Cross-well formation resistivity measurement apparatus and method

Abstract

This invention provides a casing-based formation resistivity measurement device and method, belonging to the field of petroleum geophysical exploration. The device includes a main control module, a transmitting module, and a receiving module. The main control module is connected to both the transmitting and receiving modules. The receiving module includes multiple receiving units and a logic processing unit. Each receiving unit includes a receiving electrode, a selection circuit, and an acquisition circuit. The receiving electrodes of the multiple receiving units are spaced apart on the casing. The transmitting module generates an excitation electrical signal and a correction electrical signal based on preset signal parameter values ​​and sends them to each receiving unit. The receiving module acquires the actual signal parameter values ​​and correction signal parameter values ​​of each receiving unit. The main control module determines the formation resistivity at the location of each receiving electrode based on the preset signal parameter values, the actual signal parameter values ​​of each receiving unit, and the correction signal parameter values.

Description

Technical Field

[0001] This invention relates to the field of petroleum geophysical exploration technology, specifically to a casing-through formation resistivity measuring device and a casing-through formation resistivity measuring method. Background Technology

[0002] Many oilfield production wells have entered the mid-to-late stages of development after years of exploitation, requiring new assessments of formation resistivity and oil saturation in the casing section to determine development plans and improve production efficiency. Furthermore, due to various factors, open-hole formation resistivity measurements were not completed, and oil layer misjudgments and incorrect identifications caused by technical limitations, as well as re-evaluations of reservoirs with secondary oil and gas migration, measurements are also necessary in casing wells to obtain reservoir information. Traditional open-hole measurement instruments cannot meet this need; therefore, downhole measurement instruments capable of passing through the casing are required.

[0003] Currently, there are also tubular instruments on the market. These instruments require the electrodes to be tightly attached to the tubing when they are working, and the next point can only be measured after the current point is measured. This measurement method can only measure point by point and cannot perform continuous measurement, which is very inefficient. Summary of the Invention

[0004] To address the aforementioned technical deficiencies, this invention provides a casing-through formation resistivity measurement device and method. The casing-through formation resistivity measurement device transmits an excitation electrical signal to the casing and continuously measures the actual electrical signal flowing on the casing at each receiving electrode using multiple receiving electrodes spaced apart, thereby improving measurement efficiency. The formation resistivity at each receiving electrode is obtained based on the actual signal parameter value of the actual electrical signal corresponding to each receiving electrode, the parameter value of the correction electrical signal, and the parameter value of the preset signal, thereby improving the accuracy of the measurement results.

[0005] The first aspect of the present invention provides a casing-through formation resistivity measuring device, comprising: a main control module, a transmitting module and a receiving module, wherein the main control module is connected to the transmitting module and the receiving module respectively, and the receiving module includes multiple receiving units and a logic processing unit, wherein each receiving unit includes a receiving electrode, a selection circuit and an acquisition circuit, and the receiving electrodes of the multiple receiving units are spaced apart on the casing. The main control module is used to send parameter values ​​of a preset signal to the transmitting module; The transmitting module is used to receive parameter values ​​of a preset signal from the main control module, generate an excitation electrical signal and a correction electrical signal according to the parameter values ​​of the preset signal, send the excitation electrical signal to the ground, and send the correction signal to the selection circuit of each receiving unit. The receiving electrode is used to receive the excitation electrical signal flowing on the sleeve, and to obtain the actual electrical signal that the excitation electrical signal flows to the receiving electrode. The selection circuit is used to select whether to output the actual electrical signal or the correction electrical signal at the receiving electrode to the acquisition circuit. The acquisition circuit is used to convert the actual electrical signal or the correction electrical signal to obtain a digital signal of the actual electrical signal or the correction electrical signal, and output the digital signal to the logic processing unit to obtain the parameter value of the actual electrical signal or the parameter value of the correction electrical signal. The main control module is also used to determine the formation resistivity at the location of each receiving electrode on the casing based on the parameter values ​​of the preset signal, the parameter values ​​of the actual electrical signal of each receiving electrode, and the parameter values ​​of the corresponding correction electrical signal of each receiving electrode.

[0006] In this embodiment of the invention, the transmitting module includes: a transmitting electrode and a transmitting unit, wherein the transmitting unit is connected to the main control module and the transmitting electrode respectively; The transmitting unit is used to receive parameter values ​​of a preset signal from the main control module, generate an excitation electrical signal according to the parameter values ​​of the preset signal, and send the excitation electrical signal to the transmitting electrode; The transmitting electrode is used to send an excitation electrical signal to the sleeve.

[0007] In this embodiment of the invention, the transmitting unit includes: a first FPGA chip and a signal processing circuit; The input terminal of the first FPGA chip is connected to the main control module and is used to receive the parameter value of the preset signal and generate a sine wave signal according to the parameter value of the preset signal. The signal processing circuit is used to amplify and filter the sinusoidal signal to obtain an excitation electrical signal.

