CN-121993178-A - Electromagnetic wave mode-while-drilling conversion relay transmission method and system

CN121993178ACN 121993178 ACN121993178 ACN 121993178ACN-121993178-A

Abstract

The invention relates to the technical field of underground measurement while drilling data transmission, in particular to an electromagnetic wave mode-while-drilling conversion relay transmission method and system. The method comprises the steps of collecting measurement data through a double-insulation controlled dipole emission structure and emitting signals, receiving the measurement data signals through a repeater arranged along a drill string, determining equivalent emission impedance characteristics through outputting detection signals to an external medium and collecting effective values of voltage and current of an output end, receiving transmissible guide responses formed by the measurement data signals, judging the type of a current well section based on the equivalent emission impedance characteristics and the transmissible guide responses, selecting to switch to a casing guide injection path or an open hole coupling injection path according to a well Duan Leixing, and relaying the signals based on corresponding emission parameter sets. The invention realizes the intelligent recognition and conversion of the signal mode, improves the relay transmission success rate and stability of the casing well measurement data signal, shortens the link establishment distance and reduces the power consumption and risk caused by the working condition uncertainty.

Inventors

ZHANG ZHENHUA
ZHAI XIPING
LI RUNQI
WANG HAIQI
XU YUEQING
CAI WEI
ZHAO ZHIXUE
GAO MING
PEI FEI
XU YUNLONG
WANG ZHENLEI
WANG SHUQING
LIU HAIBO
YU HONGBO

Assignees

大庆钻探工程有限公司
中国石油天然气集团有限公司

Dates

Publication Date: 20260508
Application Date: 20251225

Claims (15)

