Pipe ram annular adjustable restriction for managed pressure drilling with changeable rams

Abstract

An apparatus includes a housing and at least two pipe ram systems engageable with the housing. Each of the at least two pipe ram systems comprises an actuator, a bonnet and a sealing pipe ram element. The at least two pipe ram systems are disposed on opposed sides of the housing. A carousel is disposed proximate at least one of the at least two pipe ram systems. The carousel has mounted thereon a plurality of pipe ram systems. The carousel is rotatable to orient a selected one of the plurality of pipe ram systems toward a receiving bore in the housing.

Claims

1. A system, comprising: a drill string extending into a wellbore drilled through subsurface formations; a pump having an inlet in fluid communication with a supply of drilling fluid, the pump having an outlet in fluid communication with an interior of the drill string; a conduit extending from a selected axial position in the wellbore to a position proximate a surface end of the wellbore; at least one well fluid outflow control disposed on an interior surface of the conduit; wherein the at least one well fluid outflow control comprises a first pipe ram system, a second pipe ram system, and a carousel carrying thereon a plurality of interchangeable pipe ram systems, the first and second pipe ram systems disposed on opposite sides of a well fluid outlet control housing, and the first and second pipe ram systems selectively operable to provide a controlled flow restriction between the first and second pipe ram systems and the drill string; and wherein the carousel is disposed proximate the well fluid outlet flow control housing and is operable to rotate to a position such that one of the plurality of interchangeable pipe ram systems is in alignment with a bore on the well fluid outlet control housing.

2. The system of claim 1 wherein each of the first pipe ram system, the second pipe ram system, and the plurality of interchangeable pipe ram systems comprises a linear actuator.

3. The system of claim 2 wherein each of the first pipe ram system, the second pipe ram system, and the plurality of interchangeable pipe ram systems comprises a linear position sensor arranged to measure a respective amount of linear movement of each of the first pipe ram system, the second pipe ram system, and the plurality of interchangeable pipe ram systems.

4. The system of claim 1 wherein each of the first pipe ram system, the second pipe ram system, and the plurality of interchangeable pipe ram systems comprises a linear position sensor arranged to measure an amount of linear movement of a respective ram seal element forming part of the first pipe ram system, the second pipe ram system, and the plurality of interchangeable pipe ram systems.

5. The system of claim 1 further comprising a pressure sensor arranged to measure pressure of drilling fluid between the drill string and the conduit at a position below the at least one well fluid outflow control.

6. The system of claim 1 further comprising at least one flow meter arranged to measure rate of flow of drilling fluid into the drill string from the pump.

7. The system of claim 1 further comprising a flow meter arranged to measure a rate of flow of drilling fluid out of the conduit.

8. The system of claim 1 further comprising a pressure sensor arranged to measure pressure of drilling fluid at an inlet to the interior of the drill string.

9. The system of claim 1 further comprising a control unit in signal communication with a pressure sensor arranged to measure pressure of drilling fluid at an inlet to the interior of the drill string, the control unit in signal communication with a flow rate sensor arranged to measure a flow rate of fluid into the interior of the drill string, and at least one of a flow rate sensor arranged to measure a rate of fluid outflow from the conduit and a pressure sensor arranged to measure a pressure of fluid in the wellbore upstream of the well fluid outflow control, the control unit operable to maintain a selected fluid pressure in the conduit by selectively operating the plurality of pipe ram systems.

10. A method, comprising: pumping drilling fluid through a drill string extended into a wellbore drilled through subsurface formations; returning the pumped drilling fluid through an annular space between an exterior of the drill string and an interior of a conduit disposed to a selected depth in the wellbore; selectively restricting outflow of fluid from the interior of the conduit by operating at least one well fluid outflow control disposed in the conduit, the at least one well fluid outflow control comprising a first pipe ram system, a second pipe ram system, a housing, and a carousel disposed proximate the housing, the carousel having thereon a plurality of interchangeable pipe ram systems, and the first and second pipe ram systems disposed in the housing and selectively operable to provide a controlled flow restriction between the first and second pipe ram systems and the drill string; withdrawing the first pipe ram system from the housing to the carousel; rotating the carousel such that one of the plurality of interchangeable pipe ram systems on the carousel other than the first pipe ram system is in alignment with a receiving bore in the housing; and engaging the one of the plurality of interchangeable pipe ram systems in the receiving bore.

