Oil content state reliable prediction interval determination method and system based on acoustic wave response

Abstract

The application provides an oil content state reliable prediction interval determination method and system based on acoustic wave response, which comprises the following steps: obtaining acoustic wave peak value data of each oil content state under different pressure conditions, arranging each oil content state in ascending order under the same pressure condition and dividing the oil content state interval; calculating the acoustic wave response index of each oil content state, and calculating the acoustic wave resolution coefficient of each interval, the average acoustic wave resolution coefficient of each interval under each pressure condition, the pressure consistency coefficient of each oil content state and the pressure consistency coefficient of each interval; calculating the comprehensive reliability index of each interval according to the average acoustic wave resolution coefficient and the pressure consistency coefficient of each interval, and identifying the oil content state interval with effective and reliable acoustic wave response according to a preset identification rule. The application can eliminate the interference of the pressure condition on the absolute magnitude of the acoustic wave peak value, make the acoustic wave response under different pressure conditions comparable, screen out the oil content state interval with effective acoustic wave response capable of effectively distinguishing the oil content state change and realizing reliable prediction.

Description

Technical Field

[0001] This invention relates to the field of high-pressure oil and gas acoustic monitoring and reservoir property identification technology, and in particular to a method and system for determining the reliable prediction range of oil-bearing state based on acoustic response. Background Technology

[0002] In physical simulation experiments of fractured-vuggy reservoirs and high-pressure oil and gas acoustic monitoring, acoustic response is often used to characterize changes in the medium under different oil-bearing conditions. Existing methods typically use the acoustic peak value, acoustic energy, or the fitting relationship between the acoustic peak value and oil content to determine or invert the oil-bearing state.

[0003] However, in high-pressure oil and gas environments, the peak value of acoustic waves is affected not only by the oil content but also by pressure conditions, medium compressibility, boundary contact conditions, and the response characteristics of the experimental setup. The absolute values ​​of acoustic peak values ​​obtained under different pressure conditions are often not directly comparable. If the original peak values ​​are used directly for oil content identification, it is easy to misjudge the amplitude changes caused by pressure as changes in the oil content.

[0004] Furthermore, in the low oil content range and the high oil content end range, the difference in acoustic response between adjacent oil-bearing states may be small, and the acoustic response may exhibit low sensitivity or plateau characteristics. If the ability of the acoustic response to distinguish between adjacent oil-bearing states is not determined in advance, and inversion is performed solely based on the fitted curve, it is easy to lead to insufficient reliability in the identification and recognition of low-sensitivity regions.

[0005] Therefore, it is necessary to provide a method that can eliminate the interference of pressure conditions on the absolute magnitude of acoustic peak values, making acoustic responses under different pressure conditions comparable, so as to screen out the oil-bearing state intervals that can effectively distinguish changes in oil-bearing state and thus achieve reliable prediction. This method does not directly invert the oil content from the acoustic peak value; instead, it first classifies the reliability of the acoustic responses in each oil-bearing state interval, thereby improving the stability and reliability of the high-pressure oil and gas acoustic response identification results. Summary of the Invention

[0006] The purpose of this invention is to provide a reliable prediction interval determination method for oil-bearing state based on acoustic response, in order to solve the identification error problems caused by the inability to directly compare acoustic peak values ​​under different pressure conditions, insufficient resolution of low-sensitivity areas, and unstable reliability of pressure-affected areas when directly using acoustic peak values ​​or acoustic peak value fitting relationships for oil-bearing state identification in the prior art.

[0007] To solve the above technical problems, the technical solution of the present invention is as follows:

[0008] A method for determining reliable oil-bearing state prediction intervals based on acoustic response is proposed to identify oil-bearing state intervals within a study area that can be accurately predicted using acoustic response, including...

[0009] S1. Obtain the peak acoustic data of each oil-bearing state under different pressure conditions and the corresponding state parameters of each oil-bearing state. Under the same pressure condition, sort the state parameters of each oil-bearing state in ascending order and divide the oil-bearing states with adjacent state parameters into an interval.

[0010] S2. Calculate the range of acoustic peak value variation between the lowest and highest oil-bearing states under the same pressure conditions; and calculate the acoustic response index for each oil-bearing state accordingly.

[0011] S3. Calculate the acoustic resolution coefficient that characterizes the change of acoustic response index in each interval; and calculate the average acoustic resolution coefficient of the same interval under each pressure condition accordingly.

[0012] S4. Calculate the pressure consistency coefficient that reflects the dispersion of acoustic response under different pressure conditions in the same oil-bearing state, and calculate the pressure consistency coefficient for each interval accordingly.

[0013] S5. Calculate the comprehensive reliability index of each interval based on the pressure consistency coefficient and the average acoustic resolution coefficient of each interval, and identify the oil-bearing state interval that can be accurately predicted by acoustic waves according to the preset identification rules based on the average acoustic resolution coefficient and the comprehensive reliability index.

[0014] Furthermore, the acquisition of peak acoustic wave data is specifically as follows:

[0015] Acoustic wave signals are acquired using an acoustic wave acquisition device; wherein the sampling frequency is not less than twice the highest effective frequency of the acoustic wave signal.

