Single control line safety valve insensitive to hydrostatics of the production tubing and control line

Abstract

Safety valves and methods of using safety valves. The safety valve is installed in a wellbore with hydrostatic pressure. The safety valve is configured to operate at the pressure of the production tubing well. The pressure is applied to the safety valve using a single control line. The safety valve uses an accumulator in fluid communication with the control line, so that the pressure acting on the accumulator is fluidly connected to the pressure in the control line. The safety valve is insensitive to hydrostatic pressure. Figure for abstract: Figure 1

Description

Title of the invention: Single control line safety valve insensitive to hydrostatics of the production tubing and the control line Technical field

[0001] The present disclosure relates generally to drilling operations, and more particularly to the installation and use of a single control line safety valve, insensitive to hydrostatic pressure and production tubing pressure, without the need for well workover or the addition of a second control line for operation of the safety valve.

[0002] STATE OF THE ART

[0003] For some drilling operations, it may be desirable to install or replace a safety valve. For example, some safety valves may be wireline retrieved and installed in the wellbore via a cable. The installation and / or use of safety valves in high hydrostatic pressure wellbores may present additional obstacles due to the force of the hydrostatic pressure acting on the valve components. For high hydrostatic pressure wellbores, a balance line may be used to counterbalance the hydrostatic pressure acting on the valve components. However, the use of a balance line requires the addition of another control line for the safety valve. Adding a second control line may be too expensive for some drilling operations.

[0004] Safety valves are an important component of drilling operations. The present invention provides improved apparatus and methods for installing and using a single control line safety valve.

[0005] BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Illustrative examples of the present disclosure are described in detail below with reference to the accompanying drawing figures, which are incorporated by reference herein, and in which:

[0007] [Fig.l] is a diagram illustrating the use of an exemplary safety valve according to one or more examples described herein;

[0008] [Fig.2] is a diagram continuing to illustrate the use of the example safety valve of [Fig.l] according to one or more examples described herein;

[0009] [Fig.3] is a diagram continuing to illustrate the use of the example safety valve of [Fig.l] and 2 according to one or more examples described herein;

[0010] [Fig.4] is a diagram continuing to illustrate the use of the example safety valve of [Fig.l] - 3 according to one or more examples described herein; and

[0011] [Fig.5] is a diagram continuing to illustrate the use of the example safety valve of [Fig.l] - 4 according to one or more examples described herein;

[0012] The illustrated figures are examples only and are not intended to state or imply any limitation with respect to the environment, architecture, design or process in which the various examples may be implemented. DETAILED DESCRIPTION

[0013] The present disclosure relates generally to drilling operations, and more particularly to the installation and use of a single control line safety valve, insensitive to hydrostatic pressure and production tubing pressure, without the need for well workover or the addition of a second control line for operation of the safety valve.

[0014] In the following detailed description of several illustrative examples, reference is made to the accompanying drawings which are an integral part of this document and in which specific examples capable of being implemented are illustrated. These examples are described in sufficient detail to enable those skilled in the art to practice them, and it is understood that other examples may be used and that logical structural, mechanical, electrical, and chemical modifications may be made without departing from the spirit or scope of the disclosed examples. In order to avoid details which are not necessary to enable those skilled in the art to practice the examples described herein, the description may omit certain information known to those skilled in the art.The following detailed description should therefore not be taken in a limiting sense, and the scope of the illustrative examples is defined only by the appended claims.

[0015] Unless otherwise indicated, all numbers expressing amounts of ingredients, properties such as molecular weight, reaction conditions, etc. used in this specification and the associated claims are to be understood as being modified in all cases by the term "about". Therefore, unless otherwise indicated, the numerical parameters set forth in the following specification and the appended claims are approximations that may vary depending on the desired properties sought to be achieved by the examples of the present invention. At the very least, and without seeking to limit the application of the doctrine of equivalents to the scope of the claim, each numerical parameter should at least be interpreted in light of the number of significant figures reported and by applying ordinary rounding techniques. It should be noted that where "about" is at the beginning of a numerical list, "about" modifies each number in the numerical list. Furthermore, in some numerical lists of ranges, certain stated lower limits may be greater than certain stated upper limits. Those skilled in the art will recognize that the selected subset will require the selection of an upper limit exceeding the selected lower limit.