1. An electromagnetic wave mode-while-drilling conversion relay transmission method is characterized by comprising the following steps of: the underground transmitting step is that through a double-insulation controlled dipole transmitting structure arranged on a drilling tool, measurement while drilling data are collected and corresponding measurement data signals are transmitted; A relay transmission step of determining an equivalent transmission impedance characteristic by arranging at least one repeater along the drill string, receiving the measurement data signal, and by outputting a detection signal to an external medium and collecting output terminal voltage and current effective values, and receiving a transmissible pilot response formed by the measurement data signal; Judging the current well section type as a sleeve section, an open hole section or a near window transition section based on the equivalent emission impedance characteristic and the transmissible guiding response, switching the repeater to a sleeve guiding injection path if the current well section type is judged as the sleeve section, switching the repeater to an open hole coupling injection path if the current well section type is judged as the open hole section, adopting a conservative injection parameter and improving the detection frequency if the current well section type is judged as the near window transition section; And based on the transmission parameter set corresponding to the switched injection path, relay forwarding is carried out on the received measurement data signals to form an uplink transmission link.
2. The electromagnetic wave mode-while-drilling conversion relay transmission method according to claim 1, characterized in that: the equivalent transmitting impedance is characterized in that when the repeater transmits a detection signal which does not bear measuring data, the voltage and the current effective value of the output port of the repeater are synchronously acquired and calculated; The transmissible pilot response is acquired by a repeater from a pilot response formed by a measurement data signal transmitted by a previous stage in a sleeve composite medium; the equivalent emission impedance characteristics comprise impedance amplitude Z eq and impedance phase characteristics phi; the transmissible pilot response includes an axial differential potential signal DeltaV and/or a pilot current indicative amount I g ; And/or the axial differential potential signal is acquired by two sampling points which are arranged at the outer part of the repeater and are axially arranged at intervals and a differential front-end circuit connected with the sampling points; the pilot current indication quantity is acquired through a ring-shaped sensing element or a current sensing element arranged outside the repeater.
3. The method for electromagnetic wave mode-while-drilling conversion relay transmission according to claim 2, wherein the method for discriminating the current well section type as the casing section, the open hole section or the near window transition section based on the equivalent emission impedance characteristic and the transmissible guiding response comprises the following steps: When the equivalent transmitting impedance amplitude Z eq , the impedance phase characteristic phi, the axial differential potential signal delta V and the pilot current indicating quantity I g are in the corresponding sleeve section characteristic intervals, judging that the sleeve section is the sleeve section; When the equivalent emission impedance amplitude Z eq , the impedance phase characteristic phi, the axial differential potential signal delta V and the pilot current indication quantity I g are in the corresponding stratum load interval, judging that the stratum load interval is an open hole section; And when the equivalent emission impedance amplitude Z eq , the impedance phase characteristic phi, the axial differential potential signal delta V and the pilot current indication quantity I g are positioned between the characteristic interval of the casing section and the stratum load interval, judging as a near window transition section.
4. The electromagnetic wave mode-while-drilling conversion relay transmission method according to claim 3, wherein before the step of judging the current well section type as the casing section, the open hole section or the near window transition section based on the equivalent transmission impedance amplitude and the transmissible guiding response, the method further comprises the steps of judging a receiving threshold, specifically comprising: if the equivalent transmitting impedance amplitude Z eq , the impedance phase characteristic phi, the axial differential potential signal delta V or the pilot current indicating quantity I g is not in any interval, or the interval type where one or two indexes are located is not corresponding to the interval type where the other indexes are located, the repeater controls to adjust the output detection signal and then re-transmit the detection signal; The adjustment comprises the steps of improving pilot frequency density, switching detection frequency points, adjusting duty ratio and/or delaying retry.
5. The electromagnetic wave mode-while-drilling conversion relay transmission method according to claim 1, characterized in that: The emission parameter sets corresponding to the sleeve guide injection path and the naked eye coupling injection path at least comprise frequency points, a boosting target, a duty ratio upper limit, a matching network gear, a pilot frequency period and a current amplitude limit; the corresponding transmitting parameter set at least comprises a frequency point, a boosting target, a duty ratio upper limit, a matching network gear, a pilot frequency period and a charge balance control parameter.
6. The electromagnetic wave mode-while-drilling conversion relay transmission method according to claim 2, characterized in that: The equivalent transmitting impedance amplitude Z eq =V rms /I rms , wherein V rms 、I rms is the effective value of the output voltage and the current acquired by the relay transmitting terminal; Wherein, the ; ; Wherein N is the number of the collected sample points, v N is the voltage discrete sampling sequence, i N is the current discrete sampling sequence; the equivalent transmit impedance phase The method comprises the following steps of detecting the phase of a voltage fundamental wave, detecting the phase of a current fundamental wave, and detecting the phase of the current fundamental wave.
7. A relay transmission system for implementing the electromagnetic wave mode-while-drilling conversion relay transmission method of any one of claims 1 to 6, comprising: a downhole transmitting unit comprising the dual insulated controlled dipole transmitting structure for performing the downhole transmitting step; At least one downhole relay unit comprising the relay arranged in series along a drill string for performing the relay transmitting step; the ground receiving unit is used for receiving and demodulating the measurement data signals transmitted in relay through the underground relay unit; The underground transmitting unit, the underground relay unit and the ground receiving unit form a segmented relay signal transmission link.
