WO2021073421A1 - 一种隐伏资源预测方法及岩石电磁学测井系统 - Google Patents

一种隐伏资源预测方法及岩石电磁学测井系统 Download PDF

Info

Publication number
WO2021073421A1
WO2021073421A1 PCT/CN2020/118634 CN2020118634W WO2021073421A1 WO 2021073421 A1 WO2021073421 A1 WO 2021073421A1 CN 2020118634 W CN2020118634 W CN 2020118634W WO 2021073421 A1 WO2021073421 A1 WO 2021073421A1
Authority
WO
WIPO (PCT)
Prior art keywords
electromagnetic
rock
electrode
resistivity
complex impedance
Prior art date
Application number
PCT/CN2020/118634
Other languages
English (en)
French (fr)
Inventor
何兰芳
Original Assignee
中国科学院地质与地球物理研究所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 中国科学院地质与地球物理研究所 filed Critical 中国科学院地质与地球物理研究所
Publication of WO2021073421A1 publication Critical patent/WO2021073421A1/zh
Priority to US17/716,426 priority Critical patent/US20220299671A1/en

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/18—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/18—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging
    • G01V3/30—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging operating with electromagnetic waves

Definitions

  • the invention belongs to the technical field of mineral resource exploration, and relates to mineral (oil and gas) logging and prospecting, in particular to a concealed resource prediction method for stratum attribute recognition and resource prediction, and a rock electromagnetic logging system used in the resource prediction method.
  • Drilling is one of the most direct methods to obtain underground formation information, and it is also the most important exploration method to verify and discover hidden minerals (oil and gas) resources.
  • Logging also known as geophysical logging
  • geophysical logging is a method of measuring geophysical parameters by using geophysical properties such as electrochemical properties, electrical conductivity, acoustic properties, and radioactivity of rock formations.
  • Commonly used logging methods are resistivity logging, electromagnetic induction logging and electromagnetic wave propagation logging.
  • Resistivity logging is to use a specific device to emit and receive a DC electric field in the well to obtain the electrical parameters of the formation.
  • the commonly used output parameter is the formation resistivity, which is easily affected by drilling fluids and well tools.
  • Electromagnetic induction logging is the use of electromagnetic induction to establish an electric field in the formation to measure the electrical conductivity of the formation.
  • array induction logging is also extended. The measurement principle is similar to that of ordinary electromagnetic induction logging tools, but the coil The number has increased significantly.
  • Electromagnetic wave propagation logging also known as ultra-high frequency dielectric logging, is to distinguish between oil and water layers by measuring the parameters closely related to the formation dielectric constant (electromagnetic wave propagation time and electromagnetic wave attenuation rate) to determine the water in the formation A method of logging content. Because electromagnetic induction logging and electromagnetic wave propagation logging receive the secondary field generated by electromagnetic induction, the excitation electromagnetic field not only requires a high frequency (25000 Hz-1G Hz), but also the maximum penetration depth is very small, only 10 to tens of centimeters.
  • the purpose of the present invention is to solve the problem of poor prediction effect of hidden minerals (metals, oil and gas, etc.) resources caused by the traditional resistivity logging technology due to the single output parameter, narrow frequency range, poor recognition ability of complex environment, and shallow penetration depth.
  • a resource prediction method is provided, which uses broadband emission electromagnetic waves (especially including lower frequency emission electromagnetic waves) to perform complex impedance measurement and analysis in mining areas, so as to improve the success rate of resource prediction in mining areas.
  • the present invention adopts the following technical solutions to achieve it.
  • the method for predicting hidden resources includes the following steps:
  • A2 Feature factor extraction According to the results of complex impedance measurement, extract resistivity and phase information of different set frequencies of the ore body or oil and gas reservoir and the surrounding rock sample in the exploration area, and then obtain the ore body or oil and gas reservoir and the surrounding rock sample in the same frequency band The impedance phase difference or resistivity ratio of multiple set frequencies, and the obtained impedance phase difference or resistivity ratio is used as the electromagnetic characteristic factor;
  • A3 Resource prediction According to the acquired electromagnetic characteristic factors, according to the set standards, predict the hidden resources in the detection area.
  • the detection area is an area that needs to predict ore-bearing, water-bearing or oil and gas resources.
  • step A1 the purpose of step A1 is to realize the complex impedance measurement under different set frequencies of the wellbore or roadway in the exploration area, and the ore body or oil and gas reservoir and surrounding rock samples obtained from the wellbore or roadway in the exploration area can be measured.
  • Complex impedance measurement can be achieved by performing complex impedance logging in the well along the borehole or roadway.
  • the setting frequency range is 0.001 ⁇ 10000Hz. In a preferred implementation manner, the set frequency range is 0.001 to 0.01 Hz.
  • Electromagnetic waves in this frequency range have a greater penetration depth than mid-to-high frequency (frequency greater than 0.01Hz) electromagnetic waves, and can detect a wider range of information around the borehole.
  • the rock electromagnetic measurement system used When measuring the complex impedance of the sample, the rock electromagnetic measurement system used includes a container containing a medium solution and an impedance analyzer set at both ends of the core sample.
  • the contact position between the core sample and the container is provided with conductive glue, and
  • the electrode connected to the impedance analyzer and the reference electrode are inserted into the medium solution;
  • the applied frequency range of the impedance analyzer is 0.001-10000 Hz; in a preferred implementation manner, the applied frequency range of the impedance analyzer is 0.001-0.01 Hz.
  • the impedance analyzer can directly measure the complex impedance.
  • the medium solution is copper sulfate or silver chloride solution, and the corresponding electrode is copper or silver.
  • the reference electrode is a non-polarized reference electrode, such as a silver-silver chloride electrode, which uses a disclosed electrode.
  • the rock electromagnetism measurement system provided by the present invention isolates the two through the conductive glue arranged between the medium solution (or colloid) and the core sample, which can overcome the influence brought by the low-frequency polarization reaction, and can realize the low frequency Circumstances measure the complex impedance of the core sample, so that the complex impedance measurement can be effectively expanded from the intermediate frequency (0.01-100 Hz) to the wide frequency band (0.001 to 10000 Hz), especially the low frequency.
  • the rock electromagnetic logging system used is similar to the DC resistivity logging device, which can be done in two ways to realise:
  • the rock electromagnetic logging system includes a transmitting-receiving device placed on the ground and an electrode device placed in the well; the electrode device includes a transmitting electrode and a receiving electrode, and the transmitting electrode is transmitted through a transmission line and the transmitting-receiving device.
  • the receiving electrode is connected to the receiving end of the signal transmitting-receiving device through a transmission line; the transmitting-receiving device transmits electromagnetic waves with a frequency range of 0.001 to 10000 Hz into the logging through the transmitting electrode, and the transmitting-receiving device measures through the receiving electrode Obtain the complex impedance at the location of the electrode device in the logging.
  • the frequency range of the transmitting-receiving device transmitting electromagnetic waves into the logging through the transmitting electrode is 0.001-0.01 Hz.
  • the rock electromagnetic logging system includes a transmitting device placed on the ground and a receiving device and an electrode device placed in the well; the electrode device includes a transmitting electrode and a receiving electrode, and the transmitting electrode is connected to the transmitting end of the transmitting device through a transmission line Connect, the receiving electrode is connected to the receiving end of the receiving device through a transmission line; the transmitting device transmits electromagnetic waves in the logging frequency range from 0.001 to 10000 Hz through the transmitting electrode, and the receiving device obtains the location of the electrode device in the logging through the receiving electrode.
  • the complex impedance In a preferred implementation manner, the frequency range of the signal transmitting device to emit electromagnetic waves into the logging through the transmitting electrode is 0.001 to 0.01 Hz.
  • the transmitting part of the transmitting-receiving device in the first implementation mode or the transmitting device in the second implementation mode can use a signal generator or other devices with electromagnetic wave transmitting function to transmit broadband electromagnetic wave signals with different set frequencies to the underground. Record the emission current.
  • the receiving part of the transmitting-receiving device in the first implementation manner or the receiving device in the second implementation manner may adopt a magnetotelluric signal acquisition device, and the AC voltage of the receiving electrode can be measured and recorded on the ground or in the well. Then according to the recorded emission current and AC voltage, the complex impedance is calculated by Ohm's law.
  • step A2 the purpose of step A2 is to first extract the electromagnetic characteristic factors based on the results of the complex impedance measurement, mainly to extract the resistivity and phase information of the target layer in the detection area at different set frequencies, and then according to the target layer Phase information, calculated to obtain the detection area in the same frequency band (such as low frequency band (0.001-0.01Hz), medium frequency band (0.01-100Hz) or high frequency band (100-10000Hz)) in multiple set frequency phase difference or resistivity ( Or impedance mode) ratio, and the obtained impedance phase difference or resistivity ratio of the detection area in the same frequency band is used as the electromagnetic characteristic factor; in order to facilitate comparison with the set standard, multiple impedance phase differences or resistivity ratios can also be selected The average value of is used as the electromagnetic characteristic factor.
  • the electromagnetic characteristic factor such as low frequency band (0.001-0.01Hz), medium frequency band (0.01-100Hz) or high frequency band (100-10000Hz)
  • Or impedance mode Or impedance mode
  • the average value of is used as the electromagnetic characteristic
  • the resistivity and phase of different set frequencies are used as electromagnetic characteristic factors. Because different types of ore bodies and surrounding rocks have different frequency dispersion effects, the impedance phase difference or resistivity ratio of the ore bodies or oil and gas reservoirs in the exploration area and the surrounding rocks in the same frequency band can reflect the ore-bearing or oil and gas reservoirs of the resources. Then predict whether the exploration area contains minerals (or oil and gas).