[0008] In this embodiment of the invention, the signal processing circuit includes: a boost sub-circuit, a linear phase-shift filter, and a power amplifier connected in sequence; The input terminal of the boost sub-circuit is connected to the output terminal of the first FPGA chip and is used to receive the sine wave signal. The boost sub-circuit is used to boost the sine wave signal to obtain an amplitude-amplified sine wave signal. The linear phase-shift filter is used to filter the amplified sine wave signal to obtain a filtered sine wave signal. The power amplifier is used to amplify the power of the filtered sine wave signal to obtain the excitation electrical signal.

[0009] In this embodiment of the invention, the selection circuit is used to select to receive the actual electrical signal from the receiving electrode or to receive the correction electrical signal from the transmitting module, and to amplify the received actual electrical signal or correction electrical signal to obtain the amplified actual electrical signal or correction electrical signal.

[0010] In this embodiment of the invention, the selection circuit includes: a relay, a first preamplifier circuit, a second preamplifier circuit, a two-to-one switch, and a programmable amplifier circuit; The relay is used to select whether to receive an actual electrical signal from the receiving electrode or a correction electrical signal from the transmitting module, and to select whether to transmit the actual electrical signal to a first preamplifier circuit or a second preamplifier circuit based on the signal strength value of the actual electrical signal, and to select whether to transmit the correction electrical signal to a first preamplifier circuit or a second preamplifier circuit based on the signal strength value of the correction electrical signal. The first preamplifier circuit is used to preamplify the actual electrical signal or the correction electrical signal according to the first amplification factor; The second preamplifier circuit is used to preamplify the actual electrical signal or the correction electrical signal according to the second amplification factor; The two-to-one switch is used to select whether the first preamplifier circuit and the programmable amplifier circuit are connected or the second preamplifier circuit and the programmable amplifier circuit are connected. The programmable amplifier circuit is used to programmatically amplify the actual electrical signal or correction electrical signal processed by the first preamplifier circuit, and to programmatically amplify the actual electrical signal or correction electrical signal processed by the second preamplifier circuit.

[0011] In this embodiment of the invention, the acquisition circuit is used to receive the actual electrical signal and the correction electrical signal output from the selection circuit, and to perform analog-to-digital conversion on the analog signals of the actual electrical signal and the correction electrical signal after processing by the selection circuit to obtain the digital signal of the actual electrical signal and the digital signal of the correction electrical signal.

[0012] In this embodiment of the invention, the acquisition circuit includes: a filter, an ADC driver, and a high-speed ADC chip; The filter is used to filter the actual electrical signal and the correction electrical signal after they have been processed by the selection circuit, so as to obtain the filtered actual electrical signal and the filtered correction electrical signal. The ADC driver is used to preprocess the filtered actual electrical signal and the correction electrical signal so that the filtered actual electrical signal and the correction electrical signal can safely enter the high-speed ADC chip. The high-speed ADC chip is used to perform analog-to-digital conversion on the actual electrical signal and the correction electrical signal after preprocessing by the ADC driver, so as to obtain the digital signal of the actual electrical signal and the digital signal of the correction electrical signal.

[0013] In this embodiment of the invention, the logic processing unit is a second FPGA chip; The second FPGA chip is connected to the acquisition circuit and is used to receive the digital signal of the actual electrical signal and the digital signal of the correction electrical signal from the acquisition circuit. It determines the actual signal parameters of the actual electrical signal based on the digital signal of the actual electrical signal and determines the scale signal parameters of the correction electrical signal based on the digital signal of the correction electrical signal.

[0014] In this embodiment of the invention, the main control module includes: a digital processing chip; The digital processing chip is connected to the transmitting module and the receiving module respectively, and is used to send the parameter value of the preset signal to the transmitting module, and to receive the parameter value of the actual electrical signal from each receiving electrode and the parameter value of the corresponding correction electrical signal of each receiving electrode. Based on the parameter values ​​of the preset signal, the parameter values ​​of the actual electrical signal of each receiving electrode, and the parameter values ​​of the corresponding correction electrical signal of each receiving electrode, the formation resistivity at the location of each receiving electrode is determined.

[0015] In this embodiment of the invention, the digital processing chip further includes a clock unit, which is connected to the transmitting module and the receiving module respectively, and is used to provide clock signals to the transmitting module and the receiving module respectively.

[0016] A second aspect of the present invention provides a method for measuring formation resistivity through a casing, the method being applied to the formation resistivity measuring device through a casing as described above, the method comprising: The parameter values ​​of the preset signal are transmitted from the main control module to the transmitting module; The transmitting module receives parameter values ​​of a preset signal from the main control module, generates an excitation electrical signal and a correction electrical signal based on the parameter values ​​of the preset signal, sends the excitation electrical signal to the ground, and sends the correction signal to the selection circuit of each receiving unit. The excitation electrical signal flowing on the sleeve is received by each receiving electrode to obtain the actual electrical signal at the receiving electrode. The selection circuit selects to output the actual electrical signal or the correction electrical signal at the receiving electrode to the acquisition circuit. The acquisition circuit converts the actual electrical signal or the correction electrical signal to obtain the digital signal of the actual electrical signal or the correction electrical signal. The digital signal is then output to the logic processing unit to obtain the parameter value of the actual electrical signal or the parameter value of the correction electrical signal. The main control module determines the formation resistivity at the location of each receiving electrode on the casing by using the preset signal parameter values, the actual electrical signal parameter values ​​of each receiving electrode, and the corresponding correction electrical signal parameter values ​​of each receiving electrode.

