ACOUSTIC DATALINK USEFUL IN DOWNHOLE APPLICATIONS

A method for telemetering data from a Remote Data Source (RDS) in a Bottom Hole Assembly (BHA) for subterranean drilling. The BHA has a Bottom Mounted Mud Pulser (BMMP), a Main Processing Unit (MPU) and an acoustic sensor uphole from the BMMP, and an RDS downhole from the BMMP. The method includes encoding RDS data into a first encoded data signal; translating the first encoded data signal into an acoustic data signal; causing the acoustic data signal to follow an acoustic pathway at least partially uphole to the acoustic sensor; causing the acoustic sensor to translate the acoustic data signal into a second encoded data signal; causing the MPU to decode the second encoded data signal into RDS data and send said decoded RDS data to the BMMP; and causing the BMMP to telemeter RDS data received from the MPU in at least an uphole direction.

FIELD OF THE DISCLOSURE

This disclosure is directed generally to subterranean drilling technology, and more specifically to acoustic datalink technology, allowing near-bit tools, sensors, etc. to communicate with the surface via existing mud pulse telemetry equipment conventionally deployed further uphole.

BACKGROUND OF THE DISCLOSED TECHNOLOGY

In a downhole drilling environment with a bottom hole assembly (BHA) that includes an Measurement While Drilling (MWD) system telemetering to the surface via a bottom-mounted mud pulser, it is sometimes desirable to place additional electronic components below the pulser for, just for example, data-gathering and/or steering purposes. One example of a data-gathering component would be a Dynamics While Drilling or Diagnostics While Drilling (DWD) tool that monitors drill string torque, annular pressure, etc. An example of a steering component would be a Rotary Steerable System (RSS) that is used to steer the drill bit in a deviated portion of the wellbore. In such cases, it is beneficial to establish data transmission between the MWD tool processing unit (MPU) located uphole from the pulser and the Remote Data Sources (RDS) located downhole from the pulser, since the MWD MPU has the ability to send data to the surface via telemetry being monitored by drilling personnel. The personnel can then use the additional RDS information to make adjustments to drilling parameters, resulting in benefits such as in faster rates of progress and/or reductions in damage to drillstring components.

Current MWD systems are preferably retrievable, meaning they are preferably located near the uphole end of the BHA so that they can be retrieved (via fishing operations, for example) if the BHA becomes stuck further downhole or even lost in hole. The MWD system's mud pulser (advantageously, a servo-driven mud pulser) is usually located a short distance downhole from the MWD system itself. In this way, the pulser can telemeter MWD data robustly and accurately to the surface while still also being retrievable. Often the mud pulser is located just uphole from the Universal Bottom Hole Orientation (UBHO) sub since the UBHO sub is rarely retrievable. In such deployments, the MWD system including the mud pulser are retrievable. However, as noted in the previous paragraph, remote data sources (RDS) such as DWD or RSS have to be near the bit to be effective, and so are necessarily located downhole from the MWD system and the UBHO sub. A “shorthop” datalink thus has to be established between the RDS and the MWD system so that the MWD MPU may send RDS data as well as MWD data to the mud pulser for telemetry to the surface.

Electromagnetic (EM) shorthop technology is currently available to transfer RDS data uphole for further telemetering to the surface. EM shorthop technology calls for RDS data to be modulated onto an EM signal generated by a transmitter located nearby. The broadcast EM signal passes through the downhole formation, and is received at another point in the drillstring. This technology is known to be used to allow remote data sources to communicate with MWD systems further uphole. The distance capability of this data transmission is in the range of 10 to 80 feet. However, there are performance issues that plague EM shorthops. First, EM transmission tends to consume considerable electrical power. Downhole electrical power is generally provided by batteries, and so is typically a finite resource. Shortened battery life will result in a less time spent drilling in between trips to the surface to replace the spent battery. Second, the distance over which the EM signal can be robustly transmitted is highly dependent on the composition of the downhole formation that is being bored. Some formations, such as salt, tend to attenuate an EM signal substantially. Other formations require complex calculations to determine optimal spacing between the transmitter and receiver, along with the necessary power requirements for signal generation. Third, current antenna technology used for transmitting the EM signal is prone to shorting out and causing a failure in data transmission. Fourth, most EM shorthop systems call for an antenna to be placed inside the drillstring for better protection against the drilling environment. This interior antenna deployment requires that a non-metallic “window” be placed in the drillstring collar to allow the EM signal to pass through the collar and into the formation. This window creates a weak point in the drillstring that is subject to mechanical failure if drilling parameters such as weight-on-bit, build rate, or torque are allowed to get too high.

