Patent Grant
9657540
This application is a U.S. National Stage of International Application No. PCT/US2012/046857, filed Jul. 16, 2012.
The present disclosure relates to systems, assemblies, and methods for conveying perforating and/or logging tools (hereinafter referred to as a “tool string”) in a wellbore where adverse conditions may be present to challenge downward movement of the tool string in the wellbore.
In oil and gas exploration it is important to obtain diagnostic evaluation logs of geological formations penetrated by a wellbore drilled for the purpose of extracting oil and gas products from a subterranean reservoir. Diagnostic evaluation well logs are generated by data obtained by diagnostic tools (referred to in the industry as logging tools) that are lowered into the wellbore and passed across geologic formations that may contain hydrocarbon substances. Examples of well logs and logging tools are known in the art. Examples of such diagnostic well logs include Neutron logs, Gamma Ray logs, Resistivity logs and Acoustic logs. Logging tools frequently are used for log data acquisition in a wellbore by logging in an upward (up hole) direction, from a bottom portion of the wellbore to an upper portion of the wellbore. The logging tools, therefore, need first be conveyed to the bottom portion of the wellbore. In many instances, wellbores can be highly deviated, or can include a substantially horizontal section. Such wellbores make downward movement of the logging tools in the wellbore difficult, as gravitational force becomes insufficient to convey the logging tools downhole.
The present disclosure relates to systems, assemblies, and methods for conveying perforating and/or logging tools (hereinafter referred to as a “tool string”) in a wellbore where adverse conditions may be present to challenge downward movement of the tool string in the wellbore. The disclosed systems, assemblies, and methods can reduce risk of damage to the tool string and increase speed and reliability of moving the tool string into and out of wellbores. For example, certain wells can be drilled in a deviated manner or with a substantially horizontal section. In some conditions, the wells may be drilled through geologic formations that are subject to swelling or caving, or may have fluid pressures that make passage of the tool string unsuitable for common conveyance techniques. The present disclosure overcomes these difficulties and provides several technical advances.
The present disclosure relates generally to a pump down tool string that is connected to the lower end of an electric wireline or slickline cable that is spooled off a truck located at the surface. As used herein the terms “cable” and “line” and “wireline” are used interchangeably and unless described with more specificity may include an electric wireline cable or a slickline cable. The subject method and system is used in some implementations in a cased wellbore or in other implementations is applicable in a partially cased wellbore. The tool string is especially adapted for use in highly deviated wellbores wherein it is a known practice to pump fluid from the surface behind a tool string to assist the tool in moving down the deviated wellbore.
General background of pump down tool technology is known in the art and is disclosed in pending application PCT/US/2010/44999. The automated pump-down system described in the afore referenced PCT patent application depends on sensor data to provide line tension and line speed. Typically, these readings would come from sensors and calculations done at the surface as prior art pump down operations do not include a tool string that has the capability to transmit this information from the tool string. Using surface data to describe events happening in the wellbore is not optimum due to the delay in the response of the sensors at the surface as well as the inaccuracies caused by the effect of wellbore conditions on the readings. Changes in tension at the cable head of the tool string and real tool string speed would not be instantaneously measured due to dampening effects of stretching of the wireline cable and different wellbore fluids. Accuracy of those measurements would also be affected by cable stretch, wellbore fluids, and well geometry.
If the pump pressure of the fluid behind the tool string is too great it may result in excessive downhole tension on the cable head that will result in breaking the cable or pulling the cable out from the cable head. It is desirable to control the pump pressure or line speed of the cable to keep the tension in the cable within safe parameters.
In some implementations, the pump down tool string of the present disclosure includes a device that measures the tension in the cable at the cable head and transmits that data as an analog signal to the surface via an electric wireline cable or other transmission means, and uses that data to control pumps and/or line speed.