[0017] The casing-connected formation resistivity measuring device provided by this invention improves measurement efficiency by transmitting an excitation electrical signal to the casing and continuously measuring the actual electrical signal at each receiving electrode of the excitation electrical signal flowing on the casing through multiple receiving electrodes arranged at intervals on the casing. The formation resistivity at each receiving electrode is obtained based on the actual signal parameter value of the actual electrical signal corresponding to each receiving electrode, the parameter value of the correction electrical signal, and the parameter value of the preset signal, thereby improving the accuracy of the measurement results.

[0018] Other features and advantages of the technical solution of the present invention will be described in detail in the following detailed embodiments section. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure of the casing-through formation resistivity measuring device provided in an embodiment of the present invention; Figure 2 This is a structural block diagram of the transmitting module provided in an embodiment of the present invention; Figure 3 This is a structural block diagram of the first selection circuit provided in an embodiment of the present invention; Figure 4 This is a structural block diagram of the first acquisition circuit provided in an embodiment of the present invention; Figure 5 This is a flowchart of the method for measuring formation resistivity through casing provided in an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached figures 01-Main control module, 02-Transmitting circuit, 03-First receiving unit, 04-Second receiving unit, 05-Third receiving unit, T-Transmitting electrode, R1-First receiving electrode, R2-Second receiving electrode, B-Far electrode. Detailed Implementation

[0021] To make the technical solutions and advantages of the embodiments of the present invention clearer, the exemplary embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In this invention, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] In developing this invention, the inventors discovered that many oilfield production wells, after years of exploitation, have entered the mid-to-late stages, requiring new assessments of formation resistivity and oil saturation in the casing section to determine development plans and improve production efficiency. Furthermore, due to various factors, open-hole formation resistivity measurements have not been completed, and oil layer misjudgments and re-evaluations of reservoirs with secondary oil and gas migration caused by technical limitations also necessitate measurements in casing wells to obtain reservoir information. Traditional open-hole measurement instruments cannot meet this need; therefore, downhole measurement instruments capable of passing through the casing are required.

[0026] Currently, there are also tubular instruments on the market. These instruments require the electrodes to be tightly attached to the tubing when they are working, and the next point can only be measured after the current point is measured. This measurement method can only measure point by point and cannot perform continuous measurement, which is very inefficient.

[0027] To address the aforementioned problems, this invention provides a casing-through formation resistivity measurement device, comprising: a main control module, a transmitting module, and a receiving module. The main control module is connected to both the transmitting and receiving modules. The receiving module includes multiple receiving units and a logic processing unit. Each receiving unit includes a receiving electrode, a selection circuit, and a data acquisition circuit. The receiving electrodes of the multiple receiving units are spaced apart on the casing. The main control module is used to send parameter values ​​of a preset signal to the transmitting module. The transmitting module is used to receive the parameter values ​​of the preset signal from the main control module, generate an excitation electrical signal and a correction electrical signal based on the parameter values ​​of the preset signal, send the excitation electrical signal to the formation, and send the correction signal to the selection circuit of each receiving unit. The receiving electrode is used to receive the excitation electrical signal flowing on the casing, and obtain the actual electrical signal at the receiving electrode. The selection circuit is used to select to output the actual electrical signal or the correction electrical signal at the receiving electrode to the acquisition circuit. The acquisition circuit is used to convert the actual electrical signal or the correction electrical signal to obtain the digital signal of the actual electrical signal or the correction electrical signal, and output the digital signal to the logic processing unit to obtain the parameter value of the actual electrical signal or the parameter value of the correction electrical signal. The main control module is also used to determine the formation resistivity at the location of each receiving electrode on the casing according to the parameter value of the preset signal, the parameter value of the actual electrical signal of each receiving electrode, and the parameter value of the corresponding correction electrical signal of each receiving electrode. The casing-connected formation resistivity measuring device provided by the present invention transmits an excitation electrical signal to the formation and continuously measures the actual electrical signal at each receiving electrode of the excitation electrical signal flowing on the casing through multiple receiving electrodes arranged at intervals, thereby improving the measurement efficiency. The formation resistivity at each receiving electrode is obtained based on the actual signal parameter value of the actual electrical signal corresponding to each receiving electrode, the parameter value of the correction electrical signal, and the parameter value of the preset signal, thereby improving the accuracy of the measurement results.

