Chinese Academy of Sciences

Institute of Geology and Geophysics, Cas

Qihui Zhen

Qingyun Di

Yuliang Wang

Quanmin Yang

Wenxiu Zhang

Xinzhen He

Jiansheng Du

Hui Wu

Zhiyao Liu

Jing Ou

Jiwen Xiao

Xin Wu

Guoqiang Xue

Tianxin Zhang

A method of encoding and decoding downlink instructions based on mud flow rate includes an encoding method and a decoding method. The encoding method and the decoding method are configured to transmit and receive instructions by controlling the mud flow rate during drilling process. The method of encoding and decoding downlink instructions based on mud flow rate does not require a fixed threshold of voltage as a judgement standard for '0' and “1” symbols, but uses voltage change rate as a standard for judging the level transition, avoiding decoding failure caused by the inability of voltage sampling values to reach the fixed threshold after well depth is increased.

Method of encoding and decoding downlink instructions based on mud flow rate

A service table for polling data of downhole transmission devices in MWD includes a frame number, a number of data items of a data frame, a number of cycles of the data frame in a polling process, a device address of each of the data items, a measurement parameter, a valid bit number, a valid byte number of the data frame, a total frame number, a total polling frame number H and a total polling frame number L, an error polling frame number H and an error polling frame number L, and a transmission status bit flag. The service table architecture for polling data of a downhole transmission device in MWD has been used in actual drilling devices and has completed field operations for multiple wells. Compared to the simplified service tables in the past, the service table can support multiple downhole transmission devices working simultaneously, which has improved drilling efficiency and saved drilling costs.

Service table for polling data of downhole transmission device in measurement-while-drilling

A reception compensation apparatus based on airborne transient electromagnetic method is disclosed, and includes a receiver coil, a transmitter coil, at least one compensation coil, and at least one compensation magnetic core, where the transmitter coil is disposed around a periphery of the receiver coil. The at least one compensation magnetic core is disposed around an outer surface of the transmitter coil. The at least one compensation coil is disposed around an outer surface of the compensation magnetic core.

Reception compensation apparatus based on airborne transient electromagnetic method

A short-offset transient electromagnetic transmission system, including: an electromagnetic transmitter with transmission power supplies P, P, P, P, grounding electrodes A, B, C, D, F, and transmission wires LA, LB, LB, LC, LC, LD, LD, LE. The electrodes A and B are connected to the transmission power supply Pvia the wires LA and LB. The electrodes B and C are connected to the transmission power supply Pvia the wires LBand LC. The electrodes C and D are connected to the transmission power supply Pvia the wires LCand LD. The electrodes D and E are connected to the transmission power supply Pvia the wires LDand LE. The wires LA and LBare pulled from the electromagnetic transmitter to the electrode B and the wires LDand LE are pulled from the electromagnetic transmitter to the electrode D in a twisted-pair manner.

Short-offset transient electromagnetic transmission system

A ground receiving front-end compensation system for intelligent guide drilling borehole-ground electromagnetic transmission is provided, and includes a ground sensing module located below the underground wellhead, a ground system located between the underground wellhead and the measuring electrode, a measuring electrode and a compensation electrode; the ground system, the measuring electrode and the compensation electrode are located at the same side of the underground wellhead, a measuring electrode spacing (a first preset distance) is a distance from the underground wellhead to the measuring electrode; a compensation electrode spacing (a second preset distance) is a distance from the underground wellhead to the compensation electrode, the second preset distance is greater than the first preset distance; an induction signal of the ground sensing module enters the ground system, and the ground system outputs compensation current based on the induction signal, and compensates the measuring signal based on the compensation current.

Ground receiving front-end compensation system for intelligent guide drilling borehole-ground electromagnetic transmission

A ground transmitting system and method for electromagnetic transmission between a well and a ground for intelligent drill guiding includes a well site power generation device, a ground transmitting device and current transmission ground electrodes. The well site power generation device, the ground transmitting device and the current transmission ground electrodes are connected in sequence. The well site power generation device is used for supplying power to the ground transmitting device. The ground transmitting device is used for sending generated current waveform to the current transmission ground electrodes through a transformer. The current transmission ground electrodes are used for sending the current waveform to an underground receiver through a drill pipe and strata to complete a ground transmitting for the electromagnetic transmission between the well and the ground for the drill guiding.

Ground transmitting system and method for electromagnetic transmission between well and ground for intelligent drill guiding

The present disclosure provides an inductive magnetic sensor, which includes a signal pre-amplifying measurement circuit, a feedback loop, a magnetic core and coil group, a low-noise autozero processing circuit, and an output protection module. The magnetic core and coil group is electrically connected between the signal pre-amplifying measurement circuit and the feedback loop, the signal pre-amplifying measurement circuit comprises the low-noise autozero processing circuit, and the feedback loop and the low-noise autozero processing circuit are electrically connected to the output protection module respectively. By introducing the resonant notch filter, it may extend the passband to the low frequency, and extend the low-frequency characteristic of the magnetic sensor, to obtain a better low-frequency magnetic sensor. The present disclosure further provides an electromagnetic prospecting equipment.

Inductive magnetic sensor and electromagnetic prospecting equipment

An all-band magnetic sensor is provided. The all-band magnetic sensor comprises an induction coil, a voltage measurement module, and an integrator; the induction coil is used for generating an induced electromotive force according to magnetic flux passing therethrough; an impedance transformation circuit is connected to the output end of the induction coil and used for improving the loop resistance of the induction coil; the voltage measurement module is electrically connected to the impedance transformation circuit, and used for measuring the induced electromotive force generated by the induction coil; and the integrator is electrically connected to the voltage measurement module, and used for expanding a bandwidth.

All-band magnetic sensor

The present invention discloses a CSAMT transmitter, including: a first transmitter, where the first transmitter includes a first generator, a first rectifier module, a first transmission module, and a second transmission module, the first generator is connected to the first transmission module and the second transmission module by using the first rectifier module; and a second transmitter, where the second transmitter includes a second generator, a second rectifier module, a third transmission module, and a fourth transmission module, the second generator is connected to the third transmission module and the fourth transmission module by using the second rectifier module, where the first transmission module is connected to the third transmission module, and the second transmission module is connected to the fourth transmission module; the first transmission module has the same voltage as the third transmission module, and the second transmission module has the same voltage as the fourth transmission module.

CSAMT transmitter

A soft-switching control circuit of a boost-type PFC converter is provided. The boost-type PFC converter is a three-phase six-switch boost-type PFC converter, which includes six primary switching transistors and an auxiliary switching transistor. The control circuit includes a primary switch control circuit configured to output driving signals for the primary switching transistors by a one-cycle control algorithm to drive two of the primary switching transistors, and an auxiliary switch control circuit configured to provide a reset signal to the primary switch control circuit for governing a command from the primary switch control circuit to the primary switching transistors. The auxiliary switch control circuit outputs a driving signal for the auxiliary switching transistor to control the auxiliary switching transistor. The primary switch control circuit includes a section selecting circuit, an integrating circuit, a merging circuit and a comparing circuit. Therefore, the disclosure can reduce cost with the simple control.

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Beijing, China

Qihui Zhen