Flow diversion in managed pressure drilling operations

Abstract

A method can include connecting an apparatus between a pump and a standpipe, pumping fluid to the standpipe through a main flow line of the apparatus having a mass flowmeter connected therein, and pumping the fluid through a bypass flow line of the apparatus having another mass flowmeter connected therein to a return flow line upstream of a choke manifold, without the fluid flowing through the standpipe. A flow measurement and diversion apparatus can include an inlet connected to a pump, an outlet connected to a standpipe, and another outlet connected to a return flow line, a main flow line connected between the inlet and one outlet, and a mass flowmeter connected in the main flow line, and a bypass flow line connected between the inlet and the other outlet, and another mass flowmeter connected in the bypass flow line.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of the filing date of US provisional application no. 63 / 743,453 filed on 9 Jan. 2025. The entire disclosure of the prior application is incorporated herein by this reference for all purposes.BACKGROUND

[0002] This disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an example described below, more particularly provides for flow diversion in managed pressure drilling operations.

[0003] In managed pressure drilling operations, it is important to precisely control pressure in a wellbore being drilled. Typically, the wellbore is closed off at surface (for example, using an item of equipment known to those skilled in the art as a rotating control device, rotating control head, rotating diverter or pressure control device). Flow into a drill string, and flow out of an annulus formed between the drill string and the wellbore, are controlled to thereby control the pressure in the wellbore. The pressure in the wellbore may be maintained in an over-balanced condition, an under-balanced condition, or a balanced condition.

[0004] Therefore, it will be readily appreciated that improvements are continually needed in the art of controlling fluid flow and pressure in managed pressure drilling operations. The present disclosure provides such improvements, which may be used with a variety of different well configurations and drilling operations.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 is a representative partially cross-sectional schematic view of an example of a well system and associated method which can embody principles of this disclosure.

[0006] FIG. 2 is a representative schematic view of an example of a flow measurement and diversion apparatus that may be used with the FIG. 1 system and method, the apparatus being in a normal flow configuration.

[0007] FIG. 3 is a representative schematic view of the flow measurement and diversion apparatus in a diverted flow configuration.DETAILED DESCRIPTION

[0008] Representatively illustrated in FIG. 1 is a system 10 for use with a subterranean well, and an associated method, which can embody principles of this disclosure. However, it should be clearly understood that the system 10 and method are merely one example of an application of the principles of this disclosure in practice, and a wide variety of other examples are possible.

[0009] Therefore, the scope of this disclosure is not limited at all to the details of the system 10 and method as described herein and / or depicted in the drawings.

[0010] In the FIG. 1 example, a drill string 12 is positioned in a wellbore 14. The drill string 12 has a drill bit 16 connected at a distal end thereof for the purpose of drilling into the earth.

[0011] As depicted in FIG. 1, a pump 18 is used to maintain a flow of fluid 20 through the drill string 12 in the wellbore 14. In this example, the fluid 20 enters the drill string 12 at the surface via a standpipe 22, which may be connected to the drill string via a top drive, a kelly, or other equipment (not shown). The fluid 20 exits the drill string 12 in the wellbore 14 via nozzles (not shown) in the drill bit 16.

[0012] A composition of the fluid 20 can change during a drilling operation. For example, a density of the fluid 20 may be changed to provide for varying formation pressures to which the wellbore 14 is exposed. Thus, it is not necessary for the composition of the fluid 20 to remain fixed during the drilling operation.

[0013] The fluid 20 returns to the surface via an annulus 24 formed between the drill string 12 and the wellbore 14. In managed pressure drilling operations, the annulus 24 may be isolated from the atmosphere at the surface by well equipment 26 known to those skilled in the art as a rotating control device, rotating drilling head, rotating blowout preventer, rotating control head, etc. In well control operations, the well equipment 26 may be an annular blowout preventer, pipe rams, or other equipment. However, the scope of this disclosure is not limited to use of any well equipment to isolate an annulus from the atmosphere at the surface.

[0014] The returned fluid 20 may pass from the well equipment 26 through a return flow line 40 to a choke manifold 28 and various types of fluid conditioning equipment 30 (such as, a gas separator, a shale shaker, etc.) prior to flowing into a reservoir 32 (also known as a “mud pit”). The pump 18 draws fluid 20 from the reservoir 32. Note that the FIG. 1 example is simplified for purposes of clarity of illustration and description, and those skilled in the art will appreciate that additional equipment or different equipment may be used, depending in part on the particular well operation being performed.

[0015] In the FIG. 1 example, a flow measurement apparatus 34 is connected between the pump 18 and the standpipe 22. Thus, the fluid 20 exiting the pump 18 passes through the flow measurement apparatus 34 and the standpipe 22 prior to entering the drill string 12. In this manner, characteristics of the fluid 20 (such as, volumetric and mass flow rate, density, other rheological parameters, etc.) can be accurately measured as it is being introduced into the well. In some examples, another flow measurement apparatus (or another type of flow measurement apparatus) may also measure characteristics of the fluid 20 after it exits the well (such as, a flowmeter connected downstream of, or as part of, the choke manifold 28).

[0016] In the FIG. 1 example, the pump 18 may be of the type known as a triplex pump or rig pump. A flow rate produced by the pump 18 can in some cases be relatively high. In particular, the flow rate can be high enough to cause excessive wear and damage to a conventional mass flowmeter of the type that is designed to be connected downstream of, or as part of, the choke manifold 28.

