Oil field water flooding extra-high water content later-stage double-fixing and double-changing adjusting method

Abstract

The invention relates to the technical field of oil and gas development, in particular to an oil field water drive extra-high water content later-stage double-setting and double-changing adjusting method. The method comprises the steps of determining a first abnormal characteristic value by analyzing abnormal change characteristics of stratified pressure and stratified flow in a stratified water injection test process and combining a difference degree between the abnormal change characteristics of the stratified pressure and the abnormal change characteristics of the stratified flow; acquiring a second abnormal characteristic value based on the sudden change peak value characteristics by analyzing the sudden change peak value characteristics of the layered pressure and the layered flow; determining an abnormal blockage evaluation value by combining the first abnormal characteristic value and the second abnormal characteristic value, regulating and controlling the separated layer water injection test process by using the abnormal blockage evaluation value, and measuring a separated layer indication curve of the separated layer injection well after regulation and control; and performing double-fixed double-change adjustment based on the layered indication curve. According to the method, the abnormal blockage characteristics in the separated layer water injection testing process are accurately evaluated, and the process of the separated layer water injection testing is more accurately controlled.

Description

Technical Field

[0001] This invention relates to the field of oil and gas development technology, specifically to a dual-fixed and dual-replacement adjustment method for the late stage of water-drive ultra-high water cut in oilfields. Background Technology

[0002] As oilfield waterflooding enters the ultra-high water-cut development stage, dynamic heterogeneity intensifies. The "general water injection at the injection end and stratified oil production at the production end" approach is no longer suitable for effective water injection in stratified injection wells. Optimization of stratified water injection methods is needed by combining dynamic and static data, as well as reservoir engineering and information technology, to promote the gradual development of stratified water injection technology towards more refined water injection and precise control. However, due to the large reservoir span and significant permeability differences, the average number of subdivided water injection segments per well has reached more than five. Precise waterflooding injection schemes require field testing for implementation and realization, posing significant challenges to testing adjustments and the stability of water distribution across segments. The key to effective water injection lies in how to efficiently implement and execute precise water injection schemes in the field.

[0003] To ensure the continuous and effective utilization of each segment in a stratified injection well, a "double-fixed, double-replaced" stratified water injection method is proposed. This method achieves the goal of "good water injection and sufficient water injection" through "qualitative measurement, demand-based pressure setting, segment rotation, and well point rotation." The qualitative measurement typically involves using a pressurized stratified water injection test to measure the stratified indicator curve, and then using this curve to redetermine the segment properties of each segment in the stratified injection well. However, during the measurement of the stratified indicator curve using the pressurized stratified water injection test, the segment nozzles are prone to abnormal blockage due to water impurities. This causes the stratified indicator curve to shift towards the pressure axis. Existing technology does not accurately monitor the abnormal blockage characteristics of the segment nozzles in real time, making it impossible to accurately control the stratified water injection test process. This results in poor quality of the directly measured stratified indicator curve, affecting the accuracy of subsequent segment property redetering. Summary of the Invention

[0004] To address the technical problem that existing technologies cannot accurately control the process of stratified water injection testing, resulting in poor quality of directly measured stratification indicator curves, the present invention aims to provide a dual-fixed-dual-change adjustment method for the later stage of ultra-high water cut water drive in oilfields. The specific technical solution adopted is as follows:

[0005] This invention proposes a dual-fixed and dual-replacement adjustment method for the late stage of ultra-high water cut in oilfield water drive, which includes the following steps:

[0006] Obtain the stratified pressure sequence and stratified flow rate sequence at each acquisition time during the stratified water injection test of the stratified injection well;

[0007] Anomaly feature analysis is performed on the layered pressure sequence and layered flow sequence to obtain the pressure anomaly sequence and flow anomaly sequence at each acquisition time. Based on the anomaly features within the pressure anomaly sequence and flow anomaly sequence, and combined with the degree of difference between the pressure anomaly sequence and flow anomaly sequence, the first anomaly feature value at each acquisition time is determined.

[0008] Abrupt change feature analysis is performed on the layered pressure sequence and layered flow sequence to obtain the pressure abrupt change sequence and flow abrupt change sequence at each acquisition time; based on the abrupt change peak characteristics within the pressure abrupt change sequence and flow abrupt change sequence, a second abnormal feature value is determined at each acquisition time; combined with the first abnormal feature value and the second abnormal feature value, the abnormal congestion assessment value at the current acquisition time is obtained;

[0009] The abnormal blockage assessment value is used to regulate the stratified water injection test process. After regulation, the stratification indicator curve of the stratified injection well is measured. Based on the stratification indicator curve, a dual-fixed and dual-replacement adjustment is performed, which includes experimental qualitative measurement, on-demand pressure setting, stratification system rotation, and well point rotation.

[0010] Preferably, the method for obtaining the pressure anomaly sequence includes:

[0011] The hierarchical stress sequence at each acquisition time is used as the input of the LOF anomaly detection algorithm, and the local outlier factor of each element in the hierarchical stress sequence is obtained by using the LOF anomaly detection algorithm.

[0012] The sequence of local outliers of all elements in the stratified pressure sequence, arranged in chronological order, is used as the pressure anomaly sequence for each acquisition time.

[0013] Preferably, the method for obtaining the traffic anomaly sequence includes:

[0014] The hierarchical flow sequence at each acquisition time is used as the input to the LOF anomaly detection algorithm, and the local outlier factor of each element in the hierarchical flow sequence is obtained by using the LOF anomaly detection algorithm.

[0015] The sequence of local outliers of all elements in the hierarchical flow sequence, arranged in chronological order, is used as the flow anomaly sequence for each acquisition time.

[0016] Preferably, the method for obtaining the first abnormal feature value includes:

[0017] Based on the changes within the pressure anomaly sequence and flow anomaly sequence, the cumulative anomaly level at each acquisition time is obtained;

[0018] The degree of difference between the pressure anomaly sequence and the flow anomaly sequence is calculated, and the first anomaly feature value at each acquisition time is obtained based on the cumulative anomaly degree and the degree of difference.

[0019] Preferably, the method for obtaining the cumulative anomaly level includes:

[0020] Calculate the first-order difference sequence of the pressure anomaly sequence as the pressure anomaly change sequence at each acquisition time;

[0021] Calculate the first-order difference sequence of the flow anomaly sequence as the flow anomaly change sequence at each collection time;

[0022] The cumulative degree of anomaly at each acquisition time is determined based on the positive numbers in the abnormal pressure change sequence and the abnormal flow rate change sequence.

[0023] Preferably, the method for obtaining the stress mutation sequence includes:

[0024] Calculate all first-order difference values ​​within the stratified pressure sequence, and use the absolute values ​​of all first-order difference values ​​within the stratified pressure sequence arranged in chronological order as the pressure mutation sequence for each acquisition moment.

[0025] Preferably, the method for obtaining the flow mutation sequence includes:

[0026] Calculate all first-order difference values ​​within the hierarchical flow sequence, and use the sequence of absolute values ​​of all first-order difference values ​​within the hierarchical flow sequence in chronological order as the flow mutation sequence for each acquisition time.