[0016] Under various pressure conditions, acoustic wave acquisition is performed after the pressure reaches the target value corresponding to each pressure condition and meets the stability criterion. The stability criterion is that the pressure fluctuation is less than a preset threshold and lasts for a preset time. Single or multiple repeated measurements are performed for each pressure condition and oil-containing state. During each measurement, the peak value of the waveform is extracted within a fixed time window according to a unified rule. The unified rule is the first peak value, the maximum peak value, the peak-to-peak value, or the envelope peak value.

[0017] When performing multiple measurements, the arithmetic mean of the peak waveforms extracted from each measurement under the same pressure condition and the same oil-containing state is taken as the peak sound wave under that pressure condition and the same oil-containing state.

[0018] Furthermore, under the same pressure conditions, the state parameters of each oil-bearing state are sorted in ascending order, and adjacent oil-bearing states are divided into an interval, specifically:

[0019] The state parameter of the oil-bearing state is the oil content. The oil content is sorted in ascending order from low to high, and two adjacent oil-bearing states are divided into an oil-bearing state interval, denoted as:

[0020]

[0021] in, Let j be the j-th oil-bearing state interval, representing the continuous range of oil content variation from the j-th oil-bearing state to the (j+1)-th oil-bearing state;

[0022] The oil content is the oil content corresponding to the j-th oil-bearing state after sorting by oil content in ascending order.

[0023] This represents the oil content corresponding to the (j+1)th oil-bearing state after sorting by oil content in ascending order.

[0024] , where n is the total number of oil-bearing state intervals.

[0025] Furthermore, in step S2, the range of sound wave peak value variation is:

[0026]

[0027] in, This is the i-th pressure condition;

[0028] For pressure conditions The range of acoustic peak value variation from the lowest oil content state to the highest oil content state;

[0029]

[0030] in, For pressure conditions The peak acoustic wave value corresponding to the lowest oil content state;

[0031] At the lowest oil content;

[0032]

[0033] in, For pressure conditions The peak acoustic wave value corresponding to the highest oil content state;

[0034] This represents the highest oil content.

[0035] The acoustic response index is:

[0036]

[0037] in, For pressure conditions and oily state The normalized acoustic response index under the given conditions;

[0038] .

[0039] Furthermore, the acoustic resolution coefficient, which characterizes the change in the acoustic response index in each interval, is calculated as follows:

[0040]

[0041] in, To be under pressure conditions Below, oil-bearing state range The acoustic resolution coefficient;

[0042] For pressure conditions and oily state The normalized acoustic response index under the given conditions;

[0043] For pressure conditions and oily state The normalized acoustic response index under the given conditions;

[0044] The average acoustic resolution coefficient for the same interval under various pressure conditions is calculated as follows:

[0045]

[0046] in, Oil-bearing state range Average acoustic resolution coefficient under various pressure conditions;

[0047] Oil-bearing state range The sum of the acoustic resolution coefficients under all pressure conditions;

[0048] m is the total number of all pressure conditions;

[0049] i is the pressure condition index.

[0050] Furthermore, the pressure uniformity coefficient for the dispersion of acoustic response under different pressure conditions in the same oil-bearing state is calculated as follows:

[0051]

[0052] in, Oily state Pressure consistency coefficient under different pressure conditions;

[0053] Oily state The degree of pressure dispersion under different pressure conditions;

[0054] This represents the minimum pressure dispersion under different pressure conditions for all oil-bearing states;

[0055] This represents the maximum value of the pressure dispersion under different pressure conditions for all oil-bearing states;

[0056] This is a numerical stability term used in the normalization calculation of pressure dispersion to avoid... When the value is zero or close to zero, division by zero or numerical instability may occur.

[0057]

[0058] in, For pressure conditions and oily state The normalized acoustic response index under the given conditions;

[0059] Under the same oil-containing state Average values ​​of the acoustic response index under different pressure conditions;

[0060] Oily state The sum of squares of the deviations of the acoustic response index under all pressure conditions from the average acoustic response index under the oil-bearing state.

[0061] m is the total number of all pressure conditions;

[0062] The pressure consistency coefficient for each interval is calculated as follows:

[0063]

[0064] in, Oil-bearing state range Pressure consistency coefficient;

[0065] Oily state Pressure consistency coefficient under different pressure conditions.

[0066] Furthermore, the comprehensive reliability index for each interval is calculated as follows:

[0067]

[0068] in, Oil-bearing state range The overall reliability index;

[0069] The average acoustic resolution coefficient for the oil-bearing state range after normalization.

[0070] This is the weighting coefficient for sound wave resolution. ;

[0071] Oil-bearing state range Pressure consistency coefficient;

[0072] For pressure consistency weighting coefficient, and .

[0073] Furthermore, the preset recognition rules are as follows: setting an effective recognition threshold, a reference recognition threshold, and a reliable recognition threshold;

[0074] First, compare the average acoustic resolution coefficient of each oil-bearing state range with the effective identification threshold;

[0075] If the average acoustic resolution coefficient of any oil-containing state interval is less than the effective identification threshold, it is determined that the acoustic resolution capability of the oil-containing state interval is insufficient and belongs to the low-sensitivity area.

[0076] If the average acoustic resolution coefficient of the oil-bearing state interval is greater than or equal to the effective identification threshold, then the comprehensive reliability index of each oil-bearing state interval is compared with the reference identification threshold and the reliable identification threshold.

[0077] When the comprehensive reliability index of the oil-bearing state range is greater than or equal to the reliability identification threshold, the oil-bearing state range is determined to be a reliable identification area that can be accurately predicted using acoustic response.

