Patent Publication Number: US-2012043069-A1

Title: Downhole wireline wireless communication

Description:
FIELD 
     The present invention relates to oil and gas downhole technology, and more particularly, to wireless communication with down-hole drilling tools and drill strings. 
     BACKGROUND 
     In the oil and gas exploration industry, downhole tools, such as measurement-while-drilling (MWD) tools, logging while drilling (LWD) tools, and rotary steerable drilling tools accumulate large amounts of data. Such measured data may be formation data, drilling data, directional data, and environmental data, to name a few examples. This data will eventually need to be read by equipment above ground. Because the telemetry data rate through a large volume of drilling mud is relatively slow, reading the accumulated data has involved bringing the tool above ground to the drilling platform, or bringing a reading device to the below-ground tool and making a wet connection. 
     Bringing a tool above ground can take time, which may be costly, especially in deep or problematic drilling environments. Wet connections to a below-ground tool rely on a physical connection in the drilling fluid (drilling mud), which may also be problematic. Furthermore, in some cases a tool may get stuck in a borehole, in which case it may be very difficult to retrieve the measured data from the tool by traditional surface-read means. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a tool or drill string, and a downhole wireline, according to an embodiment of the present invention. 
         FIG. 2  illustrates a method according to an embodiment of the present invention. 
         FIG. 3  illustrates a method for use in smart wells according to the embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the description that follows, the scope of the term “some embodiments” is not to be so limited as to mean more than one embodiment, but rather, the scope may include one embodiment, more than one embodiment, or perhaps all embodiments. 
       FIG. 1  illustrates a tool or drill string according to an embodiment of the present invention. (Embodiments may also be directed to smart casings.) For simplicity of illustration, some of the components in  FIG. 1  are labeled by their common names. The illustration in  FIG. 1  is pictorial in nature, and is not meant to delineate details of a drilling tool or drill string.  FIG. 1  shows a portion of the tool or drill string cross-hatched in  FIG. 1 , inside a borehole. Skid devices for centering the tool or drill string within the borehole are not shown for simplicity. Drilling mud is present in the bore and the annulus, but is not illustrated for simplicity. 
     Measured data is stored in memory device  102 . As is well known in the art of MWD and LWD, memory device  102  may comprise standard memory chips that are packaged to withstand the harsh environment encountered in the oil and gas industry. The embodiment illustrated in  FIG. 1  has antenna  104  embedded in the tool. (For ease of discussion, the tool or drill string in  FIG. 1  will be referred to simply as “tool”.) Antenna  104  is driven by tool transceiver  106  by way of transmission line  108 . Tool transceiver  106  has access to data stored in memory device  102 . For simplicity, memory device  102  is shown coupled to tool transceiver  106  by way of link  110 , but in practice other interface components may be utilized, such as a memory controller or processor, for example. 
     Link  110  need not be a wired communication link. For example, link  110  may be an acoustic link, or a wireless link, such as for example an EM (Electromagnetic) short-hop link. 
     To access data stored in memory device  102 , line transceiver  111  is lowered into the bore of the tool by line  112 . Line  112  may be a wireline, for example, with one or more conductors to provide power to line transceiver  111  and to provide communication from line transceiver  111  to above-ground equipment. In other embodiments, line  112  may be a slickline, in which case line transceiver  111  comprises a power source and memory to store data, and the stored data may be recovered when line transceiver  111  is raised to the surface. For some embodiments, line  112  may also be an optical fiber. 
     To transfer data from the tool to line transceiver  111 , digital data stored in memory  102  is provided to tool transceiver  106  for modulation to a radio frequency (RF) signal, whereupon the RF signal is transmitted by tool antenna  104  and is received by an antenna built into line transceiver  111 . For other embodiments, the antenna coupled to line transceiver  111  may be part of line  112 . Various well-known modulation formats may be utilized, and well-known communication protocols may be implemented. As just one example, the modulation format and protocols may be similar to, or a modified version of, the IEEE 802.11 standard. 