[0027] Preferably, the method for obtaining the second abnormal feature value includes:

[0028] Based on the maximum peak value within the stress mutation sequence, obtain the maximum peak mutation ratio and the maximum peak position within the stress mutation sequence;

[0029] Based on the maximum peak value within the flow mutation sequence, obtain the maximum peak value mutation ratio and the maximum peak value rank within the flow mutation sequence;

[0030] Based on the difference between the maximum peak position in the pressure mutation sequence and the maximum peak position in the flow mutation sequence, and combined with the maximum peak mutation ratio in the pressure mutation sequence and the maximum peak mutation ratio in the flow mutation sequence, the second abnormal feature value at each acquisition time is determined.

[0031] Preferably, the method for obtaining the maximum peak mutation ratio and the maximum peak position within the stress mutation sequence includes:

[0032] The stress mutation sequence is used as input to the peak detection algorithm, which is then used to obtain the maximum peak value and the position of the maximum peak value within the stress mutation sequence.

[0033] The ratio between the maximum peak value in the stress mutation sequence and the mean value of the elements in the stress mutation sequence is taken as the maximum peak mutation ratio in the stress mutation sequence.

[0034] Preferably, the method for obtaining the maximum peak mutation ratio and the maximum peak position within the flow mutation sequence includes:

[0035] The flow mutation sequence is used as input to the peak detection algorithm, and the peak value and its position within the flow mutation sequence are obtained using the peak detection algorithm.

[0036] The ratio between the maximum peak value in the flow mutation sequence and the mean value of the elements in the flow mutation sequence is taken as the maximum peak value mutation ratio in the flow mutation sequence.

[0037] Preferably, the method for obtaining the abnormal congestion assessment value includes:

[0038] The sum of the first abnormal feature value at the current acquisition time and the preset adjustment constant is used as the first product factor, the sum of the second abnormal feature value at the current acquisition time and the preset adjustment constant is used as the second product factor, and the product of the first product factor and the second product factor is used as the abnormal congestion assessment value at the current acquisition time.

[0039] Preferably, the method for controlling the stratified water injection test process includes:

[0040] Based on the abnormal blockage assessment value calculated in real time during the initial stable phase after the start of the stratified water injection test, the judgment range for the regulation of the stratified water injection test process is obtained.

[0041] Based on the judgment interval of the stratified water injection test process, determine whether the stratified water injection test can continue at the current sampling time. If the stratified water injection test cannot continue, the stratified water injection test must be stopped first, and then the mud, sand and aquatic plants in the stratified water nozzles should be removed or the clogged water nozzles should be replaced before the stratified water injection test can be restarted.

[0042] Preferably, the method for obtaining the judgment interval includes:

[0043] The abnormal blockage assessment value calculated in real time during the initial stable phase after the start of the stratified water injection test is used as the input of the 3sigma detection algorithm. The 3sigma range of the abnormal blockage assessment value is obtained by using the 3sigma detection algorithm, and the 3sigma range is used as the judgment interval for the process control of the stratified water injection test.

[0044] Preferably, the method for determining whether the stratified water injection test can continue includes:

[0045] If the abnormal blockage assessment value at the current acquisition time is less than or equal to the upper limit of the judgment interval, the stratified water injection test can continue.

[0046] If the abnormal blockage assessment value at the current acquisition time is greater than the upper limit of the judgment interval, the stratified water injection test cannot continue.

[0047] Preferably, the method for implementing the experimental properties includes:

[0048] Based on the slope of the stratification indicator curve, the water absorption index of each segment of the stratified injection well is calculated;

[0049] The lower and upper quartiles of the water absorption index of all segments in a stratified injection well with preset injection well parameters are used as the low and high thresholds for judging water absorption capacity, respectively.

[0050] If the water absorption index of each segment of a stratified injection well is less than or equal to the low threshold, then the segment is designated as a reinforcing layer; if the water absorption index of each segment of a stratified injection well is greater than the low threshold and less than or equal to the high threshold, then the segment is designated as a replacement layer; if the water absorption index of each segment of a stratified injection well is greater than the high threshold, then the segment is designated as a suppressing layer.

[0051] The present invention has the following beneficial effects:

[0052] This invention provides a reliable data foundation for analyzing abnormal blockage characteristics of stratified nozzles by acquiring stratified pressure and flow sequences at each acquisition moment during the stratified water injection test of a stratified injection well. By extracting the pressure and flow anomaly sequences at each acquisition moment, the abnormal changes in stratified pressure and flow within the stratified section are more clearly revealed. Based on the abnormal features within the pressure and flow anomaly sequences, and combined with the degree of difference between the pressure and flow anomaly sequences, the first abnormal feature value is measured more accurately, thus fully reflecting the significance of the synchronous abnormal changes in stratified pressure and flow within the stratified section, which is used for accurate real-time monitoring of abnormal blockage characteristics of stratified nozzles. By extracting the pressure and flow mutation sequences at each acquisition moment, the abrupt changes in stratified pressure and flow within the stratified section when the nozzle is blocked are more clearly revealed. Furthermore, by combining the peak characteristics of the mutations within the pressure and flow mutation sequences, the second abnormal feature value is measured more accurately, fully reflecting the significance of the synchronous abrupt changes in stratified pressure and flow, which is used for accurate real-time monitoring of abnormal blockage characteristics of stratified nozzles. By combining the first and second abnormal characteristic values, the abnormal blockage characteristics of the stratified water nozzles are accurately assessed and monitored in real time. The abnormal blockage assessment value is used to precisely control the stratified water injection test process. After control, the stratification indicator curve of the stratified injection well is measured, and a dual-fixed-dual-change adjustment is performed based on the stratification indicator curve. This invention, by accurately assessing the abnormal blockage characteristics during the stratified water injection test, more accurately controls the stratified water injection test process, improves the quality of the measured stratification indicator curve, and avoids affecting the accuracy of subsequent re-determination of stratification properties. Attached Figure Description

[0053] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a flowchart of a method for adjusting the dual-fixed and dual-replacement mechanism in the later stage of ultra-high water cut water drive in oilfields, provided by an embodiment of the present invention.

[0055] Figure 2 This is a schematic diagram of the well locations for a five-point well network provided in one embodiment of the present invention. Detailed Implementation

[0056] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a dual-fixing and dual-changing adjustment method for ultra-high water cut oilfield waterflooding based on the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0058] For stratified injection wells in the late stage of ultra-high water cut water-drive in oilfields, this invention provides a specific implementation method for a dual-fixed-double-change adjustment method in the late stage of ultra-high water cut water-drive in oilfields. This method includes experimental qualitative analysis, on-demand pressure setting, alternating injection layers, and alternating well points to achieve the goal of injecting sufficient and adequate water. During the experimental qualitative analysis, stratified water injection tests are conducted on each layer of the stratified injection well, and the stratification indicator curve is measured using a pressure-boosting method. However, the water nozzles in the stratified injection test layers are prone to abnormal blockage due to impurities in the water, resulting in poor quality of the measured stratification indicator curve and affecting the accuracy of subsequent layer re-determination. Therefore, it is necessary to accurately monitor the abnormal blockage characteristics of the water nozzles in the layers in real time to accurately control the progress of the stratified water injection test and improve the quality of the measured stratification indicator curve.