  • step A3 the purpose of step A3 is to predict the resource situation of the detection area based on electromagnetic characteristic factors.
  • the relevant standards can be set based on empirical measurement data. Then the electromagnetic characteristic factors are compared with the set standards to predict the ore (or oil and gas).
  • the present invention further provides another concealed resource prediction method, including the following steps:
  • B2 Feature factor extraction and model construction Based on the results of complex impedance measurement, extract resistivity and phase information at different set frequencies, and use resistivity and phase as electromagnetic feature factors; then obtain the results based on electromagnetic characteristics and rock geochemical analysis The correlation relationship of the geochemical characteristics of, obtain the geochemical characteristic factors at different set frequencies, and further establish the resistivity-phase-rock attribute model based on the obtained electromagnetic characteristic factors and geochemical characteristic factors at different set frequencies;
  • B3 Resource prediction Use the established resistivity-phase-rock attribute model to predict hidden resources in the exploration area.
  • step B1 the purpose of step B1 is to realize the complex impedance measurement of the detection area at different set frequencies, and the complex impedance measurement can be performed on the ore body or oil and gas reservoir samples obtained from the depth direction of the detection area (that is, the target layer), or
  • the implementation of complex impedance logging in the well along the wellbore or roadway is the same as the complex impedance measurement method of the exploration area in the first resource prediction method given above, and will not be further elaborated here.
  • step B2 the purpose of step B2 is to extract electromagnetic characteristic factors and geochemical characteristic factors based on the results of complex impedance measurement, and then construct a resistivity-phase-rock attribute model. Calculate the real and imaginary parts of the impedance through the Fourier transform of the measured complex impedance (the corresponding impedance amplitude and phase can be obtained through the real and imaginary parts), and on this basis, the impedance amplitude is multiplied by the sample's morphological coefficient Or the installation coefficient of the target rock mass/oil/gas reservoir/surrounding rock target layer (for the calculation of the installation coefficient, please refer to: Wang Lanwei, Zhang Shizhong, Zhang Yu, Hu Zhe, & Yan Rui. 2014.
  • the relationship between the electromagnetic characteristic factors obtained by the complex impedance measurement and the geochemical characteristic factors obtained by the rock geochemical analysis is established; in the later stage, the electromagnetic characteristic factors of the rock are obtained by the complex impedance measurement, and then based on The establishment of the relationship between the two can quickly obtain the rock geochemical characteristic factors of the exploration area; then based on the comprehensive analysis of the obtained rock-related electromagnetic characteristic factors and geochemical characteristic factors, the rock-related resistivity can be established -Phase-chemical property model.
  • the relationship between the factors can be displayed through graphics, mathematics or physical expressions.
  • the geochemical characteristic factors of the exploration area can be obtained by analogy or analogy.
  • the analogy method is to compare the relevant (electromagnetic and petrology) information of the ore-bearing (oil and gas) target with the electromagnetic characteristics of different characteristic types of deposits or reservoirs to obtain the iconic geochemical characteristic factors that can characterize the exploration area. , Establish the corresponding resistivity-phase-rock attribute model, and analyze the mineralization of the exploration area through comparison.
  • the analogy method is to use the ore-bearing target to establish a rock electromagnetic model, infer the geochemical characteristic factors of the ore body or oil and gas reservoir based on the measured electromagnetic characteristic factors, and establish the corresponding resistivity-phase-rock attribute model, and then use The constructed model predicts and analyzes the potential mineralization of the exploration area.
  • the present invention has the following beneficial effects:
  • the present invention adopts a wide frequency (between 0.001 and 10000 Hz) frequency sweeping method, which can realize wide frequency complex impedance measurement of rocks, and predict potential minerals or oil and gas resources through the acquired rock electromagnetic characteristic factors alone or in combination with geochemical characteristics.
  • the present invention is based on the fact that different rock ores have different dispersion responses in the frequency band, and the impedance phase difference or resistivity ratio of the ore body or oil and gas reservoir in the detection area and the surrounding rock at multiple set frequencies is obtained by the differential method. And use the calculated phase difference or resistivity ratio to predict the ore-bearing or oil-gas resources of the target layer in the exploration area.
  • the present invention establishes the relationship between electromagnetics and the geochemical characteristics of the mineral or oil and gas target layer through rock electromagnetic analysis, and uses electromagnetic and geochemical analysis to predict the mineral or oil and gas resources of the target layer in the exploration area. At the same time, the electromagnetic and geochemical properties of the rock formation are considered, which can further improve the prediction success rate.
  • the present invention can realize the measurement of complex impedance of rocks in the exploration area under the excitation of electromagnetic waves of very low frequency (0.001 ⁇ 0.01Hz), so it can greatly increase the penetration depth in rock logging (penetration from 1 meter to 1 meter). More than ten meters), this can predict hidden targets in a larger range around the wellbore or roadway.
  • Figure 1 is a schematic diagram of a rock electromagnetic measurement system based on core complex impedance measurement provided by the present invention; in the figure, 1-rock electromagnetic measurement system, 11-core sample, 12-impedance analyzer, 13-copper sulfate Gel, 14-copper plate, 15-reference electrode, 16-conductive glue.
  • Figure 2 is a schematic diagram of a rock electromagnetic measurement system based on logging technology provided by the present invention.
  • 2-petroelectromagnetic logging system a 21-transmitting and receiving device, 22-electrode device.
  • Figure 3 is a schematic diagram of another rock electromagnetic measurement system based on logging technology provided by the present invention.
  • 3-petroelectromagnetic logging system b 31-transmitting device, 32-receiving device, 33-electrode device.
  • Figure 4 shows the petrophysical characteristics of the ore body and surrounding rock obtained in Application Example 1.
  • Figure 5 shows the petrophysical characteristics of organic-rich shale and surrounding rock (shale sandstone) obtained in Application Example 2.
  • Figure 6 is a schematic diagram of the correlation analysis results between resistivity characteristics and geochemical characteristics given in Application Example 3; (a) is a schematic diagram of the correlation analysis results between resistivity characteristics and TOC, and (b) is the correlation between calcium oxide content and loss on ignition Schematic diagram of analysis results.
  • Figure 7 is a schematic diagram of the correlation analysis results between the resistivity characteristics and the geochemical characteristics (quartz content) given in Application Example 3.
  • Figure 8 shows the resistivity-phase-geochemical attribute model constructed by using the analogy method to extract the earth's characteristic factors in Application Example 3.
  • (a)-(d) are the results of the known X well measurement
  • (e)-(h) are To predict the measurement results of Well Y
  • (a) and (e) are depth-resistivity curves
  • (b) and (f) are depth-total organic carbon curves
  • (c) and (g) are depth-impedance phase curves
  • ( d)-(h) is the depth-quartz content curve.
  • Figure 9 shows the resistivity-phase-geochemical attribute model and actual measurement results of the application example 3 extracted and predicted by the analogy method of the earth characteristic factors, where (a)-(b) are the electromagnetic measurement results of the predicted well (XD well), ( c) is the TOC content of the XD well obtained by analogy, (d) is the gas desorption volume actually measured in the prediction well (XD well).
  • Copper sulfate colloid is obtained by mixing about 1L of saturated copper sulfate solution and about 5Kg of flour (which can also be replaced by clay).
  • a through hole is opened at the position where the outer wall of the container is in contact with the core sample 11, and a conductive glue 16 is provided between the position where the core sample is in contact with the copper sulfate colloid.
  • the transmitting ports A and B of the impedance analyzer 12 are respectively connected to the copper plate 14 inserted into the copper sulfate colloid 13 through wires, and the receiving ports M and N of the impedance analyzer are respectively connected to the reference electrode 15 inserted into the copper sulfate colloid 13 through wires.
  • Copper plate-copper sulfate constitutes a metal-metal salt.
  • the reference electrode is used as a reference electrode when measuring various electrode potentials. In this embodiment, a silver-silver chloride electrode is used.
  • the impedance analyzer applied frequency range is 0.001 ⁇ 10000Hz.
  • the working principle of the rock electromagnetic measurement system 1 is to accurately measure the AC voltages loaded on both ends of the sample at different set frequencies and the current through the sample, and then obtain the resistivity and impedance at different set frequencies according to the calculation method given above Phase.
  • the conductive glue set between the copper sulfate colloid and the core sample can isolate the two, which can overcome the influence brought by the low-frequency polarization reaction, so as to achieve the measurement of the complex impedance of the core sample at low frequencies, which effectively expands The measurement of complex impedance measurement in a wide frequency band.
  • Traditional measurement is difficult to overcome the influence of low-frequency polarization response, and the measurement low-frequency range is generally greater than 0.01 Hz.
  • the rock electromagnetic logging system a2 based on logging technology provided in this embodiment, as shown in FIG. 2, includes a transmitter and receiver device 21 placed on the ground and an electrode device 22 placed in logging; the electrode device includes transmitter Electrodes (A, B) and receiving electrodes (M, N), the transmitting electrodes (A, B) are connected to the transmitting end of the transmitting and receiving device through a transmission line, and the receiving electrodes (M, N) are connected to the receiving end of the signal transmitting and receiving device through the transmission line connection.
  • the transmitting part of the transmitting and receiving device is used to transmit electromagnetic waves in the frequency range of 0.001 to 10000 Hz.
  • a signal generator or other devices with electromagnetic wave transmitting function can be used to transmit broadband electromagnetic wave signals with different set frequencies to the underground and record the transmitted current.