[0017] The flow measurement and diversion apparatus 34 in the system 10 of FIG. 1 uses a mass flowmeter connected in a bypass flow line. A flow restrictor or choke in the bypass flow line prevents the mass flowmeter from being exposed to undesirably high flow rates. This is especially beneficial in situations where the fluid flowing through the mass flowmeter has a relatively high density.

[0018] While the drill string 12 is being used to drill the wellbore 14, and while the fluid 20 is being circulated through the drill string and annulus 24, the flow rates of the fluid into and out of the wellbore can be precisely controlled, in order to precisely control pressure in the wellbore. Measurements of mass and volumetric flow rates, temperatures, densities, and calculation of rheological parameters (such as, coefficients of a Herschel-Bulkley model) for the fluid 20 flowing into the drill string 12 and out of the annulus 24 at the surface enable enhanced precision of the downhole pressure control.

[0019] However, when the fluid 20 is not being circulated through the drill string 12 and the annulus 24 (such as, when making up or breaking out threaded connections 38 in the drill string while tripping in or out of the wellbore 14), it can be difficult to maintain precise downhole pressure control. In the FIG. 1 system 10, the flow measurement and diversion apparatus 34 can be used to divert the flow of the fluid 20 from the standpipe 22 to the return flow line 40, while also enabling continued measurement of relevant parameters, so that precise downhole pressure control can be maintained, even though the fluid is not being circulated through the drill string 12 and annulus 34.

[0020] A control system 36 is used to coordinate operation of the choke manifold 28 and the flow measurement and diversion apparatus 34. This enables a smooth transition from flow directed toward the standpipe 22 to flow directed toward the return flow line 40. For example, the control system 36 can be used to control operation of one or more chokes of the choke manifold 28 to variably restrict return flow of the fluid 20 (e.g., from the annulus 24 or otherwise through the return flow line 40), and to control operation of one or more valves and chokes of the apparatus 34. The control system 36 can receive parameter measurements from sensors (such as, flowmeters, temperature sensors, pressure sensors, etc.) of the choke manifold 28 and the apparatus 34 to enable determination of present downhole pressure (for example, using a suitably configured hydraulics model) and to determine how the choke manifold 28 and apparatus 34 should be operated to maintain a desired downhole pressure.

[0021] As depicted in FIG. 1, a main flow line 42 of the apparatus 34 is connected to the standpipe 22 and a bypass flow line 44 is connected to the return flow line 40 between the well equipment 26 and the choke manifold 28. In other examples, the bypass flow line 44 could instead be connected to the well equipment 26, or to the annulus 24 below the well equipment 26 (such as, to a flow spool or casing valve connected below the well equipment 26). Preferably, the bypass flow line 44 is in direct, or substantially direct, communication with the annulus 24, so that precise control of pressure in the wellbore 14 is enabled.

[0022] Referring additionally now to FIG. 2, a schematic view of an example of the flow measurement and diversion apparatus 34 is representatively illustrated. The FIG. 2 flow measurement and diversion apparatus 34 may be used with the system 10 and method of FIG. 1, or it may be used with other systems and methods. For convenience, the apparatus 34 is described below as it may be used with the FIG. 1 system 10 and method.

[0023] In the FIG. 2 example, the flow measurement and diversion apparatus 34 includes an inlet 46 and at least two outlets 48, 50. The inlet 46 is connected to the pump 18, the outlet 48 is connected to the standpipe 22 (such as, via a standpipe manifold), and the outlet 50 is connected to an inlet side of the choke manifold 28 (such as, via the return flow line 40).

[0024] The main flow line 42 extends between the inlet 46 and the outlet 48. The fluid 20 flows through the main flow line 42 to the standpipe 22 when the fluid is being circulated through the drill string 12 and the annulus 24 (for example, while the drill string is being used to drill the wellbore 14).

[0025] Valves 52, 54 connected in the main flow line 42 are open when the fluid 20 is being flowed from the inlet 46 to the outlet 48. Actuators 56, 58 of the respective valves 53, 54 are operated by the control system 36 (see FIG. 1).

[0026] Also connected in the main flow line 42 is a mass flowmeter 60 (such as, a Coriolis flowmeter). One or more sensors 62 measure differential pressure across the mass flowmeter 60 and temperature at the mass flowmeter. Certain rheological parameters (such as, the Herschel-Bulkley coefficients) can be determined and used by a hydraulics model of the control system 36, based on the pressure, temperature and mass flow rate measurements.

[0027] The bypass flow line 44 extends between the inlet 46 and the outlet 50. The fluid 20 flows through the bypass flow line 44 when the fluid is not being circulated through the drill string 12 and the annulus 24 (for example, during making up or breaking out threaded connections 38).

[0028] A valve 64 and a choke 66 connected in the bypass flow line 44 are open when the fluid 20 is being flowed from the inlet 46 to the outlet 50. Actuators 68, 70 of the respective valve 64 and choke 66 are operated by the control system 36.

[0029] Also connected in the bypass flow line 44 is a mass flowmeter 72 (such as, a Coriolis flowmeter). One or more sensors 74 measure differential pressure across the mass flowmeter 72 and temperature at the mass flowmeter. Certain rheological parameters (such as, the Herschel-Bulkley coefficients) can be determined and used by the hydraulics model of the control system 36, based on the pressure, temperature and mass flow rate measurements.

