1. Technical Field
Embodiments of the subject matter disclosed herein generally relate to methods and valves and, more particularly, to mechanisms and techniques for interrupting a flow of liquid through a valve.
2. Discussion of the Background
During the past years, with the increase in price of fossil fuels, the interest in developing new oil production fields has dramatically increased. However, the availability of land-based production fields is limited. Thus, the industry has now extended drilling to offshore locations, which hold a vast amount of oil reserves. One characteristic of the offshore locations is the high pressure to which the drilling equipment is subjected. It is conventional to have parts of the drilling equipment designed to withstand pressures up to 30,000 psi. In addition, the materials used for the various components of the drilling equipment are desired to be corrosion resistant and to resist high temperatures.
Existing technologies for extracting oil from offshore fields use a system 10 as shown in
However, during normal drilling operation, unexpected events may occur that could damage the well and/or the equipment used for drilling. One such event is the uncontrolled flow of gas, oil or other well fluids from an underground formation into the well. Such event is sometimes referred to as a “kick” or a “blowout” and may occur when formation pressure inside the well exceeds the pressure applied to it by the column of drilling fluid (mud). This event is unforeseeable and, if no measures are taken to prevent it, the well and/or the associated equipment may be damaged. Although the above discussion was directed to subsea oil exploration, the same is true for land oil exploration.
Thus, a blowout preventer (BOP) might be installed on top of the well to seal the well in case that one of the above events is threatening the integrity of the well. The BOP is conventionally implemented as a valve to prevent the release of pressure either in the annular space, i.e., between the casing and the drill pipe, or in the open hole (i.e., hole with no drill pipe) during drilling or completion operations. Recently, a plurality of BOPs are installed on top of the well for various reasons.
However, ultra-deep water exploration presents a host of other drilling problems, such as substantial lost circulation zones, well control incidents, shallow-water flows, etc. Thus, many of these wells are lost due to significant mechanical drilling problems. These events increase the cost of drilling and reduce the chances that oil would be extracted from those wells.
A new technology for deep water exploration, which is discussed with regard to
The system shown in
The conventional drill string valve 46 is placed inside the casing 44, close to the drill bit 30. Thus, the drill string valve 46 is a downhole tool and this valve is illustrated in
A few disadvantages of the drill string valve 46 shown in
A spring package includes the long coil spring 58, or tandem springs that make up a long spring, and are installed in a spring chamber 66. Buckling of the long springs 58 has been observed. The buckling increase a friction between the springs and the package as the coils contact with an outer diameter and an inner diameter of the spring chamber 66. Also, the spring package is open to borehole fluids in this design. Even if the spring area is packed in grease, the grease eventually is replaced with mud during drilling.
Another disadvantage of the system shown in
Accordingly, it would be desirable to provide systems and methods that avoid the afore-described problems and drawbacks.
According to one exemplary embodiment, there is a drill string valve assembly that includes first, second and third portions forming an elongated housing having an inside cavity, the elongated housing extending along an axis and having a substantially constant outer diameter; and a drill string valve provided inside the cavity, to extend from the first portion to the third portion. The second portion has an extension that fits inside a groove of the third portion and prevents the second portion to linearly move relative to the third portion and also allows the second portion to rotate relative to the third portion, and the second portion has a distal region provided with a thread configured to engage a corresponding thread of the first portion such that a rotation of the second portion relative to the third portion determines a tight connection between the first portion and the second portion.
According to another exemplary embodiment, there is a drill string valve assembly that includes first portion, second portion and third portion forming an elongated housing having an inside cavity, the elongated housing extending along an axis and having a substantially constant outer diameter; a drill string valve provided inside the cavity, to extend from the first portion to the third portion; and at least one of a displacement sensor configured to determine a linear displacement of a spring provided inside the drill string valve and a load transducer configured to determine a spring compression existing in the spring. The second portion has an extension that fits inside a groove of the third portion and prevents the second portion to linearly move relative to the third portion and also allows the second portion to rotate relative to the third portion, and the second portion has a distal region provided with a thread configured to engage a corresponding thread of the first portion such that a rotation of the second portion relative to the third portion determines a tight connection between the first portion and the second portion.
According to still another exemplary embodiment, there is a method for assembling a drill string valve assembly. The method includes a step of providing first, second and third portions to be connected to each other; attaching a drill string valve to the third portion; rotating the second portion to the third portion such that an extension of the second portion fits into a groove of the third portion; and threading a portion of the second portion with a corresponding portion of the first portion so that the drill string valve is sealed inside the first, second and third portions.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments. In the drawings:
The following description of the exemplary embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. The following embodiments are discussed, for simplicity, with regard to the terminology and structure of a drill string valve that is provided offshore. However, the embodiments to be discussed next are not limited to this type of valve, but may be applied to other systems that are configured to interrupt a fluid flow.
Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
According to an exemplary embodiment, a novel drill string valve has a substantially constant outer diameter, includes a loading mechanism for loading a valve spring of a spring package, the valve spring includes a wave spring, the spring package is immersed in an oil filled chamber and the oil filled chamber pressure is compensated from an annulus pressure. The above noted features are discussed next in more details. It is noted that the following exemplary embodiments may include one or more of these features or other features and no exemplary embodiment should be construed to require all these features or a specific combination of the features noted above.
According to an exemplary embodiment,
A second end 76 of the drill string valve 70 is configured to have a lower cap 78. Cavity 79 should be understood as extending from the first end 74 to the second end 76. Cavity 79 includes plural chambers, as will be discussed later. A compensating piston 120 seals the cavity 79 from a mud 60 existent in the casing 44. A fluid 80 may flow through a conduit 81 of the drill string valve 70. The conduit 81 extends inside the cavity 79, from an upper flow nozzle 82 to a lower flow nozzle 84. In operation, the drill string valve 70 of this embodiment may be positioned vertically or substantially vertically and it has the first end 74 displaced above the second end 76, such that mud from the vessel enters, in this order, first end 74, upper flow nozzle 82, conduit 81, lower cap 78, and lower flow nozzle 84. It is noted that the drill string valve 70 is part of the drill string 24 (see
According to an exemplary embodiment, a body of the drill string valve 70 may include three portions, first portion 86A, second portion 86B, and third portion 86C. The first two portions 86A and 86B may be connected together via a valve body 92 and the second portion 86B may be connected to the third portion 86C via a spring load cartridge 110.
Sliding valve 50 is configured to slide to and from cone seal 56, along a Z direction, as shown in
In one exemplary embodiment, the wave spring 98 is not a coil spring but rather has one or more of the shapes shown in
When deployed subsea, the sliding valve 50 of the drill string valve 70 is biased by the actuator 94 to actively engage the cone seal 56, thus sealing the conduit 81. The bias applied by the actuator 94 to the sliding valve 50 is a result of the compression of the wave spring 98. As will be discussed next, the wave spring 98 is initially deployed uncompressed inside the drill string valve 70, in order to avoid possible hazardous conditions. An advantage of the wave spring 98 is its reduced length in comparison to a conventional coil spring for generating a same spring force.
The threaded stop 100 configured to load the biasing cartridge 90 is discussed next with regard to
According to an exemplary embodiment, the spring load cartridge 110 includes a hydraulic piston 102 and a threaded stop 100. A port 106 into loading chamber 108 provides access to pump hydraulic fluid into the loading chamber 108 to actuate hydraulic piston 102. Thus, hydraulic piston 102 moves from right to left in
Once the desired first force in the wave spring 98 is achieved, the hydraulic pressure applied to the loading chamber 108 is maintained constant and the threaded stop 100 is advanced toward the spring until the threaded stop 100 picks up the load of the wave spring 98, i.e., the threaded stop 100 fixes the spring spacer 99. At this point, the applied hydraulic pressure may be released from the loading chamber 108. Port 106 may be connected to a pump that pumps, for example, oil for activating the hydraulic piston 102. Other mechanism for hydraulic piston 102 may be used as would be appreciated by those skilled in the art.
The spring load cartridge 110 defines the border for loading chamber 108 and also provides a mating thread to the threaded stop 100. Once the spring load bias has been set, the lower section 86C is assembled, and the tool is ready to be installed in its collar.
According to an exemplary embodiment, the spring load cartridge 110 breaks the continuity of the external tubes 86B and 86C that constitute the outside wall of the drill string valve 70. In other words, the outside wall of the drill string valve may be made up of plural tubes. For example, the embodiment shown in
Still with regard to
Compensating chamber 118 communicates via a port 122 with an annulus space around the drill string valve 70 for providing annulus pressure 112 inside a chamber 124 of the compensating chamber 118, between the compensating piston 120 and the lower cap 78. In this way, the borehole fluids are separated from the clean oil present in the biasing chamber 96 and part of the loading chamber 108.
The next paragraphs summarize some of the features and/or advantages of the exemplary embodiments discussed above. While an exemplary embodiment may include one or more of these features/advantages, there are exemplary embodiments that include none of these features/advantages. The drill string valve body assembly has a constant outer diameter that enables horizontal or vertical insertion into the bore of the drill string valve collar.
