Abstract:
A method for surveillance of a well includes the steps of providing a pumping system in a wellbore that penetrates a formation; producing a fluid from the formation into the wellbore; injecting a fraction of the fluid from the wellbore into the formation via operation of the pumping system; surveying the pumping system in real-time via a sensor that senses well data; determining in real-time the correlation of a well parameter with a preselected threshold well parameter, wherein the well parameter is related to the sensed well data; and outputting a signal in response to the well parameter exceeding the preselected threshold parameter.

Description:
TECHNICAL FIELD 
       [0001]    The present application relates in general to well systems and more particularly to injection wells. 
       BACKGROUND 
       [0002]    It is often desired to inject a fluid into a subterranean geological formation. With reference to hydrocarbon operations it is often desired to dispose of the produced water through reinjection and/or to inject a fluid, typically water, as a method of tertiary hydrocarbon production. Typically, the injection fluid is pumped from the surface of the well, through the well and into the geological formation. For example, reservoir fluid is produced from the well to the surface. The produced fluid is separated into the primarily hydrocarbon fractions, or phases, and a primarily water fraction. It may be necessary to chemically treat the water fraction to make it again compatible with the reservoir formation. The water fraction is then injected into the reservoir formation via the wellbore. To monitor and control the water injection, data such as pressure and flow rate are obtained at the surface (wellhead). This process of injecting is often inefficient and the manner of monitoring the injection of fluids is often inaccurate. 
       SUMMARY 
       [0003]    One embodiment of a method includes the steps of operating a pump disposed in a wellbore to inject a fluid into a formation penetrated by the wellbore; obtaining a well parameter in real-time; and outputting a signal in response to a correlation of the well parameter and a preselected threshold parameter. 
         [0004]    An embodiment of a method for surveillance of a well includes the steps of providing a pumping system in a wellbore that penetrates a formation; producing a fluid from the formation into the wellbore; injecting a fraction of the fluid from the wellbore into the formation via operation of the pumping system; surveying the pumping system in real-time via a sensor that senses well data; determining in real-time the correlation of a well parameter with a preselected threshold well parameter, wherein the well parameter is related to the sensed well data; and outputting a signal in response to the well parameter exceeding the preselected threshold parameter. The method may further include separating, in the wellbore, the fluid into a primarily oil fraction and a primarily water fraction, wherein the primarily water fraction is the fraction of the fluid injected into the formation by an electric submersible pump system of the pump system. The method may also include the step of producing the primarily oil fraction of the fluid from the wellbore by a second pump of the pump system. In some embodiments, the well parameter may be derived from the sensed well data and the well parameter may be an injectability parameter. The well data may be sensed in the wellbore, proximate to the formation zone in which the fluid is injected. 
         [0005]    An embodiment of an injection well surveillance system includes a wellbore penetrating a formation; a fluid separation system disposed in the wellbore, the system separating a primarily oil fraction and a primarily water fraction from a fluid produced from a producing zone of the formation into the wellbore; a pump system disposed in the wellbore, the pump system including an injection pump injecting the primarily water fraction into an injection zone of the formation; a sensor disposed in the wellbore, the sensor sensing well data; and a control center to receive the sensed well data and to output a signal in response to a correlation of a well parameter associated with the sensed well data and a threshold well parameter. 
         [0006]    The foregoing has outlined some of the features and technical advantages of the present application in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter which form the subject of the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The foregoing and other features and aspects will be best understood with reference to the following detailed description of a specific embodiment, when read in conjunction with the accompanying drawings, wherein: 
           [0008]      FIG. 1  is a schematic illustration of an embodiment of a well surveillance and control system; 
           [0009]      FIG. 2  is a diagrammatic illustration of an automated system that can be utilized to acquire and manipulate data, according to an embodiment; 
           [0010]      FIG. 3  is a flowchart of one embodiment of a method of utilizing the surveillance and control system; 
           [0011]      FIG. 4  is a flowchart of one embodiment of a method of utilizing the surveillance and control system to obtain well data in real-time and to utilize the data to optimize operation of the well system; 
           [0012]      FIG. 5  is an elevation view of an embodiment of a wellsite including a plurality of wells deploying pumping systems; 
           [0013]      FIG. 6  is a schematic representation of an embodiment of network and remote observation and/or control station; 
           [0014]      FIG. 7  is a schematic illustrating a well completed with a downhole fluid separator and a pump system adapted to inject a portion of the wellbore fluid and to produce a portion of the wellbore fluid to the surface; and 
           [0015]      FIG. 8  is a graphical illustration of a Hall plot that can be derived and displayed from well data acquired, according to an embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views. 
