Patent Publication Number: US-11041381-B2

Title: Systems and methods for measuring rate of penetration

Description:
This application is a divisional application of U.S. application Ser. No. 15/828,555 with the same title filed on Dec. 1, 2017 which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     Drilling in the oil and gas industry is a complicated and difficult endeavor. Many of the challenges stem from the fact that access to data within a wellbore is difficult to obtain. Some wells are thousands of feet deep. One measurement of particular importance to drilling operations is called the Rate of Penetration (“ROP”) and it refers to how fast a drill string is entering the well. There have been many attempts to calculate ROP. Some of the existing methods are time and labor intensive and potentially less accurate than ideal. The present disclosure is directed at calculating ROP in an efficient manner. 
     SUMMARY 
     Embodiments of the present disclosure are directed to systems for calculating rate of penetration (ROP). The systems include a drill string having a plurality of pipe segments coupled together end-to-end with the drill string being configured to advance into a wellbore during a drill operation. The systems also includes a first rangefinder and a second rangefinder configured to observe the pipe segments as the pipe segments advance into the wellbore. The first rangefinder is spaced apart from the second rangefinder in a direction generally aligned with the drill string. The first and second rangefinders locate at least one identifier on one or more pipe segments. The systems also include a calculation component configured to calculate a distance between two identifiers on the drill string and to calculate the ROP as a ratio of summed multiple measurements between identifiers and elapsed time. 
     Other embodiments of the present disclosure are directed to systems for measuring a rate of penetration (ROP) of a drill string in a wellbore including a first rangefinder positioned at a wellsite and being configured to observe the drill string as the drill string is being constructed and lowered into the wellbore, the drill string comprising a plurality of pipe segments, and a second rangefinder positioned at the wellsite and being configured to observe the drill string as the drill string is being constructed and lowered into the wellbore. The second rangefinder is spaced apart from the first rangefinder. The first and second rangefinders are configured to observe a first identifier and a second identifier on one or more of the pipe segments and to measure a distance between each rangefinder and each identifier. A distance between the first and second rangefinders is known. The systems also include a computation component configured to calculate a distance between the first and second identifiers using the distances between each rangefinder and each identifier and the distance between the first and second rangefinders, and to calculate the ROP by repeatedly calculating distances between consecutive identifiers and summing the lengths. The ROP for a given time period is equal to the ratio of the summed lengths and the given time period in terms of distance per unit time. 
     Still further embodiments of the present disclosure are directed to methods for calculating rate of penetration (ROP) for a drill string. The methods include positioning two rangefinders relative to the drill string, the drill string comprising a plurality of segments, wherein the rangefinders observe the segments as the segments enter a wellbore. The rangefinders are separated by a distance along the drill string. The methods also include periodically measuring a distance between points on the drill string and each of the rangefinders, calculating a length of the segments from the distance between two points on the drill string from the distance from the two rangefinders and the two points, and adding the length to a running total length. The methods can also include calculating a ratio of the running total length and an elapsed time corresponding to the running total length. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a schematic side cross-sectional view of a drill rig  10  according to embodiments of the present disclosure. 
         FIG. 2  is a schematic illustration of a connection between two pipe segments  20  according to embodiments of the present disclosure. 
         FIG. 3  is a schematic illustration of a connection between two pipe segments  20  having a rounded profile  30  at the connection according to embodiments of the present disclosure. 
         FIG. 4  is a schematic illustration of a connection between pipe segments  20  in which one segment has a chamfered profile  32  and another pipe section has a notched profile  34 . 
         FIG. 5  is a schematic illustration of a connection between two pipe segment  20  which are equipped with RFID tags  36  according to embodiments of the present disclosure. 
         FIG. 6  is another illustration of a connection between pipe segments  20  according to embodiments of the present disclosure. 
         FIG. 7  is a diagram of the relationship between rangefinder(s) and a pipe segment according to embodiments of the present disclosure. 
