A method for controlling resistivity logging through casing

Abstract

The present invention relates to a through-casing resistivity logging measurement control method, and belongs to the technical field of oil and gas field engineering logging. The logging method comprises: determining a calibration well section, measuring the calibration well section, calculating a reference correlation coefficient between reference detection signals, and obtaining a correlation coefficient threshold; measuring the target well section, calculating the logging correlation coefficient between the logging detection signals, and if the logging correlation coefficient exceeds the correlation coefficient threshold, then the measurement is terminated; if the logging correlation coefficient does not exceed the correlation coefficient threshold, then the detection is repeated until the logging correlation coefficient exceeds the correlation coefficient threshold. The present invention is based on the characteristic that when the measuring electrode and the casing are in good contact, the logging detection signals received by different measuring electrodes have a high correlation, and the correlation coefficient threshold is obtained according to the calibration well section; then, the calculated logging correlation coefficient of the target well section is compared with the correlation coefficient threshold, so that the contact quality of the measuring electrode and the casing can be judged, so that the measurement result is more accurate.

Description

Technical Field

[0001] The invention relates to a through-casing resistivity logging measurement control method, belonging to the technical field of oil and gas field engineering logging. Background Art

[0002] As oil and gas development enters a high water-cut period, in order to evaluate the remaining oil and gas reserve equivalent in the oil well and the development potential of non-target layers, through-casing resistivity logging, as an important production logging method, provides important data support for workers in related industries.

[0003] Through-casing resistivity logging is usually carried out using through-casing resistivity logging instruments. The instrument is mainly divided into two parts, the host computer and the downhole instrument. The host computer is a human-computer interaction device that mainly realizes command input, data reception, and results display. The downhole instrument completes the measurement arm control, low-frequency current transmission, and measurement data collection according to the instructions from the host computer. Generally, there are 6 electrodes on the downhole instrument, which are mainly divided into two categories, namely, the transmitting electrode and the measuring electrode. The transmitting electrode is on the upper and lower sides of the instrument, marked by A and B. The measuring electrode is arranged in the middle of the instrument, marked by U, M1, N, and M2. All electrodes are placed on the retractable measuring arm. During the logging process, when the logging instrument reaches the target layer, the upper unit will require the downhole instrument to open the measuring arm. Through timing, pressure measurement and other operations, after confirming that the electrode on the measuring arm is in contact with the well wall, the transmitting electrode will transmit low-frequency current signals to the casing in time, and at the same time, the measuring electrode will receive the voltage signal from the casing. The measurement value of the measuring electrode U is regarded as the potential difference between the measuring point and the surface, and the measured potential values ​​of the measuring electrodes M1, N, and M2 are used to calculate the leakage current part of the downhole instrument transmitting current flowing into the formation. Finally, according to the electrode measurement results and combined with the apparent resistivity formula, the resistivity of the formation at different depths can be calculated.

[0004] The traditional logging process is manually controlled. However, as a point measurement instrument, the through-casing resistivity logging instrument requires the instrument measurement support arm to be extended and retracted for each point measurement, which results in a long overall instrument measurement time. In order to ensure the stability of manual control, long-term continuous measurement is not possible, and the measurement time is necessarily extended due to the fluctuations in personal work status. This not only increases the measurement cost of through-casing resistivity logging, but also the measurement results are greatly affected by personal work status and environment, and are not accurate.

[0005] In order to avoid environmental influences on the accuracy of logging results, some people have proposed methods for correcting environmental factors. For example, the Chinese invention patent application document with application publication number CN106842342A discloses a through-casing resistivity logging method and device with automatic correction for electrode measurement influence. The method is to evaluate the environmental resistance in the measurement area by adding an ammeter to the electrode network, and then correct the electrode measurement differences caused by environmental differences by solving the resistance network parameters.

[0006] However, the basis of the above measurement method is based on the perfect contact between the measuring electrode and the casing. In the measurement process of the through-casing resistivity instrument, an important basis for successful implementation is to ensure the close contact between the transmitting electrode, the receiving electrode and the casing. However, in the actual logging process, due to the inevitable corrosion and scaling of the casing, it is difficult to ensure the effective contact between the measuring electrode and the casing during logging implementation, resulting in distortion of the signal received by the measuring electrode. Therefore, the above method is not only difficult to ensure the validity of the measurement results, but also cannot avoid the influence of personal working conditions on the measurement results.

[0007] In order to ensure the validity of the measurement results, field engineers are generally required to screen and judge the measurement data in real time during the measurement process, control the instrument based on the judgment results, and re-measure the bad points, which increases the measurement cost. Summary of the invention

[0008] The purpose of the present application is to provide a through-casing resistivity logging measurement control method to solve the problems of low effectiveness, high cost and inaccurate measurement results of existing logging methods.