[0078] When the comprehensive reliability index of the oil-bearing state range is greater than or equal to the reference identification threshold and less than the reliability identification threshold, the oil-bearing state range is determined to be the reference identification range.

[0079] When the overall reliability index of the oil-bearing state range is less than the reference identification threshold and the average acoustic resolution coefficient is greater than or equal to the effective identification threshold, the oil-bearing state range is identified as a pressure-enhanced zone.

[0080] Furthermore, the effective identification threshold is set as the median of the average acoustic resolution coefficient across all oil-bearing state ranges;

[0081] The reference identification threshold is set as the 25th percentile of the comprehensive reliability index for all oil-containing condition ranges;

[0082] The reliability identification threshold is set as the 75th percentile of the comprehensive reliability index for all oil-containing condition ranges.

[0083] This invention also provides a system for determining the effective identification interval of oil-bearing state using acoustic waves in high-pressure oil and gas, used to execute the method for determining the reliable prediction interval of oil-bearing state based on acoustic wave response as described in any one of the claims, including...

[0084] The acoustic signal acquisition module is used to acquire acoustic signals under different pressure conditions and different oil content states;

[0085] The data processing module is used to process the collected acoustic signals to obtain the peak acoustic data under various pressure conditions and oil-containing states; under the same pressure conditions, the oil-containing states are arranged in ascending order of oil content from low to high, and two oil-containing states with adjacent oil content are divided into oil-containing state intervals.

[0086] The calculation module calculates the range of acoustic peak values ​​between the lowest and highest oil-bearing states under the same pressure conditions, the acoustic response index of each oil-bearing state, the acoustic resolution coefficient characterizing the change of the acoustic response index in each interval, the average acoustic resolution coefficient under each pressure condition, the pressure consistency coefficient of the acoustic response dispersion of the same oil-bearing state under different pressure conditions, the pressure consistency coefficient of each interval, and the comprehensive reliability index of each interval, based on the acoustic peak data.

[0087] The identification module is used to identify the oil-bearing state range that can be accurately predicted using sound waves based on the preset identification rules.

[0088] The present invention has the following beneficial effects:

[0089] This invention normalizes the acoustic peak values ​​under each pressure condition using the low oil content and the highest oil content conditions, thereby converting the acoustic response under different pressure conditions into an acoustic response index on a uniform scale, reducing the influence of pressure condition differences on the absolute magnitude of the acoustic peak value.

[0090] This invention does not directly invert oil content using acoustic peak values. Instead, it first calculates the acoustic resolution coefficient for each oil-bearing state interval to evaluate whether the acoustic response can distinguish between adjacent oil-bearing states. Then, it combines pressure consistency for reliability classification, ultimately identifying oil-bearing state intervals that can be reliably predicted using acoustic responses. This avoids misjudgments caused by directly inverting oil content in low-sensitivity regions, significantly improving the stability and reliability of high-pressure oil and gas acoustic identification results. Furthermore, this invention introduces a pressure consistency coefficient across pressure conditions, which can identify intervals where the acoustic response has a certain resolution capability but is strongly affected by pressure. These intervals are then classified as reference identification areas or pressure-affected areas, further improving the reliability of the identification results.

[0091] This invention employs a two-level judgment method that combines acoustic resolution gating with comprehensive reliability grading. This avoids the problem of resolution and pressure consistency canceling each other out in a single comprehensive index, making the division of the low-sensitivity zone, reliable identification zone, reference identification zone, and pressure-affected zone clearer.

[0092] The effective identification threshold, reference identification threshold, and reliable identification threshold of this invention are adaptively determined based on the statistical distribution of the average acoustic resolution coefficient and comprehensive reliability index of all oil-bearing state intervals, eliminating the need for manually pre-setting fixed thresholds. Therefore, it is applicable to determining the effective identification interval under different pressure conditions and different oil-bearing state interval divisions. Attached Figure Description

[0093] Figure 1 This is a schematic diagram showing the variation of peak acoustic wave value with oil content under different pressure conditions.

[0094] Figure 2 This is a schematic diagram showing the change of the acoustic response index with oil content under different pressure conditions.

[0095] Figure 3 This is a schematic diagram showing the variation curves of the average acoustic resolution coefficient for each oil-bearing state range.

[0096] Figure 4 This is a schematic diagram of the overall reliability index variation curve for each oil-bearing state range. Detailed Implementation

[0097] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0098] The present invention provides a method for determining a reliable prediction interval for oil-bearing state based on acoustic response, used to identify oil-bearing state intervals within a study area that can be accurately predicted using acoustic response, comprising:

[0099] S1. Obtain the peak acoustic wave data of each oil-bearing state under different pressure conditions and the corresponding state parameters of each oil-bearing state. Under the same pressure conditions, sort the state parameters of each oil-bearing state in ascending order and divide the oil-bearing states with adjacent state parameters into an interval.

[0100] The acquisition of peak acoustic wave data is as follows:

[0101] Acoustic wave signals are acquired using an acoustic wave acquisition device; the acoustic wave acquisition device includes a piezoelectric acoustic wave sensor, an ultrasonic transducer, an acoustic emission sensor, or other acoustic wave acquisition devices capable of acquiring the acoustic wave response of a medium.

[0102] The sampling frequency is determined based on the dominant frequency range of the acoustic signal and meets the actual resolution requirements for peak extraction. Preferably, it is not less than twice the highest effective frequency of the acoustic signal.