[0030] Note that the main flow line 42 and the bypass flow line 44 are not connected directly to each other downstream of the mass flowmeters 60, 72.

[0031] Instead, the main flow line 42 is connected to the standpipe 22 (such as, via a standpipe manifold, not shown), and the bypass flow line 44 is connected to the choke manifold 28 (such as, via the return flow line 40, the well equipment 26, etc.).

[0032] In one example, the choke 66 is fully closed and the valve 54 is open when it is desired for the fluid 20 to flow to the outlet 48 via the main flow line 42, and the choke 66 is open and the valve 54 is closed when it is desired for the fluid 20 to flow to the outlet 50 via the bypass flow line 44. The valves 52, 64 normally remain open.

[0033] The choke 66 enables gradual diversion of the flow of the fluid 20 from the outlet 48 to the outlet 50 in preparation for certain operations (such as, making up or breaking out a threaded connection 38), or for gradual diversion of flow from the outlet 50 to the outlet 48 in preparation for circulating the fluid through the drill string 12 and annulus 24 (such as, in a drilling operation). This gradual diversion provides for smooth flow direction transitions between the standpipe 22 and the choke manifold 28, thereby avoiding abrupt pressure fluctuations in the wellbore 14.

[0034] The choke 66 can be gradually opened prior to closing the valve 54 when it is desired to divert flow of the fluid 20 to the choke manifold 28. The valve 54 can be opened and then the choke 66 gradually closed when it is desired to divert flow of the fluid 20 from the choke manifold 28 to the standpipe 22.

[0035] Referring additionally now to FIG. 3, the apparatus 34 is representatively illustrated after flow of the fluid 20 has been diverted from the standpipe 22 to the choke manifold 28. The fluid 20 now flows through the bypass flow line 44 instead of the main flow line 42.

[0036] In the FIG. 3 configuration, the valve 54 is closed and the choke 66 is open. The mass flowmeter 72 and the sensors 74 enable mass flow rate to be measured and rheological characteristics of the fluid 20 to be determined, thereby enabling precise control of downhole pressure, while the fluid is not being circulated through the drill string 12 and the annulus 24.

[0037] It may now be fully appreciated that the above disclosure provides significant advancements to the art of controlling fluid flow and pressure in managed pressure drilling operations. In an example described above, the flow measurement and diversion apparatus 34 provides for determination of rheological characteristics of the fluid 20, even while the fluid is not being circulated through the drill string 12 and the annulus 24. The apparatus 34 also provides for diversion of flow from the standpipe 22 to upstream of the choke manifold 24.

[0038] The above disclosure provides to the art a method for use with a subterranean well. In one example, the method can comprise: connecting a flow measurement and diversion apparatus 34 between a pump 18 and a standpipe 22; pumping fluid 20 from the pump 18 to the standpipe 22 through a main flow line 42 of the flow measurement and diversion apparatus 34, the main flow line 42 having a first mass flowmeter 60 connected therein; and pumping the fluid 20 from the pump 18 through a bypass flow line 44 of the flow measurement and diversion apparatus 34 to a return flow line 40 upstream of a choke manifold 28, without the fluid 20 flowing through the standpipe 22, the bypass flow line 44 having a second mass flowmeter 72 connected therein.

[0039] The method may include measuring differential pressure across the first mass flowmeter 60 while the fluid 20 is pumped from the pump 18 to the standpipe 22.

[0040] The method may include measuring differential pressure across the second flowmeter 72 while the fluid 20 is pumped from the pump 18 to the return flow line 40.

[0041] The method may include closing a valve 54 connected in the main flow line 42 after the step of pumping the fluid 20 from the pump 18 through the bypass flow line 44. The method may include closing a choke 66 connected in the bypass flow line 44 after the step of pumping the fluid 20 from the pump 18 through the main flow line 42.

[0042] The main flow line 42 and the bypass flow line 44 may not be connected directly to each other downstream of the first and second mass flowmeters 60, 72.

[0043] The connecting step may comprise connecting the bypass flow line 44 to well equipment 26 comprising a rotating control device.

[0044] The standpipe 22 may be connected to a drill string 12 in the step of pumping the fluid 20 from the pump 18 to the standpipe 22.

[0045] The method may include making up a threaded connection 38 in the drill string 12 after the step of pumping the fluid 20 from the pump 18 through the bypass flow line 44.

[0046] The method may include breaking out a threaded connection 38 in the drill string 12 after the step of pumping the fluid 20 from the pump 18 through the bypass flow line 44.

[0047] The above disclosure also provides to the art a system 10 for use with a subterranean well. In one example, the system 10 can include: a flow measurement and diversion apparatus 34 comprising an inlet 46 connected to a pump 18, a first outlet 48 connected to a standpipe 22, and a second outlet 50 connected to a return flow line 40. The flow measurement and diversion apparatus 34 can include a main flow line 42 connected between the inlet 46 and the first outlet 48, and a first mass flowmeter 60 connected in the main flow line 42; and a bypass flow line 44 connected between the inlet 46 and the second outlet 50, and a second mass flowmeter 72 connected in the bypass flow line 44. The second outlet 50 may be connected to the return flow line 40 upstream of a choke manifold 28.

