Patent Application
20180187506
In subsea landing string systems (“SLSS”), a tubular string may extend downward from a vessel (e.g., a ship) floating on the surface of the water to a wellhead positioned on the seafloor. The tubular string may be affected by weather conditions. For example, during bad weather, the wind and/or the waves may cause the vessel to move around on the surface of the water. The upper end of the tubular string moves together with the vessel. The lower end of the tubular string, however, remains stationary, as it is coupled to the wellhead. Thus, the tubular string may tilt with respect to vertical, which may exert a force on the tubular string. When the force exceeds a predetermined threshold, a blow-out preventer (“BOP”) positioned near the wellhead may be automatically actuated, causing one or more rams of the BOP to cut the tubular string to alleviate the force and prevent the leakage of hydrocarbons into the water. Cutting the tubular string, however, increases the time to restart operations.
In some instances, an emergency shutdown and disconnect (“ESD”) system may be coupled to the wellhead. If a user on the vessel determines that the force on the tubular string is approaching or exceeding the predetermined threshold, the user may actuate the ESD, causing the ESD system to shut-in the well and unlatch the tubular string from the wellhead. The tubular string may then drift with the vessel. If the user actuates the ESD system quickly enough, the ESD system may unlatch the tubular string before the BOP is actuated, preserving the tubular string and reducing the time to restart operations. However, if the user does not actuate the ESD system quickly enough, the BOP may cut the tubular string.
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 key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
A method for initiating an emergency shutdown and disconnect (ESD) sequence is disclosed. The method includes measuring an angle of the tubular member with respect to vertical using a sensor that is coupled to the tubular member. The method also includes determining whether the angle exceeds a predetermined threshold for a predetermined amount of time. The ESD sequence is initiated when the angle exceeds the predetermined threshold for the predetermined amount of time.
In another embodiment, the method includes measuring a first angle of the tubular member using a first sensor that is coupled to the tubular member at a first location and measuring a second angle of the tubular member using a second sensor that is coupled to the tubular member at a second location that is different than the first location. The method also includes determining whether the first angle exceeds a first predetermined threshold a first predetermined number of times that is greater than one, or the second angle exceeds a second predetermined threshold a second predetermined number of times that is greater than one. The method also includes initiating the ESD sequence when the first angle exceeds the first predetermined threshold the first predetermined number of times or when the second angle exceeds the second predetermined threshold the second predetermined number of times.
A system is also disclosed. The system includes a tubular member, and instrumentation module, and a controller. The instrumentation module is coupled to the tubular member, and the instrumentation module includes a sensor that measures an angle of the tubular member. The controller determines whether the angle exceeds a predetermined threshold for a predetermined amount of time, a predetermined number of times that is greater than one, or both. In response to the angle exceeding the predetermined threshold for the predetermined amount of time, the predetermined number of times that is greater than one, or both, the controller disconnects at least a portion of the tubular member from subsea well equipment, shut-in a well, or both.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present teachings and together with the description, serve to explain the principles of the present teachings. In the figures:
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying figures. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the system and method disclosed herein may be practiced without these specific details.
In at least one embodiment, the latch assembly 24 may include a latch mandrel having a weakened area 26. The weakened area 26 may be positioned in a housing 28 that protects the latch assembly 24 against bending loads while still allowing the latch assembly 24 to disconnect and separate upon application of a predetermined tensile load on the latch assembly 24. The weakened area 26 may allow the tubular member 22 to separate into an upper portion 42 and a lower portion 44 upon application of the predetermined tensile load. For example, the predetermined tensile load may be applied by providing a sufficient lifting force on the tubular member 22 from the surface; however, the tensile load also may also or instead be applied by hydraulic pistons or other mechanisms. In another example, the latch assembly 24 may include a release mechanism (e.g. a collet or other releasable assembly), which may enable a controlled disconnect of the tubular member 22 at the latch assembly 24. In this latter example, the controlled disconnect may be accomplished via a suitable hydraulic actuator or other type of actuator constructed to enable selective separation of the release mechanism and thus release of an upper latch assembly portion from a lower latch assembly portion.