[0028] Figure 1 This is a schematic diagram of the structure of the casing-through formation resistivity measuring device provided in an embodiment of the present invention. Figure 2 This is a structural block diagram of the transmitting module provided in an embodiment of the present invention. Figure 3 This is a structural block diagram of the first selection circuit provided in an embodiment of the present invention. Figure 4 This is a structural block diagram of the first acquisition circuit provided in an embodiment of the present invention. Figure 1-4As shown in this embodiment, a casing-through formation resistivity measurement device includes: a main control module 01, a transmitting module, and a receiving module. The main control module 01 is connected to both the transmitting module and the receiving module. The transmitting module includes a transmitting electrode T and a transmitting unit, each of which includes a first FPGA chip and a signal processing circuit. The receiving module includes multiple receiving units and a second FPGA chip. Each receiving unit includes a receiving electrode, a selection circuit, and a data acquisition circuit. The main control module 01 includes a digital processing chip. Multiple receiving electrodes are spaced apart on the casing. Each receiving electrode receives an excitation electrical signal flowing on the casing, obtaining the actual electrical signal at the receiving electrode. The main control module 01 sends parameter values ​​of a preset signal to the transmitting module; specifically, the main control module 01 sends parameter values ​​of a preset signal to the first FPGA chip. The transmitting module receives parameter values ​​of a preset signal from the main control module 01, generates an excitation electrical signal and a correction electrical signal based on the parameter values ​​of the preset signal, and transmits the excitation electrical signal to the formation. The excitation electrical signal flows through the casing via the mud. It also sends correction electrical signals to the selection circuits of multiple receiving units. Specifically, the first FPGA chip generates a sine wave signal based on the parameter values ​​of the preset signal. The signal processing circuit amplifies and filters the sine wave signal generated by the first FPGA chip to obtain an amplified and filtered sine wave signal. The amplified and filtered sine wave signal with the same preset parameter values ​​is transmitted as an excitation electrical signal to the transmitting electrode T and sent as a calibration signal to each receiving unit. The transmitting electrode T is mounted on the casing and transmits the excitation electrical signal to the casing. The receiving electrode is used to receive the excitation electrical signal flowing on the casing, obtaining the actual electrical signal at the receiving electrode. The selection circuit is used to select whether to output the actual electrical signal or the correction electrical signal at the receiving electrode to the acquisition circuit. The acquisition circuit is used to convert the actual electrical signal or the correction electrical signal to obtain a digital signal, and output the digital signal to the logic processing unit to obtain the parameter value of the actual electrical signal or the parameter value of the correction electrical signal. The main control module 01 is also used to determine the formation resistivity at the location of each receiving electrode on the casing based on the parameter value of the preset signal, the parameter value of the actual electrical signal of each receiving electrode, and the parameter value of the corresponding correction electrical signal of each receiving electrode.

[0029] Furthermore, such as Figure 1As shown, in this embodiment, the receiving module includes three receiving units: a first receiving unit 03, a second receiving unit 04, and a third receiving unit 05. The first receiving unit 03 includes a first receiving electrode R1, a first selection circuit, and a first acquisition circuit. The second receiving unit 04 includes a second receiving electrode R2, a second selection circuit, and a second acquisition circuit. The third receiving unit 05 includes a far electrode B, a third selection circuit, and a third acquisition circuit. The far electrode B, along with the transmitting electrode T, the first receiving electrode R1, the second receiving electrode R2, and the far electrode B, forms a loop.

[0030] The excitation electrical signal is emitted by the transmitting electrode T onto the sleeve, flows and attenuates on the sleeve, and the actual electrical signal of the excitation electrical signal reaching the first receiving electrode R1 is the first actual electrical signal, the actual electrical signal of the excitation electrical signal reaching the second receiving electrode R2 is the second actual electrical signal, and the actual electrical signal of the excitation electrical signal reaching the far electrode B is the third actual electrical signal.

[0031] The transmitting circuit 02 transmits a correction electrical signal to the formation. The correction electrical signal propagates in the formation and is received by the first selection circuit as the first correction electrical signal, the second selection circuit as the second correction electrical signal, and the third selection circuit as the third correction electrical signal.

[0032] The first selection circuit corresponds to the location of the first receiving electrode R1 in the formation, and the transmitting circuit 02 corresponds to the location of the transmitting electrode T in the formation. The correction signal attenuates as it flows from the transmitting circuit 02 to the first selection circuit, becoming the first correction signal, with the attenuation value being the first attenuation value. This first attenuation value is considered the standard attenuation caused by objective factors when the excitation signal travels from the transmitting electrode T to the first receiving electrode R1. These objective factors include attenuation due to component factors, conductor factors, and environmental factors. When calculating the formation resistivity at the first receiving electrode R1, the first correction signal arriving at the first selection circuit is collected, and the first attenuation value is obtained based on the parameter values ​​of the first correction signal. By calculating the difference between the first actual signal parameter value of the first actual signal and the parameter value of the preset signal, and then subtracting the first attenuation value, the formation resistivity at the first receiving electrode R1 can be obtained.

