Data retrieval tags

Data retrieval tags, drillstring communications systems and methods, and computer programs are disclosed. The data retrieval tag includes an insulator substrate, at least one analog memory cell disposed on the insulator substrate and an antenna coupled to the analog memory.

BACKGROUND

As activities conducted in high-temperature environments, such as well drilling, becomes increasingly complex, the importance of including electronic circuits for activities conducted in high-temperature environments increases.

In certain situations, it is useful to measure one or more properties (e.g., temperature or pressure) downhole and transmit the measured properties to a surface processor. It may be desirable to use different sensors without changing the composition of the drillstring in the borehole.

In other situations, it may be useful to provide communications between two or more nodes on a drillstring without providing a dedicated or permanent communications medium between the nodes.

Semiconductor based components, including Complementary Metal Oxide Semiconductor (CMOS) devices, may exhibit increased leakage currents at high temperatures. For example, conventional bulk-silicon CMOS devices may exhibit increased leakage currents, and hence decreased resistances, in response to an increase in the environmental temperature of the device.

DETAILED DESCRIPTION

As shown inFIG. 1, oil well drilling equipment100(simplified for ease of understanding) includes a derrick105, derrick floor110, draw works115(schematically represented by the drilling line and the traveling block), hook120, swivel125, kelly joint130, rotary table135, drillpipe140, drill collar145, subs150, and drill bit155. Drilling fluid, such as mud, foam, or air, is injected into the swivel by a drilling fluid supply line (not shown). The drilling fluid travels through the kelly joint130, drillpipe140, drill collars145, and subs150, and exits through jets or nozzles in the drill bit155. The drilling fluid then flows up the annulus between the drill pipe140and the wall of the borehole160. A drilling fluid return line165returns drilling fluid from the borehole160and circulates it to a drilling fluid pit (not shown) and back to the drilling fluid supply line (not shown). The combination of the drill collar145and drill bit155is known as the bottomhole assembly (or “BHA”). The combination of the BHA and the drillpipe140is known as the drillstring. In rotary drilling the rotary table135may provide rotation to the drill string, or alternatively the drill string may be rotated via a top drive assembly. The term “couple” or “couples” used herein is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through one or more intermediate devices.

It will be understood that the term “oil well drilling equipment” or “oil well drilling system” is not intended to limit the use of the equipment and processes described with those terms to drilling an oil well. The terms also encompass drilling natural gas wells or hydrocarbon wells in general. Further, such wells can be used for production, monitoring, or injection in relation to the recovery of hydrocarbons or other materials from the subsurface. As used herein, “oil well drilling equipment” also includes fracturing, workover, and other downhole equipment.

Also shown inFIG. 1are data retrieval tags170. The data retrieval tags170may be circulated in the drilling fluid though the borehole160. In general, in certain embodiments, the data retrieval tags170may be used to measure one or more properties while traveling in the drilling fluid160. In general, in other embodiments, the data retrieval tags170may be used as store-and-forward signaling devices for communication between elements in the oil well drilling equipment100.

A block diagram of a data retrieval tag170to place in the borehole160is shown inFIG. 2. The data retrieval tag may include one or more sensors205to measure one or more properties downhole and generate one or more signals that are representative of the measured properties. For example, the sensors205may be pressure sensors to sense pressures and generate signals indicative of the measured pressures. Other sensors205may include, for example, temperature sensors, humidity sensors, mass flow sensors, resistivity sensors, porosity sensors, or other sensors. The sensors205may sense and measure one or more other downhole properties. One or more sensors may output their signals to an analog memory system210(which is shown in greater detail inFIG. 3). In general, the analog memory system210may store one or more voltages indicative of the signals received from the one or more sensors205. Some example analog memory systems210may be read from or written to in serial. Other example analog memory systems210may be read from or written to in parallel.

The data retrieval tag170may include a power source225to power one or more of the sensors205and the analog memory system210. The power source225may be couple to and receive power from an external power coupler230. The external power coupler230may, in turn, receive power from an external power source and couple the power to one or more of the transmitter220, the analog-to-digital converter (ADC)215, and the power source225. In certain example implementations, the external power coupler may recharge the power source225, to allow the power source225to power one or more components in the data retrieval tag170while the external power coupler230is not coupling power from an external power source. For example, the power source may provide power to the analog memory system210and the one or more sensors205while the data retrieval tag170is circulating in the drilling fluid without power from the external power coupler230.

The data retrieval tag170may include the ADC215. The input of the ADC215is coupled to the analog memory system210to produce a digital representation of the analog signal from the analog memory system210. Other example data retrieval tags170may operate without the ADC215, where, for example, the transmitter220transmits an analog signal using an antenna. In these data retrieval tags170, the output of the analog memory system may be coupled to the transmitter220.