         [0017]    The present application generally relates to a system and method for remote real-time surveillance, control, and optimization of injection well systems. The devices, systems and methods described herein may enable a well operator or well field manager to better manage and optimize operation of one or more pumping systems without physically attending the wellsite. For example, the system and methodology enhances the monitoring, surveillance, diagnostics, and optimization of injection well systems using real-time and on-time data in a cost efficient manner. 
         [0018]    Referring generally to  FIG. 1 , one embodiment of an injection well surveillance and control system  20  is illustrated. In this embodiment, a wellsite  22  comprises one or more pumping systems  24  (pumps), such as electric submersible pumps (ESP), for pumping fluid. In some embodiments, pumps  24  are used to inject fluids from the well into a geological formation surrounding the well. In some embodiments, pumps  24  are used to pump hydrocarbon-based fluids, e.g. oil, from geological formations beneath the surface of the Earth via the well. 
         [0019]    Surveillance and control system  20  further comprises a remote control center  26  where surveillance data is obtained from wellsite  22  and pumping systems  24  on a real-time and on-time basis. Surveillance data may include, without limitation, data related to the well which may include surface and downhole parameters, such as pressure, temperature, fluid density, water cut of fluid, hydrocarbon fraction of fluids, fluid flow rates, pump speeds, pump temperatures, and the like. 
         [0020]    Control center  26  may comprise one or more processor-based control systems  28 , such as computer-based workstations where wellsite operators or managers can observe data obtained from wellsite  22  and pumping systems  24 . This well data can be used for analysis, planning, and decision-making with respect to operation of pumping system  24  and the overall wellsite. Additionally, control systems  28  can be used to provide control instructions to wellsite  22  along with, for example, action updates, data polling, and queries. 
         [0021]    Either at remote control center  26  or at another remote location, surveillance and control system  20  can include a data storage system  30  to retain data. Data storage system  30  also can be used to provide user security controls, alarm and alert management, business process management, and other functionality in cooperation with remote control center  26 . For example, remote control center  26  and data storage system  30  enable a multidiscipline collaboration and historical interrogation of wellsite data to aid in diagnostic analysis and optimization of pumping system operation. 
         [0022]    Control system  28  in cooperation with data storage system  30  also can be used to instigate alarms/alerts when real-time data or data trends indicate changes causing concern with respect to operation of pumping systems  24 , e.g. movement of parameter values into a sub-optimal range or beyond a predetermined threshold value. The alerts can be provided at control system  28  and/or at a variety of other monitoring locations. For example, the alerts may be provided to remote handheld devices  32 , such as cellular telephones  34  or personal digital assistants  36 . 
         [0023]    The two-way communication between wellsite  22  and the various remote locations, e.g. remote control center  26 , data storage system  30 , and remote handheld devices  32 , is accomplished over a network  38 . Network  38  can be established via a variety of transmission mechanisms, including wired and wireless mechanisms  40 . For example, the two-way communication of data between wellsite  22  and the remote locations can be sent at least in part over the Internet. Portions of the network may be hardwired, may comprise satellites  42  for satellite transmission, may comprise cellular or radio towers  44  for wireless transfer, or may comprise a variety of other data transmission technologies for conveying data, including real-time data, between the wellsite  22  and the various remote locations of surveillance and control system  20 . 
         [0024]    Control system  28  is designed to automate processing of much of the data flow within surveillance and control system  20 . In the present example, control system  28  is a computer-based system having a central processing unit (CPU)  46 , as illustrated in  FIG. 2 . CPU  46  is a microprocessor based CPU for rapidly processing data obtained from wellsite  22 , from data storage system  30 , and/or from other locations coupled to remote control center  26  via network  38 . Furthermore, CPU  46  is operatively coupled to a memory  48 , as well as an input device  50  and an output device  52 . Input device  50  may comprise a variety of devices, such as a keyboard, mouse, voice-recognition unit, touch screen, other input devices, or combinations of such devices. Output device  52  may comprise a visual and/or audio output device, such as a monitor having a graphical user interface. Additionally, the processing may be done on a single device or multiple devices. 