[0009] To achieve the above purpose, the present application proposes a technical solution for a through-casing resistivity logging measurement control method, comprising the following steps:

[0010] 1) Determine a calibration well section, measure the calibration well section, and obtain a reference detection signal of each measuring electrode; the calibration well section is a standard mudstone section or an unused pure water layer;

[0011] 2) Calculate the reference correlation coefficient between the reference detection signals to obtain a correlation coefficient threshold for measuring whether the measurement result meets the standard;

[0012] 3) Measure the target well section to obtain the logging detection signal of each measuring electrode;

[0013] 4) calculating the well logging correlation coefficient between the well logging detection signals, and comparing the well logging correlation coefficient with the correlation coefficient threshold;

[0014] 5) If the logging correlation coefficient exceeds the correlation coefficient threshold, the measurement result meets the standard and the measurement is terminated; if the logging correlation coefficient does not exceed the correlation coefficient threshold, the measurement result does not meet the standard, and the measurement position is changed for re-testing, or the abnormal measuring electrode is selected and the abnormal measuring electrode is controlled for re-testing until the logging correlation coefficient exceeds the correlation coefficient threshold.

[0015] The beneficial effect of the technical solution of the casing resistivity logging measurement control method of the present invention is as follows: based on the characteristic that when the measuring electrode is in good contact with the casing, the logging detection signals received by different measuring electrodes have a high correlation, the present invention first measures the calibration well section, the calibration well section is a well section with good quality, so the reference correlation coefficient calculated by it is a qualified correlation coefficient, and for this purpose, a correlation coefficient threshold is obtained according to the reference correlation coefficient of the calibration well section; then, the target well section is measured, and the contact quality between the measuring electrode and the casing can be judged by comparing the logging correlation coefficient measured and calculated by the target well section with the correlation coefficient threshold, and then the validity of the measurement result can be judged, and when the measurement result is invalid, the measurement position is automatically replaced for re-measurement or the abnormal measuring electrode is automatically controlled for re-measurement, so as to avoid the influence of long-term manual work on the measurement result, and make the measurement result more accurate on the basis of reducing the measurement cost.

[0016] Furthermore, in order to ensure the accuracy of the correlation coefficient threshold, several measurement positions are determined in the calibration well section, and multiple measurements are performed on each measurement position. After each measurement, the reference correlation coefficient between the reference detection signals is calculated, and then the average correlation coefficient between the reference detection signals at each measurement position is obtained. The correlation coefficient threshold is obtained based on the average correlation coefficient at different measurement positions.

[0017] Furthermore, the process of obtaining the correlation coefficient threshold according to the average correlation coefficient at different measurement positions is as follows:

[0018] P′ xy =(1-α)min(P dj (x,y));

[0019] Among them, P′ xy The correlation coefficient threshold between the reference detection signals of the measuring electrode x and the measuring electrode y; P dj (x, y) is the average correlation coefficient between the reference detection signals of the measuring electrode x and the measuring electrode y at the jth measuring position; α is the threshold coefficient; min() is the minimum value function.

[0020] Furthermore, in order to improve the accuracy of the calculation of the well logging correlation coefficient, the calculation process of the well logging correlation coefficient is as follows:

[0021]

[0022] Where P is the logging correlation coefficient between the logging detection signals of the measuring electrode x and the measuring electrode y; N is the number of data sampling points of each measuring electrode; x i When it is the i-th sampling point, the logging detection signal of electrode x is measured; y i When is the i-th sampling point, the logging detection signal of electrode y is measured.

[0023] Furthermore, in order to improve the accuracy of the contact quality judgment between the measuring electrode and the sleeve, the correlation coefficient threshold includes a plurality of correlation coefficient sub-thresholds determined according to the number of measuring electrodes and the corresponding relationship between them.

[0024] Furthermore, in order to improve the accuracy of judgment and reduce the amount of calculation, there are four measuring electrodes, namely, measuring electrode U, measuring electrode M1, measuring electrode M2, and measuring electrode N. The logging correlation coefficient calculated in step 4) includes: the logging correlation coefficient P(U, M1) between the logging detection signals of measuring electrode U and measuring electrode M1, the logging correlation coefficient P(U, M2) between the logging detection signals of measuring electrode U and measuring electrode M2, and the logging correlation coefficient P(U, N) between the logging detection signals of measuring electrode U and measuring electrode N; the corresponding correlation coefficient sub-thresholds in step 2) are 5, namely, the correlation coefficient sub-threshold P′ between measuring electrode U and measuring electrode M1. UM1 , the correlation coefficient sub-threshold P′ of the measuring electrode U and the measuring electrode M2 UM2 , the correlation coefficient sub-threshold P′ of the measuring electrode U and the measuring electrode N UN , the correlation coefficient sub-threshold P′ of the measuring electrode M1 and the measuring electrode M2 M1M2 , the correlation coefficient sub-threshold P′ of the measuring electrode M1 and the measuring electrode N M1N .

