream of the housing with a force generated by an increase in the flowing fluid acting on the flow resistor; moving a movable member in operable communication with the tubular from a first position having a smallest radial dimension no less than the full bore radial dimension to a second position having a smallest radial dimension smaller than the full bore radial dimension in response to the moving of the flow resistor, the second position having more resistance to fluid flow than the first position, the moving member having a pivot positioned between two links, the pivot moving from a dimension at least as large as the full bore radial dimension when the moveable member is in the second position; and moving the tubular relative to the housing with an urging force proportional to fluid flow acting on the movable member in the second position. [0002] Also disclosed herein is a flow-actuated actuator. The actuator includes, a tubular with a flow passageway having a first flow area, and at least one movable member in operable communication with the tubular. The at least one movable member is movable relative to the tubular between at least a first position and a second position, the at least one movable member configured to form a second flow area that is smaller than the first flow area when in the second position, the flow-actuated actuator is configured to move a I A separate member in response to fluid flow therethrough. [0003] Further disclosed herein is a method of actuating a tubular. The method includes, flowing fluid through the tubular, moving a flow resistor with a force generated by the flowing fluid acting on the flow resistor, moving a movable member in operable communication with the tubular from a first position to a second position in response to the moving of the flow resistor, the second position having more resistance to fluid flow than the first position, and moving the tubular with an urging force proportional to fluid flow acting on the movable member in the second position. [0004] Further disclosed herein is a variable flow resistant actuator. The actuator includes, a tubular, at least one member in operable communication with the tubular, having a radially movable portion movable between a first position and a second position, the radially movable portion having a smaller radial dimension in the second position than in the first position, and a biasing member biasing the radially movable portion toward the first position, and the at least one member and the biasing member are configured such that the radially movable portion is movable from the first position to the second position in response to flow therethrough. [0004A] Reference to any prior art in the specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in Australia or any other jurisdiction or that this prior art could reasonably be expected to be ascertained, understood and regarded as relevant by a person skilled in the art. [0004B] As used herein, except where the context requires otherwise the term 'comprise' and variations of the term, such as 'comprising', 'comprises' and 'comprised', are not intended to exclude other additives, components, integers or steps. BRIEF DESCRIPTION OF THE DRAWINGS [0005] The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: [0006] FIG. 1 depicts a partial cross sectional view of a flow-actuated actuator disclosed herein shown in a non-actuated position; [0007] FIG. 2 depicts a partial cross sectional view of the flow-actuated actuator of FIG. 1, shown in a flow actuation position; 2 [0008] FIG. 3 depicts a partial cross sectional view of another flow-actuated actuator disclosed herein shown in a non-actuated position; [0009] FIG. 4 depicts a partial cross sectional view of another actuator similar to that illustrated in FIG. I in a full bore position; and [0010] FIG. 5 depicts the actuator of FIG. 4 in the flow actuation position. DETAILED DESCRIPTION [0011] A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. [0012] Referring to Figures 1 and 2, an embodiment of a flow-actuated actuator 10 is illustrated generally at 10. The actuator 10 is a full bore actuator that, when non-actuated does not present its own restriction to flow. Rather the actuator presents an unencumbered full bore. As such, the actuator 10 creates no obstruction to downhole intervention, for example, when in a non-actuating position yet provides a mechanism and method for actuating a downhole tool in response to fluid flow when in an actuating position. Although 2A embodiments depicted herein are in reference to downhole applications, it should be noted that the flow-actuated actuators described herein are not limited to downhole applications, and as such can be used in any application needing a flow-actuated actuator. [0013] The actuator 10 includes, a tubular 14, a movable member 18, a biasing member 22 and a flow resistor 24. The movable member 18 is movable between a first position 26 (shown in FIG. 1), which may also be referred to as the non-actuating position; and a second position 28 (shown in FIG. 2), which may be referred to as the actuating position. The biasing member 22, depicted in this embodiment as a compression spring, biases the movable member 18 toward the first position 26. In the first position 26 neither a minimum radial dimension 32 of the movable member 18 nor a minimum radial dimension 34 of the flow resistor 24 is smaller than a smallest radial dimension 36 of the tubular 14. However, in the second position 