         FIG. 8  is a schematic illustration of a drill string  50  according to embodiments of the present disclosure. 
         FIG. 9  is a block diagram of a method  64  of calculating ROP according to embodiments of the present disclosure. 
         FIG. 10  is a  FIG. 1  is a block diagram of an operating environment for implementations of computer-implemented methods according to embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Below is a detailed description according to various embodiments of the present disclosure.  FIG. 1  is a schematic side cross-sectional view of a drill rig  10  according to embodiments of the present disclosure. The components shown in  FIG. 1  are typical to a drilling operation; however, aspects of the present disclosure are not necessarily limited to the environment shown here and may have application in other industries. In some embodiments, the drill rig  10  includes a derrick  12  which supports drilling equipment used to drill a wellbore  14 . The derrick  12  rests on the earth&#39;s surface  16  (or other appropriate surface such as a seabed or offshore rig) and is positioned over the wellbore  14 . As the drilling operation is carried out, a drill string  18  (a.k.a. string) is constructed and lowered into the wellbore  14 . The drill string  18  is constructed of pipe segments  20  which are connected end-to-end connecting the drill bit all the way up to the surface. Any number of pipe segments can be used to create a drill string of virtually any length. The next pipe segments  22  are shown and will be added to the top of the string  18  once the string is ready to move downward sufficiently. The drill string  18  can include segments that are not technically pipes, such as tools, subs, packers, and any number of other segments. For purposes of brevity and conciseness, the segments of the drill string  18  are referred to herein as pipe segments. 
     The rate of penetration (“ROP”) is calculated as the speed at which the string is constructed and can be expressed in terms of distance per unit time. In many such drilling operations, the length of the pipe segments  20  is known and a rough calculation of the ROP can be obtained simply by adding the length of the segments and dividing by the elapsed time. There are problems with this approach. For one, counting the pipe segments  20  has traditionally been carried out manually by visual inspection which requires a skilled operator to watch carefully and to correctly record each pipe segment. This is a task which becomes more difficult the higher the ROP becomes and is inherently error-prone. The systems and methods of the present disclosure provide an improved approach that eliminates the human error aspect and accounts for variability in pipe segment length and in the connections between the pipe segments. 
     According to embodiments of the present disclosure, the drill rig  10  includes rangefinders  24  and  26 , shown schematically attached to the derrick  12  at different heights and a calculation component  25 . There can be any number of rangefinders, including a single rangefinder adapted to perform as described herein. The rangefinders  24 ,  26  are at different vertical locations. At various times during the drilling operation the rangefinders  24 ,  26  identify a beginning and ending of each pipe segment  20  and calculate a distance between the beginning and ending of each pipe segment  20 . The pipe segments  20  are shown having a chamfered surface  28  at each top and bottom. The rangefinders  24 ,  26  are configured to identify the top and bottom of the pipe segments using such a feature or another identifiable feature on the pipe segments  20 . The length of each pipe segment  20  is added to a running total length number. The ROP is calculated as this length number over a predetermined time period. The rangefinders  24 ,  26  are configured to communicate with the calculation component  25  and to operate automatically to eliminate the chance for human error to affect the calculation of ROP. 
       FIG. 2  is a schematic illustration of a connection between two pipe segments  20  according to embodiments of the present disclosure. The rangefinders described above can be equipped with a technology known as edge detection. Edge detection is an image processing technique for finding the boundaries of objects within images. It works by detecting discontinuities in brightness. Edge detection is used for image segmentation and data extraction in areas such as image processing, computer vision, and machine vision. Common edge detection algorithms include Sobel, Canny, Prewitt, Roberts, and fuzzy logic methods. The pipe segments  20  have a chamfered surface  28  which is easily identifiable by a rangefinder.  FIG. 3  is a schematic illustration of a connection between two pipe segments  20  having a rounded profile  30  at the connection according to embodiments of the present disclosure.  FIG. 4  is a schematic illustration of a connection between pipe segments  20  in which one segment has a chamfered profile  32  and another pipe section has a notched profile  34 . Virtually any profile can be used, and the rangefinders can be calibrated to detect the beginning and ending of the pipe segments using the available information. 
