Automated standpipe pressure relief valve

Abstract

A system that can include a standpipe on a rig that supplies mud from one or more mud pumps to a tubular string, a rig controller, and a valve in fluid communication with the standpipe and communicatively coupled to the rig controller, where the rig controller is configured to detect a first signature of conditions of the rig based on data sources received at the rig controller, and where the rig controller causes the valve to open or close or partially open to control pressure in the standpipe based on the first signature.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority under 35 U.S.C. § 119 (e) to U.S. Provisional Patent Application No. 63 / 627,715, filed on Jan. 31, 2024, entitled “AUTOMATED STANDPIPE PRESSURE RELIEF VALVE,” by David SILJEG et al., which is assigned to the current assignee hereof and is incorporated herein by reference in its entirety.FIELD OF THE DISCLOSURE

[0002] The present invention relates, in general, to the field of drilling and processing of wells. More particularly, present embodiments relate to a system and method for controlling a standpipe pressure during subterranean operations.SUMMARY

[0003] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify indispensable features of the claimed subject matter, nor is it intended for use as an aid in limiting the scope of the claimed subject matter.

[0004] A system of one or more computers can be configured to perform particular operations or actions by virtue of having software, firmware, hardware, or a combination of them installed on the system that in operation causes or cause the system to perform the actions. One or more computer programs can be configured to perform particular operations or actions by virtue of including instructions that, when executed by data processing apparatus, cause the apparatus to perform the actions. One general aspect includes a system for managing pressure in a standpipe during a subterranean operation. The system also includes a standpipe on a rig that supplies mud from one or more mud pumps to a tubular string; a rig controller; and a valve in fluid communication with the standpipe and communicatively coupled to the rig controller, where the rig controller is configured to detect a first signature of conditions of the rig based on data sources received at the rig controller, and where the rig controller causes the valve to open or close or partially open to control pressure in the standpipe based on the first signature. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

[0005] One general aspect includes a method for managing pressure in a standpipe during a subterranean operation. The method also includes stopping a mud pump that supplies pressurized mud to the standpipe on a rig; monitoring, via a pressure sensor, the pressure in the standpipe; opening, via a rig controller, a valve when the pressure is below a first pre-determined pressure level, where the valve is in pressure communication with the standpipe; releasing the pressure through the valve until the pressure is decreased to a level below a second pre-determined pressure level; initiating a delay timer when the pressure is below the second pre-determined pressure level; closing the valve, via the rig controller, when the delay timer has expired; and adding a tubular to a tubular string while the pressure is below the second pre-determined pressure level. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

[0006] One general aspect includes a method for managing pressure in a standpipe during a subterranean operation. The method also includes monitoring, via a rig controller, data sources from the rig; detecting a first signature of conditions of the rig based on the data sources, where the first signature indicates that the pressure in the standpipe is below a first pre-determined pressure level; opening, via the rig controller, a valve in pressure communication with the standpipe in response to detecting the first signature; releasing the pressure from the standpipe through the valve; detecting a second signature of conditions of the rig based on the data sources, where the second signature indicates that the pressure in the standpipe is below a second pre-determined pressure level; initiating, via the rig controller, a delay timer when the pressure is below the second pre-determined pressure level; and closing the valve, via the rig controller, when the delay timer has expired. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other features, aspects, and advantages of present embodiments will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0008] FIGS. 1A and 1B are representative partial cross-section views of a rig used to perform subterranean operations, in accordance with certain embodiments;

[0009] FIGS. 2A and 2B are representative plots of standpipe pressure versus time during a connection to a tubular string during a subterranean operation, in accordance with certain embodiments;

[0010] FIG. 3 is a representative table of event signatures for controlling a standpipe pressure relief valve, in accordance with certain embodiments;

[0011] FIGS. 4 and 5 are representative flow charts of a method for controlling a standpipe pressure relief valve, in accordance with certain embodiments; and

[0012] FIG. 6 is a representative functional block diagram of a rig controller that can control rig equipment of the rig 10 and perform methods of the current disclosure, in accordance with certain embodiments.DETAILED DESCRIPTION

[0013] The following description in combination with the figures is provided to assist in understanding the teachings disclosed herein. The following discussion will focus on specific implementations and embodiments of the teachings. This focus is provided to assist in describing the teachings and should not be interpreted as a limitation on the scope or applicability of the teachings.

[0014] FIGS. 1A and 1B show land-based rigs. However, it should be understood that the principles of this disclosure are equally applicable to off-shore rigs where “off-shore” refers to a rig with water between the rig floor and the earth surface 6.

[0015] FIG. 1A is a representative simplified front view of a rig being utilized for a subterranean operation (e.g., tripping in or out a tubular string 58 to or from a wellbore 15), in accordance with certain embodiments. The rig 10 can include a platform 12 with a rig floor 16 and a derrick 14 extending up from the rig floor 16. The derrick 14 can provide support for hoisting the top drive 18 as needed to manipulate tubulars. A catwalk 20 and V-door ramp 22 can be used to transfer horizontally stored tubular segments 50 to the rig floor 16. A tubular segment 52 can be one of the horizontally stored tubular segments 50 that is being transferred to the rig floor 16 via the catwalk 20. A pipe handler 30 with articulating arms 32, 34 can be used to grab the tubular segment 52 from the catwalk 20 and transfer the tubular segment 52 to the top drive 18, the vertical storage area 36, the wellbore 15, etc. However, it is not required that a pipe handler 30 be used on the rig 10. The top drive 18 can transfer tubulars directly between the catwalk 20 and the top drive 18 (e.g., using an elevator coupled to the top drive).

[0016] The tubular string 58 can extend into the wellbore 15, with the wellbore 15 extending through the surface 6 into the subterranean formation 8. When tripping the tubular string 58 out of the wellbore 15, tubulars 54 are sequentially removed from the tubular string 58 to reduce the length of the tubular string 58 in the wellbore 15. When tripping the tubular string 58 into the wellbore 15, tubulars 54 are sequentially added to the tubular string 58 to extend the length of the tubular string 58 into the earthen formation 8. The top drive 18 and slips 72 (e.g., at well center 24) can cooperate together to support adding or removing tubulars 54 to or from the tubular string 58.