8. The relay transmission system of claim 7, wherein the dual insulated controlled dipole transmitting structure comprises: The upper insulation nipple and the lower insulation nipple are provided with continuous metal shells, and the upper insulation nipple and the lower insulation nipple electrically isolate the metal shells from the upper part and the lower part of the drilling tool to form two electric insulation boundaries; The metal shell is internally provided with a transmitting nipple, and the transmitting nipple is electrically connected with the metal shell and is used for transmitting corresponding measurement data signals by injecting modulation current into the metal shell; Wherein, under the limit of the two electric insulation boundaries, the metal shell forms a controlled transmitting conductor, the length of the outer surface between the upper and lower insulation pup joints is the effective dipole length, and the effective dipole length is set according to the signal transmission depth or the working section depth and the stratum resistivity; And/or, on the double-insulation controlled dipole emission structure, the effective dipole length between the upper insulation pup joint and the lower insulation pup joint is 8-15 m.
9. The relay transmission system according to claim 8, wherein: The metal shell is internally provided with a battery nipple and a central control nipple, and the tail end of the transmitting structure is provided with a measuring nipple; The battery nipple is used for supplying power to the transmitting nipple; The power driving unit, the boosting unit and the matching network are integrated in the transmitting nipple and are used for completing signal modulation output under a control instruction; the processor, the memory and the interface control circuit are configured in the central control pup joint and are used for completing measurement data acquisition management, coding modulation, emission control and state monitoring; the central control short section is used for determining equivalent emission impedance characteristics and determining emission parameters by combining the configured dipole length; and a sensor component is arranged in the measuring nipple and used for measuring the posture and geological parameters of the near-bit and outputting data to the central control nipple.
10. The relay transmission system of claim 8, wherein the effective dipole length is set according to a signal transmission depth or a working section depth and a formation resistivity, comprising: If the depth D is more than or equal to 2500m and the formation resistivity rho is less than or equal to 2Ω & m, the effective dipole length range is 12-15 m; If 1500m < D <2500m and 2< ρ < 5Ω·m, the effective dipole length takes on a value in the range of 10 to 12 m; if D is less than or equal to 1500m and ρ is more than 5 Ω & m, the effective dipole length is recommended to be 8-10 m.
11. The relay transmission system according to any one of claims 7 to 10, wherein the relay unit comprises: A receiving sensing module for receiving a transmissible pilot response formed by the probe signal in the composite medium comprising an axial differential potential signal DeltaV and/or a pilot current indicative amount I g ; the equivalent load measuring module is used for collecting the effective values of the voltage and the current of the output end of the equivalent load measuring module; The control processing module is used for controlling the injection/emission module to emit detection signals, determining equivalent emission impedance characteristics according to effective values of voltage and current, judging the type of the current well section according to the equivalent emission impedance characteristics, and controlling the injection/emission module to select a guide injection path of a sleeve or an open hole coupling injection path to carry out relay forwarding of measurement data signals according to the type of the well section; And the injection/transmission module is used for generating and outputting relay measurement data signals.
12. The relay transmission system according to claim 7, wherein: The repeater is provided with at least two conductive coupling sleeves which are arranged at intervals along the axial direction and are electrically insulated by an insulating isolation belt, and the conductive coupling sleeves are used for forming electric contact or capacitive coupling with the inner wall of the sleeve.
13. The relay transmission system according to claim 11, wherein: The repeater is provided with a controlled electric dipole injection nipple structure, and the controlled electric dipole injection nipple comprises an upper conductive electrode section, an insulating isolation section and a lower conductive electrode section; the insulating isolation section electrically isolates the upper conductive electrode section from the lower conductive electrode section; And the injection/emission module is used for respectively connecting the output of the power emission unit to the upper conductive electrode section and the lower conductive electrode section through a matching network under the open hole coupling injection mode so as to inject measurement data signals into the stratum loop.
14. The relay transmission system according to claim 7, wherein: The repeater monitors the output voltage and the output current of the system and the internal temperature of the repeater in real time, and executes soft derating operation when abnormal characteristics of overvoltage, overcurrent, overtemperature or electric leakage and breakdown occur; if abnormality still exists after the soft derate is executed, executing a hard protection operation; The soft derating includes reducing target injection strength, switching a conservative matching network gear, and/or increasing a gating threshold.
15. The relay transmission system according to any one of claims 7 to 14, wherein: In the relay forwarding process of the received measurement data signals, if the equivalent transmitting impedance characteristic and/or the corresponding impedance phase characteristic drift super-threshold value are detected, and/or the receiving quality index of the transmissible pilot response is reduced, periodically or event-triggered inserting a short pilot frequency/test sequence, and updating the equivalent transmitting impedance characteristic again; and updating the transmission parameter set by adopting a progressive adjustment strategy according to the updated equivalent transmission impedance characteristics.