[0016] In the following disclosure and in the claims, the terms "including" and "comprising" are used openly and should therefore be interpreted as meaning "including, but not limited to". Unless otherwise indicated, in this document, the term "or" does not imply mutual exclusivity.

[0017] The terms "upstream" and "downstream" may be used to refer to the location of various components relative to the bottom or end of a well. For example, a first component described as being upstream of a second component may be farther from the end of the well than the second component. Similarly, a first component described as being downstream of a well relative to a second component may be located closer to the end of the well than the second component.

[0018] The terms "upstream" and "downstream" may be used to refer to the location of various components relative to one another with respect to the flow of a sample through said components. For example, a first component described as being upstream of a second component will encounter a sample before the downstream second component encounters the sample. Similarly, a first component described as being downstream of a second component will encounter the sample after the upstream second component encounters the sample.

[0019] The present disclosure relates generally to drilling operations, and more particularly to the installation and use of a single control line safety valve in wells having high hydrostatic pressure, without the need for well workover or the addition of a second control line for operation of the safety valve. Advantageously, the safety valve may be installed in a wellbore using a cable, tubing, or other method for positioning the safety valve in the wellbore at the desired location. As an additional advantage, the safety valve may be retrieved using a cable, tubing, or other retrieval method. Another advantage is The safety valve uses a balancing piston, making it more resistant to extreme wellbore environments, such as those with high hydrostatic pressures. This feature allows the safety valve to be insensitive to the hydrostatic pressure of the production tubing or control line as well as the pressure of the production tubing. The safety valve is only sensitive to the pressure applied by the control line. In addition, the safety valve uses only one control line extending from the surface to operate, eliminating the need for a well workover or the installation of another control line. In some wells, the safety valve can be installed to work with an existing control line. Installing a second control line can prohibitively increase operational expenses.Thus, installing a safety valve that can be used with an existing control line and can be installed without workover or additional operations can significantly reduce overall remediation expenses for wellbore problems such as gas chamber leaks. In addition, the safety valve can be used in high hydrostatic pressure environments and is also insensitive to production tubing pressure. Thus, the safety valve can be operated with a single control line, even when the well hydrostatic pressure and / or control line pressure is high. Another advantage is that the safety valve does not use gas-charged valves and therefore there is no risk of gas charges leaking and failing over time.Additionally, the safety valve utilizes a built-in safety device and if control line pressure is lost or intentionally shut off, the valve's built-in safety device will push the valve closed, thus preventing uncontrolled flow through the valve.

[0020] [Fig.l] is a diagram of an exemplary safety valve, generally 5, comprising an operating piston 10, a balancing piston 15, a control line 20, a pressure-lock flow path 25, a balancing pressure line 30, a check valve 35, a poppet valve 40, a flow restrictor 45, and an accumulator 50. The opening piston 10 and the balancing piston 15 are mechanically or hydraulically linked as shown. The operating piston 10 and the balancing piston 15 are configured to translate axially along the length of the safety valve 5, as illustrated by the adjacent arrow. Production tubing well pressure is applied to the operating piston 10 and the balancing piston 15 from well lines 55 and 60 respectively. In the illustrated example, the operating piston 10 is coupled to a spring 65, itself coupled to a sliding sleeve 70.The sliding sleeve 70 is used to open a bottom valve (not shown) to open or close the . safety valve 5 and to allow the flow of fluid through the safety valve 5. This opening of the valve is achieved by translating the operating piston 10, and consequently the balancing piston 15, to the right in the illustrated figure. This translation of the operating piston 10 will compress the spring 65 which will slide the sliding sleeve 70 to force the opening of the valve.