Additionally, in some implementations the pump down tool string of the present disclosure may include a device that calculates the speed of the downhole tool string at the cable head and transmits that data as an analog or digital signal. (Examples of such devices include an accelerometer and/or a casing collar locator.)
In a first aspect, a system for pump down operations in a wellbore includes a tool string disposed in a wellbore, said tool string including a cable head having an upper end coupled to an electric wireline cable, a downhole tool coupled to the cable head, the downhole tool selected from the group consisting of perforating tools and downhole logging tools, and a downhole tension sensor located in the cable head, are alternatively located elsewhere in the tool string, said sensor adapted to obtain downhole wireline tension data and transmit the downhole wireline tension data via the electric wireline cable, a fluid pump with a fluid output operatively connected to the wellbore above the tool string, and a controller adapted to selectively adjust a pump fluid output rate of the fluid pump during pump down operations based on the downhole wireline tension data received from the downhole tension sensor.
Various implementations can include some, all, or none of the following features. The system can also include a wireline speed sensor in communication with the controller, wherein the controller is adapted to selectively adjust the pump fluid output rate during pump down operations based on wireline speed data received from the wireline speed sensor. The wireline speed sensor can be located at the surface and measures the speed of the wireline as the wireline is spooled into the wellbore. The tool speed sensor can be disposed proximal to the cable head and the speed sensor can calculate the speed of the device at the cable head and can transmit that data to a system that communicates with one or more controllers. The tool speed sensor can include a casing collar locator disposed in the tool string and one or more controllers which can calculate the speed at which the casing collar locator is passing between known casing collars spaced apart at previously known distances between the known casing collars. The controller can compare the calculated speed as the casing collar locator passes additional known casing collars and can determine if the speed of the tool string is increasing or decreasing.
In a second aspect, a system for pump down operations in a wellbore includes a tool string disposed in a wellbore, said tool string including a cable head having an upper end coupled to an electric wireline cable, and a downhole tool coupled to the cable head, the downhole tool selected from the group consisting of perforating tools and downhole logging tools, a fluid pump with a fluid output operatively connected to the wellbore above the tool string, and a downhole tool speed sensor in communication with a system that is connected to the controller, wherein the controller is adapted to selectively adjust a pump rate during pump down operations based on wireline speed data received from the downhole tool speed sensor.
Various implementations can include some, all, or none of the following features. The downhole tool speed sensor can be an accelerometer disposed proximal to the cable head and wherein the tool speed sensor calculates the speed of the device at the cable head and transmits that data to a system that is in communication with one or more controllers. The downhole tool speed sensor can include a casing collar locator disposed in the tool string and one or more controllers which can calculate the speed at which the casing collar locator is passing between known casing collars spaced apart at previously known distances between the known casing collars. The controller can compare the calculated tool speed as the casing collar locator passes additional known casing collars and can determine if the speed of the tool string is increasing or decreasing. The controller can adjust either the speed at which the wireline is spooled off at the surface or the pump output based on the downhole tool speed. The system can also include a downhole tension sensor incorporated in the cable head, or alternatively located elsewhere in the tool string, said sensor adapted to obtain downhole wireline tension data and transmit the downhole wireline tension data to the surface. The controller can be adapted to adjust the pump rate based on the downhole wireline speed data unless the downhole wireline tension reaches a predetermined tension threshold, after which the controller can automatically reduce a surface wireline speed of a wireline unit and the pump rate. The controller can be adapted to selectively adjust the pump rate during pump down operations based on downhole wireline tension data received from the downhole tension sensor. The controller can selectively adjust the wireline speed during pump down operations based on wireline tension data received from the downhole tension sensor. The system can also include a pump rate sensor in communication with the controller, wherein the controller can selectively adjust the wireline speed during pump down operations based on pump rate data received from the pump rate sensor. The controller can automate at least one control function selected from the group consisting of: a pump fluid output rate for the pump unit based on at least one of a monitored wireline speed and a monitored wireline tension, and a wireline speed based on at least a monitored pump rate for the pump. The controller can include a wireline controller typically located at the surface and a pump controller that is part of the pump. If the wireline controller notifies the pump controller that a monitored tool speed is less than a predetermined threshold, the pump controller can increase a pump rate of the pump unit in response to said notification. If the wireline controller notifies the pump controller that a monitored wireline tension is more than a predetermined threshold, the pump controller can decrease a pump rate of the pump unit in response to said notification. If the pump controller notifies the wireline controller that a monitored pump rate is less than a predetermined threshold, the wireline controller can decrease a wireline speed in response to said notification.