There is therefore a need in the art for an alternative to EM shorthop technology for establishing RDS data communication uphole to, for example, an MWD system and mud pulser for further telemetry to the surface.

SUMMARY AND TECHNICAL ADVANTAGES

The needs in the art described above in the “Background” section are addressed by a an acoustic shorthop datalink that establishes wireless data transmission between remote data sources (RDS) near the bit and, for example, an MWD telemetry system further uphole. The acoustic shorthop datalink is an advantageous alternative to existing EM shorthops serving the same purpose, whose disadvantages are described above in the “Background” section. The acoustic datalink technology disclosed herein allows a conventional retrievable MWD system and retrievable mud pulser to be used to telemeter RDS data to the surface along with MWD data. In preferred embodiments, the acoustic datalink provides components enabling an acoustic signal pathway along a desired portion of the drillstring. The acoustic pathway may run both inside and along the drillstring collar, per user design. An inventive method wises in which an electrical data signal is received from the RDS, which, once encoded, is translated into a corresponding acoustic RDS data signal. The acoustic RDS data signal travels the acoustic pathway uphole over or through various components, advantageously including the UBHO sub, until the acoustic RDS data signal reaches an acoustic sensor. The acoustic sensor translates the acoustic RDS data signal back into a corresponding electrical RDS data signal. The electrical RDS data signal is still encoded. After decoding, the decoded RDS data is passed to the MWD MPU. The MWD sends the RDS data to the mud pulser for telemetry to the surface.

According to a first aspect, therefore, this disclosure describes embodiments of a method for telemetering data from a Remote Data Source (RDS) in a Bottom Hole Assembly (BHA) for subterranean drilling oriented such that downhole is towards a drill bit and uphole is away from the drill bit, the method comprising the steps of: (a) providing a Bottom Mounted Mud Pulser (BMMP) in the BHA; (b) providing a Main Processing Unit (MPU) and an acoustic sensor uphole from the BMMP; (c) providing an RDS downhole from the BMW, wherein the RDS is configured to generate RDS data; (d) encoding the RDS data into a corresponding first encoded RDS data signal; (e) translating the first encoded RDS data signal into a corresponding acoustic RDS data signal; (f) causing the acoustic RDS data signal to follow an acoustic pathway at least partially uphole to the acoustic sensor; (g) causing the acoustic sensor to translate the acoustic RDS data signal into a second encoded RDS data signal; (h) causing the MPU to decode the second encoded RDS data signal into RDS data and send said decoded RDS data to the BMMP; and (i) causing the BMMP to telemeter RDS data received from the MPU in at least an uphole direction.

According to a second aspect, this disclosure describes a method for telemetering data from a Remote Data Source (RDS) in a Bottom Hole Assembly (BHA) for subterranean drilling oriented such that downhole is towards a drill bit and uphole is away from the drill bit, the method comprising the steps of: (a) providing a Bottom Mounted Mud Pulser (BMMP) in the BHA; (b) providing a Main Processing Unit (MPU) and an acoustic sensor uphole in the BHA from the BMMP; (c) providing an RDS downhole from the BMMP, wherein the RDS is configured to generate RDS data at the RDS; (d) providing a piezoelectric translator downhole from the BMMP; (e) encoding the RDS data into a corresponding first encoded RDS data signal; (f) causing the piezoelectric translator to translate the first encoded RDS data signal into a corresponding acoustic RDS data signal; (g) causing the acoustic RDS data signal to follow an acoustic pathway at least partially uphole to the acoustic sensor; (h) causing the acoustic sensor to translate the acoustic RDS data signal into a second encoded RDS data signal; (i) causing the MPU to decode the second encoded RDS data signal into RDS data and send said decoded RDS data to the BMMP; and (j) causing the BMMP to telemeter RDS data received from the MPU, wherein said telemetry by the BMMP is in at least an uphole direction.