[0017] To add a tubular 54 to the tubular string 58, a top drive 18 can be disconnected from the tubular string 58 at well center 24 and raised by a drawworks 44 (see FIG. 1B) to provide sufficient vertical clearance to accept the new tubular segment 54 in a vertical orientation above and aligned with a stickup height of the tubular string 58. However, residual pressure in the tubular string 58 may remain when a new tubular segment 54 is to be added. The rig operators can allow the residual pressure to bleed off through the drill bit and into the annulus 17 to a safe level to allow disconnection of the top drive 18 from the tubular string 58. This is described in more detail below.

[0018] The pipe handler 30 can be used to deliver the tubulars 54 to a well center on the rig floor 16 in a vertical orientation and hand the tubulars 54 off to an iron roughneck 38 or a top drive 18. The iron roughneck 38 can make a threaded connection between a new tubular 54 and the tubular string 58. A spinner assembly 40 can engage a body of the tubular 54 to spin a pin end 57 of the tubular 54 into a threaded box end 55 of the tubular string 58, thereby threading the tubular 54 into the tubular string 58. The wrench assembly 42 can provide a desired torque to the threaded connection, thereby completing the connection. This process can be reversed when tubulars 54 are being removed from the tubular string 58.

[0019] FIG. 1B is a representative partial cross-sectional front view of a rig 10 at a rig site 11 being used to drill a wellbore 15 in a subterranean formation 8, in accordance with certain embodiments. Rig 10 can include a top drive 18 with a drawworks 44, sheaves 19, traveling block 28, deadline anchor 47, and reel 48 used to raise or lower the top drive 18 via drilling line 46. A derrick 14 extending from the rig floor 16 can provide structural support of the rig equipment for performing subterranean operations (e.g., drilling, treating, completing, producing, testing, etc.).

[0020] The rig can be used to extend a wellbore 15 through the subterranean formation 8 by using a tubular string 58 having a bottom hole assembly (BHA) 60 at its lower end. The BHA 60 can include a drill bit 68 and multiple drill collars 62, 64 with one or more of the drill collars including one or more sensors 70 or one or more tools 69 for Logging While Drilling (LWD) or Measuring While Drilling (MWD) operations.

[0021] During drilling operations, mud can be pumped, via pumps 84, from a mud pit 88, through the standpipe 86 (arrows 90), to the top drive 18, a mud saver valve 26, an instrumented sub 78, and the tubular string 58, then delivered to a drill bit 68 through the tubular string 58 (arrows 92). The mud can exit the tubular string 58 through the drill bit 68 and into the annulus 17, where the returning mud (arrows 94) can travel up through the annulus 17 back to the surface 6. The returned mud can be directed to the mud pit 88 from a rotating control device 66, through the flow line 81, to the shaker 80. A fluid treatment 82 can inject additives as desired to the mud to condition the mud appropriately for the current well activities and possibly future well activities as the mud is being pumped back into the mud pit 88.

[0022] The amount of pressure supplied by the mud pumps 84 to the standpipe 86 can vary as the pressure requirements of the drilling system varies. Higher pressures from the pumps 84 can be needed as the tubular string 58 increases in length, as obstructions to the mud flow are increased (e.g., clogged bits, cuttings build-up in the annulus, etc.), as viscosity of the mud changes, as well as changes in other parameters or conditions of the wellbore 15. As the tubular string 58 extends further into the wellbore 15, additional tubular segments 54 can be added. This requires regular disconnections of the tubular string 58 from the top drive 18 to connect a new tubular segment 54 to the tubular string 58. When a connection is to be made, the pumps 84 can be stopped to stop circulation of the mud and allow the top drive 18 to be disconnected from the tubular string 58.

[0023] However, just because the pumps 84 are stopped, does not mean that the top drive 18 can be safely disconnected from the tubular string 58. High fluid pressure inside the tubular string 58 can remain even after the pumps 84 have stopped. This residual pressure can be bled off through the drill bit 68 and into the annulus 17. However, due to possible flow restrictions, the bleed off process can take longer than desired to reduce the pressure P3 of the mud in the tubular string 58 to a safe level for disconnection of the top drive 18.

[0024] Referring to FIGS. 1B, 2A, and 2B, the pressure P1 in the standpipe 86 can be substantially equal to the pressure P3 in the tubular string 58. Therefore, the pressure P3 at the top of the tubular string 58 can be accurately estimated from the measurements of the pressure P1 in the standpipe 86 by the pressure sensor 74. The pressure sensor 74 can measure the pressure P1 in the standpipe 86 and a plot of pressure P1 versus time t can be created to illustrate a pressure profile of the pressure P1 as a representative connection to the tubular string 58 is performed.

[0025] FIG. 2A shows a plot 205 of a pressure profile 200 of the pressure P1 through a process of connecting a new tubular segment 54 to the tubular string 58. When the connection is to be made, the pumps 84 can be stopped to cease the flow of mud through the standpipe 86. The pressure P1 will begin to decrease since the pumps 84 have stopped and the residual pressure will continue to force mud from the tubular string 58 into the annulus 17 through the drill bit 68. At time t1, the pressure P1 has been reduced to a pre-determined level p1 that can be a pressure at which damage to a relief valve can be reduced when the relief valve is actuated.

[0026] Plot 205 indicates a process where a relief valve is not utilized and the pressure P1 (and pressure P3) is allowed to bleed off into the annulus, through the drill bit 68, until the pressure P1 is below a pre-determined level p2. The pre-determined level p2 can be a safe pressure P1 (or pressure P3) at which the top drive 18 can be disconnected from the tubular string 58 while possibly maintaining desired downhole pressures in the wellbore 15. When the pumps are stopped, the pressure P1 can decrease rapidly at first, but as the pressure differential between the pressure P3 of the tubular string 58 and the pressure P2 of the annulus 17 (e.g., measured by sensor 76) is reduced, the pressure P1 can decrease more slowly. The time interval 201 can be representative of the time it takes for the pressure P1 to drop from the pre-determined level p1 (at time t1) to the pre-determined level p2 (at time t2). The time interval 201 can be representative of the time needed to wait before the top drive 18 can be disconnected from the tubular string 58 when a relief valve 100 is not used to bleed off pressure P1 in the standpipe 86.

