Patent Application
20200056714
Subsurface safety valves are typically installed during completions as a failsafe mechanism to prevent production flow in the event of an emergency or contingency on the surface. Conventional subsurface safety valves require the application of hydraulic pressure in a control line to open a unidirectional flapper or valve against a power spring influenced by the production tubing pressure at the setting depth. If the hydraulic pressure is removed, the power spring ideally counteracts the hydrostatic head in the control line and fully closes the unidirectional flapper or valve, thereby safely preventing uncontrolled production flow.
Conventional surface-controlled subsurface safety valves include tubing retrievable safety valves and wireline retrievable safety valves. Tubing retrievable safety valves are typically run-in as part of the production tubing string. The control line is disposed in the annulus between the safety valve and the wellbore and provides hydraulic pressure to the safety valve from the surface. The safety valve may be opened by the application of sufficient hydraulic pressure in the control line that forces the unidirectional flapper or valve open against the power spring at the setting depth. If the hydraulic pressure is removed, the power spring ideally counteracts the hydrostatic head in the control line and fully closes the unidirectional flapper or valve. While tubing retrievable safety valves must be run-in with the production tubing, they typically provide the largest inner diameter for production flow. In contrast, wireline retrievable safety valves may be run-in with a wireline or slickline. However, wireline retrievable safety valves must be landed in a profile or hydraulic landing nipple disposed within the production tubing. As such, wireline retrievable safety valves typically have a smaller inner diameter that restricts production flow as compared to tubing retrievable safety valves.
Offshore drilling and production in deep and ultra-deep waters has received renewed interest from operators. According to the International Energy Agency, a substantial portion of the remaining recoverable conventional oil and gas reserves lie below the seafloor in deep or ultra-deep waters where production is conducted in water depths between 5,000 and 12,000 feet or more. The wellbore may have a measured depth a further 10,000 feet or more below the seafloor. At depth, the downhole temperature may exceed 400° F. and the formation pressure may exceed 25,000 pounds per square inch (“PSI”). As such, the pressures encountered at deep and ultra-deep water depths present a number of challenges for subsurface safety valves.
According to one aspect of one or more embodiments of the present invention, a production tubing pressure insensitive wireline retrievable safety valve includes a locking mechanism to secure the wireline retrievable safety valve within a tubing retrievable safety valve, or within a hydraulic landing nipple. An upper packing and a lower packing create a hydraulic seal in an annulus surrounding a portion of the wireline retrievable safety valve. A hydraulic fluid intake port receives hydraulic fluid in the annulus surrounding the wireline retrievable safety valve within the hydraulic seal from the surface. The hydraulic fluid is communicated via at least one hydraulic fluid passage to a piston shoulder chamber disposed below the hydraulic seal to move a power piston under actuation pressure and compress a power spring disposed within a gas chamber. A ball valve disposed above the hydraulic chamber and connected to the power piston moves a ball off seat when the power piston is forced down. At least one flow port that allows fluid communication from the annulus surrounding a portion of the wireline retrievable safety valve below the hydraulic seal into a central lumen of the wireline retrievable safety valve exposed when the ball is moved off seat.
According to one aspect of one or more embodiments of the present invention, a production tubing pressure insensitive wireline retrievable safety valve includes a locking mechanism to secure the wireline retrievable safety valve within a tubing retrievable safety valve, or within a hydraulic landing nipple. An upper packing creates an upper hydraulic seal on an annulus between the wireline retrievable safety valve and the tubing retrievable safety valve above a hydraulic fluid intake port. A spacer disposes the hydraulic fluid intake port below a primary valve of the tubing retrievable safety valve. A lower packing creates a lower hydraulic seal on the annulus between the wireline retrievable safety valve and the tubing retrievable safety valve, or hydraulic landing nipple, below the hydraulic fluid intake port and the primary valve of the tubing retrievable safety valve, or within the hydraulic landing nipple. The upper hydraulic seal and the lower hydraulic seal form a hydraulic seal. A lower packing housing includes a first hydraulic fluid passage in fluid communication with the hydraulic fluid intake port and a production tubing pressure insensitive valve assembly. The valve assembly includes a seat housing having a second hydraulic fluid passage in fluid communication with the first hydraulic fluid passage and at least one flow port. A spring housing has a diameter smaller than the seat housing. A hydraulic chamber housing includes a third hydraulic fluid passage in fluid communication with the second hydraulic fluid passage. The third hydraulic fluid passage is in fluid communication with a piston shoulder chamber. The hydraulic chamber housing connects the seat housing to the spring housing. A hard seat is disposed near a distal end of the lower packing housing within the seat housing. A soft seat is disposed near a distal end of the hard seat. A ball is disposed near a distal end of the soft seat. A power piston is connected on a first distal end to the ball and on a second distal end to a nose cap housing. The power piston extends through the hydraulic chamber housing. An upper power seal seals an annulus surrounding the power piston and an upper portion of the hydraulic chamber housing. An upper power seal retainer retains the upper power seal in place. An intermediate power seal seals an annulus surrounding the power piston and a lower portion of the hydraulic chamber housing. The intermediate power seal has a diameter smaller than the upper power seal and a lower power seal. An intermediate power seal retainer retains the intermediate power seal in place. A spring ring is disposed on a top distal end of a power spring disposed within the spring housing. A nose cap housing is connected to a bottom distal end of the spring housing. The lower power seal seals an annulus surrounding the power piston and an upper portion of the nose cap housing. A lower power seal retainer retains the lower power seal in place.
