Patent Publication Number: US-2023137873-A1

Title: System and method for detecting a sinkhole

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure relates generally to geophysical monitoring, and, more particularly, to a system and method for detecting a sinkhole. 
     BACKGROUND OF THE DISCLOSURE 
     Ground instability at rig and well sites can cause sinkholes during drilling operations. The development and evolution of sinkholes has been unpredictable and can occur at locations where previous activity caused no issues. Sinkholes can be many meters in diameter and many meters deep. Sinkholes pose potential hazards to personnel, company assets, and infrastructure. 
     SUMMARY OF THE DISCLOSURE 
     According to an embodiment consistent with the present disclosure, a system and method detect an evolving sinkhole due to displacement and pose changes of a plurality of nodes distributed geographically, to detect early ground motion as an indicator and precursor of sinkhole formation. 
     In an embodiment, a system comprises a base station, a plurality of nodes, and a user device. The base station includes a transceiver. The plurality of nodes are distributed geographically around a rig, with each node including a housing, a ground stake coupled to the housing and configured to secure the respective node into the ground on the Earth&#39;s surface, a sensor configured to sense a state of the respective node relative to the ground, including a displacement of the respective node relative to the ground and a pose change of the respectively node relative to the ground, and to generate corresponding state data, and a transmitter configured to transmit the state data to the base station. The user device includes a receiver, a device processor, and an output device. The receiver is configured to receive the state data from the base station. The device processor is configured by code stored therein to generate, from the state data, a geophysical map of the ground, including the displacement and the pose change of at least one node due to an evolution of a sinkhole. The output device is configured to display the geophysical map and the sinkhole to a user. 
     The sensor is selected from the group consisting of: a global positioning system (GPS) sensor, an accelerometer, a magnetometer, a gyroscope, a Doppler measurement device, a signal time-of-fight measurement device, a triangulation device, a tilt sensor, a distance measurement device, and a barometric pressure change measurement device. The sensor can be disposed within the housing. Alternatively, the sensor can also be disposed on the ground on the Earth&#39;s surface outside of the housing. The node further includes a node processor configured by code stored therein to collect the sensor data. The sensor can be communicatively coupled to the node processor by a transmission wire. Alternatively, the sensor can be communicatively coupled to the node processor by a wireless signal. 
     In another embodiment, a system is configured to detect a sinkhole near a rig, and comprises a base station, a plurality of nodes, and a user device. The base station includes a transceiver. The plurality of nodes are distributed geographically around the rig, with each node including a housing, a ground stake, a plurality of sensors, and a transmitter. The ground stake is coupled to the housing and is configured to secure the respective node into the ground on the Earth&#39;s surface. Each of the plurality of sensors is configured to sense a state of the respective node relative to the ground, with the plurality of sensors including a displacement sensor configured to detect a displacement of the respective node relative to the ground, and including a pose sensor configured to detect a pose change of the respectively node relative to the ground, and to generate corresponding state data. The transmitter is configured to transmit the state data to the base station. The user device includes a receiver, a device processor, and an output device. The receiver is configured to receive the state data from the base station. The device processor is configured by code stored therein to determine, from the state data, the displacement and the pose change of at least one node, and to generate a geophysical map of the ground including the sinkhole. The output device is configured to display the geophysical map and the sinkhole therein to a user. 
     Each of the plurality of sensors is selected from the group consisting of: a global positioning system (GPS) sensor, an accelerometer, a magnetometer, a gyroscope, a Doppler measurement device, a signal time-of-fight measurement device, a triangulation device, a tilt sensor, a distance measurement device, and a barometric pressure change measurement device. At least one of the plurality of sensors can disposed within the housing. Alternatively, at least one of the plurality of sensors can be disposed on the ground on the Earth&#39;s surface outside of the housing. The node further includes a node processor configured by code stored therein to collect the sensor data. At least one of the plurality of sensors can be communicatively coupled to the node processor by a transmission wire. Alternatively, at least one of the plurality of sensors can be communicatively coupled to the node processor by a wireless signal. 
     In a further embodiment, a method is configured to detect a sinkhole near a rig, with the method comprising providing a plurality of nodes distributed geographically around the rig, securing each respective node into the ground on the Earth&#39;s surface around the rig, detecting a displacement of the respective node relative to the ground by a displacement sensor associated with a respective node, detecting a pose change of the respective node relative to the ground by a pose sensor associated with a respective node, generating corresponding state data of each respective node from the detected displacement and the detected pose change, transmitting the state data to a user device, determining the displacement and the pose change of at least one node from the state data, generating a geophysical map of the ground including the sinkhole, and displaying the geophysical map and the sinkhole therein to a user by an output device. 