[0048] The second outlet 50 may be connected to the return flow line 40 between a choke manifold 28 and a well equipment 26 comprising a rotating control device.

[0049] The system 10 may include at least one pressure sensor 74 configured to measure differential pressure across the second mass flowmeter 72.

[0050] The system 10 may include a choke 66 connected in the bypass flow line 44. The first outlet 48 may be free of any direct connection to the second outlet 50 downstream of the choke 66.

[0051] Also provided to the art by the above disclosure is a flow measurement and diversion apparatus 34 for use with a subterranean well. In one example, the apparatus 34 can comprise: an inlet 46 configured for connection to a pump 18, a first outlet 48 configured for connection to a standpipe 22, and a second outlet 50 configured for connection to a return flow line 40; a main flow line 42 connected between the inlet 46 and the first outlet 48, and a first mass flowmeter 60 connected in the main flow line 42; and a bypass flow line 44 connected between the inlet 46 and the second outlet 50, and a second mass flowmeter 72 connected in the bypass flow line 44.

[0052] The apparatus 34 may include at least one first pressure sensor 62 configured to measure differential pressure across the first mass flowmeter 60.

[0053] The apparatus 34 may include at least one second pressure sensor 74 configured to measure differential pressure across the second mass flowmeter 72 The apparatus 34 may include a choke 66 connected in the bypass flow line 44. The first outlet 48 may be free of any direct connection to the second outlet 50 downstream of the choke 66.

[0054] Although various examples have been described above, with each example having certain features, it should be understood that it is not necessary for a particular feature of one example to be used exclusively with that example. Instead, any of the features described above and / or depicted in the drawings can be combined with any of the examples, in addition to or in substitution for any of the other features of those examples. One example's features are not mutually exclusive to another example's features. Instead, the scope of this disclosure encompasses any combination of any of the features.

[0055] Although each example described above includes a certain combination of features, it should be understood that it is not necessary for all features of an example to be used. Instead, any of the features described above can be used, without any other particular feature or features also being used.

[0056] It should be understood that the various embodiments described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of this disclosure. The embodiments are described merely as examples of useful applications of the principles of the disclosure, which is not limited to any specific details of these embodiments.

[0057] In the above description of the representative examples, directional terms (such as “above,”“below,”“upper,”“lower,”“upward,”“downward,” etc.) are used for convenience in referring to the accompanying drawings. However, it should be clearly understood that the scope of this disclosure is not limited to any particular directions described herein.

[0058] The terms “including,”“includes,”“comprising,”“comprises,” and similar terms are used in a non-limiting sense in this specification. For example, if a system, method, apparatus, device, etc., is described as “including” a certain feature or element, the system, method, apparatus, device, etc., can include that feature or element, and can also include other features or elements. Similarly, the term “comprises” is considered to mean “comprises, but is not limited to.”

[0059] Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the disclosure, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to the specific embodiments, and such changes are contemplated by the principles of this disclosure. For example, structures disclosed as being separately formed can, in other examples, be integrally formed and vice versa. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the invention being limited solely by the appended claims and their equivalents.

Examples

Embodiment Construction

[0008]Representatively illustrated in FIG. 1 is a system 10 for use with a subterranean well, and an associated method, which can embody principles of this disclosure. However, it should be clearly understood that the system 10 and method are merely one example of an application of the principles of this disclosure in practice, and a wide variety of other examples are possible.

[0009]Therefore, the scope of this disclosure is not limited at all to the details of the system 10 and method as described herein and / or depicted in the drawings.

[0010]In the FIG. 1 example, a drill string 12 is positioned in a wellbore 14. The drill string 12 has a drill bit 16 connected at a distal end thereof for the purpose of drilling into the earth.

[0011]As depicted in FIG. 1, a pump 18 is used to maintain a flow of fluid 20 through the drill string 12 in the wellbore 14. In this example, the fluid 20 enters the drill string 12 at the surface via a standpipe 22, which may be connected to the drill strin...

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of the filing date of US provisional application no. 63 / 743,453 filed on 9 Jan. 2025. The entire disclosure of the prior application is incorporated herein by this reference for all purposes.BACKGROUND

[0002] This disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an example described below, more particularly provides for flow diversion in managed pressure drilling operations.

[0003] In managed pressure drilling operations, it is important to precisely control pressure in a wellbore being drilled. Typically, the wellbore is closed off at surface (for example, using an item of equipment known to those skilled in the art as a rotating control device, rotating control head, rotating diverter or pressure control device). Flow into a drill string, and flow out of an annulus formed between the drill string and the wellbore, are controlled to thereby control the pressure in the wellbore. The pressure in the wellbore may be maintained in an over-balanced condition, an under-balanced condition, or a balanced condition.

[0004] Therefore, it will be readily appreciated that improvements are continually needed in the art of controlling fluid flow and pressure in managed pressure drilling operations. The present disclosure provides such improvements, which may be used with a variety of different well configurations and drilling operations.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 is a representative partially cross-sectional schematic view of an example of a well system and associated method which can embody principles of this disclosure.

[0006] FIG. 2 is a representative schematic view of an example of a flow measurement and diversion apparatus that may be used with the FIG. 1 system and method, the apparatus being in a normal flow configuration.