  • the receiving part of the transmitting and receiving device uses a magnetotelluric signal acquisition device (see the magnetotelluric signal acquisition device disclosed in the CN200910081483.1 application file) to record the AC voltage by measuring the receiving electrode. Then calculate the resistivity and impedance phase according to the calculation method given above.
  • the rock electromagnetic logging system b 3 based on logging technology provided by this embodiment, as shown in FIG. 3, includes a transmitter 31 placed on the ground and a receiver 32 and an electrode device 33 placed in the logging.
  • the device and the electrode device can be nested and installed together.
  • the transmitting device is used to transmit electromagnetic waves with a frequency range of 0.001 to 10000 Hz.
  • a signal generator or other device with electromagnetic wave transmitting function can be used to transmit broadband electromagnetic wave signals with different set frequencies to the ground and record the emission current.
  • the receiving device can be a downhole electromagnetic receiver or a submarine electromagnetic receiver (the principle is the same as that of the ground electromagnetic receiver, but the volume can be as small as 15cm*5cm*5cm or even smaller) to record the AC voltage by measuring the receiving electrode.
  • the electrode device includes transmitting electrodes (A, B) and receiving electrodes (M, N).
  • the transmitting electrodes are connected to the transmitting end of the transmitting device through a transmission line, and the receiving electrodes are connected to the receiving end of the receiving device through a transmission line.
  • the transmitting device emits electromagnetic waves into the logging through the transmitting electrode and records the transmitting current.
  • the receiving device records the AC voltage by measuring the receiving electrode, and then calculates the resistivity and impedance phase according to the calculation method given above.
  • the multi-frequency impedance phase difference (or ratio) of the dispersion response can be used to distinguish between ore and non-ore.
  • the degree of difference can qualitatively reflect the metal (or indicate the surrounding rock) ore-bearing characteristics.
  • the phase difference between chalcopyrite with a grade of more than 1% and the surrounding rock in the low frequency range exceeds 5 degrees.
  • the phase difference is less than or equal to 5 degrees, it is determined that there is no chalcopyrite with a grade of more than 1% in the detection area; carbonaceous slate
  • the low-frequency phase difference between the surrounding rock and the surrounding rock exceeds 2 degrees.
  • the phase difference is less than or equal to 2
  • the process of concealed resource prediction includes the following steps:
  • A1 Complex impedance measurement within the set frequency range of 0.001 to 1000 Hz, the rock electromagnetic measurement system 1 provided in Example 1 is used to measure the ore body development area and surrounding rock area (here refers to the carbonaceous plate) from the detection area. The complex impedance measurement is performed on the core sample obtained from the rock).
  • A2 Feature factor extraction For any set frequency, the real and imaginary parts of the impedance are calculated by Fourier transform from the measured complex impedance (the corresponding impedance amplitude and phase can be obtained through the real and imaginary parts), and then On this basis, the impedance amplitude is multiplied by the morphological coefficient of the sample (the ratio of the contact surface area to the effective length of the sample) to calculate the resistivity of the target layer core sample in the ore body development area and the surrounding rock area, and the resulting resistivity and impedance phase That is, two electromagnetic characteristic factors.
  • the impedance phase of the core samples of the target layer in the ore body development area and the surrounding rock area obtained by the above method changes with frequency as shown in Figure 4.
  • the phase information of 5 frequencies 0.00126, 0.002, 0.00316, 0.00501, 0.00794Hz
  • the average value of the phase difference at 5 frequencies ie, the electromagnetic characteristic factor, 9.05 degrees in this application example.
  • A3 Resource prediction Since the average phase difference between the obtained core samples of the target layer in the ore body development area and the surrounding rock area is greater than 5 degrees, the ore body development area is determined to be a chalcopyrite development area.
  • Unconventional oil and gas (such as shale gas) rocks have different dispersion responses in a wide frequency range.
  • the multi-frequency impedance phase difference (or ratio) of the dispersion response can be used to distinguish organic-rich shale (dark color with TOC greater than 2%) Shale is the main gas producing layer of shale gas) and other rock formations.
  • the low-frequency phase difference between shale and surrounding rock with TOC content greater than 2% is more than 2 degrees. When the phase difference is less than or equal to 2 degrees, it is determined that the exploration area does not contain organic-rich shale (in this case, the upper Yangtze marine shale in China). ).
  • the process of concealed resource prediction includes the following steps:
  • A1 Complex impedance measurement within the set frequency range (0.001 ⁇ 1000Hz), the rock electromagnetic measurement system 1 provided in Example 1 is used to measure the gas-bearing layer development area and surrounding rock area (here refers to mud).
  • the complex impedance measurement is carried out on the core samples obtained from high-quality sandstone.
  • A2 Feature factor extraction For any set frequency, the real and imaginary parts of the impedance are calculated by Fourier transform from the measured complex impedance (the corresponding impedance amplitude and phase can be obtained through the real and imaginary parts), and then On this basis, the impedance amplitude multiplied by the morphological coefficient of the sample can be calculated to obtain the resistivity of the core sample in the gas-bearing zone and the surrounding rock zone. The obtained resistivity and impedance phase are the two electromagnetic characteristic factors.
  • the impedance phase of the core samples of the target layer in the gas-bearing zone and the surrounding rock zone obtained by the above method changes with frequency as shown in Figure 5.
  • the phase information of 3 frequencies 0.005, 0.0063, 0.0079Hz
  • the gas-bearing zone near 1335m depth
  • the target layer of the surrounding rock zone near 1290m depth
  • A3 Resource prediction Since the average phase difference between the obtained gas-bearing layer development area and the target layer core sample in the surrounding rock area is greater than 2 degrees, it is determined that the gas-bearing layer development area is an organic-rich shale development area.
  • This application example combines electromagnetic and geochemical analysis to construct a resistivity-phase-rock attribute model to predict oil and gas reservoirs.
  • the reservoir of organic-rich shale can be evaluated through rock electromagnetic research. Layer features.
  • the TOC of the corresponding rock formation can be obtained.
  • sample resistivity there is a negative correlation between sample resistivity and TOC, sample CaO and burning vector are closely related, which proves that the sample's CaO content is mainly determined by calcium carbonate, and carbonate mainly exhibits high resistance characteristics. Therefore, through rock electromagnetic analysis, it can be seen that TOC and low resistance are intrinsically related, carbonate and high resistance are intrinsically related, and TOC and carbonate can establish a relationship with the marine environment related to oil and gas. Therefore, through rock electromagnetism measurement It can indirectly predict the paleo-ocean environment, and predict the development of oil and gas with the development environment.
  • the hidden resource prediction process includes the following steps:
  • B1 Complex impedance measurement Extract core samples of different depths from the detection area, and use the rock electromagnetic measurement system 1 provided in Example 1 to perform complex impedance measurements on the core samples under the condition of an applied frequency range of 0.001 to 1000 Hz.
  • the measured complex impedance is Fourier transformed to calculate the real and imaginary parts of the impedance (the corresponding impedance amplitude and phase can be obtained through the real and imaginary parts), and then on this basis, The impedance amplitude is multiplied by the morphological coefficient of the sample to obtain the resistivity of the sample, and the resistivity and impedance phase obtained are the two electromagnetic characteristic factors.
  • TOC total organic carbon content
  • quartz content quartz content
  • CaO content burning vector and other geochemical characteristic factors related to oil and gas.
  • the landmark geochemical characteristic factors in this application example are TOC and quartz content.
  • TOC and quartz content can be used to evaluate the porosity and gas-bearing properties of organic-rich shale.
  • the TOC increases significantly along the depth of the 1280-1310m well section, which indicates that this section is preliminarily judged from the geochemical indicators to be beneficial to the development of shale gas; the quartz content is obvious in the 1280-1310m well section.
  • the increase indicates that the increase of brittle minerals in this section is beneficial to the development of shale gas; the phase distribution along the depth of the well section from 1280 to 1310m increases significantly, which also indicates that this section is favorable for shale gas development.
  • the combined abnormal characteristics of TOC-resistivity-quartz content-impedance phase can more accurately identify and analyze favorable areas for shale gas development than using TOC alone, and petrophysical logging can assist resource identification.
  • the hidden resource prediction process includes the following steps:
  • B1 Complex impedance measurement Extract core samples of different depths from the detection area, and use the rock electromagnetic measurement system 1 provided in Example 1 to perform complex impedance measurements on the core samples under the condition of an applied frequency range of 0.001 to 1000 Hz.
  • B2 Feature factor extraction and model construction The measured complex impedance is Fourier transformed to calculate the real and imaginary parts of the impedance (the corresponding impedance amplitude and phase can be obtained through the real and imaginary parts), and then on this basis, The impedance amplitude is multiplied by the morphological coefficient of the sample to obtain the resistivity of the sample. The resistivity and impedance phase obtained are the two electromagnetic characteristic factors.
  • the measurement results are shown in Figure 9 (a) and (b).
  • the resistivity-phase-TOC attribute model of a typical oil and gas reservoir at 0.01 Hz can be established.
  • the resistivity-phase-TOC attribute model for predicting the 2042 ⁇ 2083m section of the XD downhole by analogy based on the resistivity model shows that it exhibits the characteristics of low resistance, high polarization, and high TOC, so it can be predicted that the XD downhole 2042 ⁇ 2083m
  • the well section is a favorable area for shale gas, which is basically consistent with the 2045-2075m well section ( Figure 9d) obtained from the on-site gas content analysis of the well site.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • Remote Sensing (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • Electromagnetism (AREA)
  • Geophysics And Detection Of Objects (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