     The rangefinders can be optical using light to detect the ends of the pipe segments, or acoustic (sonar) using sound waves reflected off the pipe segments. In some embodiments the rangefinders use LIDAR, which stands for Light Detection and Ranging, which is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances). Some rangefinders can use radar technology. RFID technology can be used as well. 
       FIG. 5  is a schematic illustration of a connection between two pipe segments  20  which are equipped with RFID tags  36  according to embodiments of the present disclosure. The RFID tags  36  can be placed at the end of the pipe segments or near to the end and the rangefinders can be configured to identify the position of the RFID tags  36  and thereby calculate the ROP for the drilling operation. The RFID tags  36  can be placed a certain known distance A from the end of the pipe segment and this distance can be added into the running total length number to calculate the ROP. There can be an RFID tag  36  at each end of the pipe segment. Each tag can have a distance to its corresponding end. For example, the first tag has a distance to a first end (the top) and the second tag has a distance to the second end (the bottom) of the pipe segment. In other embodiments there can be a single RFID tag having two distances: one to the top and one to the bottom. This information can be stored in the RFID tag itself and the rangefinder is configured to read the data and incorporate it into the ROP calculation. 
       FIG. 6  is another illustration of a connection between pipe segments  20  according to embodiments of the present disclosure. The pipe segments  20  have been treated with a reflective or otherwise identifiable characteristic at an end  38  of the pipe segment. The treatment could be a knurling, a reflective coating, a paint, or another remotely identifiable characteristic which is observable by the rangefinders. In some embodiments, this treatment is applied to a region having a length B extending from the end of the pipe segment  20  the distance B into the length of the pipe segment. The rangefinders can be configured to identify the end of the pipe segment using some varied methods. In some embodiments, the rangefinders make many point calculations over the treated area  40 , and from the point calculations can derive where the end of the pipe segment is. In other embodiments, as the pipe segment moves through the observed area of the rangefinder, the treated area  40  is identified as entering or leaving the observed area. Depending on whether the observed end of the pipe segment is a top or a bottom of the given pipe segment, when the treated area  40  leaves the observed region for the rangefinders, a notation can be made indicating the beginning or ending of the pipe segment. 
       FIG. 7  is a diagram of the relationship between rangefinder(s) and a pipe segment according to embodiments of the present disclosure. Two rangefinders  24  and  26  (or a single rangefinder with similar capabilities) are positioned relative to a pipe segment  44  similar to the configuration shown in  FIG. 1 . The pipe segment  44  has a first end  46  and a second end  48 . The first end  46  can be the top and the second end  48  can be the bottom, and the first rangefinder  24  can be the top rangefinder and the second rangefinder  26  can be the bottom rangefinder. The terms top and bottom are used for convenience and not in a limiting manner. The rangefinders  24 ,  26 , are used to measure the distance d between the first end  46  and the second end  48 . The distance c is between the first rangefinder  24  and the first end  46 . The distance b is between the two rangefinders  24 ,  26 . The distance a is between the second rangefinder  26  and the second end  48 . The distance f is between the second rangefinder  26  and the first end  46 . The distance e is between the first rangefinder  24  and the second end  48 . The angle α is between a and d. The angle δ is between c and d. The angle β is between a and b. The angle θ is between e and f. The angle γ is between b and c. The angle γ 1  is between b and e. The angle γ 2  is between e and c. The rangefinders  24 ,  26 , can measure the distances a, b, c, e, and f. The distance b between rangefinders can be calculated or it is a known, fixed parameter because the rangefinders are in a fixed position on the derrick. Therefore, the distances a, b, c, e, and f are known, leaving only the distance d, the pipe segment length, unknown. The rangefinders  24 ,  26  are shown in  FIG. 7  in a vertical relationship and the pipe segment  44  is not necessarily parallel. The systems and methods disclosed herein are capable of measuring d even if the pipe segment  44  is out of alignment with the rangefinders as is shown with the angle ρ being between pipe segment d and the next pipe segment (shown in phantom). The diagram shows an irregular quadrilateral. Using the following equations starting with the cosine rule, the distance d can be obtained: 
     