Embodiments according to the first or second aspects may provide that selected ones of the MPU and the BMW are retrievable.

Embodiments according to the first or second aspects may provide that the first and second encoded RDS data signals are substantially the same.

Embodiments according to the first aspect or second aspects may provide a Universal Bottom Hole Orientation (UBHO) sub in the acoustic pathway.

Embodiments according to the first aspect may provide that the RDS is configured to generate RDS data at the RDS.

Embodiments according to the first aspect may provide that step (e) is performed downhole from the RDS.

Embodiments according to the first or second aspects may provide that the RDS is selected from at least one of the group consisting of: (1) a Diagnostics While Drilling tool; (2) a Logging While Drilling tool; (3) a Measurement While Drilling tool; (4) a Dynamics While Drilling tool; (5) a Rotary Steerable System; and (6) a smart motor.

Embodiments according to the first aspect may provide that step (e) includes amplifying the acoustic signal.

Embodiments according to the second aspect may provide that the piezoelectric translator is downhole from the RDS.

Embodiments according to the second aspect may provide that step (f) includes causing a reactive mass to amplify the acoustic signal.

According to a third aspect, this disclosure describes a Bottom Hole Assembly (BHA) for subterranean drilling oriented such that downhole is towards a drill bit and uphole is away from the drill bit, the BHA comprising: a Bottom Mounted Mud Pulser (BMMP); a Main Processing Unit (MPU) positioned an acoustic sensor positioned uphole from the BMMP; an RDS downhole positioned downhole from the BMMP, wherein the RDS is configured to generate RDS data; a piezoelectric translator positioned downhole from the BMW, wherein the piezoelectric translator is configured to translate a first encoded RDS data signal into a corresponding acoustic RDS data signal; an acoustic pathway traveling at least partially uphole from the piezoelectric translator to the acoustic sensor; wherein the acoustic pathway is configured to carry the acoustic RDS data signal to the acoustic sensor; wherein the acoustic sensor is configured to translate the acoustic RDS data signal into a second encoded RDS data signal; wherein the MPU is configured to decode the second encoded RDS data signal into RDS data and send said decoded RDS data to the BMMP, and wherein the BMMP is configured to telemeter RDS data received from the MPU in at least an uphole direction.

Embodiments according to the third aspect may provide that selected ones of the MPU and the BMMP are retrievable.

Embodiments according to the third aspect may provide that the first and second encoded RDS data signals are substantially the same.

Embodiments according to the third aspect may provide that the piezoelectric translator is positioned downhole from the RDS.

Embodiments according to the third aspect may provide a Universal Bottom Hole Orientation (UBHO) sub positioned in the acoustic pathway.

Embodiments according to the third aspect may provide that the RDS is configured to generate RDS data at the RDS.

Embodiments according to the third aspect may provide that the RDS is selected from at least one of the group consisting of: (1) a Diagnostics While Drilling tool; (2) a Logging While Drilling tool; (3) a Measurement While Drilling tool; (4) a Dynamics While Drilling tool; (5) a Rotary Steerable System; and (6) a smart motor.

Embodiments according to the third aspect may further comprise a reactive mass, wherein the reactive mass is configured to amplify the acoustic RDS data signal after translation by the piezoelectric translator.