本发明公开了一种隐伏资源预测方法及岩石电磁学测井系统，应用于矿产和油气资源勘探技术领域。本发明提供的岩石电磁学测井系统，采用宽频(0.001～10000Hz之间)扫频方式，能够实现岩石宽频复阻抗测量，并通过获取的岩石电磁学特征因子单独或结合地球化学特征进行潜在矿产或油气资源预测。

Description

一种隐伏资源预测方法及岩石电磁学测井系统 技术领域
本发明属于矿产资源勘探技术领域，涉及矿产(油气)测井和勘探，尤其涉及用于地层属性识别和资源预测的隐伏资源预测方法，以及资源预测方法中所使用的岩石电磁学测井系统。
背景技术
钻井(井孔)是获取地下地层信息最直接的手段之一，也是验证和发现隐伏矿产(含油气)资源最重要的勘探手段。测井(也称地球物理测井)是利用岩层的电化学特性、导电特性、声学特性、放射性等地球物理特性，测量地球物理参数的方法。常用的测井方法为电阻率测井、电磁感应测井和电磁波传播测井。
电阻率测井是通过特定的装置在井中发射和接受直流电场，获取地层的电性参数，常用输出参数为地层电阻率，容易受到钻井液和井具影响，同时，由于使用的频率较高或供电距离较小，最大穿透深度小。电磁感应测井是利用电磁感应的方法，在地层中建立电场，测量地层的导电特性，在此基础上还延伸出阵列感应测井，其测量原理与普通电磁感应测井仪相似，但线圈的数量显著增加。电磁波传播测井(EPT)又称为超高频介电测井，是通过测量与地层介电常数密切相关的参数(电磁波传播时间和电磁波衰减率)来区分油、水层，确定地层中水含量的一种测井方法。电磁感应测井和电磁波传播测井由于是接收电磁感应产生的二次场，激发电磁场不仅需要使用频率高(25000赫兹-1G赫兹)，而且最大穿透深度很小，只有10～几十厘米。
发明内容
本发明目的旨在针对传统电阻率测井技术因输出参数单一、频率范围窄、复杂环境识别能力差及穿透深度浅等问题所导致隐伏矿产(金属、油气等)资源预测效果差的问题，提供一种资源预测方法，使用宽频发射电磁波(特别是包含较低频率的发射电磁波)对矿区进行复阻抗测量与分析，以提高对矿区资源预测成功率。
为了达到上述目的，本发明采取以下技术方案来实现。
本发明提供的隐伏资源预测方法，包括以下步骤：
A1复阻抗测量：
在设定频率范围内，对从探测区井孔或巷道获取的矿体或油气藏、以及围岩样品进行复阻抗测量；
或者在设定频率范围内，沿探测区井孔或巷道进行井中复阻抗测量；
A2特征因子提取：依据复阻抗测量结果，提取探测区矿体或油气藏、以及围岩样品不同设定频率的电阻率和相位信息，然后获取矿体或油气藏与围岩样品在同一频段下多个设定频率的阻抗相位差或电阻率比值，并将得到的阻抗相位差或电阻率比值作为电磁学特征因子；
A3资源预测：依据获取的电磁学特征因子，按照设定的标准，对探测区隐伏资源进行预测。
上述隐伏资源预测方法，所述探测区为需要对含矿、含水或油气资源进行预测的区域。
上述隐伏资源预测方法，步骤A1的目的在于实现探测区井孔或巷道不同设定频率下的复阻抗测量，可以对从探测区井孔或巷道获取的矿体或油气藏、以及围岩样品进行复阻抗测量，或者沿井孔或巷道进行井中进行复阻抗测井来实现。设定频率范围为0.001～10000Hz。在优选的实现方式中，设定频率范围为0.001～0.01Hz，在这个频率范围内，可以较大限度减少电容效应和电磁耦合效应的影响，因此测量结果更好地反映探测介质的属性；同时这个频率范围的电磁波具有比中高频(频率大于0.01Hz)的电磁波更大穿透深度，可以探测井孔周边更大范围的信息。
对样品进行复阻抗测量时，所采用的岩石电磁学测量系统包括设置于岩芯样品两端的盛有介质溶液的容器和阻抗分析仪，所述岩芯样品与容器接触位置设置有导电胶，与阻抗分析仪连接的电极和参比电极插入介质溶液中；所述阻抗分析仪施加频率范围为0.001～10000Hz；优选实现方式中，所述阻抗分析仪施加频率范围为0.001～0.01Hz。所述阻抗分析仪能够直接测量复阻抗。所述介质溶液为硫酸铜或氯化银溶液，对应的电极为铜或银。所述参比电极为不极化参比电极，例如银-氯化银电极，采用已公开的电极。本发明提供的岩石电磁学测量系统，通过设置在介质溶液(或胶体)与岩芯样品之间的导电胶将两者隔离，能够克服低频极化反应所带来的影响，从而能够实现在低频情况对岩芯样品复阻抗的测量，从而使复阻抗测量从中频(0.01～100Hz)向宽频带(0.001～10000Hz)、特别是向低频的有效拓展。
当通过沿井孔或巷道进行井中不同设定频率的复阻抗测井获得相关复阻抗测量结果时，所采用的岩石电磁学测井系统与直流电阻率测井装置有点类似，可以通 过两种方式来实现：
(1)所述岩石电磁学测井系统包括置于地面的发射-接收装置和置于井中的电极装置；所述电极装置包括发射电极和接收电极，发射电极通过传输线与发射-接收装置的发射端连接，接收电极通过传输线与信号发射-接收装置的接收端连接；所述发射-接收装置通过发射电极向测井内发射频率范围在0.001～10000Hz内的电磁波，发射-接收装置通过接收电极测量得到测井内电极装置所在位置的复阻抗。在优选的实现方式中，所述发射-接收装置通过发射电极向测井内发射电磁波的频率范围为0.001～0.01Hz。
(2)所述岩石电磁学测井系统包括置于地面的发射装置及置于井中的接收装置和电极装置；所述电极装置包括发射电极和接收电极，发射电极通过传输线与发射装置的发射端连接，接收电极通过传输线与接收装置的接收端连接；所述发射装置通过发射电极向测井内发射频率范围在0.001～10000Hz内的电磁波，接收装置通过接收电极测量得到测井内电极装置所在位置的复阻抗。在优选的实现方式中，所述信号发射装置通过发射电极向测井内发射电磁波的频率范围为0.001～0.01Hz。
第一种实现方式中的发射-接收装置的发射部分或者第二种实现方式中的发射装置可以采用信号发生器或者具有电磁波发射功能的其他装置向地下发射包含不同设定频率的宽频电磁波信号并记录发射电流。第一种实现方式中的发射-接收装置的接收部分或者第二种实现方式中的接收装置可以采用大地电磁信号采集装置，可以在地面或井中通过测量记录接收电极交流电压。然后依据记录的发射电流和交流电压，通过欧姆定律计算得到复阻抗。
上述隐伏资源预测方法，步骤A2的目的在于依据复阻抗测量结果，首先对电磁学特征因子进行提取，主要是提取探测区目的层不同设定频率下的电阻率和相位信息，然后依据目标层的相位信息，计算得到探测区在同一频段(例如低频段(0.001-0.01Hz)、中频段(0.01-100Hz)或高频段(100-10000Hz))下多个设定频率的相位差或电阻率(或阻抗模)比值，并将得到的探测区在同一频段的阻抗相位差或电阻率比值作为电磁学特征因子；为了便于与设定的标准比较，也可以取多个阻抗相位差或电阻率比值的平均值作为电磁学特征因子。将测量得到的复阻抗通过傅里叶变换计算阻抗的实部和虚部(通过实部和虚部可获得相应的阻抗振幅和相位)，再在此基础上，阻抗振幅乘以样品的形态系数或目的岩体/油气藏/围岩目标层的装置系数(装置系数计算可参阅：王兰炜,张世中,张宇,胡哲,&顏蕊.2014. 井下地电阻率观测中装置系数的计算——以天水地震台井下观测为例.工程地球物理学报,11：50-59.)可计算电阻率。并将不同设定频率的电阻率和相位作为电磁学特征因子。由于不同类型的矿体和围岩具有不同的频散效应，因此探测区矿体或油气藏与围岩在同一频段的阻抗相位差或电阻率比值可以反映资源的含矿或油气储层情况，进而对探测区是否含矿(或油气)进行预测。
上述隐伏资源预测方法，步骤A3的目的是根据电磁学特征因子对探测区资源情况进行预测。可以根据经验测量数据，设定相关的标准。然后将电磁学特征因子与设定的标准相比较，来对含矿(或油气)进行预测。
本发明进一步提供了另外一种隐伏资源预测方法，包括以下步骤：
B1复阻抗测量：
在设定频率范围内，对从探测区井孔或巷道获取的矿体或油气藏、以及围岩样品进行复阻抗测量；
或者在设定频率范围内，沿探测区井孔或巷道进行井中复阻抗测量；
B2特征因子提取及模型构建：依据复阻抗测量结果，提取不同设定频率下的电阻率和相位信息，并将电阻率和相位作为电磁学特征因子；然后依据电磁学特征与岩石地球化学分析得到的地球化学特征的关联关系，获得不同设定频率下地球化学特征因子，进一步依据得到的不同设定频率下的电磁学特征因子及地球化学特征因子建立电阻率-相位-岩石属性模型；
B3资源预测：利用建立的电阻率-相位-岩石属性模型，对探测区隐伏资源进行预测。
上述隐伏资源预测方法，步骤B1的目的在于实现不同设定频率下的探测区复阻抗测量，可以对从探测区域深度方向(即目的层)获取的矿体或油气藏样品进行复阻抗测量，或者沿井孔或巷道进行井中进行复阻抗测井来实现，与前面给出的第一种资源预测方法中对探测区复阻抗测量方法相同，这里不再做进一步阐述。
上述隐伏资源预测方法，步骤B2的目的在于依据复阻抗测量结果，提取电磁学特征因子和地球化学特征因子，然后构建电阻率-相位-岩石属性模型。将测量得到的复阻抗通过傅里叶变换计算阻抗的实部和虚部(通过实部和虚部可获得相应的阻抗振幅和相位)，再在此基础上，阻抗振幅乘以样品的形态系数或目的岩体/油气藏/围岩目标层的装置系数(装置系数计算可参阅：王兰炜,张世中,张宇,胡哲,&顏蕊.2014.井下地电阻率观测中装置系数的计算——以天水地震台井下观测为 例.工程地球物理学报,11：50-59.)可计算电阻率。并将不同设定频率的电阻率和相位作为电磁学特征因子。
