Patent ID: 12203339

DETAILED DESCRIPTION

Reference will now be made to the exemplary embodiments illustrated in the drawings, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Alterations and further modifications of the inventive features illustrated herein, and additional applications of the principles of the inventions as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention. For purposes of this detailed description, the term downhole refers to a direction that is down the well bore of the well, and generally means relatively lower or below a referenced feature. Thus, downhole, below, lower and downward are similar in meaning in relation to positioning of features or elements of the present invention. Similarly, the term uphole refers to a direction that is up the well bore of the well, and generally means relatively higher, upward or above a referenced feature or element. Thus, the terms uphole, above, upper, and upward are similar in meaning in relation to positioning of features or elements in the present invention.

The embodiments of the present invention described herein generally provide for a valve system for a wellhead of a well such as an oil well. The valve system can include a Back Pressure Valve (BPV) with a valve tool that can be installed into the BPV with a dry rod and J-tool also known in the art. The valve tool can have an o-ring groove with an o-ring seal that can seal against a sealing surface of the BPV. When the valve tool is positioned such that the o-ring can seal with the BPV, the valve tool can act like a Two-Way Check Valve (TWCV) such that flow through the valve tool is restricted when the valve tool is in a sealed or closed position and flow is unrestricted when the valve tool is in an open position. Advantageously, both the valve tool and the BPV can remain in the tool and function simultaneously so that the BPV need not be removed in order to restrict flow in both directions in the well. This allows pressure testing of equipment and tools connected to the well head without engaging the BPV. When the testing is complete, the valve system can be removed by turning the valve tool to lower the o-ring away from the seal surface thereby allowing pressure to bleed off, and then continuing to lower the valve tool until engagement with the BPV is achieved. Then both the valve tool and the BPV can be removed from the wellhead without the need for attaching any additional removal tooling. Advantageously the process of the present invention eliminates tooling changes and improves efficiency of the pressure testing of uphole equipment and tooling such as a Christmas tree, blow-out preventor, and the like.

As illustrated inFIGS.1-4, a valve system for a wellhead of a well, indicated generally at10, is shown in accordance with an embodiment of the present invention for use in selectively restricting flow through the wellhead of the well. The valve system10can restrict the flow through the wellhead by being selectively configured in either an open or unrestricted configuration with no impediment to flow through the valve system, a one-way flow configuration with impediments to uphole flow so that only downhole flow can pass through the valve system, or a completely restricted configuration where no flow through the valve system is possible. The valve system10can include a Back Pressure Valve (BPV), indicated generally at20, and a valve tool, indicated generally at50.

The BPV20and the valve tool50can work together to selectively configure the valve system10to a desired flow configuration. In this way, the BPV and the valve tool can convert the valve system10from a fully functional BPV to a fully functional Two-Way Check Valve (TWCV) without having to remove either the BPV or the valve tool from the wellhead. It is a particular advantage of the present invention that the valve system can be configured as either a BPV or a TWCV since both types of valves are needed during the wellhead service and maintenance processes and being able to convert between the two types without having to remove one or the other saves considerable time and resources in addition to being safer for the wellhead and nearby personnel alike.

The BPV20can be removably disposable in a tubing hanger, indicated generally at4, that can be disposed in a well bore (not shown). The BPV can have a tubing hanger seal8that can seal the BPV in the tubing hanger. A bore22can extend through the BPV from a downhole end24disposed relatively lower in the well bore and to an uphole end25disposed relatively higher in the well bore.

Advantageously, the valve system10can also be installed in the tubing hanger4prior to deployment of the tubing hanger in a well and subsequently transported for fit out in a well. In one aspect, the BPV20can be installed in the tubing hanger before the tubing hanger is installed in a well. This is advantageous because it allows the valve system to be pressure tested before being deployed to the oil field and installed in a well. It will be appreciated that testing the placement and seal of the BPV in the tubing hanger before the tubing hanger is installed in a well saves time, money and other valuable resources in the field, since it provides an already tested BPV to the well.

A poppet26can be movably disposed within the bore22of the BPV20. The poppet can have a poppet seal28and a stem29. The stem can extend upward in an uphole direction away from the poppet seal. The poppet can be movable in the bore between a one-way flow position as best seen inFIG.3and a bidirectional flow position as best seen inFIG.4. When the poppet is in the one-way flow position, the seal28on the poppet can seal against a mating sealing surface30on the bore of the BPV.