It is therefore a technical advantage of the disclosed acoustic shorthop datalink to avoid drawbacks of conventional EM shorthop technology (as described above in the “Background” section). In preferred embodiments, the acoustic RDS data signal comprises high frequency vibrations travelling through the drillstring tubulars. Robust acoustic signal transmission is thus not dependent on surrounding wellbore composition, but instead on maintaining a continuous line of effective physical contact (and preferably metallic contact) from the acoustic signal transmitter to the receiver. Since drillstring components are typically, if not always, metallic, RDS data transmission according to this disclosure will be more reliable and predictable. Further, the acoustic datalink described in this disclosure obviates the need for a “window” in the drillstring collar as often required by EM shorthops. The structure integrity of drillstring collars near the bit is thus preserved. Yet further, the acoustic datalink described in this disclosure obviates the need for a fault-prone EM antenna and associated complex positional calculations.

A further technical advantage of the disclosed acoustic datalink technology is that it enables conventional and existing mud pulse telemetry to communicate RDS data with the surface.

In some embodiments, the acoustic datalink methodology described in this disclosure may be characterized to work with a shock-absorbing UBHO/pulser sub (aka “shock miser” tool) as described in U.S. Pat. No. 9,644,434. An advantage provided by the shock miser tool (as described in the '434 patent) is to dampen the mud pulser's transmitter valve from environmental vibration or shock forces from drilling operations. As a result, the shock miser tool enables the mud puller to deliver a cleaner train of acoustic mud pulses in which background environmental acoustic noise has been attenuated.

Turning now to the acoustic datalink methodology described in this disclosure, creating an acoustic datalink pathway across a shock miser tool presents an additional challenge. As noted, the shock miser tool provides features to dampen the mud pulser's transmitter valve from environmental vibration or shock forces. The acoustic datalink pathway has to avoid these features on the shock miser tool in order not to inadvertently also dampen and attenuate an acoustic RDS data signal traveling along the acoustic datalink pathway. The acoustic datalink methodology described in this disclosure may be characterized so that the acoustic datalink pathway may avoid dampening features on a shock miser tool when a shock miser tool is present.

The foregoing has rather broadly outlined some features and technical advantages of the disclosed acoustic datalink technology, in order that the following detailed description may be better understood. Additional features and advantages of the disclosed technology may be described. It should be appreciated by those skilled in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same inventive purposes of the disclosed technology, and that these equivalent constructions do not depart from the spirit and scope of the technology as described.

DETAILED DESCRIPTION

Reference is now made toFIGS. 1 through 7in describing the currently preferred embodiments of the disclosed acoustic short hop technology, and its related features.FIGS. 1 through 7should be viewed as a whole for the purposes of the following disclosure. Any part, item, or feature that is identified by part number on one ofFIGS. 1 through 7will have the same part number when illustrated on another ofFIGS. 1 through 7. It will be understood that the embodiments as illustrated and described with respect toFIGS. 1 through 7are exemplary, and the scope of the inventive material set forth in this disclosure is not limited to such illustrated and described embodiments.

FIG. 1is a block drawing illustrating schematically a general arrangement of components discussed in this disclosure.FIG. 1is intended to orient the reader to a typical drillstring arrangement of components illustrated in more detail onFIGS. 3 through 7.FIG. 1illustrates drilling operations from rig10, to which bit30is connected via drillstring20. The embodiment ofFIG. 1depicts a deviated wellbore in which bit30is driven by a positive displacement motor (PDM), or “mud motor”. The scope of this disclosure is not limited, however, to drilling operations involving deviated wellbores or PDM deployments.