In a third aspect, a method for pumping a tool string connected to an electric wireline into a wellbore includes inserting a logging tool string into a proximal upper end of the wellbore, said logging tool string including a cable head attached to a cable, a downhole tension sensor located in the cable head, or alternatively, proximal to the cable head, said sensor adapted to obtain downhole wireline tension data and transmit the downhole wireline tension data via the electric wireline cable, and a downhole wireline speed sensor, pumping a fluid into the upper proximal end of the wellbore above the tool string to assist, via fluid pressure on the tool string, movement of the tool string down the wellbore, spooling out the cable at the surface as the fluid is pumped behind the tool string and the tool string is moving down the wellbore, receiving by one or more controllers downhole wireline tension data from the downhole tensions sensor via the electric wireline cable, and receiving by the one or more controllers data from the casing collar locator via the electric wireline cable.
Various aspects can include some, all, or none of the following features. The method can also include determining if the downhole tool string speed is increasing or decreasing. The method can also include monitoring, by a controller, a downhole wireline speed, monitoring, by the controller, a downhole wireline tension, and automatically controlling, by the controller, a pump rate for pumping the tool into the wellbore based on at least one of the monitored downhole tool speed and monitored downhole wireline tension. The method can also include receiving downhole sensor data and determining the tool speed and the wireline tension from the sensor data. The method can also include increasing the pump rate in response to a reduction in the monitored tool speed. The method can also include changing the pump rate in accordance with a difference between the monitored tool speed and a predetermined threshold. The method can also include changing the wireline speed at the surface in response to a monitored pump rate. The method can also include monitoring by a controller a pump rate for pumping the tool into the wellbore, and automatically controlling, by the controller, a tool speed for the tool being pumped into the wellbore based on at least the monitored pump rate.
In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals. The drawing figures are not necessarily to scale. Certain features of the disclosure may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present disclosure is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the disclosure to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results.
In the following discussion and in the claims, the terms “including” and “comprising” are used in an inclusive fashion, and thus should be interpreted to mean “including, but not limited to.” Unless otherwise specified, any use of any form of the terms “connect,” “engage,”, “couple,” “attach,”, or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. Reference to up or down will be made for purposes of description with “up,” “upper,” “upwardly” or “upstream” meaning toward the surface of the well and with “down,” “lower,” “downwardly” or “downstream” meaning toward the terminal end of the well, regardless of the wellbore orientation. In addition, in the discussion and claims that follow, it may be sometimes stated that certain components or elements are in fluid communication. By this it is meant that the components are constructed and interrelated such that a fluid could be communicated between them, as via a passageway, tube, or conduit. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings.
Disclosed herein are systems and methods for automated monitoring and control of pump down operations. More specifically, the pump rate of a pump unit (or units), the line speed for a logging/perforating (L/P) unit, and the line tension for the L/P unit may be automatically monitored and controlled to enable efficient pump down operations. In at least some embodiments, pump down operations may be based on a predetermined line speed, a predetermined line tension and/or a predetermined pump rate. However, if any of these parameters change during pump down operations, the other parameters will be adjusted automatically. The techniques disclosed herein improve safety of pump down operations by eliminating the possibility of pumping the tools off the end of the wireline cable or other catastrophes.