As shown in
The well system (e.g., the tubular member 22) may also include one or more instrumentation modules (one is shown: 46), which measures one or more parameters. As discussed in greater detail below, when the parameter(s) exceed a predetermined threshold, the well 32 may be shut-in and/or the tubular member 22 may be separated at the latch assembly 24. This may be referred to as an emergency shut-down and disconnect (“ESD”) sequence.
The well system 20 may also include a controller 48. The instrumentation module 46 may transmit the measured parameters to the controller 48. The controller 48 may be positioned in the tubular member 22 (e.g., in the instrumentation module 46) or at the surface (e.g., on the vessel). The measured parameters may be transmitted through a communication line 50, such as an electrical line or optical fiber. In other embodiments, the measured parameters may be transmitted as electromagnetic, hydraulic, mechanical, or acoustic signals. In response to the measured parameters, the controller 48 may autonomously initiate the ESD sequence (e.g., by transmitting one or more signals through the communication line 50).
In addition to the latch assembly 24 and instrumentation module 46, the tubular member 22 may also include a plurality of valves located above and/or below the latch assembly 24. For example, the valves may include a retainer valve 68 and a bleed valve 70 positioned above the latch assembly 24. The valves also may include a flapper valve 72 and a ball valve 74 positioned below the latch assembly 24. The valves 68, 70, 72, 74 may be used to selectively block or direct fluid flow along an interior of the tubular member 22. As will be appreciated, other types of valves and other arrangements of valves also may be employed to selectively block or direct fluid flow along an interior of the tubular member 22.
The tubular member 22 also may include a tubing hanger and running tool assembly 76 and a seal assembly 78 (e.g., a packer) positioned below the latch assembly 24. The tubular member 22 may further include a space out sub 80 positioned above the retainer valve 68 and the bleed off valve 70, and a ported joint 81 positioned below the ball valve 74. The latch assembly 24 may also include a shear sub or mandrel 82 that includes the weakened area 26 to facilitate the ESD sequence.
One or more sensors 96 may be positioned at least partially within and/or be coupled to the housing 84. The sensors 96 may be configured to measure one or more parameters related to the tubular member 22. The parameters may be or include inclination, orientation (e.g., a gyroscope sensor), acceleration (e.g., an accelerometer sensor), tilt, bending, corkscrewing, fatigue, cyclical stress, tension, strain, torque, pressure, temperature, inertial measurements, depth, and the like.
In one example, the sensors 96 may be configured to measure the angle of the tubular member 22 with respect to at least one axis (e.g., the vertical axis). In another example, the sensors 96 may include three sensors, each configured to measure the angle of the tubular member 22 with respect to a different axis (e.g., X, Y, and Z axes). In another example, the sensors 96 may include three sensors, each configured to measure the angle of the tubular member 22 with respect to a different axis (e.g., X, Y, and Z axes) over time to detect corkscrewing of the tubular member 22. In another example, the sensors 96 may be configured to measure the angles of the tubular member 22 with respect to one or more axes (e.g., X, Y, and Z axes) over time to derive the cyclical stresses, which may be used to estimate a fatigue level of the tubular member 22. In another example, the sensors 96 may include three accelerometers (e.g., one for each axis), and three gyroscopes (e.g., one for each axis). In another example, the sensors 96 may also include one or more depth sensors that affect priority assigned to the measured angles. The sensors 96 may be coupled with the communication line 50 via the connectors 86. Thus, the measurements from the sensors 96 may be transmitted to the controller 48 via the communication line 50.
The controller 48 may be or include the SENTREE® system, which is a deep-water control system, available from Schlumberger Corporation, for providing fast acting control of subsea test trees/landing strings. The controller 48 may further include an electro-hydraulic control system, such as the SENTURIAN® system, available from Schlumberger Corporation, which provides electro-hydraulic controls with fast response times and hydraulic power accumulation. This enables the SENTURIAN® portion of the controller 48 to control, for example, the SENTREE® functionality, including closing of valves (e.g., closing of flapper valve 72 and retainer valve 68), as well as actuation of the latch assembly 24 to disconnect the tubular member 22. The controller 48 may be programmable so that the various control system components (e.g., the instrumentation module 46, SENTURIAN®, and SENTREE®), respond automatically when the measured parameters exceed a predetermined threshold so as to initiate the ESD sequence. If, for example, the sensors 96 of the instrumentation module 46 detect an angle that exceeds the predetermined threshold, the controller 48 may autonomously initiate the ESD sequence via, for example, the deep water control and operating systems such as SENTREE® and SENTURIAN®.