[0027] The time interval 202, (i.e., from time t2 to time t3) shows a representative time to disconnect the top drive 18, raise the top drive 18, align and connect the next tubular segment 54 to the tubular string 58, reconnect the top drive 18 to the tubular string 58, and start the pumps 84 again. The ramp up of the pressure P1 can be a much shorter time period (i.e., time interval203 from time t3 to time (4) than the time interval 201.

[0028] FIG. 2B shows a plot 215 of the pressure profile 210 of the pressure P1 through a process of connecting a new tubular segment 54 to the tubular string 58. As described above regarding FIG. 2A, when the connection is to be made, the pumps 84 can be stopped to cease the flow of mud through the standpipe 86. The pressure P1 will begin to decrease since the pumps 84 have stopped and the residual pressure will continue to force mud from the tubular string 58 into the annulus 17 through the drill bit 68. At time t1, the pressure P1 has been reduced to a pre-determined level p1 that can be a pressure at which damage to a relief valve 100 can be reduced when the relief valve 100 is actuated.

[0029] Plot 215 indicates a process where a relief valve 100 is utilized and the pressure P1 (and pressure P3) is bled off more rapidly through the relief valve, until the pressure P1 is below a pre-determined level p2. When the pumps are stopped, the pressure P1 can decrease rapidly to the pre-determined level p1 due to a pressure differential between the pressure P3 of the tubular string 58 and the pressure P2 of the annulus 17. When the pressure P1 is at or below the pre-determined level p1, the relief valve 100 can be actuated to bleed off pressure from the standpipe 86 (e.g., into the mud pit 88). The time interval 211 can be representative of the time it takes for the pressure P1 to drop from the pre-determined level p1 (at time t1) to the pre-determined level p2 (at time t2). Alternatively, or in addition to, the time interval 211 can be representative of the time needed to wait before the top drive 18 can be disconnected from the tubular string 58, such as when the timing mode is selected.

[0030] When the pressure mode is selected, a time interval 220 can be used to provide sufficient delay for pressure bleed-off to minimize any pressure that can be trapped in the standpipe 86 or tubular string 58 when the relief valve 100 is closed. The time interval 220 can vary depending on the depth of the wellbore 15, the size of the tubular string 58, configuration of high-pressure tubing on the rig 10 for routing mud, etc. The time interval 220 can be a time period used to delay closure of the relief valve 100 after the pressure sensor 74 detects that the standpipe pressure P1 has been lowered at or below the pre-determined level p2.

[0031] For example, the rig controller 250 can monitor the pressure P1 via the pressure sensor 74. When the pressure P1 is at or below the pre-determined level p2, the rig controller 250 can start a delay timer equal to the time interval 220 (e.g., 3 seconds, 5 seconds, 10 seconds, 2 minutes, etc.). When the delay timer expires, the rig controller 250 can then proceed with closing the relief valve 100. The time interval 220 can minimize mud spillage when the top drive 18 is disconnected from the tubular string 58 by ensuring any residual pressure is also bled off from the standpipe 86. As wellbore 15 is extended further into the earthen formation 8, the time interval 220 can be increased to compensate for the increased volume of mud in the system.

[0032] Regarding the time interval 211, it can be used to determine if a well event can be occurring during the bleed off time (e.g., time interval 211), where the time interval 211 is how long it takes for the pressure P1 to decrease from the pre-determined level p1 to the pre-determined level p2. The time interval 211 can be estimated by knowing the flow rate of the relief valve 100 and a pressure differential between the pre-determined level p1 and the pre-determined level p2. The flow rate can be dependent upon a pressure differential across relief valve 100. The estimation can account for a reduced flow rate through the relief valve 100 as the pressure P1 is reduced. If the actual time to bleed off the pressure P1 from the pre-determined level p1 to the pre-determined level p2 is longer than the estimated time, then a well event can be occurring during the time interval 211, and the rig controller 250 can cause the relief valve 100 to be closed or remain closed.

[0033] The time interval 212, (i.e., from time t2 to time t3) shows a representative time to disconnect the top drive 18, raise the top drive 18, align and connect the next tubular segment 54 to the tubular string 58, reconnect the top drive 18 to the tubular string 58, and start the pumps 84 again. The ramp up of the pressure P1 is represented by time interval 213 from time t3 to time t4.

[0034] As can be seen, the cycle time of the pressure profile 210 using the relief valve 100 shown in FIG. 2B can be significantly less than the pressure profile 200 without using the relief valve 100 shown in FIG. 2A. Therefore, it can be beneficial to use the relief valve 100 to shorten the cycle time for making a connection to the tubular string 58. However, manually operating the relief valve 100 can increase safety risks for the one or more operators needed to actuate the relief valve 100. Additionally, delays in communications on the rig 10 can add to difficulties in operating the relief valve 100 in a timely manner to minimize a cycle time of making a connection to the tubular string 58. Automated control of the relief valve 100 can prevent increased safety risks to operators and ensure timely actuation of the relief valve 100, thereby ensuring minimizes cycle times for tubular connections.

[0035] Automated control of the relief valve 100 can allow the rig controller 250 to monitor well conditions and drilling parameters to detect any anomalies that may be present at the time for making a connection to the tubular string 58. The rig controller 250 can determine if pressure P1, P2, or P3 is increasing over a period of time leading up to making the tubular connection, where the increased pressure can be indicative of a kick in the wellbore 15. The rig controller 250 can close the relief valve 100 or keep it closed, even though it can be time to begin the process to make a connection to the tubular string 58. The rig controller 250 can also detect unexpected trends of these pressures P1, P2, or P3 to determine if the relief valve 100 can be opened, closed, or remain closed. For example, if pressure P1, P2, or P3 is increasing during the connection process or decreasing at an unexpected rate during the connection process, the ring controller 250 can cause the relief valve 100 to be opened, closed, or remain closed.

[0036] The rig controller 250 can detect anomalies in drilling parameters (e.g., weight of bit “WOB”, rate of penetration “ROP”, hook load, flow rate from the wellbore 15 to the shakers 80, etc.) to determine if the relief valve 100 can be opened, should be closed, or should remain closed. For example, during drilling the wellbore 15 prior to making a connection of the tubular string 58, if the ROP increases unexpectedly, hook load decreases unexpectedly, WOB decreases unexpectedly, or flow rate to the shakers 80 increases unexpectedly, the rig controller 250 can determine that a well event is occurring and can prevent the relief valve 100 from being opened. The rig controller 250 can also detect trends of one or more of these drilling parameters to determine if the relief valve 100 can be opened, closed, or remain closed.