[0021] The translation of the operating piston 10 and the linked balancing piston 15 occurs at the same time. If the operating piston 10 and the linked balancing piston 15 are mechanically linked, they can also move in the same direction. It is also possible to use a hydraulic coupling to link the balancing piston and the operating piston to a hydraulic line that moves them in different directions. In order to translate the operating piston 10, hydraulic pressure is applied via the pressurized flow path 25. The pressure-locked flow path 25 may be a separate conduit component such as a line or may be a flow path present within a component. The hydraulic pressure within the pressure-locked flow path 25 is provided by the control line 20.The control line 20 extends down from the surface to upstream of the safety valve 5. The control line 20 extends down from the surface as a single control line 20 with a hydraulic fluid supply that can be used to operate coupled downhole equipment such as the safety valve 5. Downhole, the control line 20 splits into three flow paths for operation of the safety valve 5. A flow path of the control line may be a separate conduit component such as a line or may be a flow path present within a component. The first flow path 75 of the control line 20 is coupled to the check valve 35. The second flow path 80 of the control line 20 is coupled to the flapper valve 40. The third flow path 85 of the control line 20 is coupled to the flow restrictor 45.When in use, hydraulic fluid flows from the surface to the three flow paths of the control line 20. The check valve 35 is configured such that the default position closes the first flow path 75 of the control line 20. The check valve 35 may be a one-way valve that prevents backflow. Examples of the check valve 35 may include, but are not limited to, ball-on-seat valves, reed valves, flapper valves, wafer-type valves, disc valves, flapper valves, lift-and-piston valves, and the like. Flow through the check valve 35 from the first flow path 75 of the control line to the pressure-lock flow path 25 does not occur because flow is only permitted in the reverse direction. The flap valve. 40 is configured to crack at a lower pressure threshold than the check valve 35. The check valve 40 may be any type of valve having a cracking pressure suitable for the application. When the hydraulic pressure in the second flow path 80 of the control line 20 exceeds the cracking threshold of the poppet valve 40, the poppet valve 40 cracks and allows hydraulic fluid to flow past the poppet valve 40 to the pressure-locked flow path 25. The poppet valve 40 is configured to not allow flow in the direction of the balance pressure line 30 from the control line 20. Flow is only allowed from the control line 20 into the pressure-locked flow path 25 when the cracking pressure of the poppet valve 40 is exceeded. The pressure-locked flow path 25 comprises three segments.The first segment 90 of the pressure-locked flow path 25 is coupled to the check valve 35. The second segment 95 of the pressure-locked flow path 25 is coupled to the poppet valve 40. The third segment 100 of the pressure-locked flow path 25 is coupled to the operating piston 10. To translate the operating piston 10, the hydraulic pressure applied to the poppet valve 40 must exceed the threshold necessary to crack the poppet valve 40. The applied hydraulic pressure must then exceed a threshold sufficient to translate the operating piston 10 after entering the pressure-locked flow path 25.

[0022] When the poppet valve 40 cracks, the hydraulic pressure on both sides of the check valve 35 equalizes and the additional force applied by the spring of the check valve 35 maintains the valve 35 in the default closed position. At the third flow path 85 of the control line 20, the hydraulic fluid slowly passes through the flow restrictor 45, thereby maintaining the hydraulic pressure in the equalizing pressure line 30 at a level lower than the hydraulic pressure in the control line 20 and in the pressure-lock flow path 25. The flow restrictor 45 may have the same or different restrictions in different directions (e.g., a swirl restrictor). In some examples, the flow restrictor may have a cracking pressure.The increase in pressure within the pressure-locked flow path 25 causes the operating piston 10 and, consequently, the linked balancing piston 15 to translate. The operating piston 20 is translated to the right to compress the spring 65, slide the sleeve 70 and open the bottom valve. The safety valve 5 is then opened to allow flow therethrough.

[0023] Referring now to [Fig. 2], the diagram of [Fig. 1] is illustrated with the poppet valve 40 closed. If the poppet valve 40 closes while the check valve 35 is also closed, the hydraulic pressure in the pressure-lock flow path 25 is blocked. The spring-loaded poppet valve 40 and the spring-loaded check valve 35 are oriented such that they default to the closed position to shut off hydraulic flow from the control line 20 to the pressure-lock flow path 25. If the pressure falls below the cracking pressure of the poppet valve 40 or if the pressure in the equalizing pressure line 30 equalizes with the control line 20, the poppet valve 40 closes and locks the hydraulic pressure in the pressure-lock flow path 25.If the hydraulic pressure is blocked while the poppet is open, the valve 5 will be held open by retaining the hydraulic pressure applied to the operating piston 20. In addition, the accumulator 50 has begun to store the hydraulic pressure in the balance pressure line 30, because the hydraulic pressure in the balance pressure line 30 has increased steadily, but slowly, due to the restriction of the flow of hydraulic fluid through the flow restrictor 45.