         [0025]    As illustrated by the flowchart of  FIG. 3 , control system  28  and overall surveillance and control system  20  increase well management functionality while reducing costs by enabling easy use of real-time and historical data at any of a variety of locations remote from the managed wellsite. For example, surveillance and control system  20  enables the sampling of well-related parameters at individual wells within wellsite  22 , as indicated by block  54 . The system further promotes accumulation of this data at one or more remote sites, such as data storage system  30  and/or remote control center  26 , as indicated by block  56 . Control system  28  and CPU  46  enable the use of this well data to generate a variety of reports, as indicated by block  58 . The reports can be used to aid analysis, planning, and decision-making regarding operation of wellsite  22 . Additionally, the storage of data output over network  38  from wellsite  22  enables the construction of data trends, as indicated by block  60 . The data trends, including those developed on a real-time basis, also aid in the analysis, planning, and decision-making that allows operation of the wellsite to be optimized. Based on the data output from pumping systems  24  and wellsite  22 , the management of wellsite  22  can be accomplished from a variety of remote locations, such as remote control center  26 . Also based on analysis of the well data, control signals can be output from remote devices, e.g. control system  28  or remote handheld devices  32 , to wellsite  22 , as indicated by block  62 . The analysis can be automated analysis performed at control center  26 . 
         [0026]    The use of communication tools, such as network  38 , control system  28 , remote handheld devices  32 , data storage systems  30 , and other potential devices coupled into network  38 , enables a well operator to facilitate surveillance and optimization of well behavior without traveling to the specific wellsite. As illustrated in the flowchart of  FIG. 4 , the well operator can access all well-related information via network  38 , as illustrated by block  64 . In this embodiment, the well operator has access to all well-related information via the Internet. The well operator also can enable many approaches to surveillance and control from a variety of remote locations via the two-way communication network  38 , as illustrated by block  66 . 
         [0027]    Furthermore, the well operator can program control system  28  and CPU  46  to provide alerts/warnings when well-related parameters fall outside a desired range or cross a specific set point, as illustrated by block  68 . For example, alerts may be communicated when input performance thresholds or set points, such as injectability parameters of the Hall plot of  FIG. 8 , are exceed. In many applications, the set points can be changed by sending appropriate control signals to wellsite  22  from a remote location, e.g. from remote control center  26  or from remote handheld devices  32 . The use of network  38  also enables a well operator to control multiple well systems from one or more remote locations, as illustrated by block  70 . Additionally, the storage of data by data storage system  30  and the processing of both real-time and historical data on control system  28  enable a wide variety of analyses to be performed by the well operator and/or others to better plan and optimize well operation, as illustrated by block  72 . In some applications, the combination of real-time monitoring and data analysis, either automatic analysis at control center  26  or human analysis, ensures optimum performance of wellsite equipment, including electric pumping systems, variable speed drive controllers, multisensor artificial lift monitoring systems, and a variety of other components and systems. 
         [0028]    One example of a wellsite  22  and wellsite equipment used in the injection and/or production of hydrocarbon-based fluids is illustrated in  FIG. 5 . In this embodiment, wellsite  22  comprises a plurality of wellbores  74  drilled in a formation  76 . Within each wellbore  74 , a pumping system  24 , comprising an electric submersible pumping system  78 , is deployed. Instrumentation, such as a plurality of sensor devices  80 , is deployed with the pumping system  24  and may be internal to the pumping system, external to the pumping system, and/or disposed at separate locations within the wellbore  74 . Examples of sensor devices  80  include pressure sensors, flow rate sensors, temperature sensors, e.g. distributed temperature sensors, vibration sensors, multisensors, voltage sensors, current sensors, and/or other sensors able to output signals corresponding to the measured parameter in real-time. Sensor devices  80  may sense data indicative of a well or wellbore parameter and/or sense data that may be analyzed and or manipulated to be indicative of a well parameter. For example, a sensor may sense injection pressure, the injection fluid flow rate, and elapsed injection time. These sensed parameters or data may be further analyzed, for example by system  28 , and generate well parameters such as those associated with and indicative of injection performance and capability of the formation an illustrated by example in  FIG. 8 . 
         [0029]    In addition to sensor devices  80  and other surveillance equipment, surveillance and control system  20  may comprise a variety of controllable devices  82  which regulate operation of injection well  74  and pumping system  24 . Controllable devices  82  can be controlled remotely via control signals sent over network  38  from one or more remote locations, such as remote control center  26 . One example of a controllable device  82  is a variable speed drive that can be controlled remotely and in operational connection with an electrical submersible pump  78 . Controllable devices  82  may comprise a variety of other controllable devices that may be positioned at the surface and/or in the wellbore. For example, and without limitation, controllable devices may include downhole fluid separators  82   a  ( FIG. 7 ), valves, heaters, and other components that may be used in cooperation with the electric submersible pumping systems  78 . Each of the controllable devices  82  can respond to specific control instructions input at a remote location, e.g. control center  26 . 