       
         
           
             
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     From these equations γ, γ 1 , and β are known. We can find γ 2  using:
 
γ 2 =γγ 1  
 
     Using the cosine rule, we can now solve for d:
 
 d   2   =c   2   +e   2  2 ce  cos γ 2  
 
 d =√{square root over ( c   2   +e   2 2 ce  cos γ 2 )}
 
Where d is the length of the pipe segment  44 . Using these techniques and equations, the length of each pipe segment in a drill string can be measured which leads to an accurate measurement of ROP without the need for manual inspection and at any speed.
 
       FIG. 8  is a schematic illustration of a drill string  50  according to embodiments of the present disclosure. The drill string  50  is made up of pipe segments  52  and is supported by a derrick  12  and is analyzed by rangefinders  24 ,  26  similar to the configuration of  FIG. 1 . The drill string  50  also includes a drill bit  54  at a distal end of the string  50 . Each pipe segment  52  has an identifier  56  which can be an RFID tag, a reflective decal, an engraved marking, a paint, or any other suitable marking which is measurable by the rangefinders. The system can include an identifier  58  at a stationary location on the rig or near the formation. The identifier  58  can be selectively movable or fixed and provides a reference point from which to measure several distances as disclosed herein. A diagram similar to what is shown in  FIG. 7  is included as a schematic overlay in  FIG. 8 . The diagram is a trapezoid between rangefinders  24  and  26 , any arbitrary identifier  56  on one or more of the pipe segments  52 , and the reference identifier  58 . The trapezoid includes at least four legs a, b, c(t), and d(t). Leg a is between the reference identifier  58  and the second rangefinder  26 , leg b is between the first and second rangefinders  24 ,  26 , leg c(t) is between the first rangefinder  24  and an arbitrary identifier  56  on a pipe segment  52 , and leg d(t) is between the arbitrary identifier  56  and the reference identifier  58 . Two other legs can be used to make the calculations: V(t) is the vertical distance between the arbitrary identifier  56  and the reference identifier  58 , and g is the horizontal distance between the arbitrary identifier  56  and the reference identifier  58 . Theta θ(t) is the angle between d(t) and g. Between the first rangefinder  24  and the reference identifier  58  is e, between the second rangefinder  26  and the arbitrary identifier  56  is f, and the angle between e and c(t) is γ 2 . Some of the legs are described herein as varying as a function of time using “c(t)” or “V(t)” for example. In some embodiments, these legs and the distances they represent can change over time. It is to be understood that other legs that are not necessarily shown with the notation (t) can also change over time as circumstance require without departing from the scope of the present disclosure. The identifiers  56  can be at any arbitrary location on the pipe segments  52 . There can be more than one identifier  56  per pipe segment  52 . The identifiers  56  can be manufactured as part of the pipe segments, or can be applied at the rig site. 
     Legs c(t), d(t), V(t), and will vary as a function of time and thus are shown in  FIG. 8  as c(t), d(t), V(t), and θ(t). The rangefinders  24 ,  26  are configured to observe and measure the location of the identifiers  56  and perform the calculations described elsewhere in the present disclosure to calculate ROP. The rangefinders can calculate the ROP by measuring the distance between each pair of identifiers  56 . In some embodiments the following equations can be used to calculate d and V as a function of time:
 
 d ( t )= c ( t ) 2   +e   2 2 c ( t ) e  cos γ 2  
 
 V ( t )= g   2   +d ( t ) 2 2 gd ( t )cos θ( t )
 
     Combining these two equations yields:
 
 V ( t )= g   2 +[ c ( t ) 2   +e   2 2 c ( t ) e  cos γ 2 ] 2 2 g [ c ( t ) 2   +e   2 2 c ( t ) e  cos γ 2 ]cos θ( t )
 