[0024] [Fig. 3] is a diagram illustrating the equalization of hydraulic pressure in the control line 20 and the balance pressure line 30. Due to the effects of the flow restrictor 45, the flow rate of hydraulic fluid in the balance pressure line 30 is reduced relative to the flow rate of hydraulic fluid in the other two flow paths of the control line 20. The balance pressure line 30 comprises four segments. The first segment 105 of the balance pressure line 30 is the portion of the balance pressure line 30 that is coupled to the poppet valve 40. The second segment 110 of the balance pressure line 30 is the portion of the balance pressure line 30 that is coupled to the flow restrictor 45. The third segment 115 of the balance pressure line 30 is the portion of the balance pressure line 30 that is coupled to the accumulator 50.The fourth segment 120 of the balance pressure line 30 is the portion of the balance pressure line 30 which is coupled to the balance piston 15.

[0025] As the hydraulic fluid passes through the flow restrictor 45, the pressure in the equalizing pressure line 30 begins to equalize with the pressure in the control line 20. The pressure within the pressure-lock flow path 25 remains locked and the operating piston 10 holds the safety valve 5 in the open position because the spring 65 remains compressed to keep the sliding sleeve 70 moved to the right to open the poppet of the safety valve 5. The hydraulic pressure stored in the accumulator 50 has also increased, as shown by the change in level in the illustration. The poppet valve 40 and the check valve 45 remain in the closed position by default with their spring mechanisms deployed. In some examples, the flow restrictor 45 may be configured to restrict flow in one direction more than the other. For example, the flow restrictor 45 may restrict the flow of hydraulic fluid from the third flow path 85 of the control line 20 to the second segment 110 of the balance control line 30 more than from the second segment 110 of the balance control line 30 to the third flow path 85 of the control line 20.Alternatively, the flow restrictor 45 may restrict the flow of hydraulic fluid from the second segment 110 of the balance control line 30 to the third flow path 85 of the control line 20 more than from the third flow path 85 of the control line 20 to the second segment 110 of the balance control line 30.

[0026] [Fig.4] is a diagram illustrating a drop in hydraulic pressure in the control line 20. If the hydraulic pressure in the control line 20 is reduced, the resulting pressure differential may become large enough that the hydraulic pressure trapped in the pressure-locked flow path 25 exceeds the cracking pressure of the check valve 35. When the hydraulic pressure within the pressure-locked flow path 25 cracks the check valve 35, the hydraulic fluid trapped within the pressure-locked flow path 25 flows back into the control line 20. Then, the loss of pressure in the pressure-locked flow path 25 causes the operating piston 10 to translate to the left, which causes the safety valve 5 to close.The loss of pressure in the control line 20 also results in the hydraulic pressure in the balance pressure line 30 being higher than the hydraulic pressure in the control line 20. This change in hydraulic pressure will cause hydraulic fluid to flow from the balance pressure line 30 and the accumulator 50 to the control line 20 through the flow restrictor 45. The flow restrictor 45 slows the flow from the balance pressure line 30 to the control line 20. If the pressure in the control line 20 drops too slowly or too abruptly, the compressed spring 65 will provide sufficient force to translate the operating piston 10 to the left, thereby closing the safety valve 5.This forced closure occurs after a sufficient pressure drop in the pressure-lock flow path 25, such that the potential of the compressed spring 65 can overcome the force of the pressurized hydraulic fluid remaining in the pressure-lock flow path 25.

[0027] [Fig.5] is a diagram illustrating the closing of the check valve 35 after a sufficient pressure drop in the pressure-lock flow path 25. When the flow of hydraulic fluid to the control line 20 is shut off, the hydraulic pressure in the control line 20 continues to decrease. Over time, the hydraulic pressure in the pressure-lock flow path 25 will also continue to decrease until it reaches a value below the cracking pressure of the check valve 35. At that point, the compressed spring mechanism of the check valve 35 deploys and closes the check valve 35, thereby returning to its default configuration. Because the poppet valve 40 previously closed, the pressure-lock flow path 25 is now closed to the control line 20 and the balance pressure line 30. The operating piston 10 will remain translated to the left and the safety valve 5 will remain in the closed configuration.The balance pressure line 30 will also equalize with the control line 20 over time, since these lines are not sealed to each other. The accumulator 50 also returns to its default position.

[0028] It should be understood that the exemplary system illustrated by [Fig.l]-5 is only a general application of the principles of this disclosure in practice, and a wide variety of other examples are possible. Accordingly, the scope of this disclosure is not limited in any way to the details of [Fig. 1]-5 as described herein.