         [0030]    In the illustrated embodiment, controllable devices  82  e.g. pump controllers, valves, downhole separator, etc., and sensor devices  80 , interface with a site communications box  84  which is used to relay signals between the various wellsite devices and network  38 . By way of example, the site communications box  84  may comprise a satellite radio and process-assisted communicator  86  for relaying signals to and from satellite  42 . The data from wellsite  22 , for example, can be transferred to a remote management system  88  that provides Internet access to the data from a variety of Internet accessible remote locations  90 , as illustrated in  FIG. 6 . The remote management system  88  may form part of remote control center  26 , or remote management system  88  may be located separately. In the latter embodiment, control center  26  is coupled in communication with remote management system  88  via the Internet. 
         [0031]    As illustrated in  FIG. 6  and  FIG. 1 , the structure of network  38  can vary substantially. This flexibility greatly enhances the remote surveillance and control capabilities of system  20  with respect to electric submersible pumping systems  78  and other equipment at wellsite  22 . Access to surveillance and/or control can be provided at numerous remote locations  90  and to numerous types of devices. For example, surveillance and control functionality may be provided to a computer-based workstation  92  at, for example, remote control center  26 . However, surveillance and/or control capability can be provided to portable devices such as a laptop computer  94  and/or one or more types of portable handheld devices  32 . 
         [0032]    In one embodiment, surveillance and control system  20  comprises a web-based application that allows individuals to monitor and control equipment at one or more wellsites  22  from virtually anywhere in the world. In this embodiment, an operator requires only a web browser and an Internet connection to gain access at a variety of remote locations  90 . With the use of, for example, a graphical user interface, the operator can simply click on-screen buttons and select drop-down menus to easily access any monitored and/or control points, as discussed more fully below. Of course, access to the system can be controlled by various security measures, including user profile permissions as set by, for example, a project supervisor. 
         [0033]    Refer now to  FIG. 7 , wherein an embodiment of injection well  74  is illustrated. In the illustrated embodiment, pumping system  24  is adapted to pump a portion of wellbore fluid to the surface and a second portion of a wellbore fluid into a zone of geological formation  76 . In this embodiment, formation fluid is produced from zone  76   a  through casing perforations  102   a  into wellbore  74  and is identified generally wellbore fluid  100 . Although well or wellbore  74  is illustrated as a production and injection well, in other embodiments it may be either a production or an injection well. 
         [0034]    Wellbore  74  is completed with a downhole separator, generally denoted by the numeral  82   a , to promote the separation of fluid phases of wellbore fluid  100 . In the illustrated embodiment, downhole separator  82   a  promotes separation of the wellbore fluid into a primarily oil phase  100   a  and a primarily water phase  100   b . Downhole separator  82   a  may be provided in various configurations and may include sensors  80  and controllable elements  82 , such as valves and the like. Some examples of downhole separator devices and systems are disclosed in U.S. Pat. No. 6,719,048 which is incorporated herein by reference. 
         [0035]    In the illustrated embodiment of  FIG. 7 , pumping system  24  includes a first electric submersible pump  78   a  disposed to pump oil phase  100   a  to the surface and a second electric submersible pump  78   b  to inject water phase  100   b  through casing perforations  102   b  into a zone  76   b  of geological formation  76 . In this embodiment, sensor  80   b  is disposed with electric submersible pump  78   b  and includes a flow rate meter and a pressure sensor. Fluid  100   b  may be injected into zone  76   b  to facilitate disposal of the water fraction and/or in as part of a tertiary production scheme, such as a water flood. 
         [0036]    An embodiment of a method of surveillance of a wellbore is now described with reference to  FIGS. 1 through 7 . A pumping system  24  is deployed in a wellbore  74 . In this embodiment pumping system  24  is provided to pump a wellbore fluid  100  into a zone of geological formation  76 . Pumping system  24  may include a pump, such as electrical submersible pump (ESP)  78   b  to inject wellbore fluid  100  into zone  76   b  of formation  76 . A sensor  80   b  is disposed in wellbore  74  proximate to injection zone  76   b  of geological formation  76 . Sensor  80   b  may include one or more sensors which may be carried, for example as a module, in ESP pump  78   b.    