In at least one embodiment, the controller 48 may include an electrical module including at least one microcontroller and at least one data-logger board. The electrical module may receive and process the measurements from the sensors 96. For example, the microcontroller may calculate the angles of the tubular member 22 from the accelerometer and gyro data. The gyro data and an algorithm (e.g., Kalmann filter) may be used to improve the estimate by filtering out the effects from non-gravitational acceleration and noise. As mentioned above, the electrical module may use additional data from other sensors 96 (e.g., a depth sensor) to assign weights to the different measured parameters to improve the decision-making process (e.g., by improving measurements and/or calculations). For example, the gravitational acceleration may be different at different depths. The data-logger board may record the parameters. For example, the data-logger board may record the angles over time. The data-logger board may also record any processed and/or analyzed data, such as the number of stress cycles for fatigue or the values that triggered the ESD sequence so that the operator can investigate afterwards to understand if it is safe to continue. This information may be communicated with the operator when desired via a subsea electrical module (“SEM”) or via a direct communication path to the surface. In another embodiment, this information may be checked by the operator after a job to keep track of the wear on the equipment. This information may also be sold to the client.
The electrical module may interface with the SEM of the subsea control system (e.g., SENTURIAN®). Once the predetermined threshold is exceeded, the electrical module may transmit a signal to the SEM to initiate the ESD. The level/degree of the ESD may be preselected. The electrical module may be powered by surface or subsea sources. The electrical module may communicate using an electrical cable, acoustic telemetry, electromagnetic telemetry, mud pulse telemetry, a fiber optic line, or the like. For example, one or more telemetry modules may be spaced axially-apart along the tubular member 22 to relay data.
In deep water (i.e., when the tubular member 22 is long), the tubular member 22 may be more susceptible to local bending. Localized bending is present in the lower portion of the tubular member 22 in
As will be appreciated, a single instrumentation module 46 at a fixed position in the tubular member 22 may measure the inclination angle at one point in the tubular member 22 (e.g., inclination angle α or inclination angle β), but not two or more angles α, β at different locations. Thus, in the example of
The method 600 may also include measuring a parameter (e.g., inclination angle α, β) of the tubular member 22 using the instrumentation module 46, as at 604. As mentioned above, the sensors 96 in the instrumentation module 46 may measure the parameter. In one example, the well system 20 may include a plurality of instrumentation modules 46 that are axially-offset from one another along the length of the tubular member 22, and the method 600 may include measuring a parameter of the tubular member 22 with each of the instrumentation modules 46. The measured parameter may be transmitted from the instrumentation module 46 to the controller 48 (e.g., using the communication line 50).
The method 600 may also include determining whether the measured parameter exceeds a predetermined threshold, as at 606. As mentioned above, the controller 48 may determine whether the measured parameter exceeds the predetermined threshold. In at least one embodiment, determining whether the measured parameter exceeds the predetermined threshold may include determining whether the measured parameter exceeds the predetermined threshold for a predetermined amount of time (e.g., 30 seconds). The predetermined amount of time may be a single, continuous interval of time or multiple intervals of time in the aggregate. In another embodiment, determining whether the measured parameter exceeds the predetermined threshold may include determining whether the measured parameter exceeds a first predetermined threshold for a first predetermined amount of time and/or determining whether the measured parameter exceeds a second predetermined threshold for a second predetermined amount of time. The first predetermined threshold may be greater than the second predetermined threshold (e.g., 20° vs. 10°), and the first predetermined amount of time may be less than the second predetermined amount of time (e.g., 1 second vs. 30 seconds). In another embodiment, determining whether the measured parameter exceeds the predetermined threshold may include determining whether the measured parameter exceeds the predetermined threshold a predetermined number of times. The predetermined number of times may be greater than one (e.g., 5 times). This may be used to, for example, determine that the tubular member 22 is making a corkscrewing movement, reaching upper fatigue levels, etc.