[0037] Automated control of the relief valve 100 can also allow the rig controller 250 to actuate the relief valve 100 for communicating pressure pulses to downhole tools 69 for transmitting mud pulse telemetry to the downhole tools 69 through the drilling mud.

[0038] The relief valve 100 of the current disclosure can be remotely operated via the rig controller 250, which can perform full automation of the relief valve 100. The rig controller 250 can also receive commands from a rig operator via a Human Machine Interface (HMI) device and control the relief valve 100 based on the HMI commands.

[0039] The rig controller 250 can verify if conditions are acceptable to open or close the relief valve 100 based on rig conditions. These conditions can be monitored by the rig controller 250 (e.g., via sensors 70, other data sources, execution of a well plan, etc.) to detect event signatures, which can indicate that the relief valve 100 can be opened or closed. These conditions can include environmental conditions (e.g., temperature, humidity, rain, snow, sleet, winds, etc.), system pressures (e.g., standpipe pressure P1, annulus pressure P2, tubular string pressure P3, etc.), the current rig state during execution of the well plan 163 (see FIG. 6), state of event timers, state of a mud saver valve 26, state of a lower well control valve, commands from an HMI device, and rheology of the mud.

[0040] The rig controller 250 can monitor these conditions to detect event signatures and control the relief valve 100 based on these signatures. For example, an event signature can be when an operator, via the HMI device, has disabled automatic control of the relief valve 100 and the HMI device is used to send a command to the rig controller 250 to open, close, or partially open the relief valve 100. In this scenario, the rig controller 250 can check safety indicators to ensure that opening or closing the relief valve 100 will be safe for equipment and personnel, and, if the safety checks are acceptable, the rig controller 250 can execute the command received from the HMI device by sending a signal to the relief valve 100 to cause it to open, close, partially open, or partially close. These safety checks can include detecting anomalies or trends in the pressures P1, P2, or P3, or detecting anomalies or trends in the drilling parameters to indicate whether it is safe to open the relief valve or keep it closed.

[0041] Therefore, the event signature for this example can include detecting if automatic control is disabled, detecting if safety checks are acceptable, detecting valve control command from the HMI. The rig controller 250, after detecting an appropriate signature, can then send a control signal to the relief valve 100 to cause it to open or close or partially open or partially close. The safety checks can include detecting pressure levels of the pressures P1, P2, P3, detecting whether or not the pumps are stopped (e.g., pump stokes equal to “0” zero), detecting the state of top drive 18 valves (e.g., a mud saver valve 26, lower well control valve), and detecting locations of operator(s) on the rig 10.

[0042] As a way of examples, FIG. 3 shows a table 300 that includes a subset of event signatures 310 that can be based on a subset of conditions 320 (or signature elements). Each signature #1 thru #10 of the event signatures 310 can include a unique combination of the conditions 320. When the combination is detected by the rig controller 250, it can initiate one or more of the actions 330 in response to detecting the particular event signature. The following paragraphs provide further details regarding each of the signatures #1 thru #10. It should be understood that many more or fewer signatures can be included in the event signatures 310. The signatures #1 thru #10 are merely examples for discussion to illustrate the automated operation of the relief valve 100, via the rig controller 250.

[0043] For example, an event signature #1 can indicate when an operator, (e.g., via an HMI device), has disabled automatic control of the relief valve 100 by commanding the rig controller 250 to not perform automated control of the relief valve 100. The rig controller 250 detects that the safety checks indicate unacceptable safety conditions and that the strokes per minute (SPM) of the mud pumps 84 are zero. If signature #1 is detected, then the state of the remaining inputs can be irrelevant and the rig controller 250 does not affect a change to the state of relief valve 100.

[0044] For example, event signatures #2 and #3 can indicate when an operator, (e.g., via an HMI device), has disabled automatic control of the relief valve 100 by commanding the rig controller 250 to not perform automated control of the relief valve 100. The rig controller 250 detects that the safety checks indicate acceptable safety conditions and that the SPM of the mud pumps 84 are zero and a command from an HMI device is received at the rig controller 250. If signature #2 is detected, then the HMI device has sent a command to open the relief valve 100 and the state of the remaining inputs can be irrelevant. The rig controller 250 can command the relief valve 100 to open. If signature #3 is detected, then the HMI device has sent a command to close the relief valve 100 and the state of the remaining inputs can be irrelevant. The rig controller 250 can command the relief valve 100 to close. It should be understood that that the HMI device can send a command to the rig controller 250 to partially open or partially close the relief valve 100, which could each be separate signatures.

[0045] For example, an event signature #4 can indicate when the rig controller 250 detects that the SPM of the mud pumps 84 is non-zero. If signature #4 is detected, then the state of the remaining inputs can be irrelevant and the rig controller 250 can command the relief valve 100 to close if it is open, or ensure that it remains closed if it is already closed.

[0046] For example, event signatures #5, #6, and #7 can be used to detect progression through making a connection to a tubular string 58. An operator, (e.g., via an HMI device), has enabled automatic control of the relief valve 100 by commanding the rig controller 250 to perform automated control of the relief valve 100. When either one of the signatures #5, #6, and #7 is detected, it communicates to the rig controller 250 that the safety checks are acceptable, the pressure mode is enabled and the timer mode is disabled, the SPM of the mud pumps 84 is zero, the mud saver valve (if used) is closed, and the lower well control valve is closed. It should be understood that these signatures may not require that both the mud saver valve and the lower well control valve are closed. They could be programmed to indicate that one or both of the mud saver valve or the lower well control valve is closed.