[0059] The specific scheme of the dual-fixed and dual-replacement adjustment method for ultra-high water cut oilfield water drive provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0060] Please see Figure 1 The diagram illustrates a method flowchart for adjusting a double-fixed and double-replacement system in the later stage of ultra-high water cut water drive in oilfields, according to an embodiment of the present invention. The method includes the following steps:

[0061] Step S101: Obtain the stratified pressure sequence and stratified flow rate sequence at each acquisition time during the stratified water injection test of the stratified injection well.

[0062] In order to accurately monitor the abnormal blockage characteristics of the stratified water nozzles in real time and thus accurately control the process of stratified water injection testing, it is necessary to conduct stratified water injection tests on each segment of the stratified injection well during the experimental qualitative process. At the same time, it is necessary to obtain the stratified pressure sequence and stratified flow sequence at each acquisition moment during the stratified water injection test of the stratified injection well, so as to provide a reliable data foundation for the subsequent analysis of the abnormal blockage characteristics of the stratified water nozzles.

[0063] In one specific implementation of this invention, during the stratified water injection test, starting with the last segment of the stratified injection well, the nozzles of the last segment are emptied, and the nozzles of the other segments are closed. The injection volume at different injection pressure points in this segment is measured using a pressure-boosting method. After the measurement of this segment is completed, the nozzles of this segment are closed, and the nozzles of the previous segment are emptied. The injection volume at different injection pressure points in this segment is measured again using the aforementioned pressure-boosting method. This process is repeated until the injection volume at different injection pressure points in the uppermost segment is measured.

[0064] In one specific implementation of this invention, dynamic pressure sensors and flow meters are installed in each segment of the stratified injection well. The stratified pressure and flow rate are collected in real time during the stratified water injection test using the dynamic pressure sensors and flow meters. The collection time interval is 1 second, and the stratified pressure data and stratified flow rate data at each collection moment are obtained.

[0065] To facilitate subsequent analysis of water injection characteristic changes in the short period before each collection moment, the stratified pressure data and stratified flow data within 10 minutes before each collection moment are arranged in chronological order and recorded as the stratified pressure sequence and stratified flow sequence for each collection moment. This sequence is used for accurate real-time monitoring of abnormal blockage characteristics of stratified water nozzles.

[0066] Step S102: Perform anomaly feature analysis on the layered pressure sequence and layered flow sequence to obtain the pressure anomaly sequence and flow anomaly sequence at each acquisition time; determine the first anomaly feature value at each acquisition time based on the anomaly features within the pressure anomaly sequence and flow anomaly sequence, and in combination with the degree of difference between the pressure anomaly sequence and flow anomaly sequence.

[0067] Generally, if the tiered water taps become abnormally clogged due to impurities in the water, it will lead to abnormal changes in the tiered pressure and flow rate within the tier. Therefore, to accurately measure the abnormal clogging characteristics of the tiered water taps, it is necessary to perform anomaly analysis on the tiered pressure and flow rate sequences to extract the pressure and flow rate anomaly sequences at each sampling time. These sequences can respectively reflect the abnormal changes in tiered pressure and flow rate within the tier. The more significant the abnormal changes in tiered pressure and flow rate, the more likely the tiered water taps are to be abnormally clogged.

[0068] Meanwhile, because the stratified pressure and flow rate exhibit synchronous abnormal changes when the stratified water nozzles are clogged, and the cumulative abnormality of outlier changes is at a high level, a first abnormal feature value is determined for each sampling moment based on the abnormal characteristics within the pressure and flow abnormal sequences, combined with the degree of difference between the pressure and flow abnormal sequences. The smaller the difference between the pressure and flow abnormal sequences, the more it reflects the synchronous abnormal changes in stratified pressure and flow rate when the stratified water nozzles are clogged. The more significant the abnormal characteristics within the pressure and flow abnormal sequences, the more likely the stratified water nozzles in the stratified water injection test are to experience abnormal clogging. The first abnormal feature value reflects the significance of the synchronous abnormal changes in stratified pressure and flow rate within the stratified section. The larger the first abnormal feature value, the higher the significance of the synchronous abnormal changes in stratified pressure and flow rate in the stratified water injection test, and the more likely the stratified water nozzles are to experience abnormal clogging.

[0069] Step S103: Perform abrupt change feature analysis on the layered pressure sequence and layered flow sequence to obtain the pressure abrupt change sequence and flow abrupt change sequence at each acquisition time; determine the second abnormal feature value at each acquisition time based on the abrupt change peak characteristics within the pressure abrupt change sequence and flow abrupt change sequence; combine the first abnormal feature value and the second abnormal feature value to obtain the abnormal congestion assessment value at the current acquisition time.

[0070] When tiered water taps become abnormally clogged due to impurities in the water, the tiered pressure and flow rate within the tier will exhibit simultaneous and abrupt changes. Therefore, to more accurately monitor the abnormal clogging characteristics of tiered water taps in real time, it is necessary to perform abrupt change characteristic analysis on the tiered pressure and flow rate sequences, obtaining the pressure and flow rate abrupt change sequences at each sampling time, reflecting the abrupt changes in tiered pressure and flow rate within the tier when the water taps are clogged.

[0071] Generally, the smaller the absolute difference between the positions of the largest peaks in the pressure and flow rate mutation sequences, and the greater the degree of peak mutation in both sequences, the more significant the simultaneous abrupt changes in stratified pressure and flow rate within the time window. In this case, the stratified water nozzles are more likely to experience abnormal blockage. Therefore, based on the peak mutation characteristics within the pressure and flow rate mutation sequences, a second abnormal characteristic value is determined for each acquisition moment. This peak mutation characteristic fully reflects the abrupt changes in stratified pressure and flow rate, facilitating accurate real-time monitoring of abnormal blockage characteristics in stratified water nozzles. The second abnormal characteristic value reflects the significance of the simultaneous abrupt changes in stratified pressure and flow rate within the stratum. A larger second abnormal characteristic value indicates a more significant simultaneous abrupt change in stratified pressure and flow rate within the time window, and thus, a more likely abnormal blockage of the stratified water nozzles.

[0072] Because stratification faucets are susceptible to abnormal clogging due to impurities in the water, the stratification indicator curve shifts towards the pressure axis, resulting in poor quality measurements and affecting the accuracy of subsequent stratification property re-determination. Therefore, accurate real-time monitoring of abnormal clogging characteristics of stratification faucets is necessary to precisely control the stratification water injection test process and improve the accuracy of subsequent stratification property re-determination.

[0073] Based on the above analysis, the first and second abnormal characteristic values ​​respectively reflect the synchronous and abrupt changes in the stratification pressure and flow rate within the stratified section when the stratified nozzles are clogged. Therefore, to more accurately monitor the abnormal clogging characteristics of the stratified nozzles in real time, the first and second abnormal characteristic values ​​from the stratified water injection test are combined to accurately measure the abnormal clogging characteristics, obtaining the abnormal clogging assessment value at the current acquisition time. This value reflects the significance of the abnormal clogging characteristics; the larger the abnormal clogging assessment value, the greater the likelihood of abnormal clogging at the stratified nozzle. Therefore, it is necessary to more accurately control the stratified water injection test process to avoid affecting the quality of the stratification indicator curve.