As a specific example, if the monitored line tension surpasses a desired threshold, the line speed will be automatically reduced to maintain the desired line tension and the pump rate will be reduced in accordance with the amount of change in the line speed. Thereafter, if the monitored line tension drops below the predetermined threshold, the line speed will be automatically increased (up to a desired line speed) and the pump rate will be increased in accordance with the line speed. Similarly, changes in the monitored pump rate during pump down operations may result in automated changes to the line tension and/or line speed of the L/P unit.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
Like reference symbols in the various drawings indicate like elements.
The tool string 200 may be attached with a cable/wireline 111 via a cable head 211. The conveying process is conducted by pumping a fluid from the rig pump 122 into the upper proximal end of the casing string 112 (or 114) above the tool string 200 to assist, via fluid pressure on the tool string 200, movement of the tool string 200 down the wellbore 150. The pump pressure of the fluid above the tool string 200 is monitored, for example, by the truck 115, because the fluid pressure can change during the conveying process and exhibit patterns indicating events such as sticking of the tool string in the wellbore. As the tool string 200 is pumped (propelled) downwards by the fluid pressure that is pushing behind the tool string 200, the cable 111 is spooled out at the surface by the truck 115. A cable tension sensing device 117 is located at the surface and provides cable tension data to control track 115. A speed sensor device 119 located at the surface provides surface cable speed data to control track 115.
In some implementations the tool string will have sufficient weight that gravity will convey the tool string down the wellbore without the assistance of pump fluid pressure.
The tool string is securely connected with the cable 111 by cable head tool 211. The tool string may include a downhole tension sensing device 213 and a downhole speed sensing device such as an accelerometer 215. As the tool string 200 is propelled down the bore of the drill string by the fluid pressure, the rate at which the cable 111 is spooled out maintains movement control of the tool string 200 at a desired speed.
In other possible configurations, the tool string 200 may include other data logging instruments besides those discussed in
Referring to
Referring to
As used herein with regard to speed calculations and speed adjustments and corrections factors, the term “actual known depth” is the depth as determined from the casing collar locator log. The depth may also be referred to as the “expected depth.” The measured depth is the depth as calculated based on the measured amount of cable/line spooled out and measured at the surface.
In some methods of operations of the tool string 200, 200a, 200b, before entering a section of the wellbore that is highly deviated from vertical, a casing collar at a known depth will be recorded and the current depth will be adjusted or the delta will be noted. The line will be spooled into the well, the casing collar locator data, as well as the downhole line tension data will be transmitted uphole to a surface processor that is part of the system. Downhole tension data is used in speed correction algorithms that use line tension. As the tool passes a casing collar, the depth of the collar will be noted as well as the time. The average line or tool speed over the interval between collars will be calculated and compared to the average line or tool speed measured at the surface and the average calculated downhole speed. The recorded depth of the casing collar will be compared to the expected actual depth. The expected actual depth of the casing collar is based on previously recorded measurements used to determine the actual depth of the casing collar. This could be a Gamma Ray/CCL log or some other method of correlating the casing collar depth to the reference depth for the well.
As a specific example, suppose it is desired to run a tool string at a line speed of 500 feet per minute in the vertical portion 147 of wellbore 150 and run the tool at a line speed of 375 feet per minute in the horizontal portion 148 of wellbore 150. Further, suppose the L/P control unit is always trying to hold 3000 lbs of tension on tools going in the hole. For this set of desired parameters, the L/P control unit initially sets the line tension parameter at 3000 lbs and the line speed parameter at 500 ft/min (for vertical portion 47) and later 375 ft/min (for horizontal portion 48). In response, the tech control center (TCC)/pump control unit automates the pump rate to achieve the L/P variables. Once the tool string starts down wellbore 10, the TCC/pump sets an auto pump rate that ramps up to the L/P variables (e.g., within 30 seconds or so). If any of these parameters change during the pump down operations, the other parameters will be adjusted automatically. The techniques disclosed herein improve safety of pump down operations by eliminating the possibility of pumping the tools off the end of the wireline cable or other catastrophes.