Portions of the data retrieval tag170, such as the ADC215and the transmitter220and the power source225, may be coupled to an external power coupler230. The external power coupler230is generally coupled to, or within, the data retrieval tag170. The external power coupler230may receive power from an external power source to power one or more components in the data retrieval tag170. The external power source may be located downhole or at the surface. The power source225may be recharged by power from the external power coupler230. The external power coupler230may include one or more coils, magnetic device, piezo-electric devices, or other devices or combinations of devices to receive power from one or more external power sources. In addition to providing power to the transmitter220and the ADC215, the external power coupler may also signal the transmitter220or the ADC215to read output from the analog memory system210and to transmit.

In general, the transmitter220may transmit digital or analog signals indicative of the output of the analog memory system210. For example, the transmitted signals may be Amplitude Shift Keying (ASK), Phase Shift Keying (PSK), Frequency Shift Keying (FSK), or Ultra wideband (UWB) signals. In some implementations, the transmitter220may transmit an analog signal based on the output of the analog memory system210. In one example implementation, the output of the analog memory system210may be connected to the input of the transmitter220. The output of the analog memory system may control one or more of the amplitude, frequency, or duration of signals produced by the transmitter220.

Another example data retrieval tag170is shown inFIG. 3. In the block diagram, the solid lines between elements represent channels for passing information while the broken lines represent channels for providing power.

As illustrated inFIG. 3, the data retrieval tag170may include a receiver305to receive one or more signals. The signals received by the data retrieval tag170may include commands to, for example, begin or stop measuring downhole properties, transmit recorded properties, transmit other recorded data. In certain implementations, the data received by the data retrieval tag170may be for retransmission to a node sub. In general, the received signals may be digital or analog. For example, the signals may be Amplitude Shift Keying (ASK), Phase Shift Keying (PSK), Frequency Shift Keying (FSK), or Ultra wideband (UWB) signals.

The output of the receiver305may be coupled to a Digital-to-Analog converter (DAC)310. The DAC310may covert one or more digital signals received by the receiver305into analog signals for recording in the analog memory system210. In certain example implementations, the receiver305may receive an analog signal that may be stored in the analog memory system210without the DAC310.

As shown inFIG. 3, the data retrieval tag170may be fully powered by an external power source though the external power coupler230. The external power coupler230may be coupled to transmitter220, receiver305, DAC310, analog memory system210, and ADC215. The external power coupler230may receive power from an external power source and, in turn, provide power to one or more components in the data retrieval tag170.

FIG. 4is a block diagram of an example analog memory system210. The analog memory system210may include one or more clocks to generate one or more clock signals, such as Φ1and Φ2. In this example system Φ1and Φ2are out of phase (e.g., by 175°). In addition to the clock signals, the analog memory system210may receive or provide a voltage Vbb, which may be referred to as the transport tetrode gate bias. The analog memory system210may receive an input voltage Vib. The analog memory system210includes one or more analog memory cells4101 . . . S(which are shown in greater detail inFIG. 5). Each of the analog memory cells4101 . . . Smay store an analog value. The array of analog memory stages4101 . . . Smay be referred to as a bucket brigade, due to the sequential shifting of values between the memory stages4101 . . . S.

An example memory cell4101is shown inFIG. 5. The memory cell4101may include one or more capacitors, such as capacitors505and510. The memory stage may also include one or more transistors, such as transistors515,520,525, and530. The memory stage4101is designed to sequentially sample Viband shift the sampled value to the succeeding memory stage (e.g.4102), or, in the case of the final analog memory cell410S, to output the stored value. In some implementations, the values stored in the memory cells4101 . . . Smay be read or written substantially simultaneously. In other implementations, values in the analog memory cells4101 . . . Smay be read or written sequentially. Likewise, in some implementations, the memory stages4101 . . . Smay be written to in parallel.

In some implementations, the data retrieval tag170may be exposed to high temperatures, which may cause an increased leakage current in the memory stages4101 . . . S. All, or part of, the analog memory system210may be fabricated on an insulator substrates to minimize leakage currents. For example, the analog memory stages4101 . . . Smay be fabricated on an insulator substrate that exhibits a leakage current that is less than the leakage current of a silicon substrate. Example insulator substrates substrate may include at least one of sapphire or silicon carbide. Fabrication techniques may include thin-film silicon on insulator (SOI) or silicon on sapphire (SOS) fabrication, separation by implantation of oxygen (SIMOX) fabrication, or back-etched silicon on insulator (BESOI) fabrication. Other portions of the data retrieval tag170may be fabricated in bulk silicon, or the entire data retrieval tag170may be fabricated on the insulator substrate.