[0029] The systems disclosed herein may directly or indirectly affect one or more components or pieces of equipment associated with or likely to come into contact with the systems, such as, but not limited to, well casing, well liner, completion string, insert strings, drill string, coiled tubing, slickline, wireline, drill pipe, drill collars, mud motors, downhole motors and / or pumps, cement pumps, surface mounted motors and / or pumps, centralizers, turbolizers, scrapers, floats (e.g., shoes, collars, valves, etc.), logging tools and associated telemetry equipment, actuators (e.g., electromechanical devices, hydromechanical devices, etc.), sliding sleeves, production sleeves, plugs, screens, filters, flow control devices (e.g.,inflow control devices, stand-alone inflow control devices, outflow control devices, etc.), couplers (e.g. wet-connect electro-hydraulic coupler, dry-connect coupler, inductive coupler, etc.), control lines (e.g. electrical, fiber optic, hydraulic, etc.), monitoring lines, drill bits and reamers, sensors or distributed sensors, downhole heat exchangers, valves and corresponding actuation devices, tool seals, . packers, cement plugs, bridge plugs and other wellbore isolation devices or components, and so on.

[0030] A downhole device for a wellbore is provided in accordance with the disclosure and the illustrated FIGS. An exemplary downhole device includes an operating piston configured to translate axially along the length of the safety valve; a balancing piston configured to translate axially along the length of the safety valve; wherein the balancing piston is coupled to the operating piston such that the operating piston and the balancing piston translate axially at the same time; a control line; wherein the control line forms three flow paths; wherein the first flow path of the control line is coupled to a check valve; wherein the second flow path of the control line is coupled to a poppet valve; wherein the third flow path is coupled to a flow restrictor;a pressure-lock flow path comprising three segments; wherein the first segment of the pressure-lock flow path is coupled to the check valve; wherein the second segment of the pressure-lock flow path is coupled to the poppet valve; wherein the third segment of the pressure-lock flow path is coupled to the operating piston; a pressure-balance flow path comprising four segments; wherein the first segment of the balance pressure line is coupled to the poppet valve; wherein the second segment of the balance pressure line is coupled to the flow restrictor; wherein the third segment of the balance pressure line is coupled to an accumulator; wherein the fourth segment of the balance pressure line is coupled to the balance piston;the check valve coupled to the first flow path of the control line and the first segment of the pressure-lock flow path; the flapper valve coupled to the second flow path of the control line, the second segment of the pressure-lock flow path, and the first segment of the balance pressure line; the flow restrictor coupled to the third flow path of the control line and the second segment of the balance pressure line; and the accumulator coupled to the third segment of the balance pressure line.

[0031] Additionally or alternatively, the downhole device may include one or more of the following features, individually or in combination. The control line may be a single control line and there may be no other control lines coupled to the safety valve. The safety valve may be a cable retrievable safety valve. The operating piston may be further coupled to a spring. The spring may be coupled to a sliding sleeve configured to opening or closing a poppet upon sliding of the sleeve. The poppet valve may be configured to crack at a lower pressure than the check valve. The poppet valve may be spring-loaded and may be configured to crack and open upon sufficient pressure applied from the second control line flow path; the poppet spring applies a force to the poppet such that the poppet blocks flow in the direction of the second control line flow path. The poppet valve may be configured to crack when pressure is sufficient to allow flow from the second control line flow path to the second pressure-locked flow path segment.The poppet valve may be sealed to the first segment of the balance pressure line such that pressure is applied to the poppet valve from the balance pressure line without fluid flow passing through the poppet valve from the direction of the first segment of the balance pressure line. The check valve may be spring-loaded and is configured to crack and open when sufficient pressure is applied from the pressure-locked flow path. The flow restrictor may be configured to restrict flow in either direction between the third flow path of the control line and the second segment of the balance pressure line, with the flow restriction being greater in one direction than the other.

[0032] Methods of operating a safety valve are provided in accordance with the disclosure and the illustrated FIGS. An exemplary method includes providing the safety valve to a wellbore having hydrostatic pressure, the safety valve configured to operate at the pressure of the production tubing well. The method further includes applying pressure to the safety valve using a single control line; the safety valve includes an accumulator in fluid communication with the control line, such that the pressure acting on the accumulator is fluidly connected to the pressure in the control line; the safety valve is insensitive to hydrostatic pressure.