     The displacement sensor can be selected from the group consisting of: a global positioning system (GPS) sensor, an accelerometer, a Doppler measurement device, a signal time-of-fight measurement device, a triangulation device, and a distance measurement device. The pose sensor can be selected from the group consisting of: an accelerometer, a magnetometer, a gyroscope, and a tilt sensor. At least one of the plurality of sensors can be disposed within a housing of the associated node. Alternatively, at least one of the plurality of sensors can be disposed on the ground on the Earth&#39;s surface outside of a housing of the associated node. Each of the plurality of nodes includes a node processor, and at least one of the plurality of sensors is communicatively coupled to a respective node processor by a wireless signal. 
     Any combinations of the various embodiments and implementations disclosed herein can be used in a further embodiment, consistent with the disclosure. These and other aspects and features can be appreciated from the following description of certain embodiments presented herein in accordance with the disclosure and the accompanying drawings and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic of a system for detecting sinkholes, according to an embodiment. 
         FIG.  2    illustrates a node connected by wire and connected wirelessly to sensors. 
         FIG.  3    illustrates placement of nodes about a rig. 
         FIG.  4    illustrates movement of the nodes of  FIG.  3    due to an evolving sinkhole. 
         FIG.  5    is a flowchart of operation of a method according to an embodiment. 
         FIG.  6    illustrates an output device displaying a geophysical map. 
     
    
    
     It is noted that the drawings are illustrative and are not necessarily to scale. 
     DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THE DISCLOSURE 
     Example embodiments consistent with the teachings included in the present disclosure are directed to a system  10  and method  100  which detect an evolving sinkhole due to displacement and pose changes of a plurality of nodes distributed geographically. 
     As shown in  FIG.  1   , the system  10  includes the plurality of nodes  12 ,  14  which are distributed geographically around a rig, as shown and described in greater detail with reference to  FIGS.  3 - 4   . The system  10  further includes a base station  16  and a user device  18 . Each node  12 ,  14 , such as the node  12 , has a housing  19 , a processor  20 , a memory  22 , a power source  24 , a transceiver  26 , a sensor  28 , and a ground stake  30 . The ground stake  30  can be composed of a rigid material, such as aluminum. The ground stake  30  extends from the housing  19 . The processor  20  stores code therein or in the memory  22  such that the processor  20  is configured to collect sensor data from the sensor  28 , to process the sensor data, and to transmit the sensor data to the base station  16 . The power source  24  can be any known type of source of power. For example, the power source  24  can be a battery. Alternatively, the power source  24  can be a rechargeable battery. Still further, the power source  24  can be a solar panel configured to transform solar energy into electrical energy to power the node  12  and its components. In addition, the solar panel can charge a rechargeable battery, such that the rechargeable battery of the power source  24  can provide power to the node  12  and its components when solar energy is not readily available such as at night or during cloudy or inclement weather conditions. 
     The sensor  28  can include a displacement sensor configured to measure a geographic displacement of the sensor  28  due to a geophysical shift of the ground caused by an evolving sinkhole. The displacement sensor can be selected from the group consisting of: a global positioning system (GPS) sensor, an accelerometer, a Doppler measurement device, a signal time-of-fight measurement device, a triangulation device, and a distance measurement device. Alternatively, the sensor  28  can include a pose sensor configured to measure a change in pose or orientation of the sensor  28  due to a geophysical shift of the ground caused by an evolving sinkhole. The pose sensor can be selected from the group consisting of: an accelerometer, a magnetometer, a gyroscope, and a tilt sensor. 
     The plurality of nodes  12 ,  14  can be labeled Node 1, Node 2, . . . Node M, . . . Node N, in which N is greater than or equal to M, and M is greater than or equal to 2. Each node  12 ,  14  has a respective ground stake  30 ,  32  which allows the respective node  12 ,  14  to be secured on the Earth&#39;s surface at a respective location around the rig. Each node  12 ,  14  is communicatively coupled to the base station  16  through the transceiver  26 . The nodes  12 ,  14  can be wirelessly coupled to the base station  16 . 
     The base station  16  can be located on or near the rig, or remote from the rig. The base station is located in communicative proximity to each of the nodes  12 ,  14 . The base station  16  includes a processor  40 , a memory  42 , a power source  44 , and a transceiver  46 . The processor  40  stores code therein or in the memory  42  such that the processor  40  is configured to collect sensor data from the nodes  12 ,  14 , to process the sensor data, and to transmit the sensor data to the user device  18 . The power source  44  can be any known type of source of power. For example, the power source  44  can be a battery. Alternatively, the power source  44  can be a rechargeable battery. Still further, the power source  44  can be a solar panel configured to transform solar energy into electrical energy to power the base station  16  and its components. In addition, the solar panel can charge a rechargeable battery, such that the rechargeable battery of the power source  44  can provide power to the base station  16  and its components when solar energy is not readily available such as at night or during cloudy or inclement weather conditions. 