[0007] FIG. 3 is a representative schematic view of the flow measurement and diversion apparatus in a diverted flow configuration.DETAILED DESCRIPTION

[0008] Representatively illustrated in FIG. 1 is a system 10 for use with a subterranean well, and an associated method, which can embody principles of this disclosure. However, it should be clearly understood that the system 10 and method are merely one example of an application of the principles of this disclosure in practice, and a wide variety of other examples are possible.

[0009] Therefore, the scope of this disclosure is not limited at all to the details of the system 10 and method as described herein and / or depicted in the drawings.

[0010] In the FIG. 1 example, a drill string 12 is positioned in a wellbore 14. The drill string 12 has a drill bit 16 connected at a distal end thereof for the purpose of drilling into the earth.

[0011] As depicted in FIG. 1, a pump 18 is used to maintain a flow of fluid 20 through the drill string 12 in the wellbore 14. In this example, the fluid 20 enters the drill string 12 at the surface via a standpipe 22, which may be connected to the drill string via a top drive, a kelly, or other equipment (not shown). The fluid 20 exits the drill string 12 in the wellbore 14 via nozzles (not shown) in the drill bit 16.

[0012] A composition of the fluid 20 can change during a drilling operation. For example, a density of the fluid 20 may be changed to provide for varying formation pressures to which the wellbore 14 is exposed. Thus, it is not necessary for the composition of the fluid 20 to remain fixed during the drilling operation.

[0013] The fluid 20 returns to the surface via an annulus 24 formed between the drill string 12 and the wellbore 14. In managed pressure drilling operations, the annulus 24 may be isolated from the atmosphere at the surface by well equipment 26 known to those skilled in the art as a rotating control device, rotating drilling head, rotating blowout preventer, rotating control head, etc. In well control operations, the well equipment 26 may be an annular blowout preventer, pipe rams, or other equipment. However, the scope of this disclosure is not limited to use of any well equipment to isolate an annulus from the atmosphere at the surface.

[0014] The returned fluid 20 may pass from the well equipment 26 through a return flow line 40 to a choke manifold 28 and various types of fluid conditioning equipment 30 (such as, a gas separator, a shale shaker, etc.) prior to flowing into a reservoir 32 (also known as a “mud pit”). The pump 18 draws fluid 20 from the reservoir 32. Note that the FIG. 1 example is simplified for purposes of clarity of illustration and description, and those skilled in the art will appreciate that additional equipment or different equipment may be used, depending in part on the particular well operation being performed.

[0015] In the FIG. 1 example, a flow measurement apparatus 34 is connected between the pump 18 and the standpipe 22. Thus, the fluid 20 exiting the pump 18 passes through the flow measurement apparatus 34 and the standpipe 22 prior to entering the drill string 12. In this manner, characteristics of the fluid 20 (such as, volumetric and mass flow rate, density, other rheological parameters, etc.) can be accurately measured as it is being introduced into the well. In some examples, another flow measurement apparatus (or another type of flow measurement apparatus) may also measure characteristics of the fluid 20 after it exits the well (such as, a flowmeter connected downstream of, or as part of, the choke manifold 28).

[0016] In the FIG. 1 example, the pump 18 may be of the type known as a triplex pump or rig pump. A flow rate produced by the pump 18 can in some cases be relatively high. In particular, the flow rate can be high enough to cause excessive wear and damage to a conventional mass flowmeter of the type that is designed to be connected downstream of, or as part of, the choke manifold 28.

[0017] The flow measurement and diversion apparatus 34 in the system 10 of FIG. 1 uses a mass flowmeter connected in a bypass flow line. A flow restrictor or choke in the bypass flow line prevents the mass flowmeter from being exposed to undesirably high flow rates. This is especially beneficial in situations where the fluid flowing through the mass flowmeter has a relatively high density.

[0018] While the drill string 12 is being used to drill the wellbore 14, and while the fluid 20 is being circulated through the drill string and annulus 24, the flow rates of the fluid into and out of the wellbore can be precisely controlled, in order to precisely control pressure in the wellbore. Measurements of mass and volumetric flow rates, temperatures, densities, and calculation of rheological parameters (such as, coefficients of a Herschel-Bulkley model) for the fluid 20 flowing into the drill string 12 and out of the annulus 24 at the surface enable enhanced precision of the downhole pressure control.

[0019] However, when the fluid 20 is not being circulated through the drill string 12 and the annulus 24 (such as, when making up or breaking out threaded connections 38 in the drill string while tripping in or out of the wellbore 14), it can be difficult to maintain precise downhole pressure control. In the FIG. 1 system 10, the flow measurement and diversion apparatus 34 can be used to divert the flow of the fluid 20 from the standpipe 22 to the return flow line 40, while also enabling continued measurement of relevant parameters, so that precise downhole pressure control can be maintained, even though the fluid is not being circulated through the drill string 12 and annulus 34.

[0020] A control system 36 is used to coordinate operation of the choke manifold 28 and the flow measurement and diversion apparatus 34. This enables a smooth transition from flow directed toward the standpipe 22 to flow directed toward the return flow line 40. For example, the control system 36 can be used to control operation of one or more chokes of the choke manifold 28 to variably restrict return flow of the fluid 20 (e.g., from the annulus 24 or otherwise through the return flow line 40), and to control operation of one or more valves and chokes of the apparatus 34. The control system 36 can receive parameter measurements from sensors (such as, flowmeters, temperature sensors, pressure sensors, etc.) of the choke manifold 28 and the apparatus 34 to enable determination of present downhole pressure (for example, using a suitably configured hydraulics model) and to determine how the choke manifold 28 and apparatus 34 should be operated to maintain a desired downhole pressure.