这里，通过前期研究，建立复阻抗测量得到的电磁学特征因子与岩石地球化学分析得到的地球化学特征因子之间的关联关系；后期通过对岩石进行复阻抗测量得到其电磁学特征因子，再依据建立的两者之间的关联关系，便可快速得到探测区的岩石地球化学特征因子；之后依据得到的与岩石相关的电磁学特征因子和地球化学特征因子综合分析，建立与岩石相关的电阻率-相位-化学属性模型。前期研究中，通过对于若干已经探明的典型金属矿矿床或油气藏，采用前面给出的手段对上述区域的岩石进行复阻抗分析，获得与岩石相关的电阻率、相位等电磁学特征因子，并采用常规手段(主量分析、微量分析、烧矢量分析等)获得与资源相关的地球化学特征因子(如金属矿相关的金属硫化物含量、主量金属含量、石英含量等地球化学特征因子，或与油气相关的总有机碳含量(TOC)、石英含量、烧矢量、黄铁矿矿含量等地球化学特征因子)，然后通过相关系数分析和散点分析等建立电磁学特征因子与地球化学特征因子之间的关联关系，可通过图形、数学或物理表达等方式展现出。后期，在得到探测区岩石相关的电磁学特征因子之后，可通过类比方式或类推方式得到探测区地球化学特征因子。类比方式是指通过含矿(油气)目标相关(电磁学和岩石学)信息与不同特征类型的矿床或储层的电磁学特征相比较，便可得到能够表征探测区的标志性地球化学特征因子，建立相应的电阻率-相位-岩石属性模型，经比对分析探测区的含矿性。类推方式是指利用含矿目标建立岩石电磁学模型，依据测量的电磁学特征因子，推测出矿体或油气藏的地球化学特征因子情况，建立相应的电阻率-相位-岩石属性模型，进而利用构建的模型预测分析探测区的潜在含矿性。
当然，本领域技术人员可以在根据不同频段阻抗相位差或电阻率比值对矿区探测区是否含矿进行预测基础上，进一步通过构建的电阻率-相位-岩石属性模型，对探测区资源潜力进行评价，从而对探测区含矿(或油气)情况给出进一步预测，提高资源的预测成功率。
与现有技术相比，本发明具有如下有益效果：
1、本发明采用宽频(0.001～10000Hz之间)扫频方式，能够实现岩石宽频复阻抗测量，并通过获取的岩石电磁学特征因子单独或结合地球化学特征进行潜在矿产或油气资源预测。
2、本发明基于不同的岩矿石在频带范围内具有不同的频散响应，通过差分方法得到探测区矿体或油气藏与围岩在多个设定频率下的阻抗相位差或电阻率比值，并利用计算得的相位差或电阻率比值对探测区目的层的含矿或油气资源进行预测。
3、本发明通过岩石电磁学分析，建立电磁学和矿产或油气目的层地球化学特征之间的联系，利用电磁学和地球化学分析对探测区目的层的含矿或油气资源进行进行预测，由于同时考虑了岩层的电磁学和地球化学性能，因而能够进一步提高预测成功率。
4、本发明由于可以实现在极低频率(0.001～0.01Hz)的电磁波激发下对探测区岩石的复阻抗测量，因而能够极大提高岩石测井中的穿透深度(可穿透1米到十几米以上)，这样可以预测井孔或巷道周边更大范围内的隐伏目标。
附图说明
图1为本发明提供的一种基于岩芯复阻抗测量的岩石电磁学测量系统示意图；图中，1-岩石电磁学测量系统，11-岩芯样品，12-阻抗分析仪，13-硫酸铜胶体，14-铜板，15-参比电极，16-导电胶。
图2为本发明提供的一种基于测井技术的岩石电磁学测量系统示意图；2-岩石电磁学测井系统a，21-发射接收装置，22-电极装置。
图3为本发明提供的另一种基于测井技术的岩石电磁学测量系统示意图；3-岩石电磁学测井系统b，31-发射装置，32-接收装置，33-电极装置。
图4为应用例1中所得到的矿体和围岩的岩石电磁学特征。
图5为应用例2中所得的的富有机质页岩和围岩(泥质砂岩)的岩石电磁学特征。
图6为应用例3给出的电阻率特征与地球化学特征相关性分析结果示意图；(a)为电阻率特征与TOC相关性分析结果示意图，(b)为氧化钙含量与烧失量相关性分析结果示意图。
图7为应用例3给出的电阻率特征与地球化学特征(石英含量)相关性分析结果示意图。
图8为应用例3通过类比方法提取地球特征因子并构建的电阻率-相位-地球化学属性模型，其中(a)-(d)为已知X井测量结果，(e)-(h)为预测Y井测量结果，(a)、(e)为深度-电阻率曲线，(b)、(f)为深度-总有机碳曲线，(c)、(g)为深度-阻抗相位曲线，(d)-(h)为深度-石英含量曲线。
图9为应用例3通过类推方法提取地球特征因子并预测的电阻率-相位-地球化学属性模型与实测结果，其中(a)-(b)为预测井(XD井)电磁学测量结果，(c)为类推得到的XD井的TOC含量，(d)为预测井(XD井)实际测量得到的含气解吸量。
具体实施方式
下面通过实施例对本发明进行具体的描述，有必要在此指出的是本实施例只用于对本发明进行进一步说明，但不能理解为对本发明保护范围的限制，该领域的技术熟练人员可以根据上述本发明的内容对本发明做出一些非本质性的改进和调整。
实施例1
本实施例提供的基于岩芯复阻抗测量的岩石电磁学测量系统1，如图1所示，其包括两个盛有硫酸铜胶体13的容器和阻抗分析仪12，岩芯样品11放置于两个容器之间。硫酸铜胶体是由约1L饱和硫酸铜溶液和约5Kg面粉(也可以用黏土替代)混合均匀后得到。容器外壁与岩芯样品11接触的位置开设有通孔，岩芯样品与硫酸铜胶体接触的位置之间设置导电胶16。阻抗分析仪12的发射端口A、B分别通过导线与插入硫酸铜胶体13的铜板14连接，阻抗分析仪的接收端口M、N分别通过导线与插入硫酸铜胶体13的参比电极15连接。铜板-硫酸铜构成金属-金属盐。参比电极为测量各种电极电势时作为参照比较的电极，本实施例中采用的是银-氯化银电极。阻抗分析仪施加频率范围为0.001～10000Hz。
岩石电磁学测量系统1的工作原理：通过精确测量加载在样品两端的不同设定频率的交流电压与通过样品的电流，然后依据前面给出的计算方法得到不同设定频率下的电阻率和阻抗相位。通过设置在硫酸铜胶体与岩芯样品之间的导电胶将两者隔离，能够克服低频极化反应所带来的影响，从而能够实现在低频情况对岩芯样品复阻抗的测量，有效拓展了复阻抗测量在宽频带下的测量。传统的测量难以克服低频极化反应所带来的影响，测量低频范围一般大于0.01Hz。
实施例2
本实施例提供的基于测井技术的岩石电磁学测井系统a 2，如图2所示，其包括置于地面的发射接收装置21和置于测井内的电极装置22；电极装置包括发射电极(A、B)和接收电极(M、N)，发射电极(A、B)通过传输线与发射接收装置的发射端连接，接收电极(M、N)通过传输线与信号发射接收装置的接收端连接。发射接收装置的发射部分用于发射频率范围在0.001～10000Hz内的电磁波，可 以采用信号发生器或者具有电磁波发射功能的其他装置向地下发射包含不同设定频率的宽频电磁波信号并记录发射电流。发射接收装置的接收部分采用大地电磁信号采集装置(参见CN200910081483.1申请文件中公开的大地电磁信号采集装置)通过测量接收电极记录交流电压。然后依据前面给出的计算方法计算得到电阻率和阻抗相位。
实施例3
本实施例提供的基于测井技术的岩石电磁学测井系统b 3，如图3所示，其包括置于地面的发射装置31及置于测井内的接收装置32和电极装置33，接收装置和电极装置可以嵌套安装在一起。发射装置用于发射频率范围在0.001～10000Hz内的电磁波，可以采用信号发生器或者具有电磁波发射功能的其他装置向地下发射包含不同设定频率的宽频电磁波信号并记录发射电流。接收装置可以采用井下电磁接收机或海底电磁接收机(原理和地面电磁接收机相同，但体积可小到15cm*5cm*5cm甚至更小)通过测量接收电极记录交流电压。电极装置包括发射电极(A、B)和接收电极(M、N)，发射电极通过传输线与发射装置的发射端连接，接收电极通过传输线与接收装置的接收端连接。所述发射装置通过发射电极向测井内发射电磁波并记录发射电流，接收装置通过测量接收电极记录交流电压，然后依据前面给出的计算方法计算得到电阻率和阻抗相位。
应用例1
不同的岩矿石在宽频带范围内具有不同的频散响应，利用频散响应的多频率阻抗相位差(或比值)，可区分矿与非矿。差异程度能够定性反应金属(或指示围岩)含矿特征。例如品位1％以上的黄铜矿与其周围的围岩低频段相位差超过5度，当相位差小于等于5度时，即判定探测区不存在品位1％以上的黄铜矿；炭质板岩与其周围的围岩的低频段相位差超过2度，当相位差小于等于2时，即判定探测区不存在灰质板岩。
对于某一黄铜矿探测区，隐伏资源预测过程包括以下步骤：
A1复阻抗测量：在设定频率范围0.001～1000Hz内，采用实施例1中提供的岩石电磁学测量系统1分别对从探测区的矿体发育区和围岩区(这里指的是炭质板岩)获取的岩芯样品进行复阻抗测量。
A2特征因子提取：对于任一设定频率，将测量得到的复阻抗通过傅里叶变换计算阻抗的实部和虚部(通过实部和虚部可获得相应的阻抗振幅和相位)，再在此 基础上，阻抗振幅乘以样品的形态系数(接触表面积和样品有效长度的比值)可计算得到矿体发育区和围岩区目的层岩芯样品的电阻率，所得到的电阻率和阻抗相位即为两个电磁学特征因子。