[0047] When signature #5 is detected, it further indicates to the rig controller 250 that the standpipe pressure P1 is above the pre-determined level p1 (e.g., 800 psi) as well as the pre-determined level p2 (e.g., 75 psi), which can cause the rig controller 250 to ensure that the relief valve 100 is closed. With the pumps 84 stopped, the standpipe pressure P1 will begin to decrease. When signature #6 is detected, it further indicates to the rig controller 250 that the standpipe pressure P1 is below the pre-determined level p1 and above the pre-determined level p2, which can cause the rig controller 250 to command the relief valve 100 to be opened. This can increase the rate at which the standpipe pressure P1 decreases. When signature #7 is detected, it further indicates to the rig controller 250 that the standpipe pressure P1 is below the pre-determined level p1 as well as the pre-determined level p2, which can cause the rig controller 250 to start a delay timer and command the relief valve 100 to be closed after the delay timer expires, since the standpipe pressure P1 (and thus the tubular string pressure P3) would be at a safe level to allow a connection to be added to the tubular string 58.

[0048] The relief valve 100 may not be closed directly after the standpipe pressure P1 is below the pre-determined level p2. The inventors have found that closing the relief valve immediately after the standpipe pressure P1 is below the pre-determined level p2 may cause built-up pressure to be trapped in the standpipe 86. Therefore, when the standpipe pressure P1 goes below the pre-determined level p2, the rig controller 250 can pause for a pre-determined time period (e.g., 3 seconds) after the standpipe pressure drops below the pre-determined level p2 and before closing the relief valve 100. This can minimize any trapped pressure in the standpipe and substantially prevent spillage of mud when the top drive 18 is disconnected from the tubular string 58.

[0049] For example, event signatures #8 and #9 can be used to detect progression through making a connection to a tubular string 58. An operator, (e.g., via an HMI device), has enabled automatic control of the relief valve 100 by commanding the rig controller 250 to perform automated control of the relief valve 100. When either one of the signatures #8 and #9 is detected, it indicates to the rig controller 250 that the safety checks are acceptable, the pressure mode is disabled and the timer mode is enabled, the SPM of the mud pumps 84 is zero, the mud saver valve is closed, and the lower well control valve is closed. It should be understood that these signatures may not require that both the mud saver valve and the lower well control valve are closed. They could be programmed to indicate that one or both of the mud saver valve or the lower well control valve is closed.

[0050] In timer mode, the pre-determined level p2 (e.g., 75 psi) can be irrelevant for sequencing through making a connection. The “Open Timer Delay” and “Bleed Pressure (BP) Max Pause Timer Delay” can be used by the rig controller 250 to sequence through making a connection. When signature #8 is detected, it further indicates to the rig controller 250 that the standpipe pressure P1 is below the pre-determined level p1 (e.g., 800 psi) and the “Open Timer Delay” has expired. The rig controller 250 can then send a command to the relief valve 100 to open. When signature #9 is detected, it further indicates to the rig controller 250 that the standpipe pressure P1 is below the pre-determined level p1 and the “BP Max Pause Timer Delay” has expired, which can cause the rig controller 250 to command the relief valve 100 to be closed. The rig 10 can then add a tubular to the tubular string 58 and again turn the pumps 84 on to continue operations.

[0051] For example, if event signature #10 is detected, then the rig controller 250 can be configured to a mud pulse telemetry mode. The rig controller 250 can receive data to be communicated downhole and can control the relief valve 100 to create pressure pulses in the mud in the standpipe 86 to encode the data into a train of pressure pulses. These pressure pulses can propagate from the standpipe 86 to the tubular string 58 and then downhole, via the mud in the tubular string 58.

[0052] If rig 10 is operating in semi-automated or fully automated modes, other parameters can be checked before opening or closing the relief valve 100. The rig controller 250 can determine a rig state from various data sources (e.g., sensors 70) around rig 10 and can determine if the rig is tripping in a tubular string 58 into the wellbore 15. This can ensure that the criteria for opening or closing the relief valve 100 is restricted to the desired rig operation (e.g., tripping a tubular string 58 into the wellbore 15). Once it is determined that the rig 10 is performing the desired rig operation, then the rig controller 250 can perform the operations of, for example, method 400, for automatically controlling standpipe pressure during a connection to the tubular string 58.

[0053] The data sources (e.g., sensors 70) can be received by the rig controller 250 and input into a valve control module 170 (see FIG. 6), which can monitor these inputs in real time. The valve control module 170 can be a programmable logic controller (PLC) that monitors the data sources and controls the relief valve 100 based on the event signature of the inputs. The valve control module 170 can utilize artificial intelligence (e.g., machine learning, neural network, etc.) to determine the desired control of the relief valve 100 to manage the standpipe pressure P1. The valve control module 170 can receive one or more sets of training data to teach the valve control module 170 when the state of the relief valve 100 should be changed (e.g., opened, closed, partially opened, partially closed) based on the inputs.

[0054] The inputs can be recorded to build one or more training sets and this recorded data can be replicated to increase the amount of data available in the one or more training sets. Additionally, or in the alternative, the one or more training sets can be artificially produced from a data generator.

[0055] FIG. 4 is a representative flow chart of a method 400 for controlling a standpipe pressure P1 relief valve 100 during making a connection to a tubular string 58, in accordance with certain embodiments. In operation 402, the valve control module 170 of the rig controller 250 can receive a command that a connection to a tubular string 58 is being made. The command can be generated by an operator via an HMI device, when the rig controller 250 is being used to provide automated control of the standpipe pressure P1 during making a connection to the tubular string 58. It should be understood that the command can be provided by another module in the rig controller 250 when the rig 10 is fully automated and does not utilize an operator to initiate each automated sequence for controlling the standpipe pressure P1 during making the connection.

[0056] When the command is received in operation 402, the valve control module 170 can proceed to operation 404 where it can monitor inputs to the rig controller 250 to detect (or identify) a particular signature (e.g., one of the signatures #2, #6, #8 in a signatures database 172) which can indicate that the relief valve 100 should be opened. When the valve control module 170 detects the particular signature in operation 404, it can then proceed to operation 406, where the valve control module 170 can send a command to the relief valve 100 to open (at least partially) the relief valve 100. The valve control module 170 can then proceed to operation 408, where it can monitor the inputs to the rig controller 250 to detect (or identify) a particular signature (e.g., one of the signatures #3, #4, #5, #7, #9 in a signatures database 172) which can indicate that the relief valve 100 should be closed. When the valve control module 170 detects the particular signature in operation 408, the rig controller 250 can initiate a delay timer in operation 410 for delaying a desired amount of time (e.g., time interval 220). When the delay timer has expired, the rig controller 250 can then proceed to operation 412, where the valve control module 170 can send a command to the relief valve 100 to close (at least partially) the relief valve 100. With the relief valve 100 closed, the valve control module 170 can proceed to operation 402 to again wait for a command that a connection to a tubular string 58 is to be made. These operations can be repeated as needed to control standpipe pressure P1 during each tubular connection to the tubular string 58.