[0033] In this embodiment, the signal parameter values ​​include amplitude information and phase information.

[0034] Similarly, the second selection circuit corresponds to the location of the second receiving electrode R2 in the formation, and the transmitting circuit 02 corresponds to the location of the transmitting electrode T in the formation. The correction signal attenuates as it flows from the transmitting circuit 02 to the second selection circuit, becoming the second correction signal, with this attenuation value being the second attenuation value. This second attenuation value is considered the standard attenuation caused by objective factors when the excitation signal travels from the transmitting electrode T to the second receiving electrode R2. These objective factors include attenuation due to component factors, conductor factors, and environmental factors. When calculating the formation resistivity at the second receiving electrode R2, the second correction signal arriving at the second selection circuit is collected, and the second attenuation value is obtained based on the parameter values ​​of the second correction signal. By calculating the difference between the second actual signal parameter value of the second actual signal and the parameter value of the preset signal, and then subtracting the second attenuation value, the formation resistivity at the second receiving electrode R2 can be obtained.

[0035] The third selection circuit corresponds to the location of the distal electrode B in the formation, and the transmitting circuit 02 corresponds to the location of the transmitting electrode T in the formation. The correction signal attenuates as it flows from the transmitting circuit 02 to the third selection circuit, becoming the third correction signal, with the attenuation value being the third attenuation value. This third attenuation value is considered the standard attenuation caused by objective factors when the excitation signal travels from the transmitting electrode T to the distal electrode B. These objective factors include attenuation due to component factors, conductor factors, and environmental factors. When calculating the formation resistivity at the distal electrode B, the third correction signal arriving at the third selection circuit is collected, and the third attenuation value is obtained based on the parameter values ​​of the third correction signal. By calculating the difference between the parameter values ​​of the third actual signal and the parameter values ​​of the preset signal, and then subtracting the third attenuation value, the formation resistivity at the distal electrode B can be obtained.

[0036] In this embodiment, the excitation signal emitted by the transmitting electrode T is a 5-100KHz sine wave with a maximum amplitude of 10V and a maximum transmitting current of 2A; the amplitude and frequency of the transmitted signal are adjustable.

[0037] In this embodiment, the transmitting unit is connected to the main control module 01 and the transmitting electrode T respectively; the transmitting unit is used to receive the parameter value of the preset signal from the main control module 01, generate an excitation electrical signal according to the parameter value of the preset signal, and send the excitation electrical signal to the transmitting electrode T; the transmitting electrode T is used to send the excitation electrical signal to the sleeve.

[0038] Specifically, the input terminal of the first FPGA chip is connected to the main control module 01, and is used to receive the parameter value of the preset signal, and generate a sine wave signal according to the parameter value of the preset signal; the signal processing circuit is used to amplify and filter the sine wave signal to obtain an excitation electrical signal. More specifically, the input terminal of the first FPGA chip is a synchronization signal interface, and the first FPGA chip is connected to the main control module 01 through the synchronization signal interface.

[0039] Figure 2 This is a structural block diagram of the transmitting module provided in an embodiment of the present invention, such as... Figure 2 As shown, in this embodiment, the signal processing circuit includes: a boost sub-circuit, a linear phase-shift filter, and a power amplifier connected in sequence; the input terminal of the boost sub-circuit is connected to the output terminal of the first FPGA chip, and is used to receive the sine wave signal; the boost sub-circuit is used to boost the sine wave signal to obtain an amplitude-amplified sine wave signal; the linear phase-shift filter is used to filter the amplitude-amplified sine wave signal to obtain a filtered sine wave signal; the power amplifier is used to amplify the power of the filtered sine wave signal to obtain an excitation electrical signal.

[0040] The transmitting unit generates excitation and correction electrical signals based on preset signal parameter values. The frequency ranges from 5K to 100KHz, the amplitude from 0 to 10V, and the maximum current is 2A; all parameters are adjustable. The transmitting module uses an algorithm generated by the first FPGA chip to produce an adjustable-frequency sine wave. After passing through a boost circuit, the amplitude reaches + / -10V. The signal quality is then enhanced by a linear phase-shift filter before being input to a power amplifier to ensure the required transmission current, thereby increasing the transmission power and completing the signal output.

[0041] The first selection circuit is used to select to receive a first actual electrical signal from the first receiving electrode R1 or to receive a first correction electrical signal from the transmitting module, and to amplify the received first actual electrical signal or first correction electrical signal to obtain an amplified first actual electrical signal or first correction electrical signal.