The embodimentFIG. 1further illustrates a section of interest200in the Bottom Hole Assembly (BHA). FIGURE depicts BHA of interest200including, in order from uphole to downhole:Measurement-while-drilling main processing unit (MWD MPU)MWD toolReceiver SubMud PulserUniversal Bottom Hole Orientation (UBHO sub)Acoustic SubRemote Data Sources (RDS), e.g. Rotary Steerable System (RSS) or Diagnostics-while-drilling (DWD) toolsPDM and transmission

The foregoing components will be described in more detail below in context of the acoustic short hop technology described herein. This is with the exception of PDM and transmission deployments, which may be conventional. ComparingFIG. 1toFIG. 3, the “Acoustic Sub” block shown onFIG. 1will be understood to correspond to a transmitting tool202and an acoustic interface including PEC203and reactive mass204, as shown onFIG. 3and described further below. Further comparingFIG. 1toFIG. 3, the “Receiver Sub” block shown onFIG. 1will be understood to correspond to an acoustic sensor206and a receiving tool207, as shown onFIG. 3and described further below.

FIGS. 2 and 3should now be viewed together.FIG. 2is a flow chart illustrating method100. Method100represents a first method embodiment of the acoustic short hop technology described in this disclosure.FIG. 3illustrates an embodiment of BHA section of interest200correlated to method100onFIG. 2to show general locations on BHA section of interest200where the steps of method100are performed.

Step101onFIGS. 2 and 3illustrates sending data from Remote Data Sources (RDS)201to receiver controller and transmitter electronics located on board transmitting tool202. As described earlier in this disclosure, it is operationally advantageous to position certain tools, sensors or other data accumulators close to the bit in order to execute commands to tools located near the bit, or to monitor conditions in that region. RDS201may include any such tools, sensors or other data accumulators positioned close to the bit, including (without limitation) Rotary Steerable Systems (RSS), diagnostics-while-drilling (DWD) tools, “smart” motors, and other near-bit sensors. In some embodiments, RDS201may be configured to generate RDS data at the RDS itself. In other embodiments, RDS201may be configured to generate RDS data from sensors etc. located remote from the RDS itself. RDS201may send remote data to transmitting tool202via any convenient, conventional connection such as hard wiring or electromagnetic (EM) short hop, for example. A hardwiring option is used in embodiments of RDS201/transmitting tool202illustrated onFIGS. 3 through 7herein. In some non-illustrated embodiments, transmitting tool202may also provide its own RDS sensors located on transmitting tool202's chassis.

Step102onFIGS. 2 and 3illustrates transmitting tool202parsing data received from RDS201and generating a corresponding encoded electrical signal. In currently preferred embodiments, transmitting tool202uses conventional data encoding techniques to generate an optimized signal into which real-time data from multiple remote data sources are multiplexed. The scope of this disclosure is not limited to encoding or multiplexing techniques used in accumulating data from RDS201. Further, in some embodiments, encoded electrical data signal generated by transmitting tool202may be characterized as a “first encoded RDS data signal” in order to differentiate with Step109onFIGS. 2 and 3. As further described below, Step109illustrates acoustic sensor206translating acoustic signal104back into an encoded RDS data signal, which may be characterized herein as a “second encoded RDS data signal.” The scope of this disclosure is not limited to the first and second encoded RDS data signals being substantially identical, although in some embodiments they may be substantially identical.

Step103onFIG. 2 and 3illustrates transmitting tool202passing the encoded electrical signal from step103to piezoelectric crystal (PEC)203. In illustrated embodiments, PEC203is positioned uphole from transmitting tool202. The scope of this disclosure is not limited in this regard, however, and in other embodiments, PEC203may be located downhole from transmitting tool202. PEC203translates the encoded electrical signal to a corresponding acoustic signal (step104). In currently preferred embodiments, a reactive mass204amplifies the acoustic signal generated by PEC203(step105). The scope of this disclosure is not limited, however, to embodiments deploying a reactive mass204for amplification purposes. Where deployed, reactive mass204is preferably made from a high-density material such as tungsten, although the scope of this disclosure is again not limited in this regard.

Step106onFIGS. 2 and 3illustrates connecting (acoustically) an acoustic interface including PEC203and reactive mass204to the immediately uphole drillstring tubular. Acoustic interface215is described in more detail below with reference toFIGS. 5 and 5A. Referring momentarily toFIG. 5A, acoustic interface215also includes a flat face connection213and a compression stack216for promoting a strong (unattenuated) acoustic signal connection between acoustic interface215and the immediately uphole drillstring tubular. Flat face connection213and compression stack216are described below in greater detail with reference toFIG. 5A.