[0021] As depicted in FIG. 1, a main flow line 42 of the apparatus 34 is connected to the standpipe 22 and a bypass flow line 44 is connected to the return flow line 40 between the well equipment 26 and the choke manifold 28. In other examples, the bypass flow line 44 could instead be connected to the well equipment 26, or to the annulus 24 below the well equipment 26 (such as, to a flow spool or casing valve connected below the well equipment 26). Preferably, the bypass flow line 44 is in direct, or substantially direct, communication with the annulus 24, so that precise control of pressure in the wellbore 14 is enabled.

[0022] Referring additionally now to FIG. 2, a schematic view of an example of the flow measurement and diversion apparatus 34 is representatively illustrated. The FIG. 2 flow measurement and diversion apparatus 34 may be used with the system 10 and method of FIG. 1, or it may be used with other systems and methods. For convenience, the apparatus 34 is described below as it may be used with the FIG. 1 system 10 and method.

[0023] In the FIG. 2 example, the flow measurement and diversion apparatus 34 includes an inlet 46 and at least two outlets 48, 50. The inlet 46 is connected to the pump 18, the outlet 48 is connected to the standpipe 22 (such as, via a standpipe manifold), and the outlet 50 is connected to an inlet side of the choke manifold 28 (such as, via the return flow line 40).

[0024] The main flow line 42 extends between the inlet 46 and the outlet 48. The fluid 20 flows through the main flow line 42 to the standpipe 22 when the fluid is being circulated through the drill string 12 and the annulus 24 (for example, while the drill string is being used to drill the wellbore 14).

[0025] Valves 52, 54 connected in the main flow line 42 are open when the fluid 20 is being flowed from the inlet 46 to the outlet 48. Actuators 56, 58 of the respective valves 53, 54 are operated by the control system 36 (see FIG. 1).

[0026] Also connected in the main flow line 42 is a mass flowmeter 60 (such as, a Coriolis flowmeter). One or more sensors 62 measure differential pressure across the mass flowmeter 60 and temperature at the mass flowmeter. Certain rheological parameters (such as, the Herschel-Bulkley coefficients) can be determined and used by a hydraulics model of the control system 36, based on the pressure, temperature and mass flow rate measurements.

[0027] The bypass flow line 44 extends between the inlet 46 and the outlet 50. The fluid 20 flows through the bypass flow line 44 when the fluid is not being circulated through the drill string 12 and the annulus 24 (for example, during making up or breaking out threaded connections 38).

[0028] A valve 64 and a choke 66 connected in the bypass flow line 44 are open when the fluid 20 is being flowed from the inlet 46 to the outlet 50. Actuators 68, 70 of the respective valve 64 and choke 66 are operated by the control system 36.

[0029] Also connected in the bypass flow line 44 is a mass flowmeter 72 (such as, a Coriolis flowmeter). One or more sensors 74 measure differential pressure across the mass flowmeter 72 and temperature at the mass flowmeter. Certain rheological parameters (such as, the Herschel-Bulkley coefficients) can be determined and used by the hydraulics model of the control system 36, based on the pressure, temperature and mass flow rate measurements.

[0030] Note that the main flow line 42 and the bypass flow line 44 are not connected directly to each other downstream of the mass flowmeters 60, 72.

[0031] Instead, the main flow line 42 is connected to the standpipe 22 (such as, via a standpipe manifold, not shown), and the bypass flow line 44 is connected to the choke manifold 28 (such as, via the return flow line 40, the well equipment 26, etc.).

[0032] In one example, the choke 66 is fully closed and the valve 54 is open when it is desired for the fluid 20 to flow to the outlet 48 via the main flow line 42, and the choke 66 is open and the valve 54 is closed when it is desired for the fluid 20 to flow to the outlet 50 via the bypass flow line 44. The valves 52, 64 normally remain open.

[0033] The choke 66 enables gradual diversion of the flow of the fluid 20 from the outlet 48 to the outlet 50 in preparation for certain operations (such as, making up or breaking out a threaded connection 38), or for gradual diversion of flow from the outlet 50 to the outlet 48 in preparation for circulating the fluid through the drill string 12 and annulus 24 (such as, in a drilling operation). This gradual diversion provides for smooth flow direction transitions between the standpipe 22 and the choke manifold 28, thereby avoiding abrupt pressure fluctuations in the wellbore 14.

[0034] The choke 66 can be gradually opened prior to closing the valve 54 when it is desired to divert flow of the fluid 20 to the choke manifold 28. The valve 54 can be opened and then the choke 66 gradually closed when it is desired to divert flow of the fluid 20 from the choke manifold 28 to the standpipe 22.

[0035] Referring additionally now to FIG. 3, the apparatus 34 is representatively illustrated after flow of the fluid 20 has been diverted from the standpipe 22 to the choke manifold 28. The fluid 20 now flows through the bypass flow line 44 instead of the main flow line 42.