[0103] Under various pressure conditions Under the following conditions, acoustic wave acquisition is performed after the pressure reaches the target value corresponding to each pressure condition and meets the stability criterion; the stability criterion is that the pressure fluctuation is less than a preset threshold and lasts for a preset time. (Each pressure condition...) ,in, , where m is the total number of pressure conditions.

[0104] For each pressure condition and oil-containing state, perform single or multiple repeated measurements. During each measurement, extract the waveform peak value within a fixed time window according to a uniform rule. The uniform rule is the first peak value, the maximum peak value, the peak-to-peak value, or the envelope peak value.

[0105] When performing multiple measurements, the arithmetic mean of the peak waveforms extracted from each measurement under the same pressure condition and the same oil-containing state is taken as the peak sound wave under that pressure condition and the same oil-containing state.

[0106] Throughout the entire process of acquiring and identifying acoustic peak data, the acoustic acquisition conditions and peak extraction rules remain consistent.

[0107] Under the same pressure conditions, the state parameters of each oil-bearing state are sorted in ascending order, and adjacent oil-bearing states are divided into intervals, specifically:

[0108] The state parameter of the oil-bearing state is the oil content. The oil content is sorted in ascending order from low to high, and two adjacent oil-bearing states are divided into an oil-bearing state interval, denoted as:

[0109]

[0110] in, Let j be the j-th oil-bearing state interval, representing the continuous range of oil content variation from the j-th oil-bearing state to the (j+1)-th oil-bearing state;

[0111] The oil content is the oil content corresponding to the j-th oil-bearing state after sorting by oil content in ascending order.

[0112] This represents the oil content corresponding to the (j+1)th oil-bearing state after sorting by oil content in ascending order.

[0113] , where n is the total number of oil-bearing state intervals.

[0114] S2. Calculate the range of acoustic peak value variation between the lowest and highest oil-bearing states under the same pressure conditions; and calculate the acoustic response index for each oil-bearing state based on the range of acoustic peak value variation between the lowest and highest oil-bearing states under the same pressure conditions.

[0115] The range of sound wave peak value variation is:

[0116]

[0117] in, For pressure conditions The range of acoustic peak value variation from the lowest oil content state to the highest oil content state.

[0118]

[0119] in, For pressure conditions The peak acoustic wave value corresponding to the lowest oil content state;

[0120] This represents the lowest oil content.

[0121]

[0122] in, For pressure conditions The peak acoustic wave value corresponding to the highest oil content state;

[0123] This represents the highest oil content.

[0124] The acoustic response index is:

[0125]

[0126] in, For pressure conditions and oily state The normalized acoustic response index under the given conditions;

[0127] .

[0128] By normalizing the range of acoustic peak value variation between the lowest and highest oil content states, the original acoustic peak values ​​under different pressure conditions are converted into dimensionless response exponents relative to the lowest and highest oil content states under that pressure condition. The normalized response exponent for the lowest oil content state is close to 0, while the normalized response exponent for the highest oil content state is close to 1. This reduces the influence of the absolute magnitude difference in acoustic peak values ​​under different pressure conditions, making the acoustic response results comparable across different pressure conditions.

[0129] S3. Calculate the acoustic resolution coefficient representing the change of acoustic response index in each interval; and calculate the average acoustic resolution coefficient of the same interval under each pressure condition based on the acoustic resolution coefficient representing the change of acoustic response index in each interval.

[0130] The acoustic resolution coefficient, which characterizes the change in the acoustic response index in each interval, is calculated as follows:

[0131]

[0132] in, To be under pressure conditions Below, oil-bearing state range The acoustic resolution coefficient; used to characterize pressure conditions. The next adjacent oil-bearing zone The ability to distinguish changes in oil-bearing state.

[0133] For pressure conditions and oily state The normalized acoustic response index is given below.

[0134] For pressure conditions and oily state The normalized acoustic response index is given below.

[0135] The average acoustic resolution coefficient for the same interval under various pressure conditions is calculated as follows:

[0136]

[0137] in, Oil-bearing state range Average acoustic resolution coefficient under various pressure conditions.

[0138] Oil-bearing state range The sum of acoustic resolution coefficients under all pressure conditions.

[0139] m represents the total number of all pressure conditions.

[0140] i is the pressure condition index.

[0141] In step S3, the median of the acoustic resolution coefficients under various pressure conditions in the same interval can be used instead of the average acoustic resolution coefficient to reduce the impact of abnormal pressure points on the evaluation results.

[0142] acoustic resolution coefficient or average sound resolution coefficient The larger the value, the more obvious the change in acoustic response with the oil content within the oil-containing state range, and the more suitable it is as an effective identification range; conversely, the smaller the value, the weaker the change in acoustic response within the range, which may belong to a low-sensitivity range or a range that is not suitable for quantitative identification.

[0143] S4. Calculate the pressure consistency coefficient that reflects the dispersion of acoustic response under different pressure conditions for the same oil-bearing state, and calculate the pressure consistency coefficient for each interval based on the pressure consistency coefficient of acoustic response dispersion under different pressure conditions for different oil-bearing states.

[0144] The pressure uniformity coefficient for calculating the dispersion of acoustic response under different pressure conditions in the same oil-containing state is as follows:

[0145]

[0146] in, Oily state Pressure consistency coefficient under different pressure conditions; The larger the value, the more consistent the normalized acoustic response is under different pressure conditions in the oil-bearing state; The smaller the value, the more significantly the acoustic response is affected by pressure under oil-containing conditions.