Description

Electromagnetic wave mode-while-drilling conversion relay transmission method and system Technical Field The invention relates to the technical field of underground measurement while drilling data transmission, in particular to an electromagnetic wave mode-while-drilling conversion relay transmission method and system. Background In the prior art, electromagnetic wave measurement while drilling (EM-MWD) generally adopts a downhole transmitting end and a ground receiving end to form a low-frequency electromagnetic telemetry link. Downhole tools typically employ a drilling tool or casing as one of the electrodes and form an equivalent dipole structure through a gap sub to couple the modulated signal into the wellbore-formation medium for upward propagation. Under the naked eye or non-sleeve environment, the mode is easier to obtain the available uplink communication effect. However, under the working condition of a cased well, the high conductivity of the metal casing can introduce obvious shielding effect and eddy current loss, so that electromagnetic energy is strongly dissipated near the casing, and further, an uplink signal formed in the casing section by the underground transmitting end has the characteristics of unstable amplitude, poor repeatability, obvious receiving threshold drift and the like. Particularly in the rapid change areas of coupling conditions such as side drilling windows, the vicinity of casing shoes and the like, the uplink propagation path is often converted between a guiding channel along the casing, a window/near window composite coupling channel and a stratum coupling channel, so that the same transceiving structure and a fixed threshold are difficult to keep stable working in a whole well section. The problem caused by the method is that even if the underground repeater has the amplifying or forwarding function, the underground repeater can not close a link because the uplink pilot response can not be stably captured, and the problem that a receiving end can not receive a stable signal or the signal can not be decoded can occur. To increase the transmission distance, several patents have proposed arranging relay relays on the drill string. For example, the electromagnetic measurement data signal transmission repeater disclosed in CN103731191a adopts the idea of "receiving-processing-re-transmitting", and improves the quality of ground received signals by concatenating a plurality of repeaters, CN109802718a further proposes structural improvement aiming at the problem that the dipole two poles are easy to short circuit after the repeater enters a sleeve, and the ground cannot be decoded, CN205206811U and the like also disclose underground electromagnetic wave repeating structures, and the main is amplification or demodulation re-transmitting after coil receiving. At the same time, there is also a telemetry idea of using the drill pipe/casing as a conductive waveguide or coupling object, for example, US20110018734A1 proposes to arrange a wireless interface in the conductive waveguide (drill pipe) and to configure a repeater, US10760413, etc. to realize signal transmission along the casing current path by inductively coupling with the casing through a toroidal inductor. Although the prior art proposes schemes in the directions of relay, short circuit avoidance, conductor coupling transmission and the like, the prior art still generally takes 'amplification or retransmission after receiving electromagnetic signals/field intensity/potential' as a main line, and the following defects generally exist: The method for identifying the casing section, the near window transition section and the open hole section by a repeater is lacking in quantitative judgment basis for complex coupling conditions of the casing well, so that the selection of a working mode, injection topology and parameter sets is lacking in reliable basis, the threshold is multiple in experience, and the threshold is easy to drift when the well section is switched or the load is suddenly changed. When the well section enters the vicinity of the window from the casing section and then reaches the open hole section, the coupling condition and the equivalent load change greatly, if the repeater still works in a fixed mode, mode mismatch, low efficiency and even chain dropping easily occur, and when the load or the coupling condition suddenly changes, a quick and controllable online adjustment means (such as quick parameter reestimation and switching) is lacked, so that the link stability is insufficient and the management is difficult. Disclosure of Invention The invention provides a method and a system for converting and relaying electromagnetic wave while drilling mode, which are used for solving the problems that in the existing electromagnetic wave while drilling measurement, the coupling condition and equivalent load mutation are caused by the alternation of a sleeve section, a transition section and an open hole section