[0036] In the FIG. 3 configuration, the valve 54 is closed and the choke 66 is open. The mass flowmeter 72 and the sensors 74 enable mass flow rate to be measured and rheological characteristics of the fluid 20 to be determined, thereby enabling precise control of downhole pressure, while the fluid is not being circulated through the drill string 12 and the annulus 24.

[0037] It may now be fully appreciated that the above disclosure provides significant advancements to the art of controlling fluid flow and pressure in managed pressure drilling operations. In an example described above, the flow measurement and diversion apparatus 34 provides for determination of rheological characteristics of the fluid 20, even while the fluid is not being circulated through the drill string 12 and the annulus 24. The apparatus 34 also provides for diversion of flow from the standpipe 22 to upstream of the choke manifold 24.

[0038] The above disclosure provides to the art a method for use with a subterranean well. In one example, the method can comprise: connecting a flow measurement and diversion apparatus 34 between a pump 18 and a standpipe 22; pumping fluid 20 from the pump 18 to the standpipe 22 through a main flow line 42 of the flow measurement and diversion apparatus 34, the main flow line 42 having a first mass flowmeter 60 connected therein; and pumping the fluid 20 from the pump 18 through a bypass flow line 44 of the flow measurement and diversion apparatus 34 to a return flow line 40 upstream of a choke manifold 28, without the fluid 20 flowing through the standpipe 22, the bypass flow line 44 having a second mass flowmeter 72 connected therein.

[0039] The method may include measuring differential pressure across the first mass flowmeter 60 while the fluid 20 is pumped from the pump 18 to the standpipe 22.

[0040] The method may include measuring differential pressure across the second flowmeter 72 while the fluid 20 is pumped from the pump 18 to the return flow line 40.

[0041] The method may include closing a valve 54 connected in the main flow line 42 after the step of pumping the fluid 20 from the pump 18 through the bypass flow line 44. The method may include closing a choke 66 connected in the bypass flow line 44 after the step of pumping the fluid 20 from the pump 18 through the main flow line 42.

[0042] The main flow line 42 and the bypass flow line 44 may not be connected directly to each other downstream of the first and second mass flowmeters 60, 72.

[0043] The connecting step may comprise connecting the bypass flow line 44 to well equipment 26 comprising a rotating control device.

[0044] The standpipe 22 may be connected to a drill string 12 in the step of pumping the fluid 20 from the pump 18 to the standpipe 22.

[0045] The method may include making up a threaded connection 38 in the drill string 12 after the step of pumping the fluid 20 from the pump 18 through the bypass flow line 44.

[0046] The method may include breaking out a threaded connection 38 in the drill string 12 after the step of pumping the fluid 20 from the pump 18 through the bypass flow line 44.

[0047] The above disclosure also provides to the art a system 10 for use with a subterranean well. In one example, the system 10 can include: a flow measurement and diversion apparatus 34 comprising an inlet 46 connected to a pump 18, a first outlet 48 connected to a standpipe 22, and a second outlet 50 connected to a return flow line 40. The flow measurement and diversion apparatus 34 can include a main flow line 42 connected between the inlet 46 and the first outlet 48, and a first mass flowmeter 60 connected in the main flow line 42; and a bypass flow line 44 connected between the inlet 46 and the second outlet 50, and a second mass flowmeter 72 connected in the bypass flow line 44. The second outlet 50 may be connected to the return flow line 40 upstream of a choke manifold 28.

[0048] The second outlet 50 may be connected to the return flow line 40 between a choke manifold 28 and a well equipment 26 comprising a rotating control device.

[0049] The system 10 may include at least one pressure sensor 74 configured to measure differential pressure across the second mass flowmeter 72.

[0050] The system 10 may include a choke 66 connected in the bypass flow line 44. The first outlet 48 may be free of any direct connection to the second outlet 50 downstream of the choke 66.

[0051] Also provided to the art by the above disclosure is a flow measurement and diversion apparatus 34 for use with a subterranean well. In one example, the apparatus 34 can comprise: an inlet 46 configured for connection to a pump 18, a first outlet 48 configured for connection to a standpipe 22, and a second outlet 50 configured for connection to a return flow line 40; a main flow line 42 connected between the inlet 46 and the first outlet 48, and a first mass flowmeter 60 connected in the main flow line 42; and a bypass flow line 44 connected between the inlet 46 and the second outlet 50, and a second mass flowmeter 72 connected in the bypass flow line 44.

[0052] The apparatus 34 may include at least one first pressure sensor 62 configured to measure differential pressure across the first mass flowmeter 60.

[0053] The apparatus 34 may include at least one second pressure sensor 74 configured to measure differential pressure across the second mass flowmeter 72 The apparatus 34 may include a choke 66 connected in the bypass flow line 44. The first outlet 48 may be free of any direct connection to the second outlet 50 downstream of the choke 66.

[0054] Although various examples have been described above, with each example having certain features, it should be understood that it is not necessary for a particular feature of one example to be used exclusively with that example. Instead, any of the features described above and / or depicted in the drawings can be combined with any of the examples, in addition to or in substitution for any of the other features of those examples. One example's features are not mutually exclusive to another example's features. Instead, the scope of this disclosure encompasses any combination of any of the features.

[0055] Although each example described above includes a certain combination of features, it should be understood that it is not necessary for all features of an example to be used. Instead, any of the features described above can be used, without any other particular feature or features also being used.