When the parameter is an inclination angle (e.g., α or β), the predetermined threshold may be about 5°, about 10°, about 15°, about 20°, or more. When the well system 20 includes a plurality of instrumentation modules 46, the method 600 may include determining whether a parameter measured by at least one of the instrumentation modules 46 is greater than the predetermined threshold. In at least one embodiment, different instrumentation modules 46 may have different predetermined thresholds. For example, when the parameter is an inclination angle, a first instrumentation module 46 may have a threshold of 10°, and a second instrumentation module 46 may have a threshold of 15°. The threshold values may be selected based upon depth, client choice, software used, etc. If the measured parameter exceeds the predetermined threshold (i.e., YES), the method 600 may proceed to 608. If the measured parameter is less than the predetermined threshold (i.e., NO), the method 600 may wait for a predetermined period of time and loop back to 602.
The method 600 may also optionally include disconnecting at least a portion of the tubular member 22 from the subsea well equipment 34 when the measured parameter exceeds the predetermined threshold, as at 608. More particularly, the controller 48 may autonomously initiate the ESD sequence via, for example, the deep water control and operating systems such as SENTREE® and SENTURIAN®. In at least one embodiment, this may cause the surface vessel or other surface equipment to apply a tensile pulling/lifting force on the tubular member 22. For example, the latch assembly 24 may be actuated by the controller 48 to a release position so that application of a tensile pulling force above a predetermined break level causes disconnection of the tubular member 22 at the latch assembly 24. In this example, the tensile pulling force causes the weakened area 26 to break so that the upper portion 42 may separate from the lower portion 44. In another embodiment, a cutter module in the SENTREE® system may cut the coiled tubing running inside the latch assembly 24. This may allow the valves to close when disconnection occurs.
The upper portion 42 may thus be separated from the subsea well equipment 34 and be able to float/drift with the vessel 10. Before or after separation, the controller 48 may close the retainer valve 68 in a short period of time (e.g., approximately 6 or less) to prevent fluid from exiting the upper portion 42 of the tubular member 22. With the tubular member 22 disconnected from the subsea well equipment 34 in this way, the BOP 36 may not cut the tubular member 22, thus preserving the tubular member 22 for an easy reconnection to the subsea well equipment 34.
The method 600 may also include shutting-in the well 32 when the measured parameter exceeds the predetermined threshold, as at 610. In at least one embodiment, the well 32 may be shut-in without the tubular member 22 being disconnected. More particularly, the controller 48 may autonomously initiate the ESD sequence via, for example, the deep water control and operating systems such as SENTREE® and SENTURIAN®, which may block upward flow of well fluid via closure of the flapper valve 72 and/or the ball valve 74 in a short period of time (e.g., approximately one second or less). For example, the ball valve 74 may be closed as the primary barrier.
In some embodiments, any of the methods of the present disclosure may be executed by a computing system.
A processor can include a microprocessor, microcontroller, processor module or subsystem, programmable integrated circuit, programmable gate array, or another control or computing device.
The storage media 1006 can be implemented as one or more computer-readable or machine-readable storage media. Note that while in the example embodiment of
In some embodiments, computing system 1000 contains one or more ESD module(s) 1008. In the example of computing system 1000, computer system 1001A includes the ESD module 1008. In some embodiments, a single ESD module may be used to perform at least some aspects of one or more embodiments of the methods. In another embodiment, a plurality of ESD modules may be used to perform at least some aspects of methods.
It should be appreciated that computing system 1000 is one example of a computing system, and that computing system 1000 may have more or fewer components than shown, may combine additional components not depicted in the example embodiment of
Further, the methods described herein may be implemented by running one or more functional modules in information processing apparatus such as general purpose processors or application specific chips, such as ASICs, FPGAs, PLDs, or other appropriate devices. These modules, combinations of these modules, and/or their combination with general hardware are included within the scope of protection of the invention.
As used herein, the terms “inner” and “outer”; “up” and “down”; “upper” and “lower”; “upward” and “downward”; “above” and “below”; “inward” and “outward”; and other like terms as used herein refer to relative positions to one another and are not intended to denote a particular direction or spatial orientation. The terms “couple,” “coupled,” “connect,” “connection,” “connected,” “in connection with,” and “connecting” refer to “in direct connection with” or “in connection with via one or more intermediate elements or members.”
The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. Moreover, the order in which the elements of the methods described herein are illustrate and described may be re-arranged, and/or two or more elements may occur simultaneously. The embodiments were chosen and described in order to best explain the principals of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.