[0147] Oily state The degree of pressure dispersion under different pressure conditions.

[0148] It represents the minimum pressure dispersion under different pressure conditions for all oil-bearing states.

[0149] This represents the maximum value of the pressure dispersion under different pressure conditions for all oil-bearing states;

[0150] This is a numerical stability term used in the normalization calculation of pressure dispersion to avoid... When the value is zero or close to zero, division by zero or numerical instability occurs; in this embodiment, Pick .

[0151]

[0152] in, Under the same oil-containing state Average value of acoustic response index under different pressure conditions.

[0153] Oily state The sum of squares of the offsets of the acoustic response index under all pressure conditions relative to the average acoustic response index under the oil-bearing condition.

[0154] The pressure consistency coefficient for each interval is calculated as follows:

[0155]

[0156] in, Oil-bearing state range Pressure consistency coefficient.

[0157] Oily state Pressure consistency coefficient under different pressure conditions.

[0158] S5. Calculate the comprehensive reliability index of each interval based on the pressure consistency coefficient and the average acoustic resolution coefficient of each interval, and identify the oil-bearing state interval that can be accurately predicted by acoustic waves according to the preset identification rules based on the average acoustic resolution coefficient and the comprehensive reliability index.

[0159] The overall reliability index for each interval is calculated as follows:

[0160]

[0161] in, Oil-bearing state range The overall reliability index.

[0162] The normalized oil-bearing state range The average acoustic resolution coefficient.

[0163]

[0164] in, The average acoustic resolution coefficient for the entire oil-bearing range. The minimum value.

[0165] The average acoustic resolution coefficient for the entire oil-bearing range. The maximum value.

[0166] This is a dimensionless numerical stability term used in the normalization calculation of the average acoustic resolution coefficients to avoid... When the value is zero or close to zero, division by zero or numerical instability occurs; in this embodiment, Pick .

[0167] This is the weighting coefficient for sound wave resolution. ;

[0168] For pressure consistency weighting coefficient, and .

[0169] and The predetermined weighting coefficients can be determined in advance based on the emphasis placed on acoustic resolution and pressure consistency by the identification task. When greater emphasis is placed on the differences in acoustic response between adjacent oil-bearing states, the weighting can be increased. The value of ; when more emphasis is placed on the consistency of identification results under different pressure conditions, it can be improved The value of .

[0170] Unless otherwise specified, take This ensures that acoustic resolution and pressure consistency have equal weight in the overall reliability evaluation.

[0171] The preset recognition rules are: set the effective recognition threshold, the reference recognition threshold, and the reliable recognition threshold.

[0172] Effective identification threshold It is set to the median of the average acoustic resolution coefficient across all oil-bearing states.

[0173]

[0174] in, This represents the median.

[0175] Reference recognition threshold It is set as the 25th percentile of the overall reliability index for all oil-containing condition ranges.

[0176]

[0177] in, This represents the 25th percentile value.

[0178] The reliability identification threshold is set as the 75th percentile of the comprehensive reliability index for all oil-containing condition ranges.

[0179]

[0180] in, This represents the 75th percentile value.

[0181] First, based on the average acoustic resolution coefficient and effective identification threshold of each oil-bearing state range... Compare;

[0182] If the average acoustic resolution coefficient of any oil-containing state range is less than the effective recognition threshold If the sound wave resolution is insufficient in the oil-containing region, it is determined that the region is a low-sensitivity region.

[0183] If the average acoustic resolution coefficient of the oil-containing region is greater than or equal to the effective identification threshold Then, the comprehensive reliability index of each oil-bearing state range is compared with the reference identification threshold and the reliable identification threshold.

[0184] When the comprehensive reliability index of the oil-containing state range is greater than or equal to the reliability identification threshold At that time, the oil-bearing state range is determined as a reliable identification zone that can be accurately predicted using acoustic response.

[0185] When the comprehensive reliability index of the oil-containing state range is greater than or equal to the reference identification threshold and less than the reliability identification threshold When this oil-containing state range is determined, it is identified as the reference identification area;

[0186] When the overall reliability index of the oil-containing state range is less than the reference identification threshold And the average acoustic resolution coefficient is greater than or equal to the effective recognition threshold. At that time, the oil-bearing state range was determined to be a pressure-enhanced region.

[0187] This invention also provides a system for determining the effective identification interval of oil-bearing state using acoustic waves in high-pressure oil and gas, used to execute the method for determining the reliable prediction interval of oil-bearing state based on acoustic wave response as described in any one of the claims, including...

[0188] The acoustic signal acquisition module is used to acquire acoustic signals under different pressure conditions and different oil content states;

[0189] The data processing module is used to process the collected acoustic signals to obtain the peak acoustic data under various pressure conditions and oil-containing states; under the same pressure conditions, the oil-containing states are arranged in ascending order of oil content from low to high, and two oil-containing states with adjacent oil content are divided into oil-containing state intervals.

[0190] The calculation module calculates the range of acoustic peak values ​​between the lowest and highest oil-bearing states under the same pressure conditions, the acoustic response index of each oil-bearing state, the acoustic resolution coefficient characterizing the change of the acoustic response index in each interval, the average acoustic resolution coefficient under each pressure condition, the pressure consistency coefficient of the acoustic response dispersion of the same oil-bearing state under different pressure conditions, the pressure consistency coefficient of each interval, and the comprehensive reliability index of each interval, based on the acoustic peak data.