[0025] Furthermore, if P(U,M1) exceeds P′ UM1 、P(U,M2) exceeds P′ UM2 , P(U,N) exceeds P′ UN , the measurement result meets the standard and the measurement ends.

[0026] Furthermore, if P(U,M1) does not exceed P′ UM1 , and P(U,M2) exceeds P′ UM2 , P(U,N) exceeds P′ UN , then the measuring electrode M1 is an abnormal measuring electrode, and the contraction distance and contraction duration of the measuring electrode M1 are controlled, and retested until the calculated P(U,M1) exceeds P′ UM1 ;

[0027] If P(U,M1) exceeds P′ UM1 , P(U,N) exceeds P′UN , and P(U,M2) does not exceed P′ UM2 , then the measuring electrode M2 ​​is an abnormal measuring electrode, and the contraction distance and contraction duration of the measuring electrode M2 ​​are controlled, and retested until P(U,M2) is calculated to exceed P′ UM2 ;

[0028] If P(U,M1) exceeds P′ UM1 , P(U,M2) exceeds P′ UM2 , and P(U,N) does not exceed P′ UN , then the measuring electrode N is an abnormal measuring electrode, and the contraction distance and contraction duration of the measuring electrode N are controlled, and the test is repeated until P(U,N) is calculated to exceed P′ UN ;

[0029] If P(U,M1) exceeds P′ UM1 , and P(U,M2) does not exceed P′ UM2 , P(U,N) does not exceed P′ UN , then the measuring electrodes M2 and N are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes M2 and N are controlled, and retested until P(U, M2) is calculated to exceed P′ UM2 And P(U,N) exceeds P′ UN ;

[0030] If P(U,M2) exceeds P′ UM2 , and P(U,M1) does not exceed P′ UM1 , P(U,N) does not exceed P′ UN , then the measuring electrodes M1 and N are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes M1 and N are controlled, and retested until P(U,M1) is calculated to exceed P′ UM1 And P(U,N) exceeds P′ UN ;

[0031] If P(U,N) exceeds P′ UN , and P(U,M1) does not exceed P′ UM1 , P(U,M2) does not exceed P′ UM2 , then the measuring electrodes M1 and M2 are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes M1 and M2 are controlled, and retested until the calculated P(U,M1) exceeds P′ UM1 And P(U,M2) exceeds P′ UM2 .

[0032] Furthermore, if P(U,M1) does not exceed P′ UM1 , P(U,M2) does not exceed P′ UM2, P(U,N) does not exceed P′ UN , then continue to measure the logging correlation coefficient P(M1,M2) between the logging detection signals of the measuring electrode M1 and the measuring electrode M2, and the logging correlation coefficient P(M1,N) between the logging detection signals of the measuring electrode M1 and the measuring electrode N:

[0033] If P(M1,M2) exceeds P′ M1M2 、P(M1,N) exceeds P′ M1N , then the measuring electrode U is an abnormal measuring electrode, control the contraction distance and contraction duration of the measuring electrode U, and retest until the calculated P(U,M1) exceeds P′ UM1 、P(U,M2) exceeds P′ UM2 , P(U,N) exceeds P′ UN ;

[0034] If P(M1,M2) exceeds P′ M1M2 , P(M1,N) does not exceed P′ M1N ; Then the measuring electrodes U and N are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes U and N are controlled, and retested until P(U,M1) is calculated to exceed P′ UM1 、P(U,M2) exceeds P′ UM2 , P(U,N) exceeds P′ UN 、P(M1,N) exceeds P′ M1N ;

[0035] If P(M1,M2) does not exceed P′ M1M2 、P(M1,N) exceeds P′ M1N ; Then the measuring electrodes U and M2 are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes U and M2 are controlled, and retested until P(U, M1) is calculated to exceed P′ UM1 、P(U,M2) exceeds P′ UM2 , P(U,N) exceeds P′ UN 、P(M1,M2) exceeds P′ M1M2 ;

[0036] If P(M1,M2) does not exceed P′ M1M2 , P(M1,N) does not exceed P′ M1N ; then change the measuring position and retest. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flow chart of the through-casing resistivity logging measurement control method of the present invention;

[0038] Figure 2 It is a schematic diagram of the measurement process of a certain measuring point in the calibration well section of the present invention;

[0039] Figure 3 is a well logging curve of a certain well of the present invention;

[0040] Figure 4 It is a signal diagram when the measuring electrode M1 of the present invention is abnormal;

[0041] Figure 5 It is a signal diagram when the measuring electrode M1 of the present invention is normal. DETAILED DESCRIPTION

[0042] Implementation example of a method for controlling through-casing resistivity logging measurement:

[0043] The main idea of ​​the through-casing resistivity logging measurement control method is that, in order to solve the problem of inaccurate measurement results caused by casing corrosion in the prior art, the present invention is based on the characteristic that when the measuring electrode is in good contact with the casing, the logging detection signals received by different measuring electrodes have a high correlation. First, the calibration well section is measured to establish a qualified correlation coefficient threshold array; secondly, the target well section is measured, and whether the measurement result is accurate is judged by whether the logging correlation coefficient of the data measured by different measuring electrodes exceeds the corresponding sub-threshold. If the logging correlation coefficient does not exceed the corresponding sub-threshold, it indicates that the measurement result is inaccurate and needs to be re-measured; if the logging correlation exceeds the corresponding threshold, it indicates that the data is accurate and reliable, and the resistivity can be calculated, thereby improving the accuracy of resistivity logging.