[0033] Additionally or alternatively, the method may include one or more of the following features, individually or in combination. The safety valve may include an operating piston configured to translate axially along the length of the safety valve; a balancing piston configured to translate axially along the length of the safety valve; wherein the balancing piston is coupled to the operating piston such that the operating piston and the balancing piston translate axially at the same time; a control line extending down from a surface upstream of the hole; wherein the control line forms three flow paths; wherein the first flow path of the control line is coupled to a check valve; wherein the second flow path of the control is coupled to a check valve; wherein the third flow path is coupled to a flow restrictor; a pressure-lock flow path comprising three segments; wherein the first segment of the pressure-lock flow path is coupled to the check valve; wherein the second segment of the pressure-lock flow path is coupled to the check valve; a balance pressure line comprising four segments; the first segment of the balance pressure line being coupled to the check valve; the second segment of the balance pressure line being coupled to the flow restrictor; the third segment of the balance pressure line being coupled to the accumulator; the fourth segment of the balance pressure line being coupled to the pistonbalancing; the check valve coupled to the first control line flow path and the first pressure-lock flow path segment; the check valve coupled to the second control line flow path, the second pressure-lock flow path segment, and the first balancing pressure line segment; and the flow restrictor coupled to the third control line flow path and the second balancing pressure line flow path segment. The method may further include applying pressure to the poppet valve from the second control line flow path to crack the poppet valve; creating pressure in the pressure-lock flow path to translate the operating piston upon cracking the poppet valve; wherein translating the operating piston also translates the pistonbalanced coupled; and creating pressure in the balancing pressure line from the third flow path of the control line to close the poppet valve; wherein closing the poppet valve locks pressure in the pressure-locked flow path to maintain the balancing piston in its translated position. The method may also include reducing pressure in the control line, wherein reducing pressure in the control line releases pressure locked in the safety valve. It may also include releasing pressure stored in the accumulator when the pressure in the control line is reduced. The control line may be a single control line and there may be no other control lines coupled to the safety valve. The safety valve may be a cable-retrievable safety valve. The operating piston may be further coupled to a spring. Thespring may be coupled to a sliding sleeve configured to open or close a flapper upon sliding of the sleeve. The flapper valve may be configured to crack at a pressure lower than that of the check valve. The check valve may be spring-loaded and may be configured to crack and open upon sufficient pressure applied from the second control line flow path; the check valve spring applies a force to the check valve such that the check valve blocks flow in the direction of the second control line flow path. The check valve may be configured to crack when pressure is sufficient to allow flow from the second control line flow path to the second pressure-locked flow path segment.The poppet valve may be sealed to the first segment of the balance pressure line such that pressure is applied to the poppet valve from the balance pressure line without fluid flow passing through the poppet valve from the direction of the first segment of the balance pressure line. The check valve may be spring-loaded and is configured to crack and open when sufficient pressure is applied from the pressure-locked flow path. The flow restrictor may be configured to restrict flow in either direction between the third flow path of the control line and the second segment of the balance pressure line, with the flow restriction being greater in one direction than the other.

[0034] The provided systems are for actuating a safety valve in a wellbore in accordance with the disclosure and illustrated FIGS. An exemplary system includes a safety valve including an operating piston configured to translate axially along the length of the safety valve; a balancing piston configured to translate axially along the length of the safety valve; wherein the balancing piston is coupled to the operating piston such that the operating piston and the balancing piston translate axially in the same direction and at the same time; a control line extending down from the surface upstream of the hole; the control line forms three flow paths; the first flow path of the control line is coupled to a check valve; the second flow path of the control line is coupled to a poppet valve;the third flow path is coupled to a flow restrictor; a pressure-lock flow path comprising three segments; wherein the first segment of the pressure-lock flow path is coupled to the check valve; wherein the second segment of the pressure-lock flow path is coupled to the check valve; a balance pressure line comprising four segments; the first segment of the balance pressure line being coupled to the check valve; the second segment of the balance pressure line being coupled to the flow restrictor; the third segment of the balance pressure line being coupled to an accumulator; the fourth; the balance pressure line segment being coupled to the balance piston; the check valve coupled to the first control line flow path and the first pressure-lock flow path segment; the check valve coupled to the second control line flow path, the second pressure-lock flow path segment, and the first balance pressure line segment; the flow restrictor coupled to the third control line flow path and the second balance pressure line flow path segment; and the accumulator coupled to the third balance pressure line segment. The system further includes a spring coupled to the operating piston of the safety valve and a sliding sleeve coupled to the spring.