         [0037]    In this embodiment, sensor  80   b  includes a fluid flow rate sensor and a pressure sensor. Surveillance system  20  may accumulate data from sensor  80   b . The data obtained at sensors  80   b  may be analyzed and processed, for example by control system  28 , to determine a well parameter such as an injection performance parameter and/or capabilities of well  74 . For example, well data sensed at sensor  80   b  may be utilized to generate and provide well information such as that represented by the Hall Plot illustrated in  FIG. 8 . A Hall plot may be displayed on user graphical interface  96  for example. In the illustrated embodiment of  FIG. 8 , line A indicates stable injection; line B may indicate negative skin and thus injecting above the formation parting pressure; line C may be indicative of channeling or out of zone  76   b  injection of fluid  100   b ; and line D may be indicative of a positive skin. System  20  may provide alerts and warnings to an operator and/or output control signals to well  74  and the associated devices in response to the collected data and interpretation of the data. A parameter or event may be selected and input such that upon receipt of data, for example from sensor  80   b , or analysis of the received data that the selected parameter, set point, or threshold is encountered or exceed that an alert is communicated to the operator and/or an output signal is communicated to pumping system  24  and/or a controllable device  82  to actuate an action. 
         [0038]    Traditionally, injection fluids are pumped from the surface of the well down the wellbore and injected into the formation. Further, the injection pressure is often measured or sensed at the surface of the well. The illustrated embodiments provide pressure and flow rate data proximate to the injection zone  76   b  and therefore they may be more indicative of the injection capabilities of the formation and performance of the injection operations. 
         [0039]    In the illustrated embodiment of  FIG. 7  well  74  includes downhole separator  82   a  and production pump  78   a . Output signals to well  74  in response to the data from sensors  80   b  may be directed to actuating downhole separator  82   a  and/or pump system  78   a . For example, it may be desired to operate the systems to provide additional residence time to promote the separation of fluid portions  100   a  and  100   b . It may be desired to increase or reduce the rate of production of fluid portion  100   a  via pump  78   a.    
         [0040]    In one embodiment of a method of operation, receipt of well data by sensor  80   b  may indicate that a selected well parameter of concern is being approached or exceeded. Analysis or processing of well data sensed by sensor  80   b  may provide a well parameter that is of concern. For example, injection fluid flow rate and/or injection pressure may be sensed by sensor  80   b . This well data may be indicative of a well parameter, such as a high injection pressure, that corresponds to a threshold parameter of concern. In some embodiments, the sensed well data, for example, injection pressure, injection flow rate, and elapsed time, may be analyzed and processed to obtain a well parameter indicative of the injectivity or the like of the well or formation. Correlation of this obtained well parameter with a threshold parameter may indicative of an operational concern, such as those illustrated in  FIG. 8 . For example, the obtained well parameter may be indicative that a threshold parameter indicative of injection fluid  100   b  channeling has been exceeded. System  20  may communicate an alert signal to an operator that the selected threshold has been exceeded providing the operator the opportunity to take action to optimize the operation of the injection well  74  and/or communicate a signal to equipment of well  24  initiating an action. Provision of flow rate data and pressure data proximate to the injection zone may facilitate more accurate identification of injection and/or production concerns and facilitate more economic and mitigation actions. 
         [0041]    In another example, a sensor  80 , for example 80b, may sense well data indicating that the wellbore fluid being injected into the formation is primarily hydrocarbon based (fluid  100   a ) and is therefore not the desired produced water portion that is being injected. System  20  may communicate an alert to the operator that a threshold parameter indicative of the hydrocarbon, or oil, fraction of the injected wellbore fluid has been exceeded. System  20  may further communicate an output signal to controllable devices  82 , including pump system  24  and pumps  78 , actuating an action to mitigate the injection of the hydrocarbon fluid  100   a . The action actuated may include without limitation, shutting down a pump such as pump  78   b ; changing the speed of one or more of pumps  78  and thus the fluid flow rate; increasing or decreasing the resident time of fluid  100  in downhole separator  82   a ; and operating one or more valves. 
         [0042]    From the foregoing detailed description of specific embodiments of the invention, it should be apparent that systems and methods for monitoring and/or controlling wellbore operations that are novel have been disclosed. Although specific embodiments of the invention have been disclosed herein in some detail, this has been done solely for the purposes of describing various features and aspects of the invention, and is not intended to be limiting with respect to the scope of the invention. It is contemplated that various substitutions, alterations, and/or modifications, including but not limited to those implementation variations which may have been suggested herein, may be made to the disclosed embodiments without departing from the spirit and scope of the invention as defined by the appended claims which follow.