[0074] Step S104: The abnormal blockage assessment value is used to regulate the stratified water injection test process. After regulation, the stratification indicator curve of the stratified injection well is measured. Based on the stratification indicator curve, a dual-fixed and dual-replacement adjustment is performed. The dual-fixed and dual-replacement adjustment includes actual measurement, on-demand pressure setting, stratification rotation, and well point rotation.

[0075] In the double-fixed-double-replacement adjustment process, the experimental qualitative analysis typically employs a pressurized stratified water injection test to measure the stratified indicator curves. These curves are then used to redetermine the properties of each stratified segment in the injection well. However, the stratified water nozzles are prone to abnormal blockage due to impurities in the water, causing the stratified indicator curves to shift towards the pressure axis. Current technology lacks accurate real-time monitoring of these abnormal blockages, hindering accurate control of the stratified water injection test process. This results in poor quality directly measured stratified indicator curves, impacting the accuracy of subsequent re-determination of stratified properties.

[0076] Therefore, in this embodiment of the invention, the abnormal blockage assessment value is used to regulate the stratified water injection test process. When the abnormal blockage assessment value monitored in real time exceeds a certain range, it means that the stratified water nozzle has an abnormal blockage phenomenon. The stratified water injection test needs to be stopped first, and then the impurities such as mud and water plants in the stratified water nozzle are removed or the blocked water nozzle is replaced before the stratified water injection test is restarted.

[0077] Furthermore, after regulating the stratified water injection test process, the stratification indicator curves of the stratified injection wells are measured to prevent the stratification indicator curves from shifting towards the pressure axis, thereby improving the quality of the measured stratification indicator curves and ensuring the accuracy of subsequent re-determination of the properties of the stratified segments. Therefore, based on high-quality stratification indicator curves, a dual-fixed and dual-replacement adjustment is performed to accurately redetermine the properties of each segment in the stratified injection well. The dual-fixed and dual-replacement adjustment includes actual measurement of properties, demand-based pressure setting, stratum rotation, and well point rotation, which is beneficial for achieving the goal of injecting sufficient and effective water.

[0078] Preferably, in some implementations of the present invention, the method for obtaining the pressure anomaly sequence includes:

[0079] Generally, if the stratified water taps become abnormally clogged due to impurities in the water, it will lead to abnormal changes in the stratified pressure. Therefore, in order to accurately measure the abnormal clogging characteristics of the stratified water taps, it is necessary to perform anomaly analysis on the stratified pressure sequence. The stratified pressure sequence at each acquisition time is used as input to the LOF anomaly detection algorithm. The LOF anomaly detection algorithm is used to obtain the local outlier factor of each element in the stratified pressure sequence. The larger the local outlier factor, the higher the anomaly characteristic of the stratified pressure at that time.

[0080] Furthermore, the sequence of local outliers of all elements in the stratified pressure sequence in chronological order is used as the pressure anomaly sequence at each acquisition time. This reflects the outlier and anomaly change characteristics of the stratified pressure in the stratum, which is beneficial for subsequent accurate real-time monitoring of abnormal blockage characteristics of the stratified water nozzles.

[0081] Preferably, in some implementations of the present invention, the method for obtaining the traffic anomaly sequence includes:

[0082] Meanwhile, if the tiered water nozzles become abnormally clogged due to impurities in the water, it will cause abnormal changes in the stratified flow rate within the tier. Therefore, in order to accurately measure the abnormal clogging characteristics of the tiered water nozzles, it is also necessary to perform anomaly feature analysis on the stratified flow rate sequence. The stratified flow rate sequence at each acquisition time is used as input to the LOF anomaly detection algorithm. The LOF anomaly detection algorithm is used to obtain the local outlier factor of each element in the stratified flow rate sequence. The larger the local outlier factor, the higher the outlier anomaly characteristics of the stratified flow rate at that time.

[0083] Furthermore, the sequence of local outliers of all elements in the stratified flow sequence arranged in chronological order is used as the flow anomaly sequence at each acquisition time, reflecting the outlier and anomaly change characteristics of the stratified flow in the stratified section. This helps to more fully monitor the abnormal blockage characteristics of the stratified water nozzles in real time.

[0084] Preferably, in some implementations of the present invention, the method for obtaining the first abnormal feature value includes:

[0085] Generally, when tiered water nozzles become clogged, the tiered pressure and tiered flow rate exhibit synchronous outlier anomalies, and the cumulative degree of these outlier anomalies is relatively high. Therefore, the smaller the difference between the pressure anomaly sequence and the flow anomaly sequence, and the higher the cumulative degree of outlier anomalies in the tiered pressure and tiered flow rate, the more likely the tiered water nozzles in the tiered water injection test are to experience abnormal clogging.

[0086] Therefore, based on the changes within the pressure anomaly sequence and flow anomaly sequence, the cumulative anomaly degree at each acquisition time is obtained. The greater the cumulative anomaly degree, the higher the cumulative anomaly degree characterizing the outlier anomaly changes in stratified pressure and stratified flow, indicating that the stratified water nozzles in the stratified water injection test are more likely to experience abnormal blockage at this time.

[0087] Preferably, in some implementations of the present invention, the method for obtaining the cumulative anomaly level includes:

[0088] The first-order difference sequence of the pressure anomaly sequence is calculated as the pressure anomaly change sequence at each acquisition time, reflecting the first-order change characteristics of local outliers within the pressure anomaly sequence.

[0089] The first-order difference sequence of the flow anomaly sequence is calculated as the flow anomaly change sequence at each acquisition time, reflecting the first-order change characteristics of local outliers within the flow anomaly sequence.

[0090] Based on the positive numbers in the pressure anomaly change sequence and the flow anomaly change sequence, the cumulative anomaly level at each data collection time is determined. Specifically, the larger the positive numbers in both the pressure and flow anomaly change sequences, the more significantly the local outlier factors within those sequences increase over time, thus better reflecting the cumulative anomaly characteristics of outlier changes in stratified pressure and flow.

[0091] In one specific implementation of this invention, the method for calculating the cumulative anomaly level is as follows: In the formula, The cumulative anomaly level at each data collection time. It is the sum of all positive numbers within the aforementioned abnormal pressure change sequence. This is the sum of all positive numbers within the sequence of abnormal flow changes. An additive calculation method is used to statistically analyze the cumulative abnormal characteristics of outlier changes in stratified pressure and stratified flow, thereby measuring the degree of cumulative anomaly at each acquisition time.

[0092] Simultaneously, the degree of difference between the pressure anomaly sequence and the flow anomaly sequence is calculated. Based on the cumulative anomaly degree and the degree of difference, a first anomaly characteristic value is obtained for each acquisition time. This first anomaly characteristic value reflects the significance of the outlier variation characteristics of the synchronicity of stratified pressure and flow in the stratified water injection test. The larger the first anomaly characteristic value, the higher the significance of the outlier anomaly characteristics of the synchronicity of stratified pressure and flow in the stratified water injection test. In this case, the stratified water nozzles are more likely to experience abnormal blockage, thereby causing the stratified indicator curve to shift towards the pressure axis and reducing the quality of the stratified indicator curve.