The poppet26can be biased to the one-way flow position by a biasing device, indicated generally at32. In one aspect, the biasing device can be a spring34that presses the poppet upward to force the seal28onto the sealing surface30of the bore22of the BPV20. In this way, fluid flow through the BPV20is restricted to downhole flow only provided the fluid has enough pressure to overcome the force of the biasing device and move the poppet away from the sealing surface. Uphole flow from below the poppet can press the poppet against the sealing surface which tightens the seal and prevents flow upward. Hence the BPV can restrict flow to only the downhole direction when the poppet is in the one-way position.

The BPV20can also have an internal thread36. The internal thread can be positioned uphole from the poppet26. An o-ring seal surface38can be disposed in the bore22and positioned uphole from the internal thread.

The bore22can also have a flow chamber40. The flow chamber can be positioned uphole from the internal thread36and downhole from the o-ring sealing surface38. The flow chamber can have a relatively larger diameter than the internal thread and the o-ring sealing surface.

With the BPV20installed and sealed in the tubing hanger4, the wellhead tree or other equipment attached to the wellhead can be isolated from the pressure migrating across the BPV from the well cavity (not shown) below the BPV. The wellhead tree or other equipment can then be removed from the wellhead since the BPV isolates and restricts flow upward from the well. In this configuration, with the BPV installed in the hanger tubing, it is possible to pump downhole through the BPV if the well should need to be closed off.

The valve tool50can be removably disposable in the bore22of the BPV20. The valve tool can have a valve body52having a downhole end54and an uphole end56. The valve tool body52can have an external thread58associated with the downhole end54. The external thread can be sized and shaped to engage the internal thread36on the BPV20when the valve tool50is rotated into the internal thread.

The valve tool50can have an o-ring groove60positioned uphole of the external thread56. The o-ring groove can be sized and shaped to hold an o-ring62. In one aspect, the o-ring groove can be associated with a circumferential protrusion66on the valve body52. The protrusion66can have a diameter relatively larger than a diameter of the internal threads of the BPV20and relatively larger than a diameter of the valve body upward or uphole of the o-ring groove.

The circumferential protrusion66provides an advantage to the present invention in that it requires less contact between the valve tool body52and the bore22of the BPV. It will be appreciated that more contact can lead to greater resistance due to friction and drag, and would thus need more force to move the o-ring groove60into a desired position. The circumferential protrusion minimizes the contact between the valve tool body and the bore and thus requires less force to move.

Additionally, having the o-ring62and o-ring groove60above the external thread56of the valve tool50can provide an advantage in that it provides a pulling force rather than a pushing force on the o-ring groove and o-ring which can require less overall torque via the threads to move the o-ring groove and o-ring into position. Additionally, having the o-ring groove and o-ring uphole from the threads can reduce sediment and foreign material from the threads to settle on the o-ring which could compromise the sealing ability of the o-ring. Likewise, the o-ring seal can prevent material from falling down in to the threads which could result in the BPV becoming stuck due to foreign material binding in the threads.

In use, the valve tool50can be moved upward and downward within the bore22by rotating the external thread58on the valve tool into the internal thread36of the BPV20. In this way, the valve tool can be moved between a closed position as best seen inFIG.2, a partially open position as best seen inFIG.3, and a fully open position as best seen inFIG.4. With the valve tool installed migration of pressure in either direction in the well can be restricted and new equipment, such as a well tree or blowout preventer, can be installed and the connections of the equipment to the wellhead can be pressure integrity tested from above.

In the closed position shown inFIG.2, the o-ring groove60and o-ring62are positioned adjacent to the sealing surface38in the BPV. The o-ring62can be disposed within the o-ring groove60such that the o-ring can contact and seal against the seal surface38of the BPV20when the o-ring groove is in the closed position. With the o-ring sealed against the seal surface flow cannot pass through the valve system10in either direction.

In the partially open position shown inFIG.3, the o-ring groove60and o-ring62are positioned within the flow chamber40. In this position the o-ring62does not contact any surfaces of the BPV and fluid can flow freely past the o-ring. However, while fluid can flow in either direction past the o-ring, flow is still restricted via the poppet26in the BPV20to downhole flow having sufficient pressure to overcome the biasing device holding the poppet closed. Uphole flow from below the poppet is still restricted by the poppet in the BPV. In this way the valve system10of the present invention is in a partially open configuration since fluid can flow but only in one direction through the valve system.