Data corresponding to the control parameters 304 are received from system sensors, which are arranged to monitor the respective control parameters from appropriate locations on the pumping unit, wireline unit and/or wireline tool, or otherwise on the drilling platform or in the wellbore, and are coupled to the controller 302. Pressure also may be monitored by the controller 302 to account for pumping limitations.
In at least some embodiments, a wireline speed sensor 310, a wireline tension sensor 312, and a pump rate sensor 314 provide sensor data to the controller 302. Other sensor data might be relayed to the controller, for example, relating to the position and/or orientation of the wireline tool in the wellbore. The sensor data from the wireline speed sensor 310 may correspond directly to wireline speed data or to data that enables the wireline speed to be calculated. The sensor data from the wireline tension sensor 312 may correspond directly to wireline tension data or to data that enables the wireline tension to be calculated. The sensor data from the pump rate sensor 314 may correspond directly to pump rate data or to data that enables the pump rate to be calculated.
During pump down operations, such as pump-and-log or pump-and-perf, the controller 302 analyzes new sensor data from the sensors 310, 312, 314 and is configured to automatically direct the pump unit 308 to adjust its pump rate in response to changes in a monitored wireline speed and/or monitored wireline tension. Additionally, the controller 302 may automatically direct the wireline unit 306 to adjust its wireline speed in response to changes in a monitored pump rate. For example, the controller 302 may direct the pump unit 308 to increase its pump rate in response to a decrease in the monitored wireline speed in order to maintain the speed at which the tool is advanced. Of course, this action assumes the wireline tension to be unchanging, or changing proportional to speed. If, to the contrary, the wireline tension is decreasing at a non-proportional rate to the rate at which the speed is decreasing, this would likely indicate that the tool is entering debris, and the appropriate action would then be to decrease the pump rate, or shut off the pump altogether, in order to prevent the tool getting stuck. It will therefore be appreciated that control of the pump rate in dependence on the wireline speed will preferably also be dependent upon the wireline tension. Additionally or alternatively, the controller 302 may direct the wireline unit 306 to reduce its wireline speed and/or direct the pump unit 308 to reduce its pump rate in response to an increase in the monitored wireline tension. In at least some embodiments, comparisons of control parameter values to predetermined threshold values (e.g., greater than or less than comparisons) for wireline speed, wireline tension, and pump rate may be considered by the controller 302 in addition to (or instead of) directional changes (an increase/decrease) for the control parameters.
In system 400A of
In system 400B of
The controller 302 of
The processor 504 is configured to execute instructions read from the system memory 506. The processor 504 may, for example, be a general-purpose processor, a digital signal processor, a microcontroller, etc. Processor architectures generally include execution units (e.g., fixed point, floating point, integer, etc.), storage (e.g., registers, memory, etc.), instruction decoding, peripherals (e.g., interrupt controllers, timers, direct memory access controllers, etc.), input/output systems (e.g., serial ports, parallel ports, etc.) and various other components and sub-systems.
The system memory 506 corresponds to random access memory (RAM), which stores programs and/or data structures during runtime of the computer 502. For example, during runtime of the computer 502, the system memory 506 may store a pump down control application 514, which is loaded into the system memory 506 for execution by the processor 504.