[0042] Figure 3 This is a structural block diagram of the first selection circuit provided in an embodiment of the present invention, such as... Figure 3As shown, specifically, the first selection circuit includes: a relay, a first preamplifier circuit, a second preamplifier circuit, a two-to-one switch, and a programmable amplifier circuit; the relay is used to select whether to receive a first actual electrical signal from the first receiving electrode R1 or a first correction electrical signal from the transmitting module, and to select whether to transmit the actual electrical signal to the first preamplifier circuit or the second preamplifier circuit based on the signal strength value of the first actual electrical signal, and to select whether to transmit the correction electrical signal to the first preamplifier circuit or the second preamplifier circuit based on the signal strength value of the first correction electrical signal; the first preamplifier circuit... The first preamplifier circuit is used to preamplify the first actual electrical signal or the first corrected electrical signal according to a first amplification factor; the second preamplifier circuit is used to preamplify the first actual electrical signal or the first corrected electrical signal according to a second amplification factor; the two-to-one switch is used to select whether to connect the first preamplifier circuit and the programmable amplifier circuit or the second preamplifier circuit and the programmable amplifier circuit; the programmable amplifier circuit is used to programmably amplify the first actual electrical signal or the first corrected electrical signal processed by the first preamplifier circuit, and to programmably amplify the first actual electrical signal or the first corrected electrical signal processed by the second preamplifier circuit.

[0043] exist Figure 3 In this circuit, the relay includes S1 and S2, and the two-to-one switch is S3.

[0044] In this embodiment, the first acquisition circuit is used to receive a first actual electrical signal and a first correction electrical signal output from the first selection circuit, and to perform analog-to-digital conversion on the analog signals of the first actual electrical signal and the first correction electrical signal after processing by the first selection circuit to obtain digital signals of the first actual electrical signal and the first correction electrical signal.

[0045] Figure 4 This is a structural block diagram of the first acquisition circuit provided in an embodiment of the present invention, as shown below. Figure 4 As shown, specifically, the first acquisition circuit includes: a filter, an ADC driver, and a high-speed ADC chip; The filter is used to filter the first actual electrical signal and the first correction electrical signal after being processed by the first selection circuit, so as to obtain the first actual electrical signal and the first correction electrical signal after filtering. The ADC driver is used to preprocess the filtered first actual electrical signal and the first correction electrical signal so that the filtered first actual electrical signal and the first correction electrical signal can safely enter the high-speed ADC chip. The high-speed ADC chip is used to perform analog-to-digital conversion on the first actual electrical signal and the first correction electrical signal after preprocessing by the ADC driver, so as to obtain the digital signal of the first actual electrical signal and the digital signal of the first correction electrical signal.

[0046] The second FPGA chip is connected to the first acquisition circuit and is used to receive the digital signal of the first actual electrical signal and the digital signal of the first correction electrical signal from the first acquisition circuit. It determines the actual signal parameter value of the first actual electrical signal based on the digital signal of the first actual electrical signal and determines the parameter value of the first correction electrical signal based on the digital signal of the first correction electrical signal.

[0047] The second FPGA chip is connected to the second acquisition circuit and is used to receive the digital signal of the second actual electrical signal and the digital signal of the second correction electrical signal from the second acquisition circuit. It determines the actual signal parameter value of the second actual electrical signal based on the digital signal of the second actual electrical signal and determines the parameter value of the second correction electrical signal based on the digital signal of the second correction electrical signal.

[0048] The second FPGA chip is connected to the third acquisition circuit and is used to receive the digital signal of the third actual electrical signal and the digital signal of the third correction electrical signal from the third acquisition circuit. It determines the actual signal parameter value of the third actual electrical signal based on the digital signal of the third actual electrical signal and determines the parameter value of the third correction electrical signal based on the digital signal of the third correction electrical signal.

[0049] The digital processing chip is connected to the transmitting module and the receiving module respectively, and is used to send the parameter value of the preset signal to the transmitting module, and to receive the parameter value of the actual electrical signal from each receiving electrode and the parameter value of the corresponding correction electrical signal of each receiving electrode. Based on the parameter values ​​of the preset signal, the parameter values ​​of the actual electrical signal of each receiving electrode, and the parameter values ​​of the corresponding correction electrical signal of each receiving electrode, the formation resistivity at the location of each receiving electrode is determined. Specifically, the digital processing chip is connected to the second FPGA chip and is used to send the parameter values ​​of the preset signal to the transmitting module, and to receive the parameter values ​​of the actual signal from each receiving electrode and the parameter values ​​of the correction electrical signal from each receiving unit; based on the parameter values ​​of the preset signal, the parameter values ​​of the actual signal from each receiving electrode, and the parameter values ​​of the correction electrical signal from each receiving unit, the formation resistivity at the location of each receiving electrode is determined.

[0050] In this embodiment, the digital processing chip further includes a clock unit, which is connected to both the transmitting module and the receiving module, and is used to provide clock signals to both the transmitting module and the receiving module.

[0051] In this embodiment, the digital processing chip further includes a system synchronization unit, which is used to synchronize the transmitting module and the receiving module to ensure the accuracy of each sampling.