[0093] In one specific implementation of this invention, the method for calculating the first abnormal feature value is as follows: In the formula, The first abnormal feature value at each acquisition time, The cumulative anomaly level at each data collection time. To determine the degree of difference between pressure anomaly sequences and flow anomaly sequences, the measurement method can be DTW dynamic programming distance, Euclidean distance, or Mahalanobis distance. In this specific implementation, DTW dynamic programming distance is used for measurement. This is a preset division constant, used to prevent the denominator from being 0. Its value ranges from 0.01 to 0.1, and in this specific implementation, it is set to 0.05.

[0094] The calculation method for the first abnormal feature value uses a fraction to measure features with positive and negative proportional relationships. The degree of difference between the pressure anomaly sequence and the flow anomaly sequence is used to measure the synchronous outlier changes in stratified pressure and stratified flow, and is inversely proportional to the first abnormal feature value. The cumulative anomaly degree at each acquisition time is used to measure the cumulative abnormal features of outlier changes in stratified pressure and stratified flow, and is directly proportional to the first abnormal feature value.

[0095] In another specific implementation of this invention, the method for calculating the first abnormal feature value is as follows: In the formula, The first abnormal feature value at each acquisition time, The sum of all elements within the pressure anomaly sequence. The sum of all elements within the abnormal traffic sequence. To determine the degree of difference between pressure anomaly sequences and flow anomaly sequences, the measurement method can be DTW dynamic programming distance, Euclidean distance, or Mahalanobis distance. In this specific implementation, DTW dynamic programming distance is used for measurement. This is a preset division constant, used to prevent the denominator from being 0. Its value ranges from 0.01 to 0.1, and in this specific implementation, it is set to 0.05.

[0096] The calculation method for the first anomaly characteristic value uses a fraction to measure characteristics with positive and negative proportional relationships. The degree of difference between the pressure anomaly sequence and the flow anomaly sequence is used to measure the synchronous outlier changes in stratified pressure and stratified flow, and is inversely proportional to the first anomaly characteristic value. The cumulative anomaly degree is measured directly by summing. The sum in the numerator represents the cumulative anomaly degree of outlier changes in stratified pressure and stratified flow, and is directly proportional to the first anomaly characteristic value.

[0097] Preferably, in some implementations of the present invention, the method for obtaining the stress mutation sequence includes:

[0098] When the tiered water taps become abnormally clogged due to impurities in the water, it causes simultaneous and abrupt changes in the tiered pressure. Therefore, to more accurately monitor the abnormal clogging characteristics of the tiered water taps in real time, it is necessary to perform abrupt change characteristic analysis on the tiered pressure sequence. This involves calculating all first-order difference values ​​within the tiered pressure sequence and using the absolute values ​​of these first-order difference values ​​in chronological order as a pressure abrupt change sequence for each sampling time. This sequence reflects the abrupt changes in tiered pressure when the tiered water taps become clogged. The larger the absolute value of the first-order difference value, the greater the difference in the sudden change in tiered pressure.

[0099] Preferably, in some implementations of the present invention, the method for obtaining the flow mutation sequence includes:

[0100] When tiered water nozzles become abnormally clogged due to impurities in the water, it can cause simultaneous and abrupt changes in the tiered flow rates. Therefore, to more accurately monitor the abnormal clogging characteristics of tiered water nozzles in real time, it is necessary to perform abrupt change characteristic analysis on the tiered flow rate sequence. This involves calculating all first-order difference values ​​within the tiered flow rate sequence and using the absolute values ​​of these first-order difference values ​​in chronological order as the flow rate abrupt change sequence for each acquisition time. This sequence reflects the abrupt changes in tiered flow rates when the tiered water nozzles are clogged. The larger the absolute value of the first-order difference value, the greater the difference in the abrupt changes in the tiered flow rates.

[0101] Preferably, in some implementations of the present invention, the method for obtaining the second abnormal feature value includes:

[0102] Since the abrupt peak characteristics can fully reflect the abrupt changes in stratified pressure and stratified flow, it is beneficial for accurate real-time monitoring of abnormal blockage characteristics of stratified water nozzles. Therefore, in order to more clearly measure the simultaneous abrupt changes in stratified pressure, the maximum peak change ratio and the maximum peak order within the pressure abrupt change sequence are obtained based on the maximum peak value, characterizing the maximum abrupt change in stratified pressure and the maximum abrupt change time when the stratified water nozzle is blocked.

[0103] Preferably, in some implementations of the present invention, the method for obtaining the maximum peak mutation ratio and the maximum peak position within the stress mutation sequence includes:

[0104] To more clearly measure the simultaneous and abrupt changes in stratified pressure, the pressure abrupt change sequence is used as input to a peak detection algorithm to obtain the maximum peak value and its position within the pressure abrupt change sequence.

[0105] Furthermore, in order to eliminate the physical dimensions of stratification pressure and more accurately reflect the abrupt peak characteristics of stratification pressure, the ratio between the maximum peak value in the pressure abrupt sequence and the mean value of the elements in the pressure abrupt sequence is used as the maximum peak abrupt ratio in the pressure abrupt sequence, which characterizes the maximum abrupt amount and the maximum abrupt moment of stratification pressure when the stratification faucet is blocked.

[0106] To more clearly measure the simultaneous abrupt changes in stratified flow, the maximum peak change ratio and the maximum peak position within the flow abrupt change sequence are obtained based on the maximum peak value within the flow abrupt change sequence, thus characterizing the maximum abrupt change in stratified flow and the maximum abrupt change time when the stratified water nozzle is blocked.

[0107] Preferably, in some implementations of the present invention, the method for obtaining the maximum peak change ratio and the maximum peak position within the flow change sequence includes:

[0108] To more clearly measure the simultaneous and abrupt changes in stratified traffic, the traffic abrupt change sequence is used as input to a peak detection algorithm, which is then used to obtain the maximum peak value and its position within the traffic abrupt change sequence.

[0109] Furthermore, in order to eliminate the physical dimensions of stratified flow and more accurately reflect the abrupt peak characteristics of stratified flow, the ratio between the maximum peak value in the flow abrupt sequence and the mean value of the elements in the flow abrupt sequence is used as the maximum peak abrupt ratio in the flow abrupt sequence, which characterizes the maximum abrupt amount and the maximum abrupt time of stratified flow when the stratified water nozzle is blocked.

[0110] In one specific implementation of this invention, the peak detection algorithm is the AMPD (Automatic Multiscale Peak Detection) algorithm. In other specific implementations, it can also be a derivative-based peak detection algorithm.

[0111] Generally, the smaller the absolute difference between the positions of the largest peaks in the pressure and flow rate mutation sequences, and the greater the degree of peak mutation in the pressure and flow rate mutation sequences, the more significant the simultaneous abrupt changes in stratified pressure and flow rate within the time window. In this case, the stratified water nozzles are more likely to experience abnormal blockage.