通过上述方法得到的矿体发育区和围岩区目的层岩芯样品阻抗相位随频率的变化如图4所示。在低频段频率小于0.01Hz范围内，提取5个频率(0.00126,0.002,0.00316,0.00501,0.00794Hz)的矿体发育区和围岩区目的层(埋深310m)的相位信息，然后计算两者在5个频率的相位差平均值(即电磁学特征因子，本应用例为9.05度)。
A3资源预测：由于得到的矿体发育区和围岩区目的层岩芯样品的相位差平均值大于5度，因此判定矿体发育区为黄铜矿发育区。
当然，也可以先分别计算矿体发育区和围岩区目的层岩芯样品5个频率下的阻抗相位平均值，然后再计算矿体发育区和围岩区目的层岩芯样品的阻抗相位平均值的差值，并将其作为电磁学特征因子。
应用例2
对于油气资源，岩石的含油气性不同表现为不同岩石电磁学特征，因而测井电阻率是油气分析的重要指标之一。非常规油气(例如页岩气)石在宽频带范围内具有不同的频散响应，利用频散响应的多频率阻抗相位差(或比值)，可区分富有机质页岩(TOC大于2％的暗色页岩，是页岩气的主要产气层)和其它岩层。例如TOC含量大于2％以上的页岩和围岩低频段相位差超过2度，当相位差小于等于2度时，即判定探测区不含富有机质页岩(这里指中国上扬子海相页岩)。
对于某一富有机质页岩探测区，隐伏资源预测过程包括以下步骤：
A1复阻抗测量：在设定频率范围(0.001～1000Hz)内，采用实施例1中提供的岩石电磁学测量系统1分别对探测区的含气层发育区和围岩区(这里指的是泥质砂岩)获取的岩芯样品进行复阻抗测量。
A2特征因子提取：对于任一设定频率，将测量得到的复阻抗通过傅里叶变换计算阻抗的实部和虚部(通过实部和虚部可获得相应的阻抗振幅和相位)，再在此基础上，阻抗振幅乘以样品的形态系数可计算得到含气层发育区和围岩区目的层岩芯样品的电阻率，所得到的电阻率和阻抗相位即为两个电磁学特征因子。
通过上述方法得到的含气层发育区和围岩区目的层岩芯样品阻抗相位随频率的变化如图5所示。在低频段频率小于0.01Hz范围内，提取3个频率(0.005，0.0063， 0.0079Hz)含气层发育区(深度1335米附近)和围岩区目的层(深度1290米附近)的相位信息，然后计算两者在3个频率的相位平均值的差值(即电磁学特征因子，本应用例为3.14度)。
A3资源预测：由于得到的含气层发育区和围岩区目的层岩芯样品的相位差平均值大于2度，因此判定含气层发育区为富有机质页岩发育区。
应用例3
本应用例是电磁学和地球化学分析相结合，构建电阻率-相位-岩石属性模型来对油气储层进行预测。
利用富有机质页岩的粘土矿物、脆性矿物、TOC、黄铁矿等页岩气储层评价要素与测井电阻率和相位的关系，这样便可以通过岩石电磁学研究评价富有机质页岩的储层特征。
建立电磁学特征与岩石地球化学特征的关联关系
通过对典型油气藏(华南上扬子板块西南缘)进行电磁学分析和地球化学分析，建立两者的关联关系，具体包括以下步骤：
(i)从油气藏井孔提取不同深度的岩芯样品，在设定频率范围(0.001～10000Hz)下，采用实施例1中提供的岩石电磁学测量系统1对岩芯样品进行复阻抗测量。将测量得到的复阻抗通过傅里叶变换计算阻抗的实部和虚部(通过实部和虚部可获得相应的阻抗振幅和相位)，再在此基础上，阻抗振幅乘以样品的形态系数可计算得到岩芯样品的电阻率，所得到的电阻率和阻抗相位即为两个电磁学特征因子。
(ii)采用常规主量分析、总有机碳分析、荧光分析法等获得与油气相关的总有机碳含量(TOC)、石英含量、CaO含量、烧矢量等地球化学特征因子。
(iii)将0.01Hz下测量得到的对数电阻率与TOC测试数据进行汇总，如图6(a)所示。对TOC与对数电阻率进行相关性分析，如图所示，拟合得到两者的关系式为：
Y 对数电阻率＝-0.563*X TOC+3.165。
根据上述分析，在该频率下测试得到岩芯样品的电阻率后，便可得到对应岩层的TOC。
将CaO(氧化钙)与烧失量的测试数据进行汇总，如图6(b)所示。对CaO与烧失量进行相关性分析，拟合得到两者的关系式为：
Y 烧失量＝0.66*X CaO+7.15。
根据上述分析，可以发现，样品电阻率和TOC存在负相关关系，样品CaO和烧矢量密切相关，证明样品的CaO含量主要由含钙碳酸岩决定，碳酸盐主要表现为高阻特征。因而，通过岩石电磁学分析可知，TOC和低阻存在内在联系，碳酸盐和高阻存在内在联系，TOC和碳酸盐又可以和油气相关的海洋环境建立联系，因此，通过岩石电磁学测量可间接预测古海洋环境，并同发育环境预测油气发育情况。
将0.01Hz下测量得到的岩芯样品的对数电阻率与石英含量的测试数据进行汇总，如图7所示，其中X井表示的是典型油气藏(华南上扬子板块西南缘)对应井孔测量得到的石英含量与对数电阻率的测试数据汇总结果，Y井表示的是第一探测区测量得到的石英含量与对数电阻率的测试数据汇总结果，Z井表示的是第二探测区测量得到的石英含量与对数电阻率的测试数据汇总结果。由于这些数据没有展现出较好的相关性，因此对这些数据进行散点分析，通过拟合(如双对数线性)或趋势分析，可得出石英含量和岩石电阻率和阻抗的关系。
通过上述分析，便可建立典型油气藏在该频率下的电磁学特征与地球化学特征之间的关联关系。
进一步地，将岩芯样品的对数电阻率、相位、TOC和石英含量的测试数据进行汇总，便可得到图8(a)-(d)所示的已知X井在0.01Hz频率下关联分析后建立的电阻率-相位-TOC、电阻率-相位-石英含量的属性模型。
与此类似的，可以建立不同特征类型的矿床或储层的电磁学特征与地球化学特征之间的关联关系，以及建立相应的电阻率-相位-岩石属性模型。
(一)对于第一油气探测区(相应的井孔为预测Y井)，隐伏资源预测过程包括以下步骤：
B1复阻抗测量：从探测区提取不同深度的岩芯样品，采用实施例1中提供的岩石电磁学测量系统1在施加频率范围为0.001～1000Hz条件下，对岩芯样品进行复阻抗测量。
B2特征因子提取及模型构建：将测量得到的复阻抗通过傅里叶变换计算阻抗的实部和虚部(通过实部和虚部可获得相应的阻抗振幅和相位)，再在此基础上，阻抗振幅再乘以样品的形态系数即为样品的电阻率，所得到的电阻率和阻抗相位即为两个电磁学特征因子。
采用常规主量分析、总有机碳分析、荧光分析法等获得与油气相关的总有机碳含量(TOC)、石英含量、CaO含量、烧矢量等地球化学特征因子。
然后将得到的预测Y井测量得到的电磁学特征与不同特征类型的储层的电磁学特征对比，便可得到与之类似的电阻率-相位-岩石属性模型，进而从中能够看出可以表征第一油气藏探测区的地球化学特征因子，本应用例中的标志性地球化学特征因子为TOC和石英含量。
将0.01Hz下测量得到的岩芯样品的对数电阻率、相位、TOC和石英含量的测试数据进行汇总，便可建立典型油气藏在0.01Hz下的电阻率-相位-TOC、电阻率-相位-石英含量的属性模型，如图8(e)-(h)所示。
B3资源预测：
将得到的预测Y井下1280～1310m井段的电阻率-相位-TOC、电阻率-相位-石英含量的属性与图8(a)-(d)模型中给出相应部分进行比较，可知其表现出低阻-高极化-高TOC-高石英等特征，因此可以预测Y井1280-1310m井段为页岩气有利区。
从图8中建立的电阻率-相位-TOC、电阻率-相位-石英含量的属性模型，利用TOC、石英含量可以评价富有机质页岩的孔隙度与含气性。例如，从图8中可以看出，TOC沿深度在1280～1310m井段明显升高，这说明从地球化学指标上初步判断本段有利于页岩气发育；石英含量在1280～1310m井段明显升高，这说明本段脆性矿物增加有利于页岩气开发；相位沿深度分布在1280～1310m井段明显升高，同样表明本段对页岩气发育有利。由此可见，通过TOC-电阻率-石英含量-阻抗相位的组合异常特征比单纯利用TOC能更精确识别分析页岩气发育的有利区，岩石电磁学测井可以辅助资源识别。
(二)对于第三油气探测区(相应的井孔记为预测XD井)，隐伏资源预测过程包括以下步骤：
B1复阻抗测量：从探测区提取不同深度的岩芯样品，采用实施例1中提供的岩石电磁学测量系统1在施加频率范围为0.001～1000Hz条件下，对岩芯样品进行复阻抗测量。
B2特征因子提取及模型构建：将测量得到的复阻抗通过傅里叶变换计算阻抗的实部和虚部(通过实部和虚部可获得相应的阻抗振幅和相位)，再在此基础上，阻抗振幅再乘以样品的形态系数即为样品的电阻率，所得到的电阻率和阻抗相位即为两个电磁学特征因子，测量结果如图9(a)和(b)所示。
利用(iii)节中的电阻率－TOC模型Y 对数电阻率＝-0.563*X TOC+3.165，便可类推出 推测XD井所对应的地球化学特征因子及分布情况，得到本应用例中的标志性地球化学特征因子TOC，并利用推测TOC可预测含气有利区，如图9(c)所示。
将0.01Hz下测量得到的岩芯样品的对数电阻率、相位、TOC测试(或预测)数据进行汇总，便可建立典型油气藏在0.01Hz下的电阻率-相位-TOC的属性模型。
B3资源预测：
根据电阻率模型类推得到的预测XD井下2042～2083m井段的电阻率-相位-TOC的属性模型，可知其表现出低阻-高极化-高TOC等特征，因此可以预测XD井下2042～2083m井段为页岩气有利区，与井场现场含气量解析的结果2045～2075m井段(图9d)基本吻合。