[0057] FIG. 5 is a representative flow chart of method 420 for controlling a relief valve 100 to produce mud pulse telemetry, in accordance with certain embodiments. Operation of the relief valve 100 can be used to produce pressure pulses in the standpipe pressure P1, which can propagate through the standpipe 86, the top drive 18, and the tubular string 58 to downhole tools 69. The downhole tool(s) 69 can receive the pressure pulses and decode the data encoded therein. However, it is not a requirement that the downhole tool(s) receive or decode the data.

[0058] In operation 422, data, to be encoded into mud pulse telemetry, can be received by the rig controller 250 (or a pulse telemetry module 174) via a wired or wireless network 154. In operation 424, the rig controller 250 can send commands (e.g., open, close, partially open, partially close) to the relief valve 100 to produce pressure pulses in the mud in the standpipe 86. Each time the relief valve 100 is opened (at least partially), the standpipe pressure P1 will drop, and when the relief valve 100 is closed again, the standpipe pressure P1 can increase. This cycle of reducing the standpipe pressure P1 and then increasing it again, can cause a pressure pulse (e.g., a negative pressure pulse). Each time the relief valve 100 is opened and closed, a pressure pulse can be produced in the standpipe 86. In this way, the length of the pressure pulse can be varied as well as the frequency of when a pressure pulse is produced. Therefore, the rig controller 250 (or pulse telemetry module 174) can receive the data to be encoded, create a pulse train of pressure pulses that is representative of the encoded data, and (in operation 426) transmit the pressure pulses downhole through the mud in the tubular string 58.

[0059] In operation 428, the pressure pulses can be received by one or more downhole tools 69. In operation 430, one or more downhole tools 69 can detect the pressure pulses and decode the data that was encoded therein. Thus, the relief valve 100 and the rig controller 250 can provide communication to downhole tools 69 via mud pulse telemetry.

[0060] FIG. 6 is a representative functional block diagram of a rig controller 250 that can control rig equipment of the rig 10 and can perform methods of the current disclosure (e.g., controlling standpipe pressure), in accordance with certain embodiments. The rig controller 250 can include one or more local or remote processing units 160 that can be locally or remotely positioned relative to the rig 10 or downhole. Each processing unit 160 can include one or more processors 162 (e.g., microprocessors, programmable logic arrays, programmable logic devices, etc.), non-transitory memory storage devices 164, peripheral interface 166, human machine interface (HMI) device(s) 168, and possibly a remote telemetry interface 165 for internet communication or satellite network communication. The HMI devices 168 can include devices such as a touchscreen, a laptop, a desktop computer, a workstation, or wearables (e.g., smart phone, smart watch, tablet, etc.). These components of the rig controller 250 can be communicatively coupled together via one or more networks 154, which can be wired or wireless networks.

[0061] The processors 162 can be configured to read instructions from one or more non-transitory memory storage devices 164 and execute those instructions to perform any of the methods or operations described in this disclosure. A peripheral interface 166 can be used by the rig controller 250 to receive sensor data from sensors 70, 74, 76 around the rig 10 or downhole and collect data on the rig operations being performed. The peripheral interface 166 can also be used by the rig controller 250 to send commands to personnel or rig equipment (such as a standpipe pressure relief valve 100) to control rig operations during a subterranean operation. The rig controller 250 can receive a well plan 163 via the network 154 (or peripheral interface 166) and can determine a rig state based on the well plan 163 and data from the sensors 70.

[0062] A valve control module 170 can be configured to collect data from the data sources (e.g., sensors 70), and determine whether to open or close (or at least partially open) the relief valve 100. The valve control module 170 can be configured to identify event signatures (e.g., FIG. 3) in the collected data and control the relief valve 100 based on the identified event signatures. The valve control module 170 can compare the collected event signature to one or more of historical event signatures stored in a signatures database 172. Based on the comparison of these signatures, the valve control module 170 can initiate control of the relief valve 100 to manage standpipe pressure P1. Timers 176 can supply delay timers for the rig controller 250 such as to implement the Open Timer Delay, the BP Max Pause Timer Delay, or the delay timer mentioned in operation 410 of method 400.

[0063] The rig controller 250 can include one or more processors with the one or more processors distributed about the rig 10, such as in an operator's control hut, in a pipe handler 30, in an iron roughneck 38, in a vertical storage area 36, in the imaging systems, in various other robots, in the top drive 18, at various locations on the rig floor 16 or the derrick 14 or the platform 12, at a remote location off of the rig 10, at downhole locations, etc. It should be understood that any of these processors can perform control or calculations locally or can communicate to a remotely located processor for performing the control or calculations. Each of the processors can be communicatively coupled to a non-transitory memory, which can include instructions for the respective processor to read and execute to implement the desired control functions or other methods described in this disclosure. These processors can be coupled via a wired or wireless network 154.

[0064] The rig controller 250 can control the rig equipment autonomously (e.g., without periodic operator interaction,), semi-autonomously (e.g., with limited operator interaction such as initiating a subterranean operation, adjusting parameters during the operation, etc.), or manually (e.g., with the operator interactively controlling the rig equipment via remote control interfaces to perform the subterranean operation).

[0065] As used herein, the terms “comprises,”“comprising,”“includes,”“including,”“has,”“having,” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0066] The use of “a” or “an” is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise.

[0067] The use of the word “about”, “approximately”, “generally”, or “substantially” is intended to mean that a value of a parameter is close to a stated value or position. However, minor differences may prevent the values or positions from being exactly as stated. Thus, differences of up to ten percent (10%) for the value are reasonable differences from the ideal goal of exactly as described. A significant difference can be when the difference is greater than ten percent (10%).