     This equation gives V(t) which is defined as the rate at which any arbitrary identifier  56  passes into the well. V(t) can be calculated continuously to yield a real-time ROP. 
     The drill bit  54  can represent the extreme end of the string  50 . The first segment AA is measured between the drill bit  54  and the next pipe segment&#39;s identifier  56   a , the second segment BB between the identifier  56   a  and the next identifier  56   b . Segments CC and DD are calculated the same way. The position of the identifier  56  relative to the pipe segment  52  does not affect the calculation provided the angle between any two pipe segments is small. There can be virtually any number of identifiers  56  on the drill string. There can be pipe segments that do not have an identifier. Provided that no two identifiers are farther apart than the rangefinders&#39; range, the identifiers can be in any position. 
       FIG. 9  is a block diagram of a method  64  of calculating ROP according to embodiments of the present disclosure. The method  64  begins  66 . The initial measurement of ROP can be to identify a first point on the drill string from which the second measurement will be taken. The initial measurement can be taken from a drill bit or another component representing an extreme, deepest point on the drill string, or it can be any arbitrary point along the drill string from which the measurements will be taken. At  68  the rangefinder detects an end of a pipe segment or an identifier or whatever suitable observable component is being measured. After locating the first end/identifier, at  70  the rangefinders continue taking periodic measurements. The frequency of the measurements can vary according to the expected ROP. The slower the ROP, the more infrequent the measurements can be. The method  64  continues by checking for a second end/identifier at  72 . Once the second end/identifier enters the observed range of the rangefinders, the method  64  includes calculating a length of the pipe segment. The calculations can be carried out as described above. At  74  the second end is designated as the new first end and the method  64  continues at  70  by taking periodic measurements. At  76  the ROP is updated by adding the current pipe segment length to a running total for a given portion of the drill string and dividing by the elapsed time. The method  64  can also include a check of whether the frequency of periodic measurements taking at  70  is too fast or too slow and if so, updating the frequency of periodic measurements. 
       FIG. 10  is a block diagram of an operating environment for implementations of computer-implemented methods according to embodiments of the present disclosure.  FIG. 10  and the corresponding discussion are intended to provide a brief, general description of a suitable computing environment in which embodiments may be implemented. 
     Generally, program modules include routines, programs, components, data structures, and other types of structures that perform particular tasks or implement particular abstract data types. Other computer system configurations may also be used, including hand-held devices, multiprocessor systems, microprocessor-based or programmable consumer electronics, minicomputers, mainframe computers, and the like. Distributed computing environments may also be used where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices. 
     Referring now to  FIG. 10 , an illustrative computer architecture for a computer  122  utilized in the various embodiments will be described. The computer architecture shown in  FIG. 10  may be configured as a desktop or mobile computer and includes a central processing unit  2  (“CPU”), a system memory  4 , including a random access memory  6  (“RAM”) and a read-only memory (“ROM”)  8 , and a system bus  110  that couples the memory to the CPU  2 . 
     A basic input/output system containing the basic routines that help to transfer information between elements within the computer, such as during startup, is stored in the ROM  8 . The computer  122  further includes a mass storage device  114  for storing an operating system  116 , application programs  180 , and other program modules, which will be described in greater detail below. 
     The mass storage device  114  is connected to the CPU  2  through a mass storage controller (not shown) connected to the bus  110 . The mass storage device  114  and its associated computer-readable media provide non-volatile storage for the computer  122 . Although the description of computer-readable media contained herein refers to a mass storage device, such as a hard disk or CD-ROM drive, the computer-readable media can be any available media that can be accessed by the computer  122 . The mass storage device  114  can also contain one or more databases  260 . 
     By way of example, and not limitation, computer-readable media may comprise computer storage media and communication media. Computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EPROM, EEPROM, flash memory or other solid state memory technology, CD-ROM, digital versatile disks (“DVD”), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by the computer  122 . 
     According to various embodiments, computer  122  may operate in a networked environment using logical connections to remote computers through a network  120 , such as the Internet. The computer  122  may connect to the network  120  through a network interface unit  122  connected to the bus  110 . The network connection may be wireless and/or wired. The network interface unit  122  may also be utilized to connect to other types of networks and remote computer systems. The computer  122  may also include an input/output controller  124  for receiving and processing input from a number of other devices, including a keyboard, mouse, or electronic stylus (not shown in  FIG. 10 ). Similarly, an input/output controller  124  may provide output to a display screen, a printer, or other type of output device (not shown). 
     As mentioned briefly above, a number of program modules and data files may be stored in the mass storage device  114  and RAM  6  of the computer  122 , including an operating system  116  suitable for controlling the operation of a networked personal computer. The mass storage device  114  and RAM  6  may also store one or more program modules. In particular, the mass storage device  114  and the RAM  6  may store one or more application programs  180 . 
     The foregoing disclosure hereby enables a person of ordinary skill in the art to make and use the disclosed systems without undue experimentation. Certain examples are given to for purposes of explanation and are not given in a limiting manner.