[0191] The identification module is used to identify the oil-bearing state range that can be accurately predicted using sound waves based on the preset identification rules.

[0192] The following section uses a physical simulation experiment of acoustic response of fractured-vuggy reservoir medium under different pressure and oil content conditions as an example to illustrate the specific implementation process of the method for determining the reliable prediction interval of oil-bearing state based on acoustic response described in this invention.

[0193] In this embodiment, eight pressure conditions are set, namely 0.1 MPa, 10 MPa, 20 MPa, 30 MPa, 40 MPa, 50 MPa, 60 MPa and 70 MPa;

[0194] There are 21 oil-containing states, with oil content of 0, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95 and 1.00 respectively.

[0195] In the calculation of the comprehensive reliability index, the weighting coefficient for acoustic resolution capability is... Pressure consistency weighting coefficient .

[0196] In this embodiment, the peak acoustic wave values ​​under different pressure conditions generally show a non-linear increasing trend with increasing oil content. In regions with low oil content, the peak acoustic wave values ​​are generally small, and the differences in peak values ​​under different pressure conditions are small. As the oil content increases, the peak acoustic wave values ​​enter a rapid growth phase. When the oil content further increases, the differences in peak values ​​under different pressure conditions gradually increase. This phenomenon indicates that directly using the absolute value of the peak acoustic wave value to invert the oil content state is easily affected by the combined influence of low-sensitivity regions and changes in pressure conditions. Therefore, normalization processing and reliability classification evaluation are required.

[0197] The peak acoustic wave data of 21 oil-containing states under 8 pressure conditions were obtained, as shown in Table 1.

[0198] Table 1

[0199] like Figure 1 As shown, Figure 1 This diagram illustrates the variation of peak acoustic wave value with oil content under different pressure conditions. It is used to explain the influence of pressure conditions on the original peak acoustic wave value, and the absolute values ​​under different pressure conditions cannot be directly compared.

[0200] Table 2 shows the peak acoustic waves corresponding to the lowest and highest oil content states under the same pressure conditions, as well as the range of variation of the peak acoustic waves between the lowest and highest oil content states.

[0201] Table 2

[0202] As shown in Table 2, the peak value of the acoustic wave at the lowest oil content under each pressure condition is a non-zero minimum, while the peak value of the acoustic wave at the highest oil content condition generally increases with increasing pressure. Specifically, the peak value of the acoustic wave at the highest oil content condition is 59.256907 mV at 0.1 MPa and 113.236119 mV at 70 MPa.

[0203] The results show that, at the highest oil content, the absolute values ​​of the acoustic peak values ​​differ significantly under different pressure conditions; meanwhile, the acoustic peak value at the lowest oil content has a non-zero background response, and the acoustic peak value at the lowest oil content under the corresponding pressure conditions should be subtracted during normalization.

[0204] The acoustic response indices of various oil-containing states under different pressure conditions in this embodiment are shown in Table 3.

[0205] Table 3

[0206] like Figure 2 As shown, Figure 2 This diagram illustrates the variation of the acoustic response index with oil content under different pressure conditions. It serves to demonstrate the comparability of acoustic responses under different pressure conditions after normalization and provides input for subsequent calculation of the acoustic resolution coefficient.

[0207] In this embodiment, the acoustic resolution coefficients of each oil-bearing state range under various pressure conditions, the average acoustic resolution coefficients of each oil-bearing state range, and their comparison results with the effective identification threshold are shown in Table 4. Table 4 yields the effective identification threshold for this embodiment. =0.561226.

[0208] Table 4

[0209] like Figure 3 As shown, Figure 3 This is a schematic diagram of the average acoustic resolution coefficient variation curve for each oil-bearing state interval. It is used to screen oil-bearing state intervals that meet the acoustic resolution capability requirements based on the comparison between the average acoustic resolution coefficient and the effective identification threshold.

[0210] In this embodiment, each oil-containing state Pressure dispersion under different pressure conditions and various oil-bearing states Pressure consistency coefficient under different pressure conditions As shown in Table 5.

[0211] Table 5

[0212] In this embodiment, the comprehensive reliability index of each interval and the determination of the oil-bearing state interval that can be accurately predicted using sound waves are shown in Table 6. The reliability identification threshold is: The reference recognition threshold is: The effective identification threshold is: .

[0213] like Figure 4 As shown, Figure 4 This is a schematic diagram of the change curve of the comprehensive reliability index for each oil-bearing state interval. It is used to determine the interval by comparing the comprehensive reliability index with the reliability identification threshold and the reference identification threshold.

[0214] Table 6

[0215] As shown in Table 6, when the oil-containing state range is When the oil content is 0.00-0.35%, the oil content state range is: The average acoustic resolution coefficient is lower than the effective recognition threshold, indicating that the acoustic response in this range is not sensitive to changes in oil content, and therefore it is determined to be a low-sensitivity region.

[0216] When the oil-containing state range is When the oil content is 0.35-0.60%, the oil content state range is: The average acoustic resolution coefficient is greater than the effective identification threshold, indicating high acoustic resolution capability and good pressure consistency. The overall reliability index is at a high level, therefore it is determined to be a reliable identification area.