Claims (10)

  1. 一种隐伏资源预测方法，其特征在于包括以下步骤：
    A1复阻抗测量：
    在设定频率范围内，对从探测区井孔或巷道获取的矿体或油气藏、以及围岩样品进行复阻抗测量；
    或者在设定频率范围内，沿探测区井孔或巷道进行井中复阻抗测量；
    A2特征因子提取：依据复阻抗测量结果，提取探测区矿体或油气藏、以及围岩样品不同设定频率的电阻率和相位信息，然后获取矿体或油气藏与围岩样品在同一频段下多个设定频率的阻抗相位差或电阻率比值，并将得到的阻抗相位差或电阻率比值作为电磁学特征因子；
    A3资源预测：依据获取的电磁学特征因子，按照设定的标准，对探测区隐伏资源进行预测。
  2. 根据权利要求1所述资源预测方法，其特征在于设定频率范围为0.001～10000Hz。
  3. 根据权利要求2所述资源预测方法，其特征在于设定频率范围为0.001～0.01Hz。
  4. 根据权利要求1至3任一权利要求所述资源预测方法，其特征在于所述探测区为需要对含矿、含水或油气资源进行预测的区域。
  5. 一种隐伏资源预测方法，其特征在于包括以下步骤：
    B1复阻抗测量：
    在设定频率范围内，对从探测区井孔或巷道获取的矿体或油气藏、以及围岩样品进行复阻抗测量；
    或者在设定频率范围内，沿探测区井孔或巷道进行井中复阻抗测量；
    B2特征因子提取及模型构建：依据复阻抗测量结果，提取不同设定频率下的电阻率和相位信息，并将电阻率和相位作为电磁学特征因子；然后依据电磁学特征与岩石地球化学分析得到的地球化学特征的关联关系，获得不同设定频率下地球化学特征因子，进一步依据得到的不同设定频率下的电磁学特征因子及地球化学特征因子建立电阻率-相位-岩石属性模型；
    B3资源预测：利用建立的电阻率-相位-岩石属性模型，对探测区隐伏资源进行预测。
  6. 根据权利要求5所述资源预测方法，其特征在于设定频率范围为 0.001～10000Hz。
  7. 根据权利要求6所述资源预测方法，其特征在于设定频率范围为0.001～0.01Hz。
  8. 根据权利要求5至7任一权利要求所述资源预测方法，其特征在于所述探测区为需要对含矿、含水或油气资源进行预测的区域。
  9. 一种岩石电磁学测井系统，其特征在于用于沿井孔或巷道进行井中不同设定频率下的复阻抗测量，该岩石电磁学测量系统包括置于地面的发射-接收装置和置于井孔或巷道中的电极装置；所述电极装置包括发射电极和接收电极，发射电极通过传输线与发射-接收装置的发射端连接，接收电极通过传输线与信号发射-接收装置的接收端连接；所述发射-接收装置通过发射电极向测井内发射频率范围在0.001～10000Hz内的电磁波，发射-接收装置通过接收电极测量得到测井内电极装置所在位置的复阻抗。
  10. 一种岩石电磁学测井系统，其特征在于沿井孔或巷道进行井中不同设定频率下的复阻抗测量，该岩石电磁学测井系统包括置于地面的发射装置及置于井孔或巷道中的接收装置和电极装置；所述电极装置包括发射电极和接收电极，发射电极通过传输线与发射装置的发射端连接，接收电极通过传输线与接收装置的接收端连接；所述发射装置通过发射电极向测井内发射频率范围在0.001～10000Hz内的电磁波，接收装置通过接收电极测量得到测井内电极装置所在位置的复阻抗。
PCT/CN2020/118634 2019-10-18 2020-09-29 一种隐伏资源预测方法及岩石电磁学测井系统 WO2021073421A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US17/716,426 US20220299671A1 (en) 2019-10-18 2022-04-08 Concealed mineral resource prediction method and logging system based on petro-electromagnetism