11. The method of claim 10 further comprising measuring a pressure of the drilling fluid in the conduit below the well fluid outflow control, and automatically operating the at least one well fluid outflow control to maintain a selected pressure in the wellbore.

12. The method of claim 10 further comprising measuring a pressure of drilling fluid entering an interior of the drill string and measuring a flow rate of drilling fluid entering the drill string or a flow rate of drilling fluid exiting the conduit, and automatically operating the at least one well fluid outflow control to maintain a selected measured pressure and measured flow rate.

13. The method of claim 10 further comprising measuring a linear extension of pipe ram on each of the first pipe ram system and the second pipe ram system and controlling the linear extension in response to the measured linear extension and a measured pressure of fluid pumped into the drill string.

14. The method of claim 10 wherein: the housing comprises an additional carousel on an opposite side of the housing from the carousel, the additional carousel comprising a plurality of interchangeable pipe ram systems thereon; withdrawing the second pipe ram system from the housing to the additional carousel; rotating the additional carousel such that one of the plurality of interchangeable pipe ram systems of the additional carousel other than the second pipe ram system is aligned with the receiving bore; and engaging the one of the plurality of interchangeable pipe ram systems of the additional carousel with the receiving bore.

15. An apparatus, comprising: a housing; a first pipe ram system and a second pipe ram system each engageable with the housing and comprising an actuator, a bonnet and a sealing pipe ram element, the first and second pipe ram systems disposed on opposed sides of the housing; and a carousel disposed proximate at least one of the first and second pipe ram systems, the carousel having mounted thereon a plurality of interchangeable pipe ram systems, the carousel rotatable to orient a selected one of the plurality of interchangeable pipe ram systems toward a receiving bore in the housing.

16. The apparatus of claim 15 wherein each of the plurality of interchangeable pipe ram systems mounted on the carousel comprises an actuator, a bonnet and a sealing pipe ram element.

17. The apparatus of claim 15 wherein at least one of the first and second pipe ram systems comprises a linear position sensor arranged to measure an amount of linear movement of the at least one pipe ram system.

18. The apparatus of claim 15 wherein each of the plurality of interchangeable pipe ram systems comprises a linear position sensor arranged to measure an amount of movement of the respective interchangeable pipe ram system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an example embodiment of a drilling system including a well pressure control apparatus.

(2) FIG. 2 shows an example embodiment of a drilling system including a well outflow control according to the present disclosure used in connection a well pressure control apparatus.

(3) FIG. 3 shows a detailed view of one example embodiment of a well outflow control. The example embodiment is shown in two different installations; one on a land based drilling unit and another on a riser used in marine drilling.

(4) FIGS. 4 and 5 show a side view and a top view, respectively, of a single, opposed actuator pipe ram.

(5) FIGS. 6 and 7 show a top view, respectively, of a double opposed-ram well fluid outflow control and an opposed actuator pipe ram with interchangeable ram and actuator assemblies.

DETAILED DESCRIPTION

(6) An example embodiment of a well drilling system 100 that may be used with a well fluid discharge control may be better understood with reference to FIG. 2. The well drilling system 100 may comprise many of the same components described with reference to the well drilling system shown in FIG. 1 and described above.

(7) Components of the example embodiment of the well drilling system in FIG. 2 may omit the backpressure system 131 and the components therein, including, for example the variable orifice choke (130 in FIG. 1), the secondary pump 128, and external to the backpressure system 131, valves 5, 125 lines 4, 119A and 119B. The RCD at the upper end of the BOP 142 may also be omitted. Flow out of the annulus 115 may be controlled by a well fluid outflow control 135 disposed in the well casing 101, above a BOP stack (not shown in FIG. 2). The well casing 101 may comprise a fluid discharge line 124 connected to the wellbore 106 above the well outflow control 135, such that the fluid actually discharged from the wellbore 106 may be at atmospheric pressure, and the wellbore 106 may not need a rotating sealing element such as a RCD (as shown in FIG. 1).