The drill string valve collar is simple in design with a long counter bore terminating at a shoulder near the bottom and an internal thread near a top for a lock ring. The overall length may be short, for example, 13 ft (4 m). The body may be inserted in the collar and may land on a shoulder at the bottom of the valve. In one application there is no fixed orientation. The drill string valve may be retained and locked in place at the upper end with a threaded lock ring 74 (see
The spring is installed in the drill string valve body at its free length (no spring load). A mechanism (loading mechanism) to load the spring is installed below the spring package. The mechanism to load the spring is integral to the drill string valve body, not an auxiliary tool. The remainder of the drill string valve body is assembled after the spring force is set.
The type of spring used for the drill string valve has an effective free length that is shorter than the free length of a coil spring, for example, half the free length of a coil spring with the same spring rate. This feature reduces system friction. The spring package, interior dynamic seals, and bearings are immersed in a pressure balanced oil system. The pressure balance is achieved with a port through the collar wall that taps onto the well bore annulus. A mating port in the lower cap of the drill string valve body channels the annulus pressure to a compensating piston separating the borehole fluids from the clean oil system.
According to another exemplary embodiment, various analytical tools, for example, sensors, may be provided inside the drill string valve. Such tools may include pressure sensors, load cell sensors, temperature sensors and sensors for determining a position of the sliding valve 50. This feature would optimize valve operation. As this type of valve opens very quickly, there is desired for the valve to open in a slower, controlled fashion to reduce the effect of pressure shocks on the well formation. Thus, the sensors discussed above may help monitor and control the drill string valve. According to an exemplary embodiment, a processor with memory capabilities may be deployed inside the drill string valve for collecting and processing the data from the above discussed sensors or others known in the art. Such capability may offer extended control of the drill string valve.
Analytical tools provide the ability to optimize a given spring for use over a wide range of operation. This will lessen the frequency of exchanging spring hardware during the course of drilling program. Simulation software provides the capability to input changing operating conditions and to determine the effects of them in a time sequence. This capability is desired for custom spring design.
This feature includes the addition of downhole diagnostic instrumentation, for example, a data acquisition system may be packaged in an electronics pressure vessel upstream of the drill string valve body. The time synchronized data acquisition may record pressures, acceleration, spring load, valve position, and temperature data. Pressure transducers ports may be positioned upstream and downstream of the valve seat for measuring local static and dynamic pressures.
A time synchronized data acquisition unit may be packaged with a linear measurement transducer to record valve position. Data ports may be built into the drill string valve body for data download, real-time data monitoring during lab testing, flow loop testing, and pre-check diagnostics prior to deployment. Hydraulic access ports may also be built into the drill string valve body for lab testing, flow loop testing and pre-deployment checks.
According to an exemplary embodiment, steps of a method for activating the drill string valve 70 are illustrated in
According to another exemplary embodiment, a drill string valve 160, different from the drill string valve 70 or other valves discussed above is now discussed with regard to
The novel drill string valve shown in
According to an exemplary embodiment, the drill string valve 160 includes a collar 162 inside of which various components are provided. For example, a motor module 180 is provided in contact with a spider 204. The spider 204 seals a motor chamber 182, in which the motor module is fixed.
Actuation of the motor 184 determines the extension or retraction of the ball screw 186 and actuation rod 190, which determine the movement of poppet 200 towards and away from poppet seat 202. When the poppet 200 is in contact with the poppet seat 202, no fluid (or an insignificant amount) passes through the drill string valve 160. The pressure vessel 192 that accommodates the motor module 180 may be connected to the spider 204, which is configured to accommodate the poppet 200. As would be recognized by one skilled in the art, appropriate seals are formed around various elements discussed above for preventing fluid entering the motor module.
A pressure inside the drill string valve 160, may be monitored by pressure sensors 222 and 224. A position of the poppet 200 may be monitored with a position sensor 228. Such a position sensor 228 and accompanying mechanism may be a LVDT, as described in Young et al., Position Instrumented Blowout Preventer, U.S. Pat. No. 5,320,325, Young et al., Position Instrumented Blowout Preventer, U.S. Pat. No. 5,407,172, and Judge et al., RAM BOP Position Sensor, U.S. Patent Application Publication No. 2008/0196888, the entire contents of which are incorporated herein by reference.
Based on the data provided by the pressure sensors 222 and 224, and optionally by flow meter 226 and/or position sensor 228, the microprocessor 230 may determine when to close or open poppet 200. The microprocessor 230 may be provided in a custom made chamber in the body of the drill string valve 160. According to an exemplary embodiment, the microprocessor 230 is configured to adjust the closing of the drill string valve 160 depending whether poppet 200 is completely closed, poppet 200 is starting to open or close, and/or poppet 200 is open. It is noted that a pressure in the annulus (i.e., outside the motor module 180) is larger when the drill string valve is closed than when the drill string valve is opened. Thus, based on the pressure measurements and/or position of the poppet, the amount of opening of the poppet 200 may be controlled, thus achieving a feed-back controlled drill string valve.