[0112] Therefore, based on the difference between the maximum peak position in the pressure mutation sequence and the maximum peak position in the flow mutation sequence, and combined with the maximum peak mutation ratio in the pressure mutation sequence and the maximum peak mutation ratio in the flow mutation sequence, a second abnormal characteristic value is determined for each acquisition time. This second abnormal characteristic value reflects the significance of the simultaneous abrupt changes in stratified pressure and flow rate within the strata. The larger the second abnormal characteristic value, the more significant the simultaneous abrupt changes in stratified pressure and flow rate within the time window, and the more likely abnormal blockage will occur in the stratified water nozzles, requiring more accurate control of the stratified water injection test process.

[0113] In one specific implementation of this invention, the method for calculating the second abnormal feature value is as follows: In the formula, The second abnormal feature value at each acquisition time. The maximum peak mutation ratio within the stress mutation sequence. The position of the largest peak within the stress mutation sequence. The maximum peak mutation ratio within the flow mutation sequence. The position of the maximum peak value within the flow mutation sequence. The value of the division by zero constant is set to 0.05 in this specific implementation.

[0114] The calculation method for the second abnormal feature value uses a fraction to measure features with positive and negative proportional relationships. The absolute difference between the positions of the largest peak values ​​in the denominator reflects the simultaneity of abrupt changes in stratified pressure and stratified flow, and is inversely proportional to the second abnormal feature value. The degree of abrupt change in the pressure abrupt change sequence and the flow abrupt change sequence is fused by addition to measure the degree of abrupt change in the pressure abrupt change sequence and the flow abrupt change sequence, and is directly proportional to the second abnormal feature value.

[0115] In another specific implementation of this invention, the method for calculating the second abnormal feature value is as follows: In the formula, The second abnormal feature value at each acquisition time. The maximum peak mutation ratio within the stress mutation sequence. The position of the largest peak within the stress mutation sequence. The maximum peak mutation ratio within the flow mutation sequence. The position of the maximum peak value within the flow mutation sequence. As a preset division-to-zero constant, this specific implementation uses a value of 0.05. A preset adjustment constant is used to avoid the product factor being 0; its value ranges from 0.1 to 1, and in this specific implementation, it is set to 0.5. The degree of mutation in the pressure mutation sequence and the flow mutation sequence is fused using a multiplication method to measure the degree of mutation in both sequences, which is proportional to the second abnormal feature value.

[0116] Preferably, in some implementations of the present invention, the method for obtaining the abnormal congestion assessment value includes:

[0117] Because stratification faucets are susceptible to abnormal clogging due to impurities in the water, the stratification indicator curve shifts towards the pressure axis, resulting in poor quality measurements and affecting the accuracy of subsequent stratification property re-determination. Therefore, accurate real-time monitoring of abnormal clogging characteristics of stratification faucets is necessary to precisely control the stratification water injection test process and improve the accuracy of subsequent stratification property re-determination.

[0118] To more accurately monitor abnormal blockage characteristics of tiered water taps in real time, the abnormal blockage characteristics are measured by combining the first and second abnormal characteristic values ​​from the tiered water injection test. Specifically, the sum of the first abnormal characteristic value at the current acquisition time and a preset adjustment constant is used as the first product factor, and the sum of the second abnormal characteristic value at the current acquisition time and the preset adjustment constant is used as the second product factor. The product of the first and second product factors is used as the abnormal blockage assessment value at the current acquisition time.

[0119] The preset adjustment constant is used to avoid the product factor being 0. Its value ranges from 0.1 to 1, and in this specific implementation, it is set to 0.5. The first and second abnormal characteristic values ​​are fused using a multiplication method to assess the abnormal blockage characteristics. This abnormal blockage assessment value reflects the significance of the abnormal blockage characteristics of the stratified water nozzles. The larger the abnormal blockage assessment value, the greater the likelihood that the stratified water nozzles will exhibit abnormal blockage characteristics. Therefore, it is necessary to more accurately control the stratified water injection test process to avoid affecting the quality of the stratification indicator curve.

[0120] Preferably, in some implementations of the present invention, the method for controlling the stratified water injection test process includes:

[0121] Generally, if the real-time monitoring value of abnormal blockage exceeds a certain range, it indicates that there is an abnormal blockage in the tiered water nozzles. The tiered water injection test should be stopped first, and then the mud, weeds and other impurities in the tiered water nozzles should be removed or the blocked water nozzles should be replaced before the tiered water injection test can be restarted.

[0122] Therefore, in order to accurately monitor the abnormal blockage characteristics of the tiered water nozzles in real time, and thus accurately control the progress of the tiered water injection test, a judgment range for regulating the tiered water injection test process is obtained based on the abnormal blockage assessment value calculated in real time during the initial stable phase after the start of the tiered water injection test.

[0123] Preferably, in some implementations of the present invention, the method for obtaining the judgment interval includes:

[0124] To accurately monitor abnormal blockage characteristics of the tiered water nozzles in real time and thus precisely control the tiered water injection test process, the abnormal blockage assessment value calculated in real time during the initial stable phase after the start of the tiered water injection test is used as the input to the 3sigma detection algorithm. The 3sigma range of the abnormal blockage assessment value is obtained using the 3sigma detection algorithm, and this 3sigma range is used as the judgment interval for regulating the tiered water injection test process. The initial stable phase refers to a period of time after the start of the tiered water injection test during which no abnormal blockage occurs in the tiered water nozzles. In this embodiment of the invention, the duration of the initial stable phase is 1 hour.

[0125] Because the stratified water nozzles are prone to abnormal blockage due to impurities in the water, causing the stratification indicator curve to shift towards the pressure axis, it is necessary to accurately control the stratified water injection test process based on the abnormal blockage assessment value, improve the quality of the measured stratification indicator curve, and avoid affecting the accuracy of subsequent re-determination of stratification properties.

[0126] Therefore, based on the judgment interval for the stratified water injection test process control, it is determined whether the stratified water injection test can continue at the current sampling time.

[0127] Preferably, in some implementations of the present invention, the method for determining whether the stratified water injection test can continue includes:

[0128] If the abnormal blockage assessment value at the current collection time is less than or equal to the upper limit of the judgment interval, it means that there is no abnormal blockage at this time, and the stratified water injection test can continue.

[0129] If the abnormal blockage assessment value at the current acquisition time is greater than the upper limit of the judgment interval, it indicates that an abnormal blockage has occurred in the stratified water nozzle. In this case, the stratified water injection test cannot continue and must be stopped. Then, the silt, weeds, and other impurities inside the stratified water nozzle should be removed, or the blocked nozzle should be replaced before restarting the stratified water injection test. After the stratified water injection test, the injection volume at different injection pressure points in each stratified injection well is obtained. Then, based on the injection volume at different injection pressure points in each stratified injection well, a stratification indicator curve is plotted. The stratification indicator curve represents the relationship between the injection pressure and the injection volume of each stratified segment.