(8) The well fluid outflow control 135 will be further explained below with reference to FIG. 3. In the present example embodiment of a well drilling system, pressure in the annulus 115 may be maintained by communicating to the control system 146 signals from the flow meter 152, pressure transducer 116, pressure sensor 147 and in some embodiments a second flow meter 126 disposed in the fluid discharge line 124. Control signals from the control system 146 may operate the well fluid outflow control 135 and the mud pump(s) 138 to maintain a selected fluid pressure in the annulus 115. The selected fluid pressure may be calculated substantially as explained above with reference to FIG. 1 and in a manner similar to operation of a controllable choke as disclosed in U.S. Pat. No. 6,904,891 issued to van Riet, incorporated herein by reference in its entirety. When the mud pump(s) are switched off, such as during adding a segment of dill pipe to the drill string 112 or removing a segment therefrom, pressure in the annulus 115 may be maintained using the fluid injection system comprising the injection fluid supply 143 which may comprise a storage tank and one or more injection pumps (not shown separately) and the pressure measurement generated by the injection fluid pressure sensor disposed anywhere in the injection fluid supply passage, e.g., at 156.

(9) One example embodiment of a well outflow control is shown schematically in FIG. 3. The well fluid outflow control 135 may comprise one or more pipe ram(s) 10 of types known to be used in blowout preventers (BOPs). Pipe rams may comprise one or more sealing elements (not shown separately for clarity) configured to sealingly engage the exterior of tubular members such as drill pipe, drill collars and other drill string components passing through a center bore of the pipe ram 10 when an associated actuator 11 is operated to urge the one or more sealing elements toward the tubular member. In some embodiments, the pipe ram may comprise two, opposed, substantially identical pipe rams that move in opposed directions when actuated. An example pipe ram that may be used in some embodiments is described on the Internet site Drillingformulas.com, in an article entitled, Ram Preventers as Well Control Equipment, available at the URL http://www.driliingformulas.co/ram-preventers-as-well-control-equipment/downloaded on Dec. 16, 2016. The pipe ram(s) 10 may be operated by the control system 146 to restrict upward flow of drilling fluid out of the wellbore (112 in FIG. 2) so as to maintain a selected setpoint fluid pressure in the wellbore (112 in FIG. 2). A fluid pressure in the wellbore upstream of the well fluid outflow control 135 may be measured by a pressure sensor 15 in fluid communication with a control line 14 coupled to or below the pipe rams 10. Flow rate may be measured in the control line 14 using a flow meter 17, for example a mass flow meter or a Coriolis-type flow meter. Signals from the pressure sensor 15 and the flow meter may be conducted to the control unit (146 in FIG. 2) to enable more precise control of the pipe rams 10 in maintaining a selected pressure in the wellbore (112 in FIG. 2) below the pipe rams 10. After leaving the pipe rams 10, fluid leaving the wellbore may be returned to the well drilling system substantially as explained with reference to FIG. 2.

(10) For land drilling, or for marine drilling with an open riser, the components shown in FIG. 3 above dividing line 19, including flow spool 12 below the pipe rams 10 may be provided. For certain types of marine drilling, wherein pressure control equipment is provided below the bottom of a drilling riser, equipment used to connect the drilling riser to a wellhead 30 on the water bottom may be used. Such equipment may comprise a BOP stack 22, a lower marine riser package 20 and a connector 16 to couple the riser to the lower marine riser package 20. Irrespective of whether the land/marine embodiment or the marine embodiment is used, the pipe ram(s) 10 may provide an automatically (or manually) adjustable flow restriction acting as the well fluid outflow control 135 so that a selected wellbore pressure or wellbore pressure profile is maintained in the well below the well fluid outflow control 135 without the need to use a rotating control device or similar rotating fluid pressure control apparatus. In some embodiments, the actuator(s) 11 may comprise a linear position sensor 11A in signal communication with the control unit (146 in FIG. 2). Measurements of position of the actuator may be used by the control unit 146 to more precisely control the actuator(s) and may be used in some cases to detect a well fluid influx or a loss of well fluid to one or more formations. Techniques for using linear position sensor measurements for such purpose are described in U.S. Pat. No. 7,562,723 issued to Reitsma.

(11) Control of well pressure may be performed automatically by accepting as input to the control system (146 in FIG. 20 measurements made by the various sensors explained with reference to FIGS. 2 and 3, and by the configuring the control system (146 in FIG. 2) to send suitable control signals to the actuators 11 on the pipe rams 10 to maintain the correct restriction on fluid outflow from the wellbore (112 in FIG. 2).

(12) An example embodiment of an opposed-element pipe ram 10 is shown in cut away (with housing omitted to show the active components) side view in FIG. 4 and top view in FIG. 5. The pipe ram 10 may include an actuator 11, which may be for example an hydraulic, pneumatic or electric actuator disposed on opposed sides of the drill string 112. The actuators 11 cooperate with a bonnet 11B to move corresponding ram seal elements 11C to selected distances from the drill string 112 such that the pipe ram 10 may provide suitable well fluid outflow control as described with reference to FIG. 2. For purposes of the present description, a combination of an actuator 11, a bonnet 11B and a ram seal element 11C may be referred to for convenience as a ram system.