In the fully open position shown inFIG.4, the o-ring is positioned in the flow chamber40of the BPV as described above, but in this position, the valve body52has been rotated sufficiently to move the valve body52into contact with the stem29. In one aspect, a relief hole70can be disposed in the downhole end54of the valve body. The relief hole can be sized and shaped to receive and engage the stem29of the poppet26. With the relief hole engaged with the stem of the poppet, the poppet can be selectively moved in the downhole direction by the valve tool50to position the poppet in the bidirectional flow position such that the valve tool50is in the fully open position and the poppet is in an open bidirectional flow position thereby allowing bidirectional flow through the valve system10.

The relief hole70can provide an advantage to the valve system10of the present invention since it is recessed within the valve tool body52. This recess lessens the total height or end to end length of the valve system10, thereby allowing the system of the present invention to be installed below the master valve (not shown) of the well tree (not shown) such that the master valve can be closed with the present invention, or portions thereof, installed in the well tubing hanger4.

Once the pressure integrity testing of newly installed equipment on the wellhead is complete, the valve system10can be retrieved from the well. Hence, the present invention can also have a contact shoulder76positioned on the valve body52uphole from the o-ring groove60. The contact shoulder can be sized and shaped to contact the uphole end25of the BPV20such that the shoulder contacts and stops further downhole movement of the valve tool50with the valve tool in the fully open position. In the fully open position, the flow can move in either direction past the valve tool and the poppet26in the BPV. In this way, the different sides of the valve system can equalize in pressure from above and below the BPV. With the pressure difference relieved across the BPV, continued torque on the valve tool50transmits torque to the body of the BPV resulting in the BPV being threadably removed from the wellhead tubing hanger4such that the BPV can be removed from the wellhead.

It will be appreciated that being able to remove the BPV by using the valve tool50is a particular advantage to the present invention since the BPV would otherwise require the valve tool to be removed and another tool sent down the wellhead to engage and remove the BPV. Being able to remove the BPV with the valve tool saves time in servicing the wellhead and provides a safer work space since fewer tools and materials are required in the wellhead and fewer trips down the well are needed.

Additionally, if well pressure is noted when the poppet seal30disengages from the BPV20, the valve tool50can be reversed until the BPV re-engages the tubing hanger4thus putting the well back under control of the BPV until the pressure in the well can be addressed.

As shown inFIG.5, the present invention also provides for a method for pressure testing a wellhead of a well using a valve system having a Back Pressure Valve (BPV) and a valve tool, indicated generally at300, including the step of setting the BPV in a tubing hanger shown at310. The valve tool can be lowered with an installation tool into the tubing hanger to engage the BPV shown at315. The valve tool can be rotated until a seal of the valve tool is engaged with a seal surface of the BPV shown at320. The installation tool can be removed from the valve tool325.

The test flange can be installed onto the well head above the BPV and valve tool330. The pressures in the well head can be tested via the test flange335. The installation tool can be reinstalled onto the valve tool340. The valve tool can be lowered with the installation tool until the seal of the valve tool is disengaged from the BPV345. The valve tool can be lowered further until a relief hole on a downhole end of the valve tool engages a poppet in the BPV and unseats the poppet allowing any built-up pressure to escape350. The valve tool can be rotated further to disengage the BPV from the tubing hanger355, and the valve system can be retrieved from the well shown at360.

The step of retrieving the valve testing system includes using the installation tool such that the BPV is removed with the valve tool via the installation tool. The step of testing the pressures includes using test pressures required by industry standards and an have pressures of more than approximately 15,000 psi.

Other benefits of the present invention include being able to use the same standard BPV and TWCV running and retrieving tools when using the BPV in an isolated configuration. Additionally, if the present invention is used as a TWCV then the BPV can be set and left in the hanger for when it is needed later to run the pressure integrity checks of an upper connection. Moreover, the present invention increases well control because the BPV can stay in place throughout nipple down and nipple up operations when well trees and tooling are installed and removed from the wellhead. Furthermore, as previously noted the present invention can reduce the total number of trips required downhole in order to perform service and maintenance on the well. Similarly, this results in a reduced risk to personnel since there are fewer times users are in operating in the dangerous red zones of an oil well. Also, overall, the present invention reduces the risk of a failed TWCV test as the BPV stays in the well with seal integrity maintained.

It is to be understood that the above-referenced arrangements are only illustrative of the application for the principles of the present invention. Numerous modifications and alternative arrangements can be devised without departing from the spirit and scope of the present invention. While the present invention has been shown in the drawings and fully described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred embodiment(s) of the invention, it will be apparent to those of ordinary skill in the art that numerous modifications can be made without departing from the principles and concepts of the invention as set forth herein.