According to one aspect of one or more embodiments of the present invention, a method of providing a deep set production tubing pressure insensitive wireline retrievable safety valve in a failed tubing retrievable safety valve includes running a communication tool into the tubing retrievable safety valve, communicating the tubing retrievable safety valve, landing a production tubing pressure insensitive wireline retrievable safety valve within a no-go shoulder profile of the tubing retrievable safety valve, locking the wireline retrievable safety valve to the tubing retrievable safety valve, and controlling an actuation pressure of the production tubing pressure insensitive wireline retrievable safety valve from the surface.
Other aspects of the present invention will be apparent from the following description and claims.
One or more embodiments of the present invention are described in detail with reference to the accompanying figures. For consistency, like elements in the various figures are denoted by like reference numerals. In the following detailed description of the present invention, specific details are set forth in order to provide a thorough understanding of the present invention. In other instances, well-known features to one of ordinary skill in the art are not described to avoid obscuring the description of the present invention.
In deep and ultra-deep water applications, tubing retrievable safety valves have a depth setting limitation due to the high hydrostatic head pressure in the control line that increases with depth. If the setting depth and hydrostatic head in the control line is excessive, the power spring within the tubing retrievable safety valve will not be able to sufficiently lift the hydraulic fluid in the control line (uncompress the power spring) to allow the valve to fully close. In an attempt to address this serious limitation, some tubing retrievable safety valves include a nitrogen charged chamber that offsets the hydrostatic head pressure. However, nitrogen charged tubing retrievable safety valves are expensive and, due to their complex design, do not include redundancy. To date, the industry has not had success in designing a wireline retrievable safety valve that reliably works at the required setting depths for the same reasons. In addition, the elevated actuation pressure required due to the production tubing pressure at the required setting depths has proven problematic. As such, the failure of a tubing retrievable safety valve in deep or ultra-deep water applications is a significant, if not catastrophic, event. However, in the field, such failures are frequently occurring at substantial cost to ongoing operations.
Production tubing pressure variations, including directional pressure reversals across sealing elements, have caused various sealing elements within the tubing retrievable safety valve to fail, resulting in the loss of nitrogen that ultimately reduces or eliminates the ability of the power spring of the safety valve to fully close at extended setting depths. Because nitrogen charged tubing retrievable safety valves do not include redundancy, when the safety valve fails, there is no viable option to continue production operations. Production operations must be ceased and the production tubing string must be pulled at substantial expense, including non-productive time, to repair or replace the failed tubing retrievable safety valve. In addition, once the production tubing retrievable safety valve fails, there are significant safety and environmental risks as well. As such, there is a long felt, but unsolved need in the industry for a wireline retrievable safety valve capable of deployment within a failed tubing retrievable safety valve at extended setting depths encountered in deep and ultra-deep water applications.
Accordingly, in one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve provides a wireline solution that does not require nitrogen assisted lift that allows for controlled production flow through a failed tubing retrievable safety valve disposed at extended setting depths encountered in deep or ultra-deep water applications. The wireline retrievable safety valve may be landed within a no-go shoulder or internal landing profile of the failed tubing retrievable safety valve and controllably open or close in a manner that is not sensitive to production tubing pressure. The safety valve may include a power spring disposed within a gas chamber below a ball valve that is not exposed to production tubing pressure and does not require nitrogen to uncompress. An upper power seal and a lower power seal may be disposed on opposing distal ends of a power piston and have the same diameter, thereby canceling out production tubing pressure forces acting on the power piston. As such, the wireline retrievable safety valve allows for an actuation pressure that is substantially lower than the production tubing pressure and ensures full closure of the ball valve when the actuation pressure is removed. In addition, the seals are not exposed to pressure reversals and the reliability of the valve mechanism is increased.