[0035] Additionally or alternatively, the system may include one or more of the following features, individually or in combination. The control line may be a single control line and there are no other control lines connected to the safety valve. The safety valve may be a cable-retrievable safety valve. The flow restrictor may be configured to restrict flow in both directions between the third flow path of the control line and the second segment of the equalization pressure line, with the flow restriction being greater in one direction than the other. The sliding sleeve may be coupled to a valve and the sliding sleeve is configured to open or close the valve upon sliding of the sleeve. The control line may be a single control line and there may be no other control lines coupled to the safety valve.The safety valve may be a cable-retrievable safety valve. The operating piston may be further coupled to a spring. The spring may be coupled to a sliding sleeve configured to open or close a poppet upon sliding of the sleeve. The poppet valve may be configured to crack at a lower pressure than the check valve. The poppet valve may be spring-loaded and may be configured to crack and open upon sufficient pressure applied from the second flow path of the control line; the poppet spring applies a force to the poppet such that the poppet blocks flow in the direction of the second flow path of the control line.The poppet valve may be configured to crack when pressure is sufficient to allow flow from the second flow path of the control line to the second segment of the pressure-lock flow path. The poppet valve may be sealed to the first segment of the balance pressure line such that pressure is applied to the poppet valve from the balance pressure line without fluid flow passing through the poppet valve from the direction of the first segment. of the balance pressure line. The check valve may be spring-loaded and is configured to crack and open when sufficient pressure is applied from the pressure-locked flow path. The flow restrictor may be configured to restrict flow in either direction between the third flow path of the control line and the second segment of the balance pressure line, with the flow restriction being greater in one direction than the other.

[0036] The foregoing description provides various examples of systems and methods of use disclosed herein, which may contain different method steps and alternative combinations of components. It is to be understood that, although individual examples may be discussed herein, the present disclosure covers all combinations of the disclosed examples, including, but not limited to, different combinations of components, combinations of method steps, and system properties. It is to be understood that the compositions and methods are described in terms of "comprising," "containing," or "including" various components or steps. The systems and methods may also "consist essentially of" or "consist of" different components and steps.

[0037] For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges of any lower bound may be combined with any upper bound to form a range that is not explicitly cited, just as ranges of any lower bound may be combined with any other lower bound to form a range that is not explicitly cited. Similarly, ranges of any upper bound may be combined with any other upper bound to form a range that is not explicitly cited. In addition, whenever a numerical range with a lower bound and an upper bound is disclosed, any numbers and ranges within the range are specifically disclosed.In particular, each range of values ​​(of the form "from about a to about b" or, equivalently, "from approximately a to b" or, equivalently, "from approximately ab") disclosed herein should be taken to state every number and range within the broader range of values, even if not explicitly cited. Thus, each individual point or value may serve as its own lower or upper bound combined with any other individual point or value or any other lower or upper bound, to constitute a range not explicitly cited.

[0038] One or more illustrative examples incorporating the examples disclosed herein are presented. For clarity, not all features of a physical implementation are described or illustrated in this application. Therefore, the disclosed systems and methods are well suited to achieve the objectives and advantages mentioned as well as those inherent therein. The particular examples disclosed above are given for illustration purposes only, and the teachings of this disclosure may be modified and practiced in different but equivalent ways, obvious to those skilled in the art and having the benefit of the teachings contained herein. Furthermore, no limitations are intended with respect to the details of construction or design set forth herein, other than those described in the claims below. It is therefore obvious that the particular illustrative examples disclosed above may be modified, combined, or altered, and all such variations are considered within the scope of this disclosure. The systems and methods described herein may be implemented in the absence of any element not specifically disclosed herein and / or any optional element disclosed herein.

[0039] Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and modifications may be made herein without departing from the spirit and scope of the disclosure as defined by the following claims.

