Patent Publication Number: US-2004051650-A1

Title: Two way data communication with a well logging tool using a TCP-IP system

Description:
[0001] This invention is related to the measurement of parameters of materials penetrated by a well borehole, and more particularly related to a system for embedding commands and data into a TCP-IP packet for communications with and retrieval of data from a well logging device conveyed in a borehole penetrating earth formation.  
       BACKGROUND OF THE INVENTION  
       [0002] Knowledge of physical, chemical, and elemental properties or “parameters” of earth formation is useful in a wide variety of fields including mining, hydrology, geology, and hydrocarbon production. In hydrocarbon production, formation density, porosity, lithology, permeability, and fluid type are used to determine, as examples, (a) if a formation contains hydrocarbon, (b) the amount of hydrocarbon contained in the formation, and (c) if the hydrocarbon can be produced from the formation. These parameters of interest are typically extracted from measurements of electromagnetic, acoustic and nuclear properties of the formation. As an example a measure of formation resistivity can be combined with other measurements to delineate hydrocarbon bearing formations from saline water bearing formations. As another example, a measure of acoustic velocity in a formation can be combined with other measurements to determine formation porosity. As yet another example, the measure of backscattered gamma radiation can be combined with other measurements to determined formation density. As a final example, a plurality of electromagnetic measurements can be combined to determine formation permeability. As a group, these measurements can therefore be used to determine the presence, the amount and the producibility of hydrocarbons in a formation.  
       [0003] Borehole instruments, or borehole “tools”, are used to measure one or more parameters of interest of formations penetrated by the borehole. Parametric measurements are usually made as a function of tool depth within the borehole, and are referred to as “logs” of the parameters. Borehole logging systems typically fall into two categories. The first category is “wireline” systems wherein the logging tool is conveyed along a borehole after the borehole has been drilled. Conveyance is provided by a wireline with one end attached to the tool and a second end attached to a winch assembly at the surface of the earth. The wireline contains one or more electrical and/or fiber optic conductors which serve as communication links between the borehole logging tool and electronic processing and power equipment at the surface of the earth. Data from response of sensors within the logging tool are telemetered to the surface using these links. In addition, commands that control tool operation are telemetered from the surface to the tool over these links. The second category is measurement-while-drilling (MWD) or logging-while-drilling (LWD) tools, wherein the logging tool is conveyed along the borehole by a drill string. Parametric measurements are made with the tool while the borehole is being drilled. Systems that measure parameters related to the borehole and the drilling operation, such as borehole direction, borehole pressure, weight on the drill bit, and the like, are usually referred to as MWD systems. Systems that measure parameters of material penetrated by the borehole are usually referred to as LWD systems. A wireline can not be used in MWD and LWD systems as a tool-surface communication link since the drill string rotates. Tool sensor response can be telemetered to the surface, and commands can be telemetered to the tool, using a variety of borehole telemetry systems. These systems including drilling fluid or drilling “mud” pulse systems, mud siren systems and electromagnetic (EM) systems.  
       [0004] Most present day logging tools generate large amounts of data per unit time and data per unit depth within the borehole. As an example, a six sensor resistivity tool can generate as much as 200 kilobytes of data per hour. A dual detector density tool can generate as much as 9,600 kilobytes of data per hour. For economic and operation reasons, multiple tools are often operated “in combination”, and data generated by combination tools increases as a function of the number of tools in the combination.  
       [0005] Wireline logging systems employing multiconductor wireline cables usually have typical bandwidth capability to transmit measured data from a tool, or from a combination of tools, to the surface in real time. LWD and MWD telemetry systems exhibit bandwidths that are orders of magnitude smaller than wireline systems. Unprocessed or “raw” sensor data, as measured by the tool&#39;s sensors, usually can not be transmitted for processing to the surface in real time using present day borehole telemetry systems. This deficiency in LWD and MWD telemetry systems is typically handled either (a) by processing raw data downhole and telemetering a lesser amount of processed data to the surface, (b) by storing raw data in downhole memory and retrieving the data when the tool is returned to the surface of the earth, or (c) by using a combination of methods (a) and (b). The, processing, of large amounts of raw data using downhole processors is often quite difficult from viewpoints of tool design, equipment reliability, tool cost, and logging operations. Processing also can require setting of processing parameters based upon characteristics of the raw data. Often, these characteristics can be determined only by inspecting the raw data, thereby introducing serious problems in the downhole data processing methodology.  