[0044] Specifically, the through-casing resistivity logging measurement control method of the present invention is as follows: Figure 1 As shown, the following steps are included:

[0045] 1) Determine a calibration well section, measure the calibration well section, obtain reference detection signals of each measuring electrode, calculate reference correlation coefficients between reference detection signals, and obtain a correlation coefficient threshold.

[0046] The process of determining the calibration well section: Based on the logging data of a well measured by the instrument, the well section with qualified measurement results is selected as the calibration well section. The qualified measurement results refer to the standard mudstone section or the unused pure water layer.

[0047] After the calibration well section is determined, first, based on the actual geological data, the on-site engineer needs to select a group of measuring points that meet the measurement quality standards (each measuring point corresponds to a measuring depth, i.e., the measuring position). The number of measuring points should be more than 10 (the number of measuring points can be adjusted according to the actual working conditions. The overall purpose is to achieve a certain amount of data and be able to show the statistical characteristics of the measurement data itself in the measured data); secondly, use the operating interface of the instrument host computer system to input measurement parameters such as measuring point spacing, output voltage, and sampling interval; finally, the operator uses the well site winch to lower the instrument to the calibration layer measurement depth and start measuring.

[0048] During the measurement process, multiple measurements are performed on each measuring point (generally the number of measurements is greater than 10 times), and voltage data of different measuring electrodes are obtained in each measurement. The voltage data obtained in each measurement is used to calculate the reference correlation coefficient between different measuring electrodes. The multiple measurements are averaged to obtain the average correlation coefficient between different measuring electrodes at each measuring point, and then the correlation coefficient threshold is obtained based on the average correlation coefficient at different measuring points.

[0049] For a certain measurement point, the calculation process of the reference correlation coefficient is as follows:

[0050]

[0051] Wherein, P is the reference correlation coefficient between the detection signals of the measuring electrode x and the measuring electrode y; N is the number of data sampling points of each measuring electrode; x i When y is the i-th sampling point, the reference detection signal of electrode x is measured; i When is the i-th sampling point, the reference detection signal of electrode y is measured.

[0052] The calculation process of the average correlation coefficient is:

[0053]

[0054] Among them, P d (x, y) is the average correlation coefficient between the reference detection signals of the measuring electrode x and the measuring electrode y; n is the total number of measurements; P m (x, y) is the reference correlation coefficient between the reference detection signals of the measuring electrode x and the measuring electrode y at the mth measurement.

[0055] Establish the correlation coefficient threshold based on the average correlation coefficient of different measurement points:

[0056] P′ xy =(1-α)min(P dj (x,y));

[0057] Among them, P′ xy The correlation coefficient threshold between the reference detection signals of the measuring electrode x and the measuring electrode y; P dj (x, y) is the average correlation coefficient between the reference detection signals of the measuring electrode x and the measuring electrode y at the jth measuring position; α is the threshold coefficient; min() is the minimum value function.

[0058] In this embodiment, there are four measuring electrodes, namely measuring electrode U, measuring electrode M1, measuring electrode M2, and measuring electrode N. The correlation coefficient threshold is composed of a number of sub-thresholds. Different measuring electrodes correspond to different sub-thresholds. The corresponding correlation coefficient sub-thresholds are 5 (here only these 5 correlation coefficient thresholds are needed to determine whether the contact between the measuring electrode and the casing is good, without too many settings), which are the correlation coefficient sub-thresholds P′ of the measuring electrode U and the measuring electrode M1. UM1 , the correlation coefficient sub-threshold P′ of the measuring electrode U and the measuring electrode M2 UM2 , the correlation coefficient sub-threshold P′ of the measuring electrode U and the measuring electrode N UN , the correlation coefficient sub-threshold P′ of the measuring electrode M1 and the measuring electrode M2 M1M2 , the correlation coefficient sub-threshold P′ of the measuring electrode M1 and the measuring electrode N M1N .