     The base station  16  is communicatively coupled to the user device  18  through the transceiver  46 . The base station  16  relays the sensor data from the nodes  12 ,  14  to the user device  18  for processing. The user device  18  includes a processor  50 , memory  52 , a display  54 , and an input device  56 . The memory  52  can store the location of a detected sinkhole for future analysis and data processing. The input device  56  can include a receiver configured to receive the sensor data from the base station  16 . The processor  50  stores code therein or in the memory  52  such that the processor  50  is configured to collect sensor data from the nodes  12 ,  14  and to process the sensor data. The processor  50  can include predetermined software configured to process the sensor data to determine the occurrence and evolution of any sinkholes in the geographic region near the rig and near the nodes  12 ,  14 . In addition, using the predetermined software applied to the sensor data, the processor  50  can generate a geophysical map including any sinkholes, and can display the geophysical map and sinkholes on the display  54 , such as shown in  FIG.  6   , described in greater detail below. 
     In the embodiment shown in  FIG.  1   , the nodes  12 ,  14  can include a sensor  28  in a housing  19 . In an alternative embodiment, as shown in  FIG.  2   , each of the nodes  12 ,  14  can communicate with sensors outside of the housing  19 . Referring to  FIG.  2   , each node  12 ,  14  can be a node  60  which includes a ground stake  62  to secure the node  60  in the ground on the Earth&#39;s surface. The node  60  is communicatively coupled to a sensor  64  having a ground stake  66  to secure the sensor  64  in the ground on the Earth&#39;s surface. In addition, the node  60  is communicatively coupled to a sensor  68  having a ground stake  70  to secure the sensor  68  in the ground on the Earth&#39;s surface. The sensor  64  can be communicatively coupled to the node  60  using a transmission line  72 . The sensor  68  can be communicatively coupled to the node  60  using a wireless communication protocol  74 . In this manner, each node  60  can have a wide geographic range of detection of sinkholes using a plurality of sensors  64 ,  68  on the Earth&#39;s surface. The nodes  12 ,  14 ,  60  with the sensors  28 ,  64 ,  68  and other components of the system  10  can be implemented at relatively low cost. 
     Referring to  FIG.  3   , a configuration  80  of nodes  90 ,  92 ,  94 ,  96 , such as the nodes  12 ,  14 ,  60  described above, is geographically distributed around a rig  82  or other structure. The rig  80  and nodes  90 ,  92 ,  94 ,  96  are on the Earth&#39;s surface above a formation  84  which can include a region  86  below ground. The nodes  90 ,  92 ,  94 ,  96  are located in initial positions and orientations above ground, as shown in  FIG.  3   . As material in the formation  84  and the region  86  moves, a sinkhole  98  can evolve, as shown in  FIG.  4   . Due to such movement of material, some nodes, such as the node  94 , can be displaced to a new location  95 , as shown in  FIG.  4   . Similarly, due to such movement of material, some nodes, such as the node  96 , can have its orientation or pose altered to a new orientation or pose  97 , as shown in  FIG.  4   . Such displacements and pose changes can be measured by the sensors in each of the nodes  90 ,  92 ,  94 ,  95 ,  96 ,  97 . The measurements are saved as sensor data. The sensor data is transmitted by the transceiver  26  of each node to the base station  16 . The sensor data is then relayed from the base station  16  to the user device  18  for further processing. 
     Referring to  FIG.  5   , a method  100  of operation of the system  10  includes reading data from the sensors  28 ,  64 ,  68  in step  102 , reading position data of the sensors and their associated nodes using a Global Positioning System (GPS) employing Real Time Kinematics (RTK) in step  104 , obtaining the position of the sensors and nodes in step  108 , calibrating the sensors in step  110  for further sensing of positions, and obtaining a displacement measurement of the sensors and nodes in step  110 . In addition, the method  100  reads acceleration measurements from an accelerometer in step  112 , obtains verticality in step  114 , and obtains a displacement measurement of the sensors and nodes in step  110 . After step  114 , the method  100  also calibrates the sensors in step  120  for further sensing of orientations or poses. 
     The method  100  also reads magnetic measurements from a magnetometer in step  116 , obtains magnetic north in step  118 , calibrates the sensors in step  120  for further sensing of orientations or poses, and obtains a pose change measurement in step  124 . Further, the method  100  reads gyroscopic data from a gyroscope in step  122 , and obtains a pose change measurement in step  124 . After steps  110  and  124 , the method  100  updates the nodes in steps  126 ,  128 ,  130  to reflect their current state due to displacement or due to a pose change. The method  100  performs network and time synchronization of the nodes  12 ,  14 ,  60  with the base station  16  in step  132 . Then the method  100  performs modeling of the state data in step  134  to determine if any sinkholes are developing in the geographic area around the rig  82 . The method  100  outputs a geophysical map in step  136 , as shown in  FIG.  6   . The method  100  then can return to step  102  to perform steps  102 - 136  repeatedly to monitor the geographic region around a rig  82  for the evolution of sinkholes. 