       [0006] In MWD and LWD logging, the storing of raw data downhole and subsequent retrieval and processing of the data at the surface of the earth is the only effective means for data bandwidths generated by present day tools and tool combinations. As discussed previously, it is also necessary to supply commands to the tool. The system must, therefore, not only retrieve data from the tool but also supply data to the tool.  
       [0007] Current systems for communicating with a LWD or MWD logging tool, once retrieved to the surface of the earth, require a communication link between the tool and a surface processor. The surface processor extracts and receives downhole data measured by the tool, and also generates command data supplied to the tool. Two-way communication between the tool and the surface processor is typically established on the drilling rig floor. It is operationally and economically advantageous to make the time duration of the communication process as short as possible. Operationally, the physical integrity of the borehole is at risk with the drill string out of the borehole and with no drilling mud circulation. Economically, drilling rig time is very expensive. The borehole is not being advanced while the drill string is removed from the borehole, and the tool and surface processor are communicating at the surface over a two way communications link. The surface processor can be a personal computer (PC) or any other suitable processing means for receiving and mathematically manipulating data from the tool, and for generating commands to be transferred to the tool. For purposes of this disclosure, a PC will be used as a surface processor, with the understanding that alternate surface processors are available.  
       [0008] Serial links between the tool and the PC, comprising electrical conductors, have been used, but these links are relatively slow and require the PC to be physically near the tool unless additional relay type hardware is used. Regarding speed, as much as three hours can be required to transfer 32,000 kilobytes of data from the tool memory to the PC. For purposes of comparison, this is the amount of data generated by a typical six sensor resistivity tool over 160 hours of logging. Nuclear tools typically generate considerably more data per unit time of logging. Parallel communication links have been used. The parallel electrical conductor links are much faster than traditional serial communication links, but the distance that the data can be transmitted is further reduced. Parallel links are still relatively slow requiring of the order of 1 hour to transfer 32,000 kilobytes of data from the tool memory to the PC. Fiber optic links provide a much greater data throughput. Fiber optic links are, however, difficult to maintain in the harsh environment of a drilling rig. Fiber optics cables are easily broken and very difficult to repair in a field environment. Wireless radio frequency (RF) links have been used, but RF interferences or “noise” generated by the drilling rig makes this type of link difficult to implement. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0009] In the accompanying drawings:  
     [0010]FIG. 1 illustrates conceptually a LWD or MWD tool linked with a surface processor so that sensor response data can be extracted from the tool and commands can be sent to the tool using a TCP-IP based system;  
     [0011]FIG. 2 illustrates conceptually a LWD or MWD tool linked with a plurality of surface processors through the Internet so that sensor response data can be extracted from the tool and commands can be sent to the tool from any or all processors;  
     [0012]FIG. 3 illustrates conceptually a combination tool comprising multiple LWD or MWD tools, wherein the combination tool is linked with a surface processor so that sensor response data can be extracted from each tool and commands can be sent to each tool through a dedicated data port; and  
     [0013]FIG. 4 illustrates conceptually a combination tool comprising multiple LWD or MWD tools, wherein the combination tool is linked with a surface processor so that sensor response data can be extracted from each tool and commands can be sent to each tool through a common data port. 
    
    
     EMBODIMENTS  
     [0014] The present invention provides methods and apparatus for communicating between a MWD or LWD logging tool and a surface processor, such as a PC, using a high speed Transmission Control Protocol-Internet Protocol based connection link referred to as TCP-IP. Discussions of TCP/IP can be found in the books Internetworking with TCP/IP, Volume 1 (ISBN0132169878), Volume 2 (ISBN0131255274) and Volume 3 (ISBN013260969X) by Douglas Corner, published by Prentice-Hall, TCP/IP illustrated, volume 1 (ISBN0201633469), volume 2 (ISBN020163354X) and volume 3 (ISBN0201634653) by Richard Stevens, published by Addison-Wesley, TCP/IP Architecture, Protocols, and Implementation with IPV6 and IP Security (ISBN0070213895) by Sidnie Feit, published by McGraw-Hill, and Internet Core Protocols (ISBN1565925726) by Eric A Hall, published by O&#39;Reilly.  