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201910993947.XA CN110703344B (zh) 2019-10-18 2019-10-18 一种隐伏资源预测方法及岩石电磁学测井系统
CN201910993947.X 2019-10-18

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US17/716,426 Continuation US20220299671A1 (en) 2019-10-18 2022-04-08 Concealed mineral resource prediction method and logging system based on petro-electromagnetism

Publications (1)

Publication Number Publication Date
WO2021073421A1 true WO2021073421A1 (zh) 2021-04-22

Family

ID=69200604

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/118634 WO2021073421A1 (zh) 2019-10-18 2020-09-29 一种隐伏资源预测方法及岩石电磁学测井系统

Country Status (3)

Country Link
US (1) US20220299671A1 (zh)
CN (1) CN110703344B (zh)
WO (1) WO2021073421A1 (zh)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110703344B (zh) * 2019-10-18 2021-03-30 中国科学院地质与地球物理研究所 一种隐伏资源预测方法及岩石电磁学测井系统
US11624853B2 (en) 2020-01-31 2023-04-11 ExxonMobil Technology and Engineering Company Methods for performing formation evaluation and related systems
CN113447990B (zh) * 2020-03-24 2024-04-02 中国石油化工股份有限公司 井场电性异常体观测方法及装置
CN114296508B (zh) * 2021-12-30 2024-04-23 长沙巨杉智能科技有限公司 岩矿石标本阻抗测量信号源生成装置
CN115879648B (zh) * 2023-02-21 2023-06-06 中国地质科学院 一种基于机器学习的三元深部成矿预测方法及系统
CN116626779B (zh) * 2023-07-21 2023-11-10 中海石油(中国)有限公司深圳分公司 一种潜山地层孔隙度计算方法及系统

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5367262A (en) * 1991-07-12 1994-11-22 Halliburton Logging Serivces, Inc. Advances in high frequency dielectric logging
CN110118995A (zh) * 2019-04-29 2019-08-13 山东省地质矿产勘查开发局第六地质大队 一种隐伏多金属矿找矿方法
CN110133737A (zh) * 2019-06-26 2019-08-16 中国科学院地质与地球物理研究所 一种隐伏矿的电磁学预测方法
CN110703344A (zh) * 2019-10-18 2020-01-17 中国科学院地质与地球物理研究所 一种隐伏资源预测方法及岩石电磁学测井系统

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2860876B1 (fr) * 2003-10-10 2006-01-06 Inst Francais Du Petrole Methode et dispositif pour mesurer l'anisotropie de resistivite d'echantillons de roche presentant des litages
ES2339361T3 (es) * 2005-07-29 2010-05-19 Prad Research And Development Limited Metodo y aparato para transmitir o recibir informacion entre un equipo de fondo de pozo y la superficie.
CN101620275A (zh) * 2009-08-12 2010-01-06 中国煤炭地质总局水文地质局 煤矿床水文地质综合勘查方法
CN102053281B (zh) * 2009-11-10 2013-01-23 中国石油化工集团公司 一种运用长偏移距瞬变电磁阵列法进行油气检测的方法
CN104088629B (zh) * 2014-05-13 2017-04-05 刘红岐 地面双电频谱探测和识别矿藏的方法
FR3049711B1 (fr) * 2016-04-01 2018-04-13 IFP Energies Nouvelles Dispositif pour la determination de parametres petrophysiques d'une formation souterraine
US10451763B2 (en) * 2016-10-27 2019-10-22 Schlumberger Technology Corporation Evaluation of formation utilizing wideband electromagnetic measurements
US11294092B2 (en) * 2018-12-03 2022-04-05 Hallburton Energy Services, Inc. Low frequency complex resistivity measurement in a formation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5367262A (en) * 1991-07-12 1994-11-22 Halliburton Logging Serivces, Inc. Advances in high frequency dielectric logging
CN110118995A (zh) * 2019-04-29 2019-08-13 山东省地质矿产勘查开发局第六地质大队 一种隐伏多金属矿找矿方法
CN110133737A (zh) * 2019-06-26 2019-08-16 中国科学院地质与地球物理研究所 一种隐伏矿的电磁学预测方法
CN110703344A (zh) * 2019-10-18 2020-01-17 中国科学院地质与地球物理研究所 一种隐伏资源预测方法及岩石电磁学测井系统

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
HE LANFANG: "Petro Electricity and Its Origin: Examples from Luobusha Ultramafic Rock and Upper Yangtze Black Shale", CHINESE DOCTORAL DISSERTATIONS FULL-TEXT DATABASE, UNIVERSITY OF CHINESE ACADEMY OF SCIENCES, CN, 1 August 2014 (2014-08-01), CN, XP055802199, ISSN: 1674-022X *

Also Published As

Publication number Publication date
CN110703344A (zh) 2020-01-17
US20220299671A1 (en) 2022-09-22
CN110703344B (zh) 2021-03-30

Similar Documents

Publication Publication Date Title
WO2021073421A1 (zh) 一种隐伏资源预测方法及岩石电磁学测井系统
CN105652329B (zh) 一种评估煤层顶板视涌水量的方法和装置
CA2921822C (en) Borehole electric field survey with improved discrimination of subsurface features
RU2419820C2 (ru) Способ и устройство для передачи или приема информации между внутрискважинным оборудованием и поверхностью
EP3039460B1 (en) Mapping resistivity distribution within the earth
US8773132B2 (en) Fracture detection via self-potential methods with an electrically reactive proppant
US20090166030A1 (en) Method to monitor reservoir fracture development and its geometry
EA012880B1 (ru) Способ получения данных о геофизических свойствах коллектора
CN101525999B (zh) 电磁随钻测量系统的适应性分析方法
CN105116453A (zh) 一种冻土带天然气水合物的瞬变电磁勘探方法及装置
NO328811B1 (no) Framgangsmate og apparat for hurtig kartlegging av submarine hydrokarbonreservoarer
CN103174413A (zh) 一种钻具以及井下随钻探测储层界面和厚度的方法
Kahraman et al. Predicting the physico-mechanical properties of rocks from electrical impedance spectroscopy measurements
HU184067B (en) Hydrocarbon prospection method and device for indirect observing hydrocarbon reservoirs
CN110094195A (zh) 一种基于凹陷电极结构的油基泥浆电成像测井方法
Wang et al. Detection of shallow buried water-filled goafs using the fixed-loop transient electromagnetic method: A case study in Shaanxi, China
Yan et al. Study on the induced polarization model in the exploration for shale gas in southern China
CN107939385B (zh) 定量计算极化值及应用的方法
RU2736446C2 (ru) Способ электрического мониторинга характеристик пласт-коллектора при разработке залежей нефти с использованием закачки пара
CN104612661B (zh) 一种随钻电磁波测井装置和方法
Jackson et al. Rapid non-contacting resistivity logging of core
Viezzoli et al. Electrical methods for detection and discrimination of saline groundwater in clay-rich sediments in northern Victoria
He et al. Hydrocarbon detection with high-power spectral induced polarization, two cases
Tian et al. Prediction study of hydrocarbon reservoir based on time–frequency domain electromagnetic technique taking Ili Basin as an example
Cao et al. Comparative Analysis and Research on Electromagnetic Detection Technology of Tunnel Groundwater

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20876480

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20876480

Country of ref document: EP

Kind code of ref document: A1