Claims

1. Claims A downhole device for a wellbore comprising: an operating piston (10) configured to translate axially along the length of the safety valve (5); a balancing piston (15) configured to translate axially along the length of the safety valve; the balancing piston being coupled to the operating piston such that the operating piston and the balancing piston translate axially at the same time; a control line (20); the control line forms three flow paths; the first flow path (75) of the control line is coupled to a check valve (35); the second flow path (80) of the control line is coupled to a flap valve (40); the third flow path (85) is coupled to a flow restrictor (45); a pressure-lock flow path (25) comprising three segments; wherein the first segment of the pressure-lock flow path is coupled to the check valve; wherein the second segment of the pressure-lock flow path is coupled to the poppet valve; wherein the third segment of the pressure-lock flow path is coupled to the operating piston; a balance pressure line (30) comprising four segments; wherein the first segment of the balance pressure line is coupled to the poppet valve; wherein the second segment of the balance pressure line is coupled to the flow restrictor; wherein the third segment of the balance pressure line is coupled to an accumulator (50); wherein the fourth segment of the balance pressure line is coupled to the balance piston; the check valve coupled to the first flow path of the control line and to the first segment of the pressure-lock flow path; the flap valve coupled to the second flow path of the control line, the second segment of the pressure-lock flow path and the first segment of the balance pressure line; the flow restrictor coupled to the third flow path of the control line and to the second segment of the balance pressure line; and the accumulator coupled to the third segment of the balance pressure line.

2. The safety valve of claim 1, wherein the control line is a single control line and wherein there are no other control lines coupled to the safety valve.

3. The safety valve of claim 1 or 2, wherein the safety valve is a cable-retrievable safety valve.

4. The safety valve according to one of claims 1 to 3, wherein the operating piston is further coupled to a spring (65).

5. The safety valve of one of claims 1 to 4, wherein the spring is further coupled to a sliding sleeve (70) configured to open or close a valve upon sliding of the sleeve.

6. The safety valve of one of claims 1 to 5, wherein the flap valve is configured to crack at a lower pressure than the check valve.

7. The safety valve according to one of claims 1 to 6, wherein the flap valve is spring loaded and is configured to crack and open when sufficient pressure is applied from the second flow path of the control line; wherein the flap spring applies a force to the flap such that the flap blocks flow from the direction of the second flow path of the control line.

8. The safety valve of one of claims 1 to 7, wherein the flapper valve is configured to crack when the pressure is sufficient to allow flow from the second flow path of the control line to the second segment of the pressure-locked flow path.

9. The safety valve of one of claims 1 to 8, wherein the flap valve is sealed to the first segment of the balance pressure line such that pressure is applied to the flap valve from the balance pressure line without that a fluid flow passes through the flap valve from the direction of the first segment of the balancing pressure line.

10. The safety valve of one of claims 1 to 9, wherein the check valve is spring loaded and is configured to crack and open when sufficient pressure is applied from the pressure-locked flow path.

11. The safety valve of one of claims 1 to 10, wherein the flow restrictor is configured to restrict flow bidirectionally between the third flow path of the control line and the second segment of the balance pressure line; wherein the flow restriction is greater in one direction than in the other.

12. A method of operating the safety valve according to one of claims 1 to 11, the method comprising: a. providing the safety valve (5) to a wellbore having hydrostatic pressure; the safety valve being configured to operate at the pressure of the production tubing well; b. applying pressure to the safety valve with a single control line; the safety valve comprises an accumulator in fluid communication with the control line such that the pressure acting on the accumulator is fluidly connected to the pressure in the control line; the safety valve is insensitive to hydrostatic pressure.

13. The method of claim 12, wherein the method further comprises: a. applying pressure to the poppet valve from the second flow path of the control line to crack the poppet valve; b. increasing pressure in the pressure-lock flow path to translate the operating piston upon cracking the poppet valve; translating the operating piston will also translate the coupled balanced piston; and c. increasing pressure in the balance pressure line from the third flow path from the control line to close the poppet valve; closing the poppet valve blocks the pressure in the pressure-lock flow path to maintain the balance piston in its translated position.

14. The method of claim 12 or 13, further comprising reducing pressure in the control line, wherein reducing pressure in the control line releases trapped pressure in the safety valve.

15. The method of one of claims 12 to 14, further comprising releasing the pressure stored in the accumulator when the pressure in the control line is reduced.

16. A safety valve operating system according to one of claims 1 to 11, comprising: a. the safety valve (5); b. a spring (65) coupled to the operating piston (10) of the safety valve; and c. a sliding sleeve (70) coupled to the spring.

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