     Communication from tool transceiver  106  to line transceiver  111  may be initiated in various ways. Transceiver  111  may transmit a signal to the tool so that the tool begins transmission. In other embodiments, a transmitter on the surface may be used to transmit a low data rate signal to put tool transceiver  106  into a transmission mode. For such an approach, a radio receiver tuned to the carrier frequency of the low data rate signal may be embedded in the tool. Other embodiments may not have such a radio receiver in the tool, so that tool transceiver  106  may be caused to initiate transmission in other ways. For example, tool transceiver  106  may be programmed to initiate transmission at certain time intervals, at certain times, or at certain depths. A mud pulse may be transmitted through the mud when line transceiver  111  is lowered into a position nearby antenna  104 , so that a sensor on the tool causes tool transceiver  106  to initiate transmission. Some embodiments may utilize rotation techniques, whereby a sudden change in torque or rotational speed of the drilling tool is sensed by a sensor on the tool to turn on tool transceiver  106 . As another example, an acoustic signal may be transmitted down the drill pipe or drill string to initiate communication. 
     These embodiments of causing the tool to initiate transmission, other than utilizing transceiver  111 , are described because, as discussed later, some embodiments may not have transceiver  111 , but rather, the functional unit represented by  111  may be a receiver without the capability to transmit a signal to the tool. 
       FIG. 2  illustrates a flow diagram according to an embodiment of the present invention. In block  202 , measurement data is stored in memory  102 . Such measurements data are well-known in the industry, and may include formation evaluation (e.g., gamma-ray, resistivity, nuclear, nuclear magnetic resonance, fluid sampling, and sonic, to name just a few), drilling (inclination, azimuth, rotational speed, vibration, rate of penetration, pressure, and weight on bit, to name just a few), tool dependent (tool serial numbers, part numbers, maintenance history, calibration history, to name just a few), or environmental data (e.g., temperature, vibration, shock, to name just a few). When the data is to be retrieved, block  204  indicates that a transceiver is lowered into the bore of the tool or drill string. In block  206 , transmission is initiated, whereby a transceiver in the tool transmits the data to the line transceiver. As described earlier, the transmission may be initiated in a number of ways. 
     In another embodiment, the wireline transceiver may be used to send information from the surface through the downhole transceiver into the tool. This may be useful for downloading new tool settings, changing sampling rates and techniques, logic, re-initializing a downhole tool, changing or upgrading downhole software, reprogramming the downhole software, and turning off selected downhole sensors, to name just a few examples. 
       FIG. 3  illustrates, in simplified form, a well and accompanying infrastructure according to an embodiment. A well is shown with surface casing  302  and intermediate casing  304 . For simplicity, not shown is various drilling equipment, such as a Kelly, drilling mud system, etc. Nearby drill collar  306  may include a number of sensors, represented by component  308 , such as inclinometers and magnetometers, to measure directional parameters (e.g., inclination, azimuth), and other instruments to measure formation properties and drilling mud properties. Lowered into drill string  310  is transceiver  312 , which communicates with tool transceiver  314 . Transceiver  312  is lowered into drill string  310  using line  316 , which may be, as discussed earlier, a wireline, slickline, fiber optical line, etc. In practice, transceiver  312  and line  316  would be hidden from view when looking from a position outside drillstring  310 , but for ease of illustration solid lines are used to illustrate these components. Data received by transceiver  312  is communicated to surface computers in surface vehicle  318 . 
     The well illustrated in  FIG. 3  may also be a smart well. An intelligent, or smart well, is a well with downhole sensors that may measure well flow properties, such as for rate, pressure, and temperature, to name just a few examples. These sensors are collectively represented by sensor  320 . In some circumstances, such if a communication link between smart well sensor  320  and the surface is down, transceiver  312  may be used to retrieve data collected by smart well sensor  320 . 
     Various modifications may be made to the disclosed embodiments without departing from the scope of the invention as claimed below. For example, as discussed earlier, some embodiments may not incorporate a line transceiver, but rather, a line receiver. Some embodiments may not incorporate a tool transceiver, but rather, a tool transmitter. Generally, a transceiver is understood to comprise a transmitter and a receiver. Furthermore, it should be understood that a transceiver as depicted in  FIG. 1  may be more general, in the sense that the transmitter and receiver are not physically integrated or co-located. That is, for example, some embodiments may have a physically separated transmitter and receiver, where each transmitter and receiver has a dedicate antenna.