     [0015] Communication occurs with the tool removed from the borehole. The majority of present day PCs are equipped to handle TCP-IP data packets. The data packets can be transferred from tool memory to the PC very rapidly thereby minimizing operational and economic problems of drilling downtime previously discussed. Transmission is two-way thereby allowing commands to be transmitted from the PC to the tool for control of the tool and the data acquisition function of the tool. TCP-IP transmission protocol is both robust and reliable thereby making the system suitable for use in the harsh drilling rig environment. The two-way data transmission function can be performed at one or more PC&#39;s remote from the drilling rig using a commercially available TCP-IP hub and the internet.  
     [0016]FIG. 1 is a conceptual illustration of a LWD or MWD tool  10  that contains one or more sensors. Only one sensor  12  is shown for purposes of clarity. The tool  10  contains circuitry  20  that is preferably in the form of a circuit board. The circuit board comprises a central processing unit (CPU)  22 , a memory  26 , and a TCP-IP converter  24 . Data from the sensor  20  pass through the CPU  22  and are stored in the memory  26  for subsequent retrieval when the tool  10  is returned to the surface of the earth. In the data retrieval process at the surface of the earth, data are withdrawn from the memory  26  under the control of the CPU  22  and transferred to the TCP-IP converter  24 , which is also under the control of the CPU. The TCP-IP converter  24  is designed to pass data, formatted in TCP-IP data packets, between the memory  26  (via the CPU  22 ) and a TCP-IP network. As shown in FIG. 1, TCP-IP packets pass from the TCP-IP converter  24  and through a tool data port  14  over a suitable link  29  to a local area network (LAN) port  28 , such as an ethernet port, of a processor such as a PC  30 . One end of the link  29  is removably attached to the data port  14  with the tool  10  at the surface. Upon completion of transfer of data from the tool and command information to the tool, the link  29  is disconnected from the data port  14  prior to resumption of the drilling operation. Other embodiments will be illustrated in subsequent sections of this disclosure.  
     [0017] Still referring to FIG. 1, the CPU  22  is preferably interfaced to the TCP-IP converter  24  through either an eight bit parallel interface or a serial peripheral interface (SPI). Only one of these interfaces may be active at a given time. The active interface is preferably selected by a single control line on a IP2022 microprocessor contained within the TCP-IP converter  24 . Both of the interfaces provide the same functionality to the CPU  22 , which includes the configuration of the TCP-IP converter, the sending of data, and the receiving of data by the tool  10 . The TCP-IP converter preferably connects to the PC  30  using a full duplex 10Base-T Ethernet connection that can reach network speeds above 8 megabits per second (Mb/s). The PC  30 , and any other network devices operationally connected to the tool  10  through the TCP-IP converter  24  can, therefore, receive data from the CPU  22  and the memory  26  which passes data to the CPU.  
     [0018] Still referring to FIG. 1, it is desirable and often necessary to send commands to the tool  10  to control tool parameters such as data acquisition functions and the operation of the tool. Tool parameters can include sensor response range, sensor timing, voltages to various tool circuits, sensor data sampling rate, and the like. Commands are generated in the PC  30  or alternately in any other suitable network device. These command data are formatted as TCP-IP packets by the PC  30  or other network devices, and pass from the LAN port  28  over the link  29  to the TCP-IP converter  24  through the tool data port  14 . The PC  30 , and any other network devices operationally connected to the tool  10  through the TCP-IP converter  24 , can, therefore, send command information to the CPU  22  and the memory  26  which receives information through the CPU.  
     [0019] To summarize, information can flow to and from the tool  10  from and to the PC  30  in the form of TCP-IP data packets. Information flowing from the tool to the PC is typically sensor response data, which can be subsequently processed by the PC to obtain measures of properties of interest. Information flowing from the PC to the tool is typically command information, which controls sensor data gathering and the overall operation of the tool.  
     [0020] The area of the TCP-IP converter circuit is about two square inches. The circuit board  20  requires about 3 Volts, and is designed to operate at a maximum temperature of about 165 degrees centigrade. Preferably, the link  29  comprises electrical conductors. In principle, a link comprising optical fibers or a RF link can be used, but with operational disadvantages discussed previously. Links comprising electrical conductors and optical fibers are physically connected to the tool and the PC. A RF link requires no physical link connection. The term “operational” connection includes all communication link connections between the tool and the PC including physical connections (e.g. electrical and optical fiber links) and non-physical connections (e.g. RF links).  