(13) Another possible embodiment of a well fluid outflow control using pipe rams 10 is shown in top view in FIG. 6. Two sets of opposed element pipe rams 10, 55, oriented at right angles to each other may be stacked vertically at right angles to each other (so as to minimize the vertical space requirement of the two sets of opposed element pipe rams 10, 55, although such feature is not intended to limit the scope of the present disclosure. In some embodiments, the two sets of opposed pipe rams 10, 55 may be disposed in the same pipe ram housing 11D and such sets of opposed element pipe rams 10, 55 may be individually controllable, e.g., by having a separate control line to the control system (146 in FIG. 2) for each ram actuator (11B in FIGS. 4 and 5), or the opposed element pipe rams 10, 55 may each have an individual actuator (11B in FIGS. 4 and 5) associated therewith operated separately and individually by the control system (146 in FIG. 2).

(14) In some embodiments, a ram system (defined above) for one or more pipe rams 10 may be changeable without the need to remove the housing 11D from its installed position. See FIG. 3 for example installed positions. In an example embodiment shown in FIG. 7, one or more ram systems, e.g., as shown at 11-1 in FIG. 7 may be engaged with the housing 11D. In the present embodiment, two opposed pipe rams 10 may be engaged with the housing 11D. In the present example embodiment, a carousel 50 may be coupled to or disposed proximate the exterior of the housing 11D. In the present example embodiment, one carousel 50 may be disposed opposite a second carousel 50 disposed on an opposed side of the housing 11D. The carousels 50 may each comprise additional ram systems 11-2, 11-3, 11-4, each such additional ram system comprising, for example, an actuator (11 in FIG. 5), a bonnet (11B in FIG. 5) and a ram seal element (11C in FIG. 5). In the present example embodiment, each carousel 50 may be capable of carrying four ram systems, 11-1, 11-2, 11-3 and 11-4. One of the ram systems, e.g., 11-1 may be inserted into and locked into the housing 11D. The insertion of a ram system 11-1 into the housing 11D may be performed, for example by a linear actuator (not shown) when the carousel 50 is rotated such that the selected ram system (e.g., 11-1) is oriented toward the housing 11D. In the event the one of the ram systems (e.g., 11-1) becomes worn or inoperative, such ram system (e.g., 11-1) may be withdrawn to the carousel 50, e.g., using a linear actuator (not shown), and then the carousel 50 may be rotated to align a replacement ram system (e.g., 11-2) with the housing 11D. The replacement ram system (e.g., 11-2) may then be urged into the housing 11D using, for example a linear actuator (not shown). The replacement ram system 11-2 may then be operated in the same manner as the replaced ram system 11-1 to enable the pipe ram 10 to perform its function as a well fluid outflow control. One carousel 50 may be provided on each of two opposed sides of the housing 11D. In some embodiments, both carousels 50 may be operated contemporaneously to replace the ram system 11-1 on both sides of the housing 11D. In some embodiments, the ram systems 11-1, 11-2, 11-3, 11-4 on each side of the housing 11D may be operated independently.

(15) The two carousels 50 shown in FIG. 7 may be operated contemporaneously or may be operated individually based on the condition of the various components of the affected ram system (e.g., 11-1 in FIG. 7). The carousel 50 may be rotated by a motor (not shown), for example, an electric motor, an hydraulic motor or a pneumatic motor.

(16) A non-limiting example of a ram system that may be used in some embodiments is described in U.S. Pat. No. 6,554,247 issued to Berckenhoff et al. and incorporated herein by reference A non-limiting example embodiment of a linear actuator and ram system servicing device that may be used in the carousel 50 are shown in U.S. Pat. No. 7,121,348 issued to Hemphill et al. and incorporated herein by reference.

(17) A well fluid outflow control according to the various aspects of the present disclosure may enable performing managed pressure drilling (MPD) without the need to use a rotating control device or similar rotating sealing element. Such capability may eliminate the time and expense of repair and maintenance of rotating control devices.

(18) While the present disclosure describes a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of what has been disclosed herein. Accordingly, the scope of the disclosure should be limited only by the attached claims.