[0052] Figure 5 This is a flowchart of a method for measuring formation resistivity through a casing, provided in an embodiment of the present invention. Figure 5 As shown, this embodiment provides a method for measuring formation resistivity through a casing. The method is applied to the casing-based formation resistivity measuring device described above, and includes: S1. The parameter values ​​of the preset signal are transmitted from the main control module 01 to the transmitting module; S2. Receive parameter values ​​of a preset signal from the main control module 01 through the transmitting module, generate an excitation electrical signal and a correction electrical signal according to the parameter values ​​of the preset signal, send the excitation electrical signal to the ground, and send the correction signal to the selection circuit of each receiving unit. S3. The excitation electrical signal flowing on the sleeve is received through each receiving electrode to obtain the actual electrical signal at the receiving electrode. The actual electrical signal or the correction electrical signal at the receiving electrode is selected and output to the acquisition circuit through the selection circuit. The actual electrical signal or the correction electrical signal is converted and processed by the acquisition circuit to obtain the digital signal of the actual electrical signal or the correction electrical signal. The digital signal is output to the logic processing unit to obtain the parameter value of the actual electrical signal or the parameter value of the correction electrical signal. S4. The main control module 01 confirms the formation resistivity at the location of each receiving electrode on the casing based on the parameter values ​​of the preset signal, the parameter values ​​of the actual electrical signal of each receiving electrode, and the parameter values ​​of the corresponding correction electrical signal of each receiving electrode.

[0053] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0054] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0055] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details described above. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention. Furthermore, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. As long as such combination does not violate the spirit of the embodiments of the present invention, it should also be considered as the content disclosed by the embodiments of the present invention.

Claims

1. A casing-through formation resistivity measuring device, characterized in that, include: The system includes a main control module, a transmitting module, and a receiving module. The main control module is connected to the transmitting module and the receiving module respectively. The receiving module includes multiple receiving units and a logic processing unit. Each receiving unit includes a receiving electrode, a selection circuit, and a data acquisition circuit. The receiving electrodes of the multiple receiving units are spaced apart on the sleeve. The main control module is used to send parameter values ​​of a preset signal to the transmitting module; The transmitting module is used to receive parameter values ​​of a preset signal from the main control module, generate an excitation electrical signal and a correction electrical signal according to the parameter values ​​of the preset signal, send the excitation electrical signal to the ground, and send the correction signal to the selection circuit of each receiving unit. The receiving electrode is used to receive the excitation electrical signal flowing on the sleeve, and to obtain the actual electrical signal that the excitation electrical signal flows to the receiving electrode. The selection circuit is used to select whether to output the actual electrical signal or the correction electrical signal at the receiving electrode to the acquisition circuit. The acquisition circuit is used to convert the actual electrical signal or the correction electrical signal to obtain a digital signal of the actual electrical signal or the correction electrical signal, and output the digital signal to the logic processing unit to obtain the parameter value of the actual electrical signal or the parameter value of the correction electrical signal. The main control module is also used to determine the formation resistivity at the location of each receiving electrode on the casing based on the parameter values ​​of the preset signal, the parameter values ​​of the actual electrical signal of each receiving electrode, and the parameter values ​​of the corresponding correction electrical signal of each receiving electrode.

2. The casing-through formation resistivity measuring device according to claim 1, characterized in that, The transmitting module includes: a transmitting electrode and a transmitting unit, wherein the transmitting unit is connected to the main control module and the transmitting electrode respectively; The transmitting unit is used to receive parameter values ​​of a preset signal from the main control module, generate an excitation electrical signal according to the parameter values ​​of the preset signal, and send the excitation electrical signal to the transmitting electrode; The transmitting electrode is used to send an excitation electrical signal to the sleeve.

3. The casing-through formation resistivity measuring device according to claim 2, characterized in that, The transmitting unit includes: a first FPGA chip and a signal processing circuit; The input terminal of the first FPGA chip is connected to the main control module and is used to receive the parameter value of the preset signal and generate a sine wave signal according to the parameter value of the preset signal. The signal processing circuit is used to amplify and filter the sine wave signal, and the amplified and filtered sine wave signal is used as the excitation electrical signal.

4. The casing-through formation resistivity measuring device according to claim 3, characterized in that, The signal processing circuit includes: a boost sub-circuit, a linear phase-shift filter, and a power amplifier connected in sequence; The input terminal of the boost sub-circuit is connected to the output terminal of the first FPGA chip and is used to receive the sine wave signal. The boost sub-circuit is used to boost the sine wave signal to obtain an amplitude-amplified sine wave signal. The linear phase-shift filter is used to filter the amplified sine wave signal to obtain a filtered sine wave signal. The power amplifier is used to amplify the power of the filtered sine wave signal to obtain the excitation electrical signal.

5. The casing-through formation resistivity measuring device according to claim 1, characterized in that, The selection circuit is used to select to receive the actual electrical signal from the receiving electrode or to receive the correction electrical signal from the transmitting module, and to amplify the received actual electrical signal or correction electrical signal to obtain the amplified actual electrical signal or correction electrical signal.