The system 500 also may comprise a computer-readable storage medium 505, which corresponds to any combination of non-volatile memories such as semiconductor memory (e.g., flash memory), magnetic storage (e.g., a hard drive, tape drive, etc.), optical storage (e.g., compact disc or digital versatile disc), etc. The computer-readable storage medium 505 couples to I/O devices 528 in communication with the processor 504 for transferring data/code from the computer-readable storage medium 505 to the computer 502. In some embodiments, the computer-readable storage medium 505 is locally coupled to I/O devices 528 that comprise one or more interfaces (e.g., drives, ports, etc.) to enable data to be transferred from the computer-readable storage medium 505 to the computer 502. Alternatively, the computer-readable storage medium 505 is part of a remote system (e.g., a server) from which data/code may be downloaded to the computer 502 via the I/O devices 528. In such case, the I/O devices 528 may comprise networking components (e.g., a network adapter for wired or wireless communications). Regardless of whether the computer-readable storage medium 505 is local or remote to the computer 502, the code and/or data structures stored in the computer-readable storage medium 505 may be loaded into system memory 506 for execution by the processor 504. For example, the pump-and-perf control application 514 or other software/data structures in the system memory 506 of
The I/O devices 528 also may comprise various devices employed by a user to interact with the processor 504 based on programming executed thereby. Exemplary I/O devices 528 include video display devices, such as liquid crystal, cathode ray, plasma, organic light emitting diode, vacuum fluorescent, electroluminescent, electronic paper or other appropriate display panels for providing information to the user. Such devices may be coupled to the processor 504 via a graphics adapter. Keyboards, touchscreens, and pointing devices (e.g., a mouse, trackball, light pen, etc.) are examples of devices includable in the I/O devices 528 for providing user input to the processor 504 and may be coupled to the processor by various wired or wireless communications subsystems, such as Universal Serial Bus (USB) or Bluetooth interfaces.
As shown in
In at least some embodiments, the commands generated by the pump control instructions 518 for the pump unit 534 cause the pump unit 534 to change its pump rate. For example, the pump control instructions 518 may generate a reduce pump rate command for the pump unit 534 in response to an increase in the monitored wireline speed and/or an increase in the monitored wireline tension. Alternatively, the pump control instructions 518 may generate an increase pump rate command for the pump unit 534 in response to a decrease in the monitored wireline speed and/or a decrease in the monitored wireline tension. Further, the wireline control instructions 516 may generate a decrease wireline speed command for the wireline unit 536 in response to a decrease in the monitored pump rate. In this manner, efficiency of pump down operations is improved while also considering safety thresholds.
Though depicted sequentially as a matter of convenience, at least some of the actions shown can be performed in a different order and/or performed in parallel. Additionally, some embodiments may perform only some of the actions shown. In some embodiments, the operations of
The method 600 starts by monitoring a wireline speed (block 602) and monitoring a wireline tension (block 604). The monitoring may be performed by sensors in communication with a hardware controller or a computer running software. In some embodiments, pressure and rate sensors could be monitored, if need be, from a transducer and flowmeter in the line rather than from the pump directly. A pump rate for pump down operations is then set based on the monitored wireline speed and monitored wireline tension (block 606). If changes to control parameters occur during pump down operations (determination block 608), the pump rate is automatically updated in response to the changes (block 610). In at least some embodiments, the control parameters correspond to the monitored wireline speed and the monitored wireline tension. For example, the pump rate may be decreased during pump down operations in response to a reduction in the monitored wireline speed. The amount of decrease in the pump rate may correspond to the difference between the monitored wireline speed and a predetermined threshold. The method 600 may additionally comprise receiving sensor data and determining the wireline speed and the wireline tension from the sensor data. Further, the method 600 may additionally comprise changing a wireline speed in response to a monitored pump rate during pump down operations.
A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. Further, the method 600 may include fewer steps than those illustrated or more steps than those illustrated. In addition, the illustrated steps of the method 600 may be performed in the respective orders illustrated or in different orders than that illustrated. As a specific example, the method 600 may be performed simultaneously (e.g., substantially or otherwise). Other variations in the order of steps are also possible. Accordingly, other implementations are within the scope of the following claims.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2012/046857 | 7/16/2012 | WO | 00 | 1/7/2015 |
| Publishing Document | Publishing Date | Country | Kind |
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| WO2014/014438 | 1/23/2014 | WO | A |
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| Number | Date | Country | |
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| 20150167414 A1 | Jun 2015 | US |