     Referring again to  FIG.  6   , the user device  18  includes a display  54  having a monitor  140 . The monitor  140  can display a geophysical map  142  on a three-dimensional (3D) grid representing a geographic region around the rig  82  shown in  FIGS.  3 - 4   . The geophysical map  142  can display terrain motions as a “heat map”, by which the geophysical map  142  graphically shows terrain on a 3D surface with colors to signify areas of change in the terrain. The geophysical map  142  is generated by the processor  50  using survey maps, actual satellite or aerial imagery, and models of the state data from the plurality of nodes  12 ,  14 ,  60 ,  90 ,  92 ,  94 ,  95 ,  96 ,  97  and sensors  28 ,  64 ,  68 . By such modeling and map generation, the geophysical map  142  can display a sinkhole  146  to a user. Legends and numerical axes on the three-dimensional grid allow a user to geographically locate the sinkhole  146 . Using the map  142 , the user can see at a glance the location, magnitude, and severity of ground motion, allowing appropriate action to be swiftly taken. Evacuation of personnel can avoid areas of terrain motion to minimize further risks and exposure. Automated alarm systems may also trigger when motion thresholds are exceeded. Automated processes may shut down equipment or take other actions as required. 
     For example, upon learning that a sinkhole is developing near a rig  82 , the rig operator can determine whether the sinkhole is within a sufficient proximity to be considered a danger to the rig  82  and to rig personnel. Thus, the system  10  and method  100  can provide an early warning of developing sinkholes and dangers associated with such sinkholes. Upon identification of developing sinkholes, equipment can be re-sited and site areas cordoned off. Personnel can be moved or evacuated. Remedial repairs can be undertaken. Automated alarm systems can alert personnel, and automated shutdown procedures can be started. 
     The system  10  can be sufficiently sensitive to detect the presence of subterranean sinkholes and predict sinkhole formation before the rig  82  and associated infrastructure is sited. Monitoring of a site prior to rig installation can show slow subsidence or terrain motions associated with future sinkhole formation. The system  10  can replace or supplement existing site survey techniques, including ground penetrating radar and resistivity methods. A decision can then be made to re-site the rig  82  before the rig  82  is installed. Accordingly, such pre-installation assessment by the system  10  has associated cost and safety benefits. Alternatively, using the system  10 , remedial repairs can be undertaken before the rig  82  is in place. Any developing sinkhole detected before siting the rig  82  and associated infrastructure can be addressed prior to capital investment in the rig  82 , again delivering cost and safety benefits. 
     Portions of the methods described herein can be performed by software or firmware in machine readable form on a tangible (e.g., non-transitory) storage medium. For example, the software or firmware can be in the form of a computer program including computer program code adapted to cause the system to perform various actions described herein when the program is run on a computer or suitable hardware device, and where the computer program can be embodied on a computer readable medium. Examples of tangible storage media include computer storage devices having computer-readable media such as disks, thumb drives, flash memory, and the like, and do not include propagated signals. Propagated signals can be present in a tangible storage media. The software can be suitable for execution on a parallel processor or a serial processor such that various actions described herein can be carried out in any suitable order, or simultaneously. 
     It is to be further understood that like or similar numerals in the drawings represent like or similar elements through the several figures, and that not all components or steps described and illustrated with reference to the figures are required for all embodiments or arrangements. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “contains”, “containing”, “includes”, “including,” “comprises”, and/or “comprising,” and variations thereof, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Terms of orientation are used herein merely for purposes of convention and referencing and are not to be construed as limiting. However, it is recognized these terms could be used with reference to an operator or user. Accordingly, no limitations are implied or to be inferred. In addition, the use of ordinal numbers (e.g., first, second, third) is for distinction and not counting. For example, the use of “third” does not imply there is a corresponding “first” or “second.” Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” “having,” “containing,” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. 
     While the disclosure has described several exemplary embodiments, it will be understood by those skilled in the art that various changes can be made, and equivalents can be substituted for elements thereof, without departing from the spirit and scope of the invention. In addition, many modifications will be appreciated by those skilled in the art to adapt a particular instrument, situation, or material to embodiments of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, or to the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. 
     The subject matter described above is provided by way of illustration only and should not be construed as limiting. Various modifications and changes can be made to the subject matter described herein without following the example embodiments and applications illustrated and described, and without departing from the true spirit and scope of the invention encompassed by the present disclosure, which is defined by the set of recitations in the following claims and by structures and functions or steps which are equivalent to these recitations.