[0059] For the jth measuring point, if Figure 2 As shown, all correlation coefficients are counted to form a correlation coefficient matrix, and the average correlation coefficients P of the measuring electrode U and the measuring electrode M1 are obtained through the correlation coefficient matrix. dj (U, M1), the average correlation coefficient P of the measuring electrode U and the measuring electrode M2 dj (U, M2), the average correlation coefficient P of the measuring electrode U and the measuring electrode N dj (U, N), the average correlation coefficient P of the measuring electrode M1 and the measuring electrode M2 dj (M1, M2), the average correlation coefficient P of the measuring electrode M1 and the measuring electrode N dj (M1,N), forming the correlation coefficient array of the measurement point.

[0060] The threshold calculation formula is used to obtain the correlation coefficient sub-threshold P′ between the measuring electrode U and the measuring electrode M1. UM1 , the correlation coefficient sub-threshold P′ of the measuring electrode U and the measuring electrode M2 UM2 , the correlation coefficient sub-threshold P′ of the measuring electrode U and the measuring electrode N UN , the correlation coefficient sub-threshold P′ of the measuring electrode M1 and the measuring electrode M2 M1M2 , the correlation coefficient sub-threshold P′ of the measuring electrode M1 and the measuring electrode N M1N , establish the correlation coefficient threshold array that meets the standard as [P′ UM1 , P′ UM2 , P′ UN , P′ M1M2 , P′ M1N ].

[0061] 2) Carry out measurement of the target layer. After each measurement, calculate the logging correlation coefficient between the logging detection signals of the measuring electrodes. If the logging correlation coefficient exceeds the correlation coefficient threshold, end the measurement; if the logging correlation coefficient does not exceed the correlation coefficient threshold, change the measurement position and re-detect, or select the abnormal measuring electrode and control the abnormal measuring electrode to re-detect until the logging correlation coefficient exceeds the correlation coefficient threshold.

[0062] The automatic control measurement mode is selected for the measurement of the target layer. The operator inputs the specific operation parameters into the upper computer system and cooperates with the winch to lower the instrument to the corresponding detection depth. Since there is an unscraped oil and dirt layer in the target layer section, the measuring electrode will not be in good contact with the casing arm, and the voltage data measured by the measuring electrode will be obviously distorted. Therefore, the correlation coefficient between the voltage signals of the measuring electrodes is calculated to determine whether the data is accurate.

[0063] Specifically, the calculation process of the well logging correlation coefficient is exactly the same as that of the reference correlation coefficient. In order to reduce excessive character explanations, the reference correlation coefficient and the well logging correlation coefficient are represented by the same characters. In order to reduce the calculation process, the processing process after the well logging correlation coefficient is determined is as follows:

[0064] There are 4 measuring electrodes, so first calculate the logging correlation coefficients between the logging detection signals of the measuring electrode U and the other three measuring electrodes. The logging correlation coefficient between the logging detection signals of the measuring electrode U and the measuring electrode M1 is recorded as P(U, M1), the logging correlation coefficient between the logging detection signals of the measuring electrode U and the measuring electrode M2 ​​is recorded as P(U, M2), and the logging correlation coefficient between the logging detection signals of the measuring electrode U and the measuring electrode N is recorded as P(U, N). After comparing these three correlation coefficients with the corresponding sub-thresholds, the following situations appear:

[0065] aP(U,M1) exceeds P′ UM1 、P(U,M2) exceeds P′ UM2 , P(U,N) exceeds P′ UN , indicating that the correlation of all measuring electrodes is strong, the data meets the requirements, and no subsequent calculation and judgment are required. The downhole control module sends a measurement completion signal to the downhole communication module to control the measurement electrode to retract and complete the measurement of the depth measurement point.

[0066] b. If the correlation coefficient of some parts does not exceed the corresponding sub-threshold, then find the abnormal measuring electrode, control the contraction distance and contraction duration of the abnormal measuring electrode, and measure again, specifically:

[0067] If P(U,M1) does not exceed P′ UM1 , and P(U,M2) exceeds P′ UM2, P(U,N) exceeds P′ UN , then the measuring electrode M1 is an abnormal measuring electrode, so the measuring electrode M1 is controlled to contract for a short distance, and the contraction time is 1 / 5 of the full contraction time, until P(U,M1) is calculated to exceed P′ UM1 If the threshold is still not exceeded after multiple measurements (usually 5 times), all measuring electrodes are controlled to shrink, and the measuring position is changed to re-measure (the changed measuring position is generally within 1m of the original measuring position to avoid other electrodes measuring the original position again);

[0068] If P(U,M1) exceeds P′ UM1 , P(U,N) exceeds P′ UN , and P(U,M2) does not exceed P′ UM2 , then the measuring electrode M2 ​​is an abnormal measuring electrode, and the contraction distance and contraction duration of the measuring electrode M2 ​​are controlled, and retested until P(U,M2) is calculated to exceed P′ UM2 ;