With regard to
Next, the operation of the drill string valve is discussed. The drill string valve is a pressure regulating check valve that uses a flow for compensation. The valve has two modes of operation, which are drilling mode with pumps on and non-drilling mode with pumps off. During the drilling mode the drill string valve becomes a flow compensated check valve. During the non-drilling mode, the drill string valve prevents the mud column above the valve from free falling when the mud pumps are turned off.
The drill string valve 70 employs a spring to control the valve opening. According to an exemplary embodiment, the design of the valve spring is dependent on the spring load, the spring rate, the flow rate, the mud weight, the back pressure of the bit nozzles, and the flow losses in the well from pipe friction, casing friction, and any downhole tools in the drill string. Because of the array of operating variables the throttling performance of a spring actuated valve is indeterminate.
The drill string valve 160 may use a microprocessor and sensor data from on board sensors to control valve position. The drilling mode is determined by measuring the broad band acceleration of the drill string valve. There is a distinctive change in the broad band when the mud pumps are turned off and on. The microprocessor may read acceleration, mud flow rate, valve position, and differential pressures. Before the tool is run, inputs for control and look-up tables for valve opening vs. time are downloaded via a communication device, for example, a computer. The look-up tables are constructed to meet the requirements of the well plan and may vary from application to application. When the microprocessor senses there is broad band response from the accelerometer, the microprocessor begins modulating the valve and controlling the valve opening based at least in part on information in the look-up table.
Returning to
According to an exemplary embodiment, the seal element and the seat of the above discussed embodiments are configured, when closed, to withstand pressures of 30,000 psi.
According to an exemplary embodiment shown in
According to an exemplary embodiment illustrated in
The first portion 404 is configured to house the electronics 412 associated with the valve module 402. The third portion 408 has a distal end 408a configured to be completely covered by the second portion 406 and partially covered by the first portion 404. The distal end 408a has a shoulder 414 which borders a groove 416 formed in the third portion 408. An extension 418 of the second portion 406 is configured to fit inside the groove 416. In one application, the extension 418 is configured to be circular. In order to fit the extension 418 around the third portion 408, the extension 418 may be formed in two pieces, e.g., two halves of a cylinder. Thus, the two halves are placed around the third portion 408 and attached to each other by, e.g., two or more screws 420. Once provided around the third portion 408, the second portion 406 may rotate relative to the third portion 408.
The second portion 406 has a distal region 406a provided with a thread 422a configured to engage a corresponding threaded region 422b of the first portion 404. Thus, after the second portion 406 is rotatably attached to the third portion 408, the first portion 404 is brought into contact with the second portion 406 and the second portion 406 is rotated relative to the first portion 404 until the two portions are tight together. Appropriate seals 424 are provided between the first and second portions to prevent a leak between the annular fluid 450 and the internal pipe fluid 452. The engagement of first portion 404 and the third portion 408 are keyed in that their radial orientations are aligned to each other. The engagement of first portion 404 and the third portion 408 have mating diameters with a light press-fit that provides a reliable seal between the cone seal 454 and sliding valve 442.
By knowing the force in the springs 434 and 436 and/or the displacement of these springs, a micro-processor 440 provided, e.g., in the electronics 412, may determine when to close or open the valve 442 for allowing or interrupting a flow through the valve module 402. The processor 440 may be configured to receive other data, e.g., flow rate from a flow meter 444 and/or pressure data from pressure sensors 446. As discussed above, the micro-processor software algorithm may be based on a user-defined relationship between some or all of the above measured quantities and valve position. The processor compares the actual valve position with the desired valve position based on this data. The processor sends a command to the motor controller board 227 (discussed above with regard to
According to an exemplary embodiment illustrated in
The disclosed exemplary embodiments provide a system and a method for closing and opening a valve through which a fluid may flow. The exemplary embodiments are intended to cover alternatives, modifications and equivalents, which are included in the spirit and scope of the invention as defined by the appended claims. Further, in the detailed description of the exemplary embodiments, numerous specific details are set forth in order to provide a comprehensive understanding of the claimed invention. However, one skilled in the art would understand that various embodiments may be practiced without such specific details.
Although the features and elements of the present exemplary embodiments are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the embodiments or in various combinations with or without other features and elements disclosed herein.
This written description uses examples of the subject matter disclosed to enable any person skilled in the art to practice the same, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other example are intended to be within the scope of the claims.