     [0021] The network can comprise the internet since TCP-IP packets are compatible with internet data transmission. This allows other network devices, such as one or more PC remote from the drilling rig, to be operationally connected the system through the internet. This embodiment of the invention is shown conceptually in FIG. 2.  
     [0022]FIG. 2 again illustrates conceptually a tool  10  comprising a sensor  12  and a circuit board  20  comprising a CPU  22 , a memory  26  and a TCP-IP converter  24 . A TCP-IP compatible hub  32  is shown connected in series with the link  29  connecting to the LAN port  28  of the PC  30 . The hub interfaces with the Internet, which is illustrated conceptually at  34 . Any number of additional PC i s (i=1, 2, . . . , N), denoted as a group at  36 , can be operationally connected to the tool  10  through the Internet  34  and the hub  32 . This embodiment allows data to be received from the tool  10 , and commands to be sent to the tool, from any location at which the Internet  34  can be accessed. Such a remote location might be a client&#39;s office. Furthermore, data can be received and commands can be sent simultaneously from the drilling rig site and from locations remote from the drilling rig site.  
     [0023] As mentioned previously, more than one type of MWD or LWD tools are run in combination for a variety of reasons including measurement correlation, and reduction in drilling rig time devoted solely to MWD and LWD measurements. A combination tool  130  is illustrated conceptually in FIG. 3. As illustrated, the combination tool comprises a tool “A” at  110 , a tool “B” at  114 , and a tool “C” at  118 . Each tool comprises at least one sensor, and a circuit board comprising a CPU, a memory and a TCP-IP converter as illustrated with tool  10  in FIGS. 1 and 2. The combination can contain as few as two tools, or as many tools as can be operated within the parameters of the drilling operation. Tools can be all LWD tools, all MWD tools, or a combination of LWD and MWD tools. As an example of the latter combination, tool A can be a directional tool, tool B can be a resistivity tool, and tool C can be a nuclear tool.  
     [0024] Still referring to FIG. 3, data stored in memory of each tool are retrieved when the combination tool  110  is returned to the surface of the earth. FIG. 3 illustrates the combination tool embodied with each tool in the combination having its own data port. That is, tool  110  has a data port  112 , tool  114  has a data port  116 , and tool  118  has a data port  120 . With this configuration, data are received and commands are sent to the tools A, B, C, etc sequentially. As an example, the link  29  is first operationally connected to the data port  112 , data are received by the PC  30  from tool A, and commands are sent from the PC to tool A. Sequentially, the link  29  (shown as a broken line to indicate a sequential connection) is operationally connected to the data port  116  and data are exchanged between the PC  30  and tool B. Again sequentially, the link  29  (shown as a broken line) is operationally connected to the data port  120  and data are exchanged between the PC  30  and tool C. This process is repeated in sequence for every tool in the combination tool  130 .  
     [0025] Referring to both FIGS. 2 and 3, it should be understood that a hub  32  can be connected in series with the link  29 , and data exchange can be performed between each tool in the combination tool  130  and any or all of the remote PC i s  36  through the internet  34  (as illustrated and discussed previously).  
     [0026]FIG. 4 illustrates conceptually yet another embodiment of the invention. A combination tool  130  is again show comprising three tools A, B and C denoted at  110 ,  114  and  118 , respectively. In this embodiment, a TCP-IP compatible data bus  140  connects the TCP-IP converter in each tool A, B and C to a data exchange module  142  comprising a single combination tool data port  144 . Again, a link  29  operationally connects the combination tool data port  144  with the PC  30  through the LAN port  28 . Under the control of the PC  30 , the data exchange module  142  directs data exchange between each tool A, B, C, etc in the combination tool through the single combination tool data port  144 . Data exchange can be serial or multiplexed, as determined by commands from the PC to the data exchange module  142 .  
     [0027] Referring to both FIGS. 2 and 4, it should be understood that a hub  32  can again be connected in series with the link  29  to the combination data port  144 , and data exchange can be performed between each tool in the combination tool  130  and any or all of remote PC i s  36  through the internet  34  (as discussed and illustrated previously).  
     [0028] One skilled in the art will appreciate that the present invention can be practiced by other that the described embodiments, which are presented for purposes of illustration and not limitation, and the present invention is limited only by the claims that follow.