[0130] Preferably, in some implementations of the present invention, the segment properties of each segment in the stratified injection well are re-determined based on the stratification indicator curve of the stratified injection well, thereby achieving the qualitative analysis of the stratified injection well, including:

[0131] As waterflooding development in oilfields deepens, the dynamic heterogeneity of oil reservoirs intensifies in the later stages of ultra-high water cut. The original static data can no longer accurately guide the division of each layer. It is necessary to redetermine the layer properties of stratified injection wells, including reinforcing layers, replacement layers, and limiting layers, based on the test results of the stratification indicator curves. Specifically, the water absorption index of each layer is calculated based on the test results of the stratification indicator curves. The water absorption index refers to the daily water injection volume per unit injection pressure difference. Its value is equal to the reciprocal of the slope of the stratification indicator curve for each layer, reflecting the water absorption capacity of each layer in the stratified injection well. The higher the water absorption index, the better the water absorption capacity of that layer.

[0132] Furthermore, the lower quartile and upper quartile of the water absorption index of all segments in the M stratified injection wells with preset injection well parameters are statistically analyzed and used as the low threshold and high threshold for judging water absorption capacity, respectively. The preset injection well parameter M is an integer not less than 30; in this embodiment, the preset injection well parameter M is 30. If the water absorption index of each segment is less than or equal to the low threshold, it indicates that the segment has poor water absorption capacity and characteristics of a low-permeability layer, and the segment is identified as a reinforcing layer. If the water absorption index of each segment is greater than the low threshold and less than or equal to the high threshold, it indicates that the segment has moderate water absorption capacity and characteristics of a medium-permeability formation, and the segment is identified as a replacement layer. If the water absorption index of each segment is greater than the high threshold, it indicates that the segment has strong water absorption capacity and characteristics of a high-permeability formation, and the segment is identified as a suppressing layer.

[0133] As a preferred embodiment of the present invention, the layered injection well is pressure-controlled on demand, which includes: after redetermining the reinforcing layer, replacement layer and limiting layer in the layered injection well, the injection pressure of the whole well is matched with the goal of layer activation to ensure that the reinforcing layer is activated.

[0134] Specifically, in the process of formulating a stratified water distribution plan, the total well injection pressure should be greater than the starting pressure of the worst-performing section. Since the starting pressure of the worst-performing section is relatively high, generally the maximum starting pressure of all sections in the stratified injection well, the total well injection pressure needs to be greater than the maximum starting pressure of all sections in the stratified injection well. ,in, Inject pressure into the entire well. This refers to the starting pressure for all sections in a stratified injection well.

[0135] Meanwhile, in multi-segment stratified injection wells, inter-segment interference can occur during stratified water distribution. Two methods are employed to implement stratified water distribution: First, adjusting the diameter of the stratified nozzles optimizes the injection scheme. By analyzing the injection volume of each segment and retrieving the stratified injection pressure from the test results of the stratified indicator curve, and then determining the wellhead injection pressure using the wellhead injection equipment, the nozzle loss value for each segment is obtained by subtracting the stratified injection pressure from the determined wellhead injection pressure. Finally, based on the injection volume and nozzle loss value of each segment, the appropriate nozzle diameter for each segment is determined from the nozzle loss curve.

[0136] Therefore, the above method can effectively increase the throttling pressure difference of the high water absorption layer by adjusting the diameter of the stratified water nozzle through the stratification indicator curve and the nozzle loss curve, and can increase the whole well water injection pressure and enlarge the water nozzle of the poor oil layer without exceeding the overlying rock pressure, so as to meet the injection needs of the poor oil layer to the greatest extent.

[0137] Secondly, by plugging the high-permeability layers, the injection pressure is increased, and water injection is initiated into the low-permeability layers. Due to the overlying rock pressure, water injection cannot be initiated in some sections, and the water absorption and initiation pressure differences between sections are large, as measured by the stratification indicator curves. Therefore, by plugging the top high-permeability layers and increasing water injection only into the low-permeability layers, especially the "bottommost low-permeability section," a new perforation top boundary can be formed, releasing the overlying rock pressure, increasing the injection pressure, and thus opening up the low-permeability layers.

[0138] As a preferred embodiment of the present invention, rotating the layers in the stratified injection wells includes:

[0139] Due to the large span, long length, and numerous layers in the water-drive development of medium- and high-permeability oilfields, the process of layered water injection is subject to problems such as pressure interference and differences in water absorption capacity between layers. The water distribution between layers according to the injection plan is difficult to adjust on-site, and the test stabilization period is short, which increases the difficulty and workload of adjustment.

[0140] To further improve the effective utilization of oil reservoirs, a rotational layer adjustment method can be implemented. Based on the oil reservoir development and water absorption capacity, the injection well's layer can be divided into upper and lower sections, with either the upper section or the lower section being injected first.

[0141] On the one hand, it can reduce the length of the well section and reduce the vertical difference in operation; on the other hand, the fracturing pressure in the lower section can be increased to the perforated section, increasing the injection pressure and further improving the start-up of the lower section.

[0142] As a preferred embodiment of the present invention, rotating well points in the stratified injection wells includes:

[0143] Taking the five-point well pattern as an example, the well location diagram of the five-point well pattern is as follows: Figure 2 As shown, position 1 represents well 1, and position 2 represents well 2. In conjunction with the rotation system, well 1 injects water into the upper segment first, then stops injecting into the lower segment; well 2 injects water into the lower segment first, then stops injecting into the upper segment, achieving pressure boosting and improved mobilization within the injection segment. Then, in the next cycle, well 1 injects water into the lower segment, then stops injecting into the upper segment; well 2 injects water into the upper segment, then stops injecting into the lower segment. This cyclical alternation achieves increased starting pressure, mobilizing previously non-water-absorbing oil layers; continuous water injection in low-permeability segments improves water absorption; and alternating water injection in high-permeability segments maintains fluid level depth, further improving oil layer mobilization.

[0144] In the implementation of the dual-fixed and dual-replacement adjustment method for ultra-high water cut in oilfield water drive provided by the present invention, water injection can be carried out in two or more layers according to the stratigraphic span and heterogeneity. In terms of well point rotation, water injection can be carried out in rotation well points for different types of area well networks.

[0145] Simultaneously, based on the dual-determination method, high-permeability zones can be identified according to the stratification indicator curves, guiding shallow profile selection and controlling high-permeability zones. It can also further identify zones with poor water absorption capacity, guiding comprehensive well group measures and improving the utilization of thin, poor-permeability oil layers.

[0146] A double-fixed and double-replacement test was conducted on the 4 injection and 9 production well groups with high water cut in the water-drive oilfield. The proportion of water-absorbing layers increased from 28.6% to 38.1%, the proportion of sandstone water-absorbing thickness increased from 32.2% to 40.9%, the water cut decreased by 3.59 percentage points, and the production increase reached 40%.

[0147] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0148] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of water-drive oilfield with ultra-high water cut, characterized in that, The method includes the following steps: Obtain the stratified pressure sequence and stratified flow rate sequence at each acquisition time during the stratified water injection test of the stratified injection well; Anomaly feature analysis is performed on the layered pressure sequence and layered flow sequence to obtain the pressure anomaly sequence and flow anomaly sequence at each acquisition time. Based on the anomaly features within the pressure anomaly sequence and flow anomaly sequence, and combined with the degree of difference between the pressure anomaly sequence and flow anomaly sequence, the first anomaly feature value at each acquisition time is determined. Abrupt change feature analysis is performed on the layered pressure sequence and layered flow sequence to obtain the pressure abrupt change sequence and flow abrupt change sequence at each acquisition time; based on the abrupt change peak characteristics within the pressure abrupt change sequence and flow abrupt change sequence, a second abnormal feature value is determined at each acquisition time; combined with the first abnormal feature value and the second abnormal feature value, the abnormal congestion assessment value at the current acquisition time is obtained; The abnormal blockage assessment value is used to regulate the stratified water injection test process. After regulation, the stratification indicator curve of the stratified injection well is measured. Based on the stratification indicator curve, a dual-fixed and dual-replacement adjustment is performed, which includes experimental qualitative measurement, on-demand pressure setting, stratification system rotation, and well point rotation.

2. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 1, characterized in that, The method for obtaining the pressure anomaly sequence includes: The hierarchical stress sequence at each acquisition time is used as the input to the LOF anomaly detection algorithm, and the local outlier factor of each element in the hierarchical stress sequence is obtained by using the LOF anomaly detection algorithm. The sequence of local outliers of all elements in the stratified pressure sequence, arranged in chronological order, is used as the pressure anomaly sequence for each acquisition time.

3. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 1, characterized in that, The method for obtaining the traffic anomaly sequence includes: The hierarchical flow sequence at each acquisition time is used as the input to the LOF anomaly detection algorithm, and the local outlier factor of each element in the hierarchical flow sequence is obtained by using the LOF anomaly detection algorithm. The sequence of local outliers of all elements in the hierarchical flow sequence, arranged in chronological order, is used as the flow anomaly sequence for each collection time.

4. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 1, characterized in that, The method for obtaining the first abnormal feature value includes: Based on the changes within the pressure anomaly sequence and the flow anomaly sequence, the cumulative anomaly level at each acquisition time is obtained; The degree of difference between the pressure anomaly sequence and the flow anomaly sequence is calculated, and the first anomaly feature value at each acquisition time is obtained based on the cumulative anomaly degree and the degree of difference.

5. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 4, characterized in that, The method for obtaining the cumulative anomaly level includes: Calculate the first-order difference sequence of the pressure anomaly sequence as the pressure anomaly change sequence at each acquisition time; Calculate the first-order difference sequence of the flow anomaly sequence as the flow anomaly change sequence at each collection time; The cumulative degree of anomaly at each acquisition time is determined based on the positive numbers in the abnormal pressure change sequence and the abnormal flow rate change sequence.

6. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 1, characterized in that, The method for obtaining the stress mutation sequence includes: Calculate all first-order difference values ​​within the stratified pressure sequence, and use the absolute values ​​of all first-order difference values ​​within the stratified pressure sequence arranged in chronological order as the pressure mutation sequence for each acquisition moment.

7. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 1, characterized in that, The method for obtaining the flow mutation sequence includes: Calculate all first-order difference values ​​within the hierarchical flow sequence, and use the sequence of absolute values ​​of all first-order difference values ​​within the hierarchical flow sequence in chronological order as the flow mutation sequence for each acquisition time.

8. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 1, characterized in that, The method for obtaining the second abnormal feature value includes: Based on the maximum peak value within the stress mutation sequence, obtain the maximum peak mutation ratio and the maximum peak position within the stress mutation sequence; Based on the maximum peak value within the flow mutation sequence, obtain the maximum peak value mutation ratio and the maximum peak value rank within the flow mutation sequence; Based on the difference between the maximum peak position in the pressure mutation sequence and the maximum peak position in the flow mutation sequence, and combined with the maximum peak mutation ratio in the pressure mutation sequence and the maximum peak mutation ratio in the flow mutation sequence, the second abnormal feature value at each acquisition time is determined.

9. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 8, characterized in that, The methods for obtaining the maximum peak mutation ratio and the maximum peak position within the stress mutation sequence include: The stress mutation sequence is used as input to the peak detection algorithm, which is then used to obtain the maximum peak value and the position of the maximum peak value within the stress mutation sequence. The ratio between the maximum peak value in the stress mutation sequence and the mean value of the elements in the stress mutation sequence is taken as the maximum peak mutation ratio in the stress mutation sequence.

10. The method for adjusting the dual-fixed and dual-replacement mechanism in the later stage of ultra-high water cut waterflooding in oilfields according to claim 8, characterized in that, The methods for obtaining the maximum peak change ratio and the maximum peak position within the flow change sequence include: The flow mutation sequence is used as input to the peak detection algorithm, which is then used to obtain the maximum peak value and the position of the maximum peak value within the flow mutation sequence. The ratio between the maximum peak value in the flow mutation sequence and the mean value of the elements in the flow mutation sequence is taken as the maximum peak value mutation ratio in the flow mutation sequence.

11. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 1, characterized in that, The method for obtaining the abnormal congestion assessment value includes: The sum of the first abnormal feature value at the current acquisition time and the preset adjustment constant is used as the first product factor, the sum of the second abnormal feature value at the current acquisition time and the preset adjustment constant is used as the second product factor, and the product of the first product factor and the second product factor is used as the abnormal congestion assessment value at the current acquisition time.

12. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 1, characterized in that, The control method for the stratified water injection test process includes: Based on the abnormal blockage assessment value calculated in real time during the initial stable phase after the start of the stratified water injection test, the judgment range for the regulation of the stratified water injection test process is obtained. Based on the judgment interval of the stratified water injection test process, determine whether the stratified water injection test can continue at the current sampling time. If the stratified water injection test cannot continue, the stratified water injection test must be stopped first, and then the mud, sand and aquatic plants in the stratified water nozzles should be removed or the clogged water nozzles should be replaced before the stratified water injection test can be restarted.

13. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 12, characterized in that, The method for obtaining the judgment interval includes: The abnormal blockage assessment value calculated in real time during the initial stable phase after the start of the stratified water injection test is used as the input of the 3sigma detection algorithm. The 3sigma range of the abnormal blockage assessment value is obtained by using the 3sigma detection algorithm, and the 3sigma range is used as the judgment interval for the process control of the stratified water injection test.

14. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 12, characterized in that, The method for determining whether the stratified water injection test can continue includes: If the abnormal blockage assessment value at the current acquisition time is less than or equal to the upper limit of the judgment interval, the stratified water injection test can continue. If the abnormal blockage assessment value at the current acquisition time is greater than the upper limit of the judgment interval, the stratified water injection test cannot continue.

15. The method for adjusting the dual-fixed and dual-replacement mechanism in the late stage of ultra-high water cut water drive in oilfields according to claim 1, characterized in that, The method for implementing the experimental properties includes: Based on the slope of the stratification indicator curve, the water absorption index of each segment of the stratified injection well is calculated; The lower and upper quartiles of the water absorption index of all segments in a stratified injection well with preset injection well parameters are used as the low and high thresholds for judging water absorption capacity, respectively. If the water absorption index of each segment of a stratified injection well is less than or equal to the low threshold, then the segment is designated as a reinforcing layer; if the water absorption index of each segment of a stratified injection well is greater than the low threshold and less than or equal to the high threshold, then the segment is designated as a replacement layer; if the water absorption index of each segment of a stratified injection well is greater than the high threshold, then the segment is designated as a suppressing layer.

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