[0068] As used herein, “tubular” refers to an elongated cylindrical tube and can include any of the tubulars manipulated around a rig, such as tubular segments, tubular stands, tubulars, and tubular string, but not limited to the tubulars shown in FIG. 1A. Therefore, in this disclosure, “tubular” is synonymous with “tubular segment,”“tubular stand,” and “tubular string,” as well as “pipe,”“pipe segment,”“pipe stand,”“pipe string,”“casing string,”“coiled tubing”, or “wireline.”

[0069] It should be noted that the X-Y-Z coordinate axes are indicated in FIGS. XX and XX, where the X-Y-Z coordinate axes are relative to the rig floor 16. Rig floor 16 forms an X-Y plane with the Z axis being substantially perpendicular with the rig floor 16. As used herein, “horizontal,”“horizontal position,” or “horizontal orientation” refers to a position that is substantially parallel with the X-Y plane. As used herein, “vertical,”“vertical position,” or “vertical orientation” refers to a position that is substantially perpendicular relative to the X-Y plane or substantially parallel with the Z axis.VARIOUS EMBODIMENTS

[0070] Embodiment 1. A system for managing pressure in a standpipe during a subterranean operation, the system comprising:

[0071] a standpipe on a rig that supplies mud from one or more mud pumps to a tubular string;

[0072] a rig controller; and

[0073] a valve in fluid communication with the standpipe and communicatively coupled to the rig controller, wherein the rig controller is configured to detect a first signature of conditions of the rig based on data sources received at the rig controller, and wherein the rig controller causes the valve to open or close or partially open to control pressure in the standpipe based on the first signature.

[0074] Embodiment 2. The system of embodiment 1, wherein the rig controller causes the valve to be closed based on the first signature and a delay timer after the first signature is detected, and wherein the valve prevents pressure loss through the valve from the standpipe when closed.

[0075] Embodiment 3. The system of embodiment 1, wherein the rig controller causes the valve to be opened based on the first signature and releases pressure through the valve from the standpipe.

[0076] Embodiment 4. The system of embodiment 3, wherein the first signature comprises a condition which indicates that pressure in the standpipe is below a first pre-determined pressure level.

[0077] Embodiment 5. The system of embodiment 4, wherein the first pre-determined pressure level is a pressure that reduces damage to the valve when the valve is opened.

[0078] Embodiment 6. The system of embodiment 4, wherein the rig controller is configured to detect a second signature of the conditions of the rig based on the data sources received at the rig controller, and wherein the rig controller causes the valve to open or close or partially open based on the second signature.

[0079] Embodiment 7. The system of embodiment 6, wherein the rig controller causes the valve to be closed based on the second signature and a time delay after the first signature is detected, and wherein the valve prevents pressure loss through the valve from the standpipe.

[0080] Embodiment 8. The system of embodiment 7, wherein the second signature comprises a condition which indicates that pressure in the standpipe is below a second pre-determined pressure level.

[0081] Embodiment 9. The system of embodiment 8, wherein the second pre-determined pressure level is below the first pre-determined pressure level.

[0082] Embodiment 10. The system of embodiment 9, wherein the second pre-determined pressure level indicates that the pressure in the standpipe is at a level where a connection to the tubular string can be made.

[0083] Embodiment 11. The system of embodiment 1, wherein the first signature indicates that strokes per minute of the one or more mud pumps is non-zero, and wherein the rig controller causes the valve to close regardless of other conditions of the rig.

[0084] Embodiment 12. The system of embodiment 11, further comprising a safety check, wherein the safety check indicates that at least a portion of a well event has occurred, and the rig controller causes the valve to close or remain closed in response to the safety check.

[0085] Embodiment 13. The system of embodiment 12, wherein the safety check indicates at least one of a trend in pressure or a trend in drilling parameters.

[0086] Embodiment 14. The system of embodiment 1, wherein the first signature indicates a mud pulse telemetry mode, wherein the rig controller receives data for transmission downhole and controls the valve to produce pressure pulses in the standpipe that are representative of the data.

[0087] Embodiment 15. The system of embodiment 14, wherein the pressure pulses are transmitted downhole through mud in the tubular string.

[0088] Embodiment 16. The system of embodiment 1, wherein the rig controller is configured to compare the first signature to one or more historical signatures stored in a signature database.

[0089] Embodiment 17. The system of embodiment 16, wherein the one or more historical signatures indicate an action to be taken if the first signature matches one of the one or more historical signatures.

[0090] Embodiment 18. A method for managing pressure in a standpipe during a subterranean operation, the method comprising:

[0091] stopping a mud pump that supplies pressurized mud to the standpipe on a rig;

[0092] monitoring, via a pressure sensor, the pressure in the standpipe;

[0093] opening, via a rig controller, a valve when the pressure is below a first pre-determined pressure level, wherein the valve is in pressure communication with the standpipe;

[0094] releasing the pressure through the valve until the pressure is decreased to a level below a second pre-determined pressure level;

[0095] initiating a delay timer when the pressure is below the second pre-determined pressure level;

[0096] closing the valve, via the rig controller, when the delay timer has expired; and

[0097] adding a tubular to a tubular string while the pressure is below the second pre-determined pressure level.

[0098] Embodiment 19. The method of embodiment 18, further comprising starting the mud pump, thereby increasing the pressure back above the first pre-determined pressure level.

[0099] Embodiment 20. The method of embodiment 19, further comprising repeating stopping, monitoring, opening, releasing, closing, adding, and starting for each time a tubular is added to the tubular string.

[0100] Embodiment 21. The method of embodiment 20, further comprising performing the stopping, monitoring, opening, releasing, closing, adding, and starting automatically via the rig controller.

[0101] Embodiment 22. A method for managing pressure in a standpipe during a subterranean operation, the method comprising:

[0102] monitoring, via a rig controller, data sources from the rig;

[0103] detecting a first signature of conditions of the rig based on the data sources, wherein the first signature indicates that the pressure in the standpipe is below a first pre-determined pressure level;

[0104] opening, via the rig controller, a valve in pressure communication with the standpipe in response to detecting the first signature;

[0105] releasing the pressure from the standpipe through the valve;

[0106] detecting a second signature of conditions of the rig based on the data sources, wherein the second signature indicates that the pressure in the standpipe is below a second pre-determined pressure level;

[0107] initiating, via the rig controller, a delay timer when the pressure is below the second pre-determined pressure level; and

[0108] closing the valve, via the rig controller, when the delay timer has expired.