[0217] When the oil-containing state range is When the oil content is 0.60-0.65%, the oil content state range is... The average acoustic resolution coefficient is greater than the effective recognition threshold, indicating a certain acoustic resolution capability, but the oil-containing state range... The overall reliability index is less than the reliable identification threshold, and the overall reliability is lower than that of the reliable identification area. Therefore, it is determined to be the reference identification area.

[0218] When the oil-containing state range is When the oil content is 0.65-0.85%, the oil content state range is: The average acoustic resolution coefficient is greater than the effective identification threshold, indicating that the oil-bearing state range is... It is not in the low-sensitivity zone for sound waves; however, the oil-containing state range is... The acoustic response under different pressure conditions is inconsistent, resulting in a lower pressure consistency coefficient and a comprehensive reliability index that is below the reliability identification threshold. Therefore, the oil state range... This area was identified as a zone of heightened pressure influence.

[0219] When the oil-containing state range is When the oil content is 0.85-1.00%, the average acoustic resolution coefficient in this range is lower than the effective recognition threshold, indicating that the acoustic response gradually plateaus under high oil content conditions, and the response difference between adjacent oil content states weakens. Therefore, this oil content range is determined to be a low-sensitivity region.

[0220] As can be seen from the above results, in this embodiment, the reliable identification region is the oil-containing state range. The oil content is 0.35-0.60%; the reference identification area is the oil-containing state range. The oil content is 0.60-0.65%; the pressure-affected zone is the oil-bearing state range. The oil content is 0.65-0.85%; the low-sensitivity zone is the oil-containing state range. and The oil content ranged from 0.00 to 0.35% and from 0.85 to 1.00%. The oil-bearing state intervals identified as low-sensitivity zones were not suitable for direct, highly reliable quantitative identification. These results demonstrate that this method can not only evaluate the ability of the acoustic response within each oil-bearing state interval to distinguish between adjacent oil-bearing states, but also identify oil-bearing state intervals where reliability is reduced due to pressure conditions.

[0221] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for determining the reliable prediction interval of oil-bearing state based on acoustic response, used to identify the oil-bearing state interval within a study area that can be accurately predicted using acoustic response, characterized in that: include S1. Obtain the peak acoustic data of each oil-bearing state under different pressure conditions and the corresponding state parameters of each oil-bearing state. Under the same pressure condition, sort the state parameters of each oil-bearing state in ascending order and divide the oil-bearing states with adjacent state parameters into an interval. S2. Calculate the range of acoustic peak value variation between the lowest and highest oil-bearing states under the same pressure conditions; and calculate the acoustic response index for each oil-bearing state accordingly. S3. Calculate the acoustic resolution coefficient that characterizes the change of acoustic response index in each interval; and calculate the average acoustic resolution coefficient of the same interval under each pressure condition accordingly. S4. Calculate the pressure consistency coefficient that reflects the dispersion of acoustic response under different pressure conditions in the same oil-bearing state, and calculate the pressure consistency coefficient for each interval accordingly. S5. Calculate the comprehensive reliability index of each interval based on the pressure consistency coefficient and the average acoustic resolution coefficient of each interval, and identify the oil-bearing state interval that can be accurately predicted by acoustic waves according to the preset identification rules based on the average acoustic resolution coefficient and the comprehensive reliability index.

2. The method for determining the reliable prediction interval of oil-bearing state based on acoustic response according to claim 1, characterized in that: The acquisition of peak acoustic wave data is as follows: Acoustic wave signals are acquired using an acoustic wave acquisition device; wherein the sampling frequency is not less than twice the highest effective frequency of the acoustic wave signal. Under various pressure conditions, acoustic wave acquisition is performed after the pressure reaches the target value corresponding to each pressure condition and meets the stability criterion. The stability criterion is that the pressure fluctuation is less than a preset threshold and lasts for a preset time. Single or multiple repeated measurements are performed for each pressure condition and oil-containing state. During each measurement, the peak value of the waveform is extracted within a fixed time window according to a unified rule. The unified rule is the first peak value, the maximum peak value, the peak-to-peak value, or the envelope peak value. When performing multiple measurements, the arithmetic mean of the peak waveforms extracted from each measurement under the same pressure condition and the same oil-containing state is taken as the peak sound wave under that pressure condition and the same oil-containing state.

3. The method for determining the reliable prediction interval of oil-bearing state based on acoustic response according to claim 1, characterized in that: Under the same pressure conditions, the state parameters of each oil-bearing state are sorted in ascending order, and adjacent oil-bearing states are divided into intervals, specifically: The state parameter of the oil-bearing state is the oil content. The oil content is sorted in ascending order from low to high, and two adjacent oil-bearing states are divided into an oil-bearing state interval, denoted as: in, Let j be the j-th oil-bearing state interval, representing the continuous range of oil content variation from the j-th oil-bearing state to the (j+1)-th oil-bearing state; The oil content is the oil content corresponding to the j-th oil-bearing state after sorting by oil content in ascending order. This represents the oil content corresponding to the (j+1)th oil-bearing state after sorting by oil content in ascending order. , where n is the total number of oil-bearing state intervals.

4. The method for determining the reliable prediction interval of oil-bearing state based on acoustic response according to claim 1, characterized in that: In step S2, the range of sound wave peak value variation is: in, This is the i-th pressure condition; For pressure conditions The range of acoustic peak value variation from the lowest oil content state to the highest oil content state; in, For pressure conditions The peak acoustic wave value corresponding to the lowest oil content state; At the lowest oil content; in, For pressure conditions The peak acoustic wave value corresponding to the highest oil content state; This represents the highest oil content. The acoustic response index is: in, For pressure conditions and oily state The normalized acoustic response index under the given conditions; Range of sound wave peak values Greater than zero.