28, the movable member 18 has a minimum radial dimension 40 that is substantially smaller than the smallest radial dimension 36 of the tubular 14. As such, the movable member 18 when in the second position 28 forms a reduced flow area 44 at the minimum radial dimension 40 in comparison to a minimum flow area 46 defined by at least one of the flow resistor 24, the movable member 18, when in the first position 26, and the tubular 14. This reduced flow area 44 creates a pressure drop due to fluid flowing, for example, fluid injected from surface, therethrough and consequently an urging force on the actuator 10 that is proportional to the fluid flow. This urging force can be used to move the tubular 14 and actuate a tool such as in opening a flapper 48 sealedly engaged with an outlet end 52 of the tubular 14, for example. A biasing element 50 that biases the tubular 14 relative to a housing 51, illustrated herein as a compression spring, is longitudinally compressed to a smaller longitudinal length when the tubular 14 is moved due to the urging forces. [0014] In this embodiment, the movable member 18 has a plurality of first links 56 and a plurality of second links 58. The first links 56 are pivotally attached to the flow resistor 24 at a first pivot 62 on one end and pivotally attached to the second links 58 at a second pivot 64 at the other end. Similarly, the second links 58 are pivotally attached to the first links 56 at the second pivot 64 at one end and pivotally attached to the tubular 14 at a third pivot 66 at the other end. This construction allows the second pivot 64 to be moved radially inwardly to form the minimum dimension 40 in response to movement of the flow resistor 24 toward the tubular 14, with the biasing member 22 being compressed in the process. 3 [0015] A flow interacting detail 70 on the flow resistor 24, illustrated herein as an annular groove on an inner surface 74 of the flow resistor 24 interacts with the fluid flow to create an urging force on the flow resistor 24 that is proportional to the fluid flow. The interacting detail 70 (as the annular groove illustrates) can be formed without reducing the minimum dimension 34 of the flow resistor 24. Doing so allows full bore access to take place through the actuator 10, as mentioned above, without the need to remove the actuator 10 from the well bore. The biasing member 22 is selected to allow the flow resistor 24 to move relative to the tubular 14 with relatively little urging force applied to the flow resistor 24. Once the flow resistor 24 begins moving toward the tubular 14 the urging force on the flow resistor 24 quickly increases since the minimum dimension 32 begins reducing toward the minimum dimension 40 thereby reducing the flow area therethrough and increasing the pressure drop associated with the fluid flow. [0016] The biasing element 50 is selected to have a greater biasing force on the tubular 14 than the biasing member 22 has on the flow resistor 24. This assures that the flow resistor 24 moves before the tubular 14 moves. In fact, the biasing element 50 can be selected such that the tubular 14 does not move unless the movable member 18 has been moved to the second position 28 wherein the forces generated by the flowing fluid are substantially greater due to the flow restriction created by the reduced flow area 44 formed by the movable member 18. [0017] The biasing member 22 and the biasing element 50 are also selected to have sufficient biasing forces to reset both the flow resistor 24 and the tubular 14 to their original, non-flow actuated positions, as illustrated in Figure 1 in response to cessation of fluid flow. [0018] Referring to FIG. 3, an alternate embodiment of a flow-actuated actuator 110 disclosed herein is illustrated. The flow-actuated actuator 110 includes, tubular 114, a movable member 118, a biasing member 122 and a flow resistor 124. The movable member 118 is movable between a first position 126, as illustrated herein in solid lines, and a second position 128, as illustrated herein in phantom lines. As with the first embodiment, the second position 128 may also be referred to as the actuating position. The biasing member 122, depicted herein as a leaf spring, biases the movable member 118 toward the first position 126. In the first position 126 neither a minimum radial dimension 132 of the movable member 118 nor a minimum radial dimension 134 of the flow resistor 124 is smaller than a smallest radial dimension 136 of the tubular 114. However, in the second position 128, the 4 movable member 118 has a minimum radial dimension 140 that is substantially smaller than the smallest radial dimension 136 of the tubular 114. As such, the movable member 118 when in the second position 128 forms a reduced flow area 144 at the minimum radial dimension 140 in comparison to the minimum flow area 146 of the tubular 114. This reduced flow area 144 creates a pressure drop due to fluid flowing therethrough and consequently an urging force on the actuator 110 that is proportional to the fluid flow. This urging force can be used to move the tubular 114 and actuate a tool such as in opening a flapper 148 sealedly engaged with an outlet end 152 of the tubular 114, for example. A biasing element 150 that biases the tubular 114 relative to a housing 151, illustrated herein as a series of wave springs, is longitudinally compressed to a smaller longitudinal length when the tubular 114 is moved due to the urging forces. [0019] In this