[0069] If P(U,M1) exceeds P′ UM1 , P(U,M2) exceeds P′ UM2 , and P(U,N) does not exceed P′ UN , then the measuring electrode N is an abnormal measuring electrode, and the contraction distance and contraction duration of the measuring electrode N are controlled, and the test is repeated until P(U,N) is calculated to exceed P′ UN ;

[0070] If P(U,M1) exceeds P′ UM1 , and P(U,M2) does not exceed P′ UM2 , P(U,N) does not exceed P′ UN , then the measuring electrodes M2 and N are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes M2 and N are controlled, and retested until P(U, M2) is calculated to exceed P′ UM2 And P(U,N) exceeds P′ UN ;

[0071] If P(U,M2) exceeds P′ UM2 , and P(U,M1) does not exceed P′ UM1 , P(U,N) does not exceed P′ UN , then the measuring electrodes M1 and N are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes M1 and N are controlled, and retested until P(U,M1) is calculated to exceed P′ UM1 And P(U,N) exceeds P′ UN ;

[0072] If P(U,N) exceeds P′ UN, and P(U,M1) does not exceed P′ UM1 , P(U,M2) does not exceed P′ UM2 , then the measuring electrodes M1 and M2 are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes M1 and M2 are controlled, and retested until the calculated P(U,M1) exceeds P′ UM1 And P(U,M2) exceeds P′ UM2 .

[0073] c. If P(U,M1) does not exceed P′ UM1 , P(U,M2) does not exceed P′ UM2 , P(U,N) does not exceed P′ UN , then continue to calculate the logging correlation coefficient P(M1,M2) between the logging detection signals of the measuring electrode M1 and the measuring electrode M2, and the logging correlation coefficient P(M1,N) between the logging detection signals of the measuring electrode M1 and the measuring electrode N:

[0074] If P(M1,M2) exceeds P′ M1M2 、P(M1,N) exceeds P′ M1N , then the measuring electrode U is an abnormal measuring electrode, control the contraction distance and contraction duration of the measuring electrode U, and retest until the calculated P(U,M1) exceeds P′ UM1 、P(U,M2) exceeds P′ UM2 , P(U,N) exceeds P′ UN ;

[0075] If P(M1,M2) exceeds P′ M1M2 , P(M1,N) does not exceed P′ M1N ; Then the measuring electrodes U and N are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes U and N are controlled, and retested until P(U,M1) is calculated to exceed P′ UM1 、P(U,M2) exceeds P′ UM2 , P(U,N) exceeds P′ UN 、P(M1,N) exceeds P′ M1N ;

[0076] If P(M1,M2) does not exceed P′ M1M2 、P(M1,N) exceeds P′ M1N ; Then the measuring electrodes U and M2 are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes U and M2 are controlled, and retested until P(U, M1) is calculated to exceed P′ UM1 、P(U,M2) exceeds P′ UM2 , P(U,N) exceeds P′ UN 、P(M1,M2) exceeds P′M1M2 ;

[0077] If P(M1,M2) does not exceed P′ M1M2 , P(M1,N) does not exceed P′ M1N

[0078] Then directly record the measurement position, detect its own air mining signal, and upload instructions to the host computer and winch under the premise of normal air mining, change the detection depth, and calculate the new measurement point position within the next 0.5m range; if any electrode air mining is abnormal, indicating that the instrument is faulty, stop measuring.

[0079] In the above embodiment, in order to improve the reliability of the contact quality judgment between the measuring electrode and the sleeve, corresponding correlation coefficient sub-thresholds are set between different measuring electrodes. As other implementation methods, a correlation coefficient threshold can also be set to complete the judgment, and the present invention does not limit this.

[0080] The method of the present invention is verified by taking a certain well as an example.

[0081] like Figure 3 As shown in the actual measurement of a well, the calibration section 2491-2499m was selected around the target layer section 2500-2510m. According to the completion curve, it can be seen that this section is a standard mudstone section with a simple geological structure and good well conditions.

[0082] After measuring the calibration well section, the correlation threshold array shown in Table 1 is obtained:

[0083] Table 1 Correlation coefficient sub-thresholds between each measuring electrode

[0084] Measuring electrode identification <![CDATA[P′ UM1 ]]> <![CDATA[P′ UM2 ]]> <![CDATA[P′ UN ]]> <![CDATA[P′ M1N ]]> <![CDATA[P′ M1M2 ]]> Correlation coefficient subthreshold 0.9812 0.9801 0.9810 0.9901 0.9891

[0085] After obtaining the correlation coefficient sub-threshold, the target layer section is measured. During a certain measurement process, P(U, M1), P(U, M2) and P(U, N) are calculated, and P(U, M1) is 0.4795, which is less than P UM1 =0.9812, and the other two groups of logging correlation coefficients are greater than the set sub-threshold, indicating that the measuring electrode M1 is an abnormal measuring electrode (in order to verify the accuracy of the abnormal electrode judgment, check the measurement results and observe the measurement results as shown in the figure). Figure 4 As shown, the signal of the measuring electrode M1 is obviously distorted, indicating that the measuring electrode M1 does not make good contact with the casing arm).