Returning toFIG. 1, the oil well drilling equipment100may include an interrogator175to receive stored memory values transmitted from data retrieval tags170. For example, the interrogator may be positioned near the drilling fluid pit to communicate with the data retrieval tags170. The interrogator175may include a power source to provide power to the data retrieval tags170via the external power coupler230. The interrogator175may include a receiver to receive signals from the data retrieval tags170. In some implementations where the data retrieval tags170receive a signal before they transmit stored measurements from their analog memory system210, the interrogator175may include a transmitter to signal the data retrieval tags to send stored measurements. The interrogator175, or another portion of the well drilling equipment100may send a signal to the data retrieval tags170to transmit or receive measurements. In some implementations, this signaling may include providing some power to the data retrieval tags170. This power provided to each data retrieval tag170may be used to power the power source225.

The interrogator175(FIG. 1) may be coupled to a terminal180. The terminal180may record stored measurements received from the data retrieval tags170. The terminal180may be interactive and allow a user to alter the behavior of the system, or the terminal180may be passive.

An example method of using a data retrieval tag170is shown inFIG. 6. The example method may be used with oil well drilling equipment100, shown inFIG. 1. The data retrieval tag170may be introduced into the drilling fluid so that the data retrieval tag170will circulate through the borehole160(block605). The data retrieval tag170may be activated, so that it will measure and record one or more property values (block610). Once the data retrieval tag170returns to the surface (e.g., though the drilling fluid return line165), the interrogator175may receive data from the data retrieval tag170(block815).

An example method of activating the data retrieval tag170, so that it measures and records one or more sensor measurements (block610) is shown inFIG. 7. An Ultra Wide Band (UWB) signal may be sent to the data retrieval tag170to signal the data retrieval tag170to record one or more property values (block705). In certain implementations, UWB signaling may be used to send other data or commands to the data retrieval tag170. In certain example implementations, the data retrieval tag170may be activated at or near the surface. In other example implementations, the data retrieval tag170may be activated downhole. In other implementations, the data retrieval tag170may be programmed to activate after a programmable interval

An example method of operation of a data retrieval tag170is shown inFIG. 8. The data retrieval tag receives an activation signal (block805). The data retrieval tag170measures (block810) and records (block815) one or more downhole properties received from one or more sensors205while it is immersed in the drilling fluid. If the data retrieval tag receives a signal to transmit the measured properties it has recorded (block820), it does so (block825), otherwise it returns to block810to continue receiving sensor measurements.

An example method of transmitting one or more measured properties (block825) is shown inFIG. 9. The data retrieval tag170may transmit the measured properties as a ultra wide band (UWB) signal (block905). Other transmissions from the data retrieval tag170, such as transmission of information to communication nodes, may be UWB signals.

In certain implementations, the data retrieval tags170may be used to facilitate (e.g., transmit or receive) communication between communication nodes disposed on the drillstring. For example, communication nodes may be disposed on or in the drillpipe140, subs150, drill collar or collars145, or the bit155. A block diagram of a communication node is shown inFIG. 10. The example communication node, indicated generally at800, includes a node receiver1005to receive a signal from a data retrieval tag170. The communication node800may include a node transmitter1010to send a signal to a data retrieval tag170. The communication node may include a data tag power coupler1015to provide power from a power source1020to the data retrieval tag170.

An example method of signaling between nodes on a drillstring is shown inFIG. 11. In general, the data retrieval tag170will be immersed in the drilling fluid. The data retrieval tag170may receive an activation signal (block1105) and receive data from a first communication node. The data retrieval tag170may receive data from the first communication node (block1110) and record the data in the analog memory system215(block1115). The data retrieval tag may wait to receive a signal to transmit the stored data (block1120). Upon receiving a signal to transmit its stored data (block1120), the data retrieval tag170may transmit the stored data (block1125) and return to block1105.

In certain implementations, the order of the method shown inFIG. 11may be altered. For example, the data retrieval tag170may transmit stored data (block1120), before receiving data from the first communications mode (block1110).

In some implementations the data retrieval tags170may be used to pass data between communication nodes downhole. In other implementations, the data retrieval tags170may be used to pass data from at least one communication node600downhole to the interrogator175or another device at the surface.

Therefore, the present invention is well-adapted to carry out the objects and attain the ends and advantages mentioned as well as those which are inherent therein. While the invention has been depicted, described, and is defined by reference to exemplary embodiments of the invention, such a reference does not imply a limitation on the invention, and no such limitation is to be inferred. The invention is capable of considerable modification, alternation, and equivalents in form and function, as will occur to those ordinarily skilled in the pertinent arts and having the benefit of this disclosure. The depicted and described embodiments of the invention are exemplary only, and are not exhaustive of the scope of the invention. Consequently, the invention is intended to be limited only by the spirit and scope of the appended claims, giving full cognizance to equivalents in all respects.