Step107onFIGS. 2 and 3illustrates allowing the encoded acoustic signal to travel uphole on connected drillstring tubulars until it reaches Universal Bottom Hole Orientation (UBHO) sub205. The scope of this disclosure is not limited to the number of drillstring tubulars (or other collared subs or mud motors) that may be in the acoustic signal pathway between acoustic interface215and UBHO sub205(if any).

Step108onFIGS. 2 and 3illustrates providing an acoustic signal pathway, or “acoustic pathway”, from UBHO sub205to receiving tool207. Note that although step108onFIG. 2refers to an acoustic pathway from UBHO sub205to receiving tool207, it will be understood with momentary reference toFIG. 3that the acoustic pathway more precisely terminates at acoustic sensor206. Acoustic sensor206then translates the received encoded acoustic signal into a corresponding encoded electrical signal and passes same to the receiver electronics located on board receiving tool207(step109). As noted above, this encoded electrical signal translated by acoustic sensor206may be characterized as a “second encoded RDS data signal”, as differentiated from a first encoded RDS data signal generated by transmitting tool202with reference to Step102. The scope of this disclosure is not limited to the first and second encoded RDS data signals being substantially identical, although in some embodiments they may be substantially identical.

The acoustic pathway disclosed on step108through UBHO sub205is described below in more detail with reference toFIG. 6A. Referring momentarily toFIG. 6A, embodiments illustrated onFIG. 6Adirect acoustic pathway AP through UBHO sub205via muleshoe sleeve217and muleshoe stinger218, and then into mud pulser211. Muleshoe stinger218onFIG. 6Aprovides large seals219and small seals220for promoting a strong (unattenuated) acoustic signal through muleshoe stinger218. In other, non-illustrated embodiments, acoustic pathway AP may be directed around or through a “shock miser” tool integrated into muleshoe stinger218. Embodiments of a “shock miser” tool are disclosed in U.S. Pat. No. 9,644,434.

Step110onFIGS. 2 and 3illustrates receiving tool207decoding the received encoded electrical signal. The decoded signal may be the original RDS data received in step101, or may be a processed version thereof.

Step111onFIGS. 2 and 3illustrates receiving tool207passing the decoded RDS data to MWD MPU210. Preferably, the connection between receiving tool207and MWD MPU210for the decoded RDS data is a hardwired connection, although the scope of this disclosure is not limited in this regard.

Step112onFIGS. 2illustrates MWD MPU210causing the decoded RDS data to be telemetered to the surface by mud pulser211. Step112is not illustrated onFIG. 3in order promote clarity and to avoid confusion. As described further below with reference toFIG. 7, MWD MPU210conventionally causes MWD data received from MWD tool208to be telemetered to the surface via mud pulser211. In accordance with inventive technology described in this disclosure, MWD MPU210also causes RDS data to be telemetered to the surface via mud pulser211along with MWD data conventionally received.

FIG. 3also illustrates battery209and drill collar212for reference in conjunction with other Figures described below.

FIGS. 4 through 7should be viewed together.FIG. 4is a general arrangement drawing of an embodiment of BHA section of interest200showing portions thereof illustrated byFIGS. 5, 6 and 7. The boundaries shown onFIG. 4betweenFIGS. 5, 6 and 7have no technical significance. They are for general reference purposes only, intended to promote a better understanding of BHA section of interest200as a whole acrossFIGS. 5, 6 and 7.

FIG. 5illustrates a portion of BHA section of interest200in which an acoustic signal is generated, in which the acoustic signal represents data from Remote Data Sources (RDS)201.