[0086] According to the above method, the measuring electrode M1 is controlled to contract for 2 minutes. After the contraction is completed, the measuring electrode M1 is re-commanded to extend for 2 minutes and 30 seconds. Then it is measured again. P(U,M1) is calculated to be 0.9948, which is greater than P UM1= 0.9812, and then proceed to the next measurement point (in order to verify the accuracy of abnormal electrode judgment, check the measurement results and observe the measurement results as follows Figure 5 As shown, the signal of the measuring electrode M1 is normal).

[0087] Finally, the logging method of the present invention is used to automatically control the casing resistivity instrument to complete the measurement of the target layer well section, and the logging curve is obtained as follows: Figure 3 As shown, the entire process no longer requires engineers to judge the data quality in real time, and all data correlation coefficients are above 0.9915, meeting the needs of actual data processing.

[0088] The beneficial effects of the present invention are:

[0089] 1. During the entire measurement process, the field engineer only participates in the work of calibrating the optimization of the well section data, and other measurement control work is performed by the instrument control module, which reduces the operation complexity and saves measurement costs.

[0090] 2. During the measurement process, the contact quality control of all measuring electrodes and sleeves has a unified standard, which improves the controllability of the overall data quality and greatly avoids the introduction of bad point information due to human fatigue and carelessness.

[0091] 3. The calibrated well section data in the through-casing resistivity instrument not only provides data support for automated measurement control, but can also be integrated into a database for different geological conditions and the electrode correlation of the instrument itself in the later stage, providing an important basis for the later data correction and interpretation combined with well condition information.

Claims

1. A through-casing resistivity logging measurement control method, characterized in that: The following steps are involved: 1) Determine a calibration well section, measure the calibration well section, and obtain a reference detection signal of each measuring electrode; the calibration well section is a standard mudstone section or an unused pure water layer; 2) Calculate the reference correlation coefficient between the reference detection signals to obtain the correlation coefficient value to measure whether the measurement result meets the standard; the process of correlation coefficient threshold is: P x ' y =(1-α)min(P dj (x,y)); where P x ' y The correlation coefficient threshold between the reference detection signals of the measuring electrode x and the measuring electrode y; P dj (x, y) is the average correlation coefficient between the reference detection signals of the measuring electrode x and the measuring electrode y at the jth measuring position; α is the threshold coefficient; min() is the minimum value function; 3) Measure the target well section to obtain the logging detection signal of each measuring electrode; 4) calculating the well logging correlation coefficient between the well logging detection signals, and comparing the well logging correlation coefficient with the correlation coefficient threshold; 5) If the logging correlation coefficient exceeds the correlation coefficient threshold, the measurement result meets the standard and the measurement is terminated; if the logging correlation coefficient does not exceed the correlation coefficient threshold, the measurement result does not meet the standard, and the measurement position is changed for re-testing, or the abnormal measuring electrode is selected and the abnormal measuring electrode is controlled for re-testing until the logging correlation coefficient exceeds the correlation coefficient threshold.

2. The through-casing resistivity logging measurement control method according to claim 1, characterized in that: In the calibration well section, several measurement positions are determined, and multiple measurements are performed on each measurement position. After each measurement, the reference correlation coefficient between the reference detection signals is calculated, and then the average correlation coefficient between the reference detection signals at each measurement position is obtained. The correlation coefficient threshold is obtained based on the average correlation coefficient at different measurement positions.

3. The through-casing resistivity logging measurement control method according to claim 1, characterized in that: The calculation process of the logging correlation coefficient is: Where P is the logging correlation coefficient between the logging detection signals of the measuring electrode x and the measuring electrode y; N is the number of data sampling points of each measuring electrode; x i When it is the i-th sampling point, the logging detection signal of electrode x is measured; y i When is the i-th sampling point, the logging detection signal of electrode y is measured.

4. The through-casing resistivity logging measurement control method according to claim 1, 2 or 3, characterized in that: The correlation coefficient threshold includes a plurality of correlation coefficient sub-thresholds determined according to the number of measuring electrodes and the corresponding relationship between them.