Prior to deployment of a deep set production tubing pressure insensitive wireline retrievable safety valve (not shown), the failed tubing retrievable safety valve 100 must be punctured for hydraulic fluid communication and the valve mechanism must be locked open. A puncture communication tool (not shown) may be run-in to the failed tubing retrievable safety valve 100 to puncture the sidewall of the safety valve 100 and the hydraulic fluid conduit 120 below a no-go shoulder or internal landing profile 105 and an upper polished bore 110 of the safety valve 100. The puncture allows communication of hydraulic fluid (not shown) between the floating rig or platform on the surface of the body of water (not shown) and the central lumen (not shown) of the tubing retrievable safety valve 100, by way of hydraulic fluid injection port 115. Once communicated, a lock-open tool (not shown) may be run-in to the failed tubing retrievable safety valve 100 to push down the flow tube (not shown) and compress the power spring (not shown) such that the primary flapper or valve (not shown) remains in a locked open position rendering the failed tubing retrievable safety valve 100 inoperable as a safety valve by itself.
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Power spring 289 may be disposed within a gas chamber formed by spring housing 290, intermediate power seal 284, hydraulic chamber housing 272, lower power seal 284, and nose cap housing 298. The gas chamber may be voided, filled with air, or charged with one or more gases, including potentially, nitrogen, although nitrogen charging is not required to uncompress power spring 289 at deep or ultra-deep water setting depths. While upper power seal 260 and lower power seal 294 are in communication with production tubing pressure, both seals have the same diameter and are disposed on opposing ends of power piston 280. As such, their pressure areas are the same and the forces acting on the power piston 280 effectively cancel each other out. As such, power spring 289 may not be exposed, or sensitive, to production tubing pressure. Thus, the actuation pressure required to compress power spring 289 may be substantially less than the production tubing pressure and when that actuation pressure is removed, power spring 289 does not require nitrogen charging to uncompress and fully close the valve 200 at a deep or ultra-deep water application setting depth.
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Advantages of one or more embodiments of the present invention may include one or more of the following:
In one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve provides a wireline solution that allows for controlled production flow through a failed tubing retrievable safety valve disposed in deep or ultra-deep water applications that typically requires removal of the production tubing string.
In one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve may be landed within a no-go shoulder profile of a failed tubing retrievable safety valve deployed in a deep or ultra-deep water wellbore.
In one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve is production tubing pressure insensitive. The safety valve may be controllably opened or closed in deep or ultra-deep water applications in a manner that is independent of the production tubing pressure.
In one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve provides an actuation pressure that is substantially lower than the production tubing pressure at a setting depth of the wireline retrievable safety valve.
In one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve includes seals that are not exposed to pressure reversals and increases reliability of the seals and the safety valve.
In one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve includes an upper power seal and a lower power seal that are exposed to production tubing pressure on opposing ends of the power piston that cancel each other out.
In one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve includes a power spring disposed within a gas chamber below the ball valve that is not exposed to production tubing pressure.
In one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve includes a power spring disposed within a gas chamber below the ball valve that is not sensitive to production tubing pressure.
In one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve includes a power spring disposed within a gas chamber below the ball valve that does not require nitrogen charging to uncompress at a setting depth, but the gas chamber may be voided, filled with air, or charged with one or more gases, potentially including nitrogen.
In one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve includes an upper power seal and a lower power seal that seal an annulus surrounding the power piston and are exposed to production tubing pressure.
In one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve include an upper power seal and a lower power seal that have the same diameter to cancel out production tubing pressure forces acting on opposing ends of the power piston.
In one or more embodiments of the present invention, a deep set production tubing pressure insensitive wireline retrievable safety valve includes an upper power seal, an intermediate power seal, and a lower power seal that are not exposed to pressure reversals and therefore increases reliability.
While the present invention has been described with respect to the above-noted embodiments, those skilled in the art, having the benefit of this disclosure, will recognize that other embodiments may be devised that are within the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the appended claims.
| Number | Date | Country | |
|---|---|---|---|
| 62718737 | Aug 2018 | US |