[0056] It should be understood that the various embodiments described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of this disclosure. The embodiments are described merely as examples of useful applications of the principles of the disclosure, which is not limited to any specific details of these embodiments.

[0057] In the above description of the representative examples, directional terms (such as “above,”“below,”“upper,”“lower,”“upward,”“downward,” etc.) are used for convenience in referring to the accompanying drawings. However, it should be clearly understood that the scope of this disclosure is not limited to any particular directions described herein.

[0058] The terms “including,”“includes,”“comprising,”“comprises,” and similar terms are used in a non-limiting sense in this specification. For example, if a system, method, apparatus, device, etc., is described as “including” a certain feature or element, the system, method, apparatus, device, etc., can include that feature or element, and can also include other features or elements. Similarly, the term “comprises” is considered to mean “comprises, but is not limited to.”

[0059] Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the disclosure, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to the specific embodiments, and such changes are contemplated by the principles of this disclosure. For example, structures disclosed as being separately formed can, in other examples, be integrally formed and vice versa. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the invention being limited solely by the appended claims and their equivalents.

Examples

Embodiment Construction

[0008]Representatively illustrated in FIG. 1 is a system 10 for use with a subterranean well, and an associated method, which can embody principles of this disclosure. However, it should be clearly understood that the system 10 and method are merely one example of an application of the principles of this disclosure in practice, and a wide variety of other examples are possible.

[0009]Therefore, the scope of this disclosure is not limited at all to the details of the system 10 and method as described herein and / or depicted in the drawings.

[0010]In the FIG. 1 example, a drill string 12 is positioned in a wellbore 14. The drill string 12 has a drill bit 16 connected at a distal end thereof for the purpose of drilling into the earth.

[0011]As depicted in FIG. 1, a pump 18 is used to maintain a flow of fluid 20 through the drill string 12 in the wellbore 14. In this example, the fluid 20 enters the drill string 12 at the surface via a standpipe 22, which may be connected to the drill strin...

Claims

1. A method for use with a subterranean well, the method comprising:connecting a flow measurement and diversion apparatus between a pump and a standpipe;pumping fluid from the pump to the standpipe through a main flow line of the flow measurement and diversion apparatus, the main flow line having a first mass flowmeter connected therein; andpumping the fluid from the pump through a bypass flow line of the flow measurement and diversion apparatus to a return flow line upstream of a choke manifold, without the fluid flowing through the standpipe, the bypass flow line having a second mass flowmeter connected therein.

2. The method of claim 1, further comprising measuring differential pressure across the first mass flowmeter while the fluid is pumped from the pump to the standpipe.

3. The method of claim 1, further comprising measuring differential pressure across the second mass flowmeter while the fluid is pumped from the pump to the return flow line.

4. The method of claim 1, further comprising closing a valve connected in the main flow line after the pumping the fluid from the pump through the bypass flow line.

5. The method of claim 4, further comprising closing a choke connected in the bypass flow line after the pumping the fluid from the pump through the main flow line.

6. The method of claim 1, in which the main flow line and the bypass flow line are not connected directly to each other downstream of the first and second mass flowmeters.

7. The method of claim 1, in which the connecting comprises connecting the bypass flow line to well equipment comprising a rotating control device.

8. The method of claim 1, in which the standpipe is connected to a drill string in the pumping the fluid from the pump to the standpipe.

9. The method of claim 8, further comprising making up a threaded connection in the drill string after the pumping the fluid from the pump through the bypass flow line.

10. The method of claim 8, further comprising breaking out a threaded connection in the drill string after the pumping the fluid from the pump through the bypass flow line.

11. A system for use with a subterranean well, the system comprising:a flow measurement and diversion apparatus comprising an inlet connected to a pump, a first outlet connected to a standpipe, and a second outlet connected to a return flow line;the flow measurement and diversion apparatus further comprising a main flow line connected between the inlet and the first outlet, and a first mass flowmeter connected in the main flow line; andthe flow measurement and diversion apparatus further comprising a bypass flow line connected between the inlet and the second outlet, and a second mass flowmeter connected in the bypass flow line.

12. The system of claim 11, in which the second outlet is connected to the return flow line upstream of a choke manifold.

13. The system of claim 11, in which the second outlet is connected to the return flow line between a choke manifold and a well equipment comprising a rotating control device.

14. The system of claim 11, further comprising at least one pressure sensor configured to measure differential pressure across the second mass flowmeter.

15. The system of claim 11, further comprising a choke connected in the bypass flow line, and in which the first outlet is free of any direct connection to the second outlet downstream of the choke.

16. A flow measurement and diversion apparatus for use with a subterranean well, the apparatus comprising:an inlet configured for connection to a pump, a first outlet configured for connection to a standpipe, and a second outlet configured for connection to a return flow line;a main flow line connected between the inlet and the first outlet, and a first mass flowmeter connected in the main flow line; anda bypass flow line connected between the inlet and the second outlet, and a second mass flowmeter connected in the bypass flow line.

17. The apparatus of claim 16, further comprising at least one first pressure sensor configured to measure differential pressure across the first mass flowmeter.

18. The apparatus of claim 17, further comprising at least one second pressure sensor configured to measure differential pressure across the second mass flowmeter.

19. The apparatus of claim 16, further comprising a choke connected in the bypass flow line.

20. The apparatus of claim 19, in which the first outlet is free of any direct connection to the second outlet downstream of the choke.

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