5. The through-casing resistivity logging measurement control method according to claim 4, characterized in that: There are 4 measuring electrodes, namely measuring electrode U, measuring electrode M1, measuring electrode M2, and measuring electrode N. The logging correlation coefficients calculated in step 4) include: the logging correlation coefficient P(U, M1) between the logging detection signals of the measuring electrode U and the measuring electrode M1, the logging correlation coefficient P(U, M2) between the logging detection signals of the measuring electrode U and the measuring electrode M2, and the logging correlation coefficient P(U, N) between the logging detection signals of the measuring electrode U and the measuring electrode N; the corresponding correlation coefficient sub-thresholds in step 2) are 5, namely the correlation coefficient sub-thresholds P(U, M1) between the measuring electrode U and the measuring electrode M1. U ' M1 , the correlation coefficient sub-threshold P of the measuring electrode U and the measuring electrode M2 U ' M2 , the correlation coefficient sub-threshold P of the measuring electrode U and the measuring electrode N U ' N , the correlation coefficient sub-threshold P of the measuring electrode M1 and the measuring electrode M2 M ′M 1M2 , the correlation coefficient sub-threshold P of the measuring electrode M1 and the measuring electrode N M ′M 1N .

6. The through-casing resistivity logging measurement control method according to claim 5, characterized in that: If P(U,M1) exceeds P U ' M1 、P(U,M2) exceeds P U ' M2 , P(U,N) exceeds P U ' N , the measurement result meets the standard and the measurement ends.

7. The through-casing resistivity logging measurement control method according to claim 5, characterized in that: If P(U,M1) does not exceed P U ' M1 , and P(U,M2) exceeds P U ' M2 , P(U,N) exceeds P U ' N , then the measuring electrode M1 is an abnormal measuring electrode, and the contraction distance and contraction duration of the measuring electrode M1 are controlled, and retested until the calculated P(U,M1) exceeds P U ' M1 ; If P(U,M1) exceeds P U ' M1 , P(U,N) exceeds P U ' N , and P(U,M2) does not exceed P U ' M2 , then the measuring electrode M2 ​​is an abnormal measuring electrode, and the contraction distance and contraction duration of the measuring electrode M2 ​​are controlled, and retested until the calculated P(U,M2) exceeds P U ' M2 ; If P(U,M1) exceeds P U ' M1 , P(U,M2) exceeds P U ' M2 , and P(U,N) does not exceed P U ' N , then the measuring electrode N is an abnormal measuring electrode, and the contraction distance and contraction duration of the measuring electrode N are controlled, and the test is repeated until the calculated P(U,N) exceeds P U ' N ; If P(U,M1) exceeds P U ' M1 , and P(U,M2) does not exceed P U ' M2 , P(U,N) does not exceed P U ' N , then the measuring electrodes M2 and N are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes M2 and N are controlled, and retested until the calculated P(U,M2) exceeds P U ' M2 And P(U,N) exceeds P U ' N ; If P(U,M2) exceeds P U ' M2 , and P(U,M1) does not exceed P U ' M1 , P(U,N) does not exceed P U ' N , then the measuring electrodes M1 and N are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes M1 and N are controlled, and retested until the calculated P(U,M1) exceeds P U ' M1 And P(U,N) exceeds P U ' N ; If P(U,N) exceeds P U ' N , and P(U,M1) does not exceed P U ' M1 , P(U,M2) does not exceed P U ' M2 , then the measuring electrodes M1 and M2 are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes M1 and M2 are controlled, and retested until the calculated P(U,M1) exceeds P U ' M1 And P(U,M2) exceeds P U ' M2 .

8. The through-casing resistivity logging measurement control method according to claim 5, characterized in that: If P(U,M1) does not exceed P U ' M1 , P(U,M2) does not exceed P U ' M2 , P(U,N) does not exceed P U ' N , then continue to calculate the logging correlation coefficient P(M1,M2) between the logging detection signals of the measuring electrode M1 and the measuring electrode M2, and the logging correlation coefficient P(M1,N) between the logging detection signals of the measuring electrode M1 and the measuring electrode N: If P(M1,M2) exceeds P′ M1M2 、P(M1,N) exceeds P′ M1N , then the measuring electrode U is an abnormal measuring electrode, and the contraction distance and contraction duration of the measuring electrode U are controlled, and retested until the calculated P(U,M1) exceeds P U ' M1 、P(U,M2) exceeds P′ UM2 , P(U,N) exceeds P′ UN ; If P(M1,M2) exceeds P′ M1M2 , P(M1,N) does not exceed P′ M1N ; Then the measuring electrodes U and N are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes U and N are controlled, and retested until P(U,M1) is calculated to exceed P′ UM1 、P(U,M2) exceeds P′ UM2 , P(U,N) exceeds P′ UN 、P(M1,N) exceeds P′ M1N ; If P(M1,M2) does not exceed P′ M1M2 、P(M1,N) exceeds P′ M1N ; Then the measuring electrodes U and M2 are abnormal measuring electrodes, and the contraction distance and contraction duration of the measuring electrodes U and M2 are controlled, and retested until P(U, M1) is calculated to exceed P′ UM1 、P(U,M2) exceeds P′ UM2 , P(U,N) exceeds P′ UN 、P(M1,M2) exceeds P′ M1M2 ; If P(M1,M2) does not exceed P′ M1M2 , P(M1,N) does not exceed P′ M1N ; then change the measuring position and retest.

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