5. The method for determining the reliable prediction interval of oil-bearing state based on acoustic response according to claim 1, characterized in that: The acoustic resolution coefficient, which characterizes the change in the acoustic response index in each interval, is calculated as follows: in, To be under pressure conditions Below, oil-bearing state range The acoustic resolution coefficient; For pressure conditions and oily state The normalized acoustic response index under the given conditions; For pressure conditions and oily state The normalized acoustic response index under the given conditions; The average acoustic resolution coefficient for the same interval under various pressure conditions is calculated as follows: in, Oil-bearing state range Average acoustic resolution coefficient under various pressure conditions; Oil-bearing state range The sum of the acoustic resolution coefficients under all pressure conditions; m is the total number of all pressure conditions; i is the pressure condition index.

6. The method for determining the reliable prediction interval of oil-bearing state based on acoustic response according to claim 1, characterized in that: The pressure uniformity coefficient for calculating the dispersion of acoustic response under different pressure conditions in the same oil-containing state is as follows: in, Oily state Pressure consistency coefficient under different pressure conditions; Oily state The degree of pressure dispersion under different pressure conditions; This represents the minimum pressure dispersion under different pressure conditions for all oil-bearing states; This represents the maximum value of the pressure dispersion under different pressure conditions for all oil-bearing states; This is the numerical stability term used in the normalization calculation of pressure dispersion. in, For pressure conditions and oily state The normalized acoustic response index under the given conditions; Under the same oil-containing state Average values ​​of the acoustic response index under different pressure conditions; Oily state The sum of squares of the deviations of the acoustic response index under all pressure conditions from the average acoustic response index under the oil-bearing state. m is the total number of all pressure conditions; The pressure consistency coefficient for each interval is calculated as follows: in, Oil-bearing state range Pressure consistency coefficient; Oily state Pressure consistency coefficient under different pressure conditions.

7. The method for determining the reliable prediction interval of oil-bearing state based on acoustic response according to claim 1, characterized in that: The overall reliability index for each interval is calculated as follows: in, Oil-bearing state range The overall reliability index; The average acoustic resolution coefficient for the oil-bearing state range after normalization. This is the weighting coefficient for sound wave resolution. ; Oil-bearing state range Pressure consistency coefficient; For pressure consistency weighting coefficient, and .

8. The method for determining the reliable prediction interval of oil-bearing state based on acoustic response according to claim 1, characterized in that: The preset recognition rules are: setting an effective recognition threshold, a reference recognition threshold, and a reliable recognition threshold; First, compare the average acoustic resolution coefficient of each oil-bearing state range with the effective identification threshold; If the average acoustic resolution coefficient of any oil-containing state interval is less than the effective identification threshold, it is determined that the acoustic resolution capability of the oil-containing state interval is insufficient and belongs to the low-sensitivity area. If the average acoustic resolution coefficient of the oil-bearing state interval is greater than or equal to the effective identification threshold, then the comprehensive reliability index of each oil-bearing state interval is compared with the reference identification threshold and the reliable identification threshold. When the comprehensive reliability index of the oil-bearing state range is greater than or equal to the reliability identification threshold, the oil-bearing state range is determined to be a reliable identification area that can be accurately predicted using acoustic response. When the comprehensive reliability index of the oil-bearing state range is greater than or equal to the reference identification threshold and less than the reliability identification threshold, the oil-bearing state range is determined to be the reference identification range. When the overall reliability index of the oil-bearing state range is less than the reference identification threshold and the average acoustic resolution coefficient is greater than or equal to the effective identification threshold, the oil-bearing state range is identified as a pressure-enhanced zone.

9. The method for determining the reliable prediction interval of oil-bearing state based on acoustic response according to claim 8, characterized in that: The effective identification threshold is set as the median of the average acoustic resolution coefficient across all oil-containing regions; The reference identification threshold is set as the 25th percentile of the comprehensive reliability index for all oil-containing condition ranges; The reliability identification threshold is set as the 75th percentile of the comprehensive reliability index for all oil-containing condition ranges.

10. A system for determining the effective acoustic identification interval of oil-bearing state in high-pressure oil and gas, used to execute the reliable prediction interval determination method for oil-bearing state based on acoustic response as described in any one of claims 1 to 9, characterized in that: include The acoustic signal acquisition module is used to acquire acoustic signals under different pressure conditions and different oil content states; The data processing module is used to process the collected acoustic signals to obtain the peak acoustic data under various pressure conditions and oil-containing states; under the same pressure conditions, the oil-containing states are arranged in ascending order of oil content from low to high, and two oil-containing states with adjacent oil content are divided into oil-containing state intervals. The calculation module calculates the range of acoustic peak values ​​between the lowest and highest oil-bearing states under the same pressure conditions, the acoustic response index of each oil-bearing state, the acoustic resolution coefficient characterizing the change of the acoustic response index in each interval, the average acoustic resolution coefficient under each pressure condition, the pressure consistency coefficient of the acoustic response dispersion of the same oil-bearing state under different pressure conditions, the pressure consistency coefficient of each interval, and the comprehensive reliability index of each interval based on the acoustic peak data. The identification module is used to identify the oil-bearing state range that can be accurately predicted using sound waves based on the preset identification rules.

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