6. The casing-through formation resistivity measuring device according to claim 5, characterized in that, The selection circuit includes: a relay, a first preamplifier circuit, a second preamplifier circuit, a two-to-one switch, and a programmable amplifier circuit; The relay is used to select whether to receive an actual electrical signal from the receiving electrode or a correction electrical signal from the transmitting module, and to select whether to transmit the actual electrical signal to a first preamplifier circuit or a second preamplifier circuit based on the signal strength value of the actual electrical signal, and to select whether to transmit the correction electrical signal to a first preamplifier circuit or a second preamplifier circuit based on the signal strength value of the correction electrical signal. The first preamplifier circuit is used to preamplify the actual electrical signal or the correction electrical signal according to the first amplification factor; The second preamplifier circuit is used to preamplify the actual electrical signal or the correction electrical signal according to the second amplification factor; The two-to-one switch is used to select whether the first preamplifier circuit and the programmable amplifier circuit are connected or the second preamplifier circuit and the programmable amplifier circuit are connected. The programmable amplifier circuit is used to programmatically amplify the actual electrical signal or correction electrical signal processed by the first preamplifier circuit, and to programmatically amplify the actual electrical signal or correction electrical signal processed by the second preamplifier circuit.

7. The casing-through formation resistivity measuring device according to claim 5, characterized in that, The acquisition circuit is used to receive the actual electrical signal and the correction electrical signal output from the selection circuit, and to perform analog-to-digital conversion on the analog signals of the actual electrical signal and the correction electrical signal after processing by the selection circuit to obtain the digital signal of the actual electrical signal and the digital signal of the correction electrical signal.

8. The casing-through formation resistivity measuring device according to claim 7, characterized in that, The acquisition circuit includes: a filter, an ADC driver, and a high-speed ADC chip; The filter is used to filter the actual electrical signal and the correction electrical signal after they have been processed by the selection circuit, so as to obtain the filtered actual electrical signal and the filtered correction electrical signal. The ADC driver is used to preprocess the filtered actual electrical signal and the correction electrical signal so that the filtered actual electrical signal and the correction electrical signal can safely enter the high-speed ADC chip. The high-speed ADC chip is used to perform analog-to-digital conversion on the actual electrical signal and the correction electrical signal after preprocessing by the ADC driver, so as to obtain the digital signal of the actual electrical signal and the digital signal of the correction electrical signal.

9. The casing-through formation resistivity measuring device according to claim 7, characterized in that, The logic processing unit is a second FPGA chip; The second FPGA chip is connected to the acquisition circuit and is used to receive the digital signal of the actual electrical signal and the digital signal of the correction electrical signal from the acquisition circuit, determine the actual signal parameter value of the actual electrical signal based on the digital signal of the actual electrical signal, and determine the parameter value of the correction electrical signal based on the digital signal of the correction electrical signal.

10. The casing-through formation resistivity measuring device according to claim 1, characterized in that, The main control module includes: a digital processing chip; The digital processing chip is connected to the transmitting module and the receiving module respectively, and is used to send the parameter value of the preset signal to the transmitting module, and to receive the parameter value of the actual electrical signal from each receiving electrode and the parameter value of the corresponding correction electrical signal of each receiving electrode. Based on the parameter values ​​of the preset signal, the parameter values ​​of the actual electrical signal of each receiving electrode, and the parameter values ​​of the corresponding correction electrical signal of each receiving electrode, the formation resistivity at the location of each receiving electrode is determined.

11. The casing-through formation resistivity measuring device according to claim 10, characterized in that, The digital processing chip further includes a clock unit, which is connected to both the transmitting module and the receiving module, and is used to provide clock signals to both the transmitting module and the receiving module.

12. A method for measuring formation resistivity through a casing, the method being applied to the formation resistivity measuring device through a casing as described in any one of claims 1-11, characterized in that, The method includes: The parameter values ​​of the preset signal are transmitted from the main control module to the transmitting module; The transmitting module receives parameter values ​​of a preset signal from the main control module, generates an excitation electrical signal and a correction electrical signal based on the parameter values ​​of the preset signal, sends the excitation electrical signal to the ground, and sends the correction signal to the selection circuit of each receiving unit. The excitation electrical signal flowing on the sleeve is received by each receiving electrode to obtain the actual electrical signal at the receiving electrode. The selection circuit selects to output the actual electrical signal or the correction electrical signal at the receiving electrode to the acquisition circuit. The acquisition circuit converts the actual electrical signal or the correction electrical signal to obtain the digital signal of the actual electrical signal or the correction electrical signal. The digital signal is then output to the logic processing unit to obtain the parameter value of the actual electrical signal or the parameter value of the correction electrical signal. The main control module determines the formation resistivity at the location of each receiving electrode on the casing by using the preset signal parameter values, the actual electrical signal parameter values ​​of each receiving electrode, and the corresponding correction electrical signal parameter values ​​of each receiving electrode.

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