The present invention relates to oil and gas downhole technology, and more particularly, to wireless communication with down-hole drilling tools and drill strings.
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.
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.
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
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.
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.
The well illustrated in
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
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US07/18860 | 8/28/2007 | WO | 00 | 9/21/2011 |