[0109] Embodiment 23. The method of embodiment 22, wherein the first signature further indicates that strokes per minute of a mud pump is zero, and wherein the mud pump delivers mud to the standpipe.

[0110] Embodiment 24. The method of embodiment 22, wherein the first signature further indicates that safety checks are acceptable.

[0111] Embodiment 25. The method of embodiment 24, wherein the safety checks indicate that trends in one or more drilling parameters or trends in one or more pressures are acceptable.

[0112] Embodiment 26. The method of embodiment 22, wherein the first signature further indicates that a mud saver valve and a lower well control valve are closed.

[0113] Embodiment 27. The method of embodiment 22, wherein the first signature further indicates a time mode is enabled and that an open timer delay has expired, which indicates that it is time to open the valve.

[0114] Embodiment 28. The method of embodiment 22, wherein the second signature further indicates that strokes per minute of a mud pump is non-zero, wherein the mud pump delivers mud to the standpipe.

[0115] Embodiment 29. The method of embodiment 22, wherein the second signature further indicates a time mode is enabled and that a bleed pressure delay has expired, which indicates that it is time to close the valve.

[0116] While the present disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and tables and have been described in detail herein. However, it should be understood that the embodiments are not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the following appended claims. Further, although individual embodiments are discussed herein, the disclosure is intended to cover all combinations of these embodiments.

Claims

1. A system for managing pressure in a standpipe during a subterranean operation, the system comprising:a standpipe on a rig that supplies mud from one or more mud pumps to a tubular string;a rig controller; anda valve in fluid communication with the standpipe and communicatively coupled to the rig controller, wherein the rig controller is configured to detect a first signature of conditions of the rig based on data sources received at the rig controller, and wherein the rig controller causes the valve to open or close or partially open to control pressure in the standpipe based on the first signature.

2. The system of claim 1, wherein the rig controller causes the valve to be closed based on the first signature and a delay timer after the first signature is detected, and wherein the valve prevents pressure loss through the valve from the standpipe when closed.

3. The system of claim 1, wherein the rig controller causes the valve to be opened based on the first signature and releases pressure through the valve from the standpipe.

4. The system of claim 3, wherein the first signature comprises a condition which indicates that pressure in the standpipe is below a first pre-determined pressure level.

5. The system of claim 4, wherein the first pre-determined pressure level is a pressure that reduces damage to the valve when the valve is opened.

6. The system of claim 4, wherein the rig controller is configured to detect a second signature of the conditions of the rig based on the data sources received at the rig controller, and wherein the rig controller causes the valve to open or close or partially open based on the second signature.

7. The system of claim 6, wherein the rig controller causes the valve to be closed based on the second signature and a time delay after the first signature is detected, and wherein the valve prevents pressure loss through the valve from the standpipe.

8. The system of claim 7, wherein the second signature comprises a condition which indicates that pressure in the standpipe is below a second pre-determined pressure level, wherein the second pre-determined pressure level is below the first pre-determined pressure level, and wherein the second pre-determined pressure level indicates that the pressure in the standpipe is at a level where a connection to the tubular string can be made.

9. The system of claim 1, wherein the first signature indicates that strokes per minute of the one or more mud pumps is non-zero, and wherein the rig controller causes the valve to close regardless of other conditions of the rig.

10. The system of claim 9, further comprising a safety check, wherein the safety check indicates that at least a portion of a well event has occurred, and the rig controller causes the valve to close or remain closed in response to the safety check.

11. The system of claim 1, wherein the first signature indicates a mud pulse telemetry mode, wherein the rig controller receives data for transmission downhole and controls the valve to produce pressure pulses in the standpipe that are representative of the data, and wherein the pressure pulses are transmitted downhole through mud in the tubular string.

12. The system of claim 1, wherein the rig controller is configured to compare the first signature to one or more historical signatures stored in a signature database, and wherein the one or more historical signatures indicate an action to be taken if the first signature matches one of the one or more historical signatures.

13. A method for managing pressure in a standpipe during a subterranean operation, the method comprising:stopping a mud pump that supplies pressurized mud to the standpipe on a rig;monitoring, via a pressure sensor, the pressure in the standpipe;opening, via a rig controller, a valve when the pressure is below a first pre-determined pressure level, wherein the valve is in pressure communication with the standpipe;releasing the pressure through the valve until the pressure is decreased to a level below a second pre-determined pressure level;initiating a delay timer when the pressure is below the second pre-determined pressure level;closing the valve, via the rig controller, when the delay timer has expired; andadding a tubular to a tubular string while the pressure is below the second pre-determined pressure level.

14. The method of claim 13, further comprising starting the mud pump, and increasing the pressure back above the first pre-determined pressure level.

15. The method of claim 14, further comprising repeating stopping, monitoring, opening, releasing, closing, adding, and starting for each time a tubular is added to the tubular string, and performing the stopping, monitoring, opening, releasing, closing, adding, and starting automatically via the rig controller.

16. A method for managing pressure in a standpipe during a subterranean operation, the method comprising:monitoring, via a rig controller, data sources from the rig;detecting a first signature of conditions of the rig based on the data sources, wherein the first signature indicates that the pressure in the standpipe is below a first pre-determined pressure level;opening, via the rig controller, a valve in pressure communication with the standpipe in response to detecting the first signature;releasing the pressure from the standpipe through the valve;detecting a second signature of conditions of the rig based on the data sources, wherein the second signature indicates that the pressure in the standpipe is below a second pre-determined pressure level;initiating, via the rig controller, a delay timer when the pressure is below the second pre-determined pressure level; andclosing the valve, via the rig controller, when the delay timer has expired.

17. The method of claim 16, wherein the first signature further indicates that strokes per minute of a mud pump is zero, and wherein the mud pump delivers mud to the standpipe.

18. The method of claim 16, wherein the first signature further indicates that a mud saver valve and a lower well control valve are closed.

19. The method of claim 16, wherein the first signature further indicates a time mode is enabled and that an open timer delay has expired, which indicates that it is time to open the valve.

20. The method of claim 16, wherein the second signature further indicates at least one of strokes per minute of a mud pump is non-zero and a time mode is enabled and that a bleed pressure delay has expired, wherein the mud pump delivers mud to the standpipe.

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