As described above, RDS201onFIG. 5may include any such tools, sensors or other data accumulators positioned close to the bit, including (without limitation) Rotary Steerable Systems (RSS), diagnostics-while-drilling (DWD) tools, “smart” motors, and other near-bit sensors.FIG. 5further depicts transmitting tool202. RDS201sends RDS data to receiver electronics located on board transmitting tool202. Although not specifically illustrated onFIG. 5, non-illustrated embodiments of transmitting tool202may provide additional RDS sensors located on transmitting tool202's chassis. RDS201onFIG. 5sends RDS data to transmitting tool202via a hard-wired connection. In other non-illustrated embodiments, RDS201may send RDS data to transmitting tool202via an electromagnetic (EM) short hop, for example. As also described above with reference toFIGS. 2 and 3, transmitting tool202parses RDS data received from RDS201and generates a corresponding encoded electrical signal. In currently preferred embodiments, transmitting tool202uses conventional data encoding techniques to generate an optimized signal into which real-time data from multiple remote data sources are multiplexed. The scope of this disclosure is not limited to encoding or multiplexing techniques used in accumulating data from RDS201.

FIG. 5Ais an enlargement as shown onFIG. 5, and depicts acoustic interface215. Acoustic interface215onFIG. 5Aincludes piezoelectric crystal (PEC)203, reactive mass204, flat face connection213and compression stack216. As also described above with reference toFIGS. 2 and 3, PEC203receives the encoded electrical RDS data signal from transmitting tool202and translates same to a corresponding encoded acoustic RDS data signal. It will be understood that PEC203will expand in response to current flow. If the current flow oscillates at a given frequency, the PEC will expand and contract at the same frequency, and these movements create vibration that can be encoded with data, creating an encoded acoustic signal.

With further reference toFIG. 5Aand as also described above with reference toFIGS. 2 and 3, reactive mass on204amplifies the encoded acoustic data signal generated by PEC203. In some embodiments, reactive mass204may also preferentially adjust the natural frequency modes of the transmission. The scope of this disclosure is not limited, however, to embodiments deploying a reactive mass204. As noted earlier, where deployed, reactive mass204is preferably made from a high-density metal such as tungsten, although the scope of this disclosure is again not limited in this regard.

FIG. 5Afurther illustrates flat face connection213and compression stack216on acoustic interface215. It will be appreciated that transmitting tool202is probe-based (i.e. located inside collar212of the drillstring. Acoustic interface215serves as a “bridge” from probe-based components to an acoustic signal pathway on the collar of the drillstring itself. Flat face connection213and compression stack216combine to promote a strong (unattenuated) acoustic signal connection between acoustic interface215and the immediately uphole drillstring tubular. Flat face connection213provides strong and tight physical contact over a substantial face area. Compression stack216forcefully compresses acoustic interface215and the immediately uphole drillstring tubular tightly together at flat face connection213. As a result, an acoustic signal can pass from acoustic interface215to the immediately uphole drillstring tubular without significant loss of signal amplitude. Such a flat face arrangement is in distinction, say, to a threaded connection across which greater acoustic signal attenuation night be expected. Compression stack216also allows incremental axial deflections between acoustic interface215and the immediately uphole drillstring tubular. In this way, compression stack216also corrects for any axial misalignment between acoustic interface215and the immediately uphole drillstring tubular, thereby keeping flat face connection213tight to reduce potential acoustic signal attenuation.

FIG. 6illustrates a portion of BHA section of interest200in which an acoustic signal pathway AP is established along which encoded acoustic data signals may travel uphole from acoustic interface215to acoustic sensor206and receiving tool207.FIG. 6Ais an enlargement as shown onFIG. 6, and depicts acoustic pathway AP traversing UBHO sub205.

FIG. 6depicts an initial portion of acoustic pathway AP flowing from acoustic interface215to UBHO sub205. It will be understood from immediately prior description ofFIGS. 5 and 5A, that once the encoded acoustic data signal traverses flat face connection213on acoustic interface215, acoustic pathway AP flows uphole until it reaches UBHO sub205.