embodiment, the movable member 118 has a plurality of orifice dogs 154 substantially oriented symmetrically about a longitudinal axis of the tubular 114. The orifice dogs 154 are moved from the first position 126 to the second position 128 in response to longitudinal movement of the flow resistor 124. This longitudinal movement of the flow resistors 124 causes ramped extenders 158 thereon to engage ramped surfaces 162 on the orifice dogs 154 moving the orifice dogs 154 to the second position 128 against the biasing of the biasing members 122 to form the minimum dimension 140. [0020] A plurality of flow-resisting elements 170 on the flow resistor 124, illustrated herein as annular grooves on an inner surface 174 of the flow resistor 124, interacts with the fluid flow to create an urging force on the flow resistor 124 that is proportional to the fluid flow. The annular groove flow-resisting elements 170, in this embodiment are formed without reducing the minimum dimension 134 of the flow resistor 124. Doing so allows full bore access through the actuator 110, as mentioned above, without the need to remove the actuator 110 from the well bore. A biasing member 178 is set to bias the flow resistor 124 against a direction of the fluid flow. A biasing force of the biasing member 178 is selected to permit the flow resistor 124 to move relative to the tubular 114 with relatively little urging force applied to the flow resistor 124. Once the flow resistor 124 begins moving toward the tubular 114 the urging force on the orifice dogs 154 generated by the fluid flow quickly increases since the minimum dimension 132 begins reducing toward the minimum dimension 140 thereby reducing the flow area therethrough and increasing the pressure drop associated with the fluid flow. 5 [0021] The biasing element 150 is selected to have a greater biasing force on the tubular 114 than the biasing member 178 has on the flow resistor 124. This assures that the flow resistor 124 moves before the tubular 114 moves. In fact, the biasing element 150 can be selected such that the tubular 114 does not move unless the movable member 118 has been moved to the second position 128 wherein the forces generated by the flowing fluid are substantially greater due to the flow restriction created by the reduced flow area 144 formed by the movable member 118. [0022] The biasing member 122, the biasing element 150 and the biasing member 178 are also selected to have sufficient biasing forces to reset the orifice dogs 154, the tubular 114, and the flow resistor 124 to their original, non-flow actuated positions, as illustrated in solid lines in Figure 3 in response to cessation of fluid flow. [0023] Referring to FIG.4 and FIG. 5 another embodiment of a flow-actuated actuator is disclosed. This embodiment, it will be appreciated, is similar in appearance to the embodiment represented in FIG. 1 and FIG. 2 but is structurally unique resulting operational distinctions allowing for use in different applications. In order to promote efficiency in description and improvement in understanding, numerals used in the description of FIG. 1 are mirrored in this discussion as 200 series numerals. Further, only numerals that represent a change in structure or use of structure relative to the FIG. 1 embodiment are addressed with respect to this embodiment. The flow interacting detail 70 from the FIG. 1 embodiment becomes shifting profile 270 in the FIG 4 embodiment. This profile is intended to be engageable by a shifting tool (not shown) that is run in the hole for the specific purpose of shifting the flow actuated actuator 210 to the operable position (illustrated in FIG. 5) or to the full bore position (illustrated in FIG. 4). In this embodiment then there is no required threshold fluid flow for frictional interaction with a flow interacting detail 70 as none is needed. Operation of the actuator 210 occurs (after mechanical shifting) based solely on the pressure drop created by the minimum dimension 40 (FIG. 5). Also because of the mechanical shifting of this embodiment, the biasing member 22 from the FIG. 1 embodiment is omitted. [0024] Further distinguishing this embodiment from the FIG. 1 embodiment is the second pivot 264. In the first embodiment the pivot is a normal hinge type pivot while in this embodiment the pivot 264 includes an eccentricity 270 such that the links 256 and 258 will want to stay in either the full bore position (FIG. 4) or the actuatable position (FIG. 5) but 6 that they will not want to stay in a position between those two. In other words, the links are configured to be bistable with respect to position. This operation can be accomplished using the eccentric cam as noted or by an overcentering arrangement or by other similar arrangements. In other respects, the actuator 210 is similar to actuator 10 as described above and the balance of the numerals used in Figures 4 and 5 are identical to those used in Figures 1 and 2. [0025] In the event that the actuator 210 is required to reassume a full bore position, a shifting tool (not shown) is run to the actuator 210, engaged with profile 270 and pulled to stretch out the links 256 and 258. In order to ensure that the actuator or part thereof is not simply pulled uphole upon an uphole pull from the shifting tool, a shoulder 272 is included or other such member to prevent uphole movement of the actuator 210 thereby enabling the stretching out of the links. [0026] While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. 7