Referring now toFIG. 6A, acoustic pathway AP flows through UBHO sub205via muleshoe sleeve217and muleshoe stinger218, and then into mud pulser211. Muleshoe stinger218onFIG. 6Afurther provides large seals219and small seals220for promoting a strong (unattenuated) acoustic signal through muleshoe stinger218. Large and small seals218,219provide acoustic insulation to acoustic pathway AP against background acoustic noise, such as shock, vibration and concussion created elsewhere in the drillstring from drilling operations. As noted above with reference toFIGS. 2 and 3, other, in non-illustrated embodiments, acoustic pathway AP may be directed around or through a “shock miser” tool integrated into muleshoe stinger218. Embodiments of a “shock miser” tool are disclosed in U.S. Pat. No. 9,644,434.

Returning now toFIG. 6, a final portion of acoustic pathway AP flows from UBHO sub205to acoustic sensor206via mud pulser211. The final portion of acoustic pathway AP may also include other tools car components immediately uphole of mud pulser211(note that the scope of this disclosure is indifferent to the presence of any other such tools or components). As shown onFIG. 6, acoustic pathway AP in this final portion is preferably through the casing of mud pulser211etc., although it will be understood that acoustic pathway AP may also flow through collar12in this portion of drillstring

Once acoustic sensor206receives the encoded acoustic data signal on acoustic pathway AP, acoustic sensor206translates the encoded acoustic signal into a corresponding encoded electrical signal. Acoustic sensor206then passes the encoded electrical signal to the receiver electronics located on board receiving tool207. In currently preferred embodiments, acoustic sensor206is an accelerometer, although the scope of this disclosure is not limited in this regard. As noted above with reference toFIGS. 2 and 3, receiving tool207decodes the encoded electrical signal received from acoustic206. The decoded signal may be the original RDS data received from RDS201by transmitting tool202, or may be a processed version thereof.

FIG. 7illustrates a portion of BHA section of interest200in which receiving tool203sends the decoded electrical RDS data signal further uphole to MWD210. Preferably, the data connection between receiving tool207and MWD MPU210a hardwired connection, although the scope of this disclosure is not limited in this regard.

MWD MPU210processes the decoded electrical RDS data signal for telemetry to the surface by mud pulser211. It will be understood that during conventional MWD operations, MWD MPU210receives MWD data generated by MWD tool208onFIG. 7. MWD MPU210encodes the MWD data signal for mud pulse telemetry, and then passes the encoded MWD data signal downhole to mud pulser211. Mud pulser211telemeters the MWD data to the surface.

According to inventive technology in this disclosure, MWD MPU210is configured also to encode the RDS data signal (as received from receiving tool207) for mud pulse telemetry. MWD MPU210may then send the encoded RDS data signal to mud pulser211along with encoded MWD data. Mud pulser211telemeters the RDS data to the surface.

Variations

1. An acoustic datalink in which there is bi-directional communication (thereby enabling surface personnel to both listen to and command the remote data sources). In such variations, transmitter and receiver components would require transceiver capability.

2. An acoustic datalink having wider application than facilitating RDS data communication with MWD systems located further uphole. The acoustic datalink described generally in this disclosure is not limited to such RDS/MWD+pulser deployments.

3. This disclosure describes an embodiment in with the acoustic sensor and receiving tool are substantially integral with the MWD system+pulser. In other embodiments, the acoustic sensor and receiving tool could be located or mounted elsewhere in the BHA or on the drillstring, internally or externally. Alternatively, the acoustic sensor and receiving tool could be a separate tool or sub.

4. As described above, embodiments of the acoustic datalink methodology described in this disclosure may be characterized to work with a shock-absorbing UBHO/pulser sub (aka “shock miser” tool) as described in U.S. Pat. No. 9,644,434.

Although the inventive material in this disclosure has been described in detail along with some of its technical advantages, it will be understood that various changes, substitutions and alternations may be made to the detailed embodiments without departing from the broader spirit and scope of such inventive material. Claimed embodiments follow.