A calculation method for jointly inverting fracture width by acoustic and electric logging

Abstract

The present invention relates to a calculation method for jointly inversing the fracture width by acoustic and electrical logging, comprising the following steps: S1: preparing rocks meeting the experimental conditions; S2: obtaining the waveforms and resistivity values of the rocks cut at various dip angles with different-width fractures, and obtaining the background array acoustic wave and array lateral resistivity values of the uncut rocks; S3: respectively constructing the inversion formulas for the acoustic attenuation of the array acoustic wave and the fracture width, and the array lateral resistivity and the fracture width according to the results obtained in step S2; S4: constructing a calculation formula for jointly inversing the fracture width by acoustic and electrical methods based on the inversion formulas for the acoustic attenuation of the array acoustic wave and the fracture width, and the array lateral resistivity and the fracture width; S5: obtaining the fracture width at the target depth according to the calculation formula for jointly inversing the fracture width by acoustic and electrical methods. This method can accurately and quickly obtain the fracture width, thereby improving the accuracy of fracture reservoir evaluation and having strong versatility.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas exploration, and more specifically, to a method for calculating fracture width by combined inversion of acoustic and electrical logging. Background Art

[0002] As the pace of oil and gas exploration continues to move deeper, fractured reservoirs have gradually become the main production layers of major oil fields. Among them, fractures, as the main storage space and seepage channels for oil and gas, are the top priority in reservoir evaluation.

[0003] The main parameters of fracture evaluation are fracture width, fracture density, and fracture inclination. At present, acoustic and electrical imaging logging technology can accurately pick up fracture inclination and fracture density. However, since imaging logging can only distinguish fractures above 50 mm, the width of fractures developed in most carbonate reservoirs, granite reservoirs and other unconventional reservoirs is mostly at the micron level. When the fracture width is less than 50 mm, there is a large deviation in the fracture width obtained by imaging logging. Accurate calculation of micron-level fracture width is also a major problem in logging evaluation. In the evaluation of fracture-type reservoirs, it is generally believed that the larger the fracture width, the better the effectiveness of the reservoir. After calculating the fracture width of a certain well section, it is conducive to the determination of the perforation position and dominant production layer of the section. At present, there are two main methods for detecting fracture width: electrical method and acoustic method. Electrical method refers to the detection of fracture width by using the change of resistivity, such as dual lateral, array lateral, and electrical imaging; acoustic method refers to the detection of fracture width by using the change of acoustic wave amplitude, such as acoustic imaging and array acoustic wave. When there are cracks in the formation, the invasion of mud during drilling will cause resistivity differences in the deep and shallow lateral directions. Dual lateral and array lateral are used to quantitatively detect the crack width based on this difference. At the same time, the resistivity value at the cracks around the well will be greatly reduced. Electrical imaging detects the crack width based on the resistivity changes received by the button electrodes on the plates near the cracks. Acoustic well logging uses transducer receivers to receive waveforms propagating in the formation. The presence of cracks will aggravate the dissipation of sound wave energy, resulting in rapid attenuation of sound wave energy after passing through the cracks. Acoustic imaging and array acoustic waves use this acoustic attenuation to quantitatively detect the crack width. Summary of the invention

[0004] In order to overcome the technical problem of inaccurate fracture width acquisition in the prior art, the present invention provides a method for calculating fracture width by combining acoustic and electrical logging with inversion.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A method for calculating fracture width by combining acoustic and electrical logging with inversion, comprising the following steps:

[0007] S1: Prepare no less than n pieces of dense rock with a certain length. Drill holes along the length direction at the center of one end of each piece of dense rock. Then, cut n - 1 pieces of dense rock into two halves from the center of the long side at different angles of inclination to complete the preparation of rocks meeting the experimental conditions, where n ≥ 3;

[0008] S2: Obtain the waveforms and resistivity values of the rocks with different angles of inclination after cutting when passing through cracks of different widths, and obtain the background array acoustic wave values of the uncut rocks;

[0009] S3: According to the results obtained in step S2, respectively construct the inversion formulas for array acoustic wave attenuation and crack width, and array lateral resistivity and crack width:

[0010] S4: Based on the inversion formulas for array acoustic wave attenuation and crack width, and array lateral resistivity and crack width, construct a calculation formula for joint acoustic and electrical inversion of crack width;

[0011] S5: Obtain the crack width at the target depth according to the calculation formula for joint acoustic and electrical inversion of crack width.

[0012] Preferably, in step S3, the steps for constructing the inversion formula for array acoustic wave attenuation and crack width are as follows: Extract the average amplitude of the Stoneley wave received by multiple probes at different crack widths and angles of inclination in the experimental records, calculate the Stoneley wave attenuation coefficient based on this, and construct a relationship between the Stoneley wave attenuation coefficient and the crack width; In step S3, the steps for constructing the inversion formula for array lateral resistivity and crack width are as follows: After measuring the array resistivity values under different crack widths and angles of inclination, construct a calculation relationship between the crack width and the array resistivity.

[0013] Preferably, in step S4, the calculation formula for joint acoustic and electrical inversion of crack width is as follows:

[0014]

[0015] where H f is the crack width obtained by joint acoustic and electrical inversion calculation, with the unit of mm, and H f1 represents the crack width calculated using the array acoustic wave, with the unit of mm, and H f2 is the crack width calculated using the array lateral apparent resistivity, with the unit of mm.

[0016] Preferably, in step S3, the inversion formula for array acoustic wave attenuation and crack width is as follows:

[0017]

[0018] where the calculation formula for the Stoneley wave attenuation coefficient R n is as follows:

[0019]

[0020] Among them, L represents the source distance of different array acoustic wave instruments, with the unit of m. represents the average amplitude of the Stoneley wave received by the array acoustic wave instrument in the uncut rock, that is, the background array acoustic wave value, with the unit of mV. represents the average amplitude of the Stoneley wave of the waveforms received by multiple probes when passing through different fracture widths, with the unit of mV.

[0021] Preferably, in the step S3, the inversion formula of the array laterolog resistivity and the fracture width is as follows:

[0022]

[0023] Among them, α1, α2, α3, α4, α5 are parameters obtained by solving a multiple linear equation with experimental values of different fracture widths, and R m is the mud resistivity, with the unit of Ω·m. MRL1, MRL2, MRL3, and MRL4 are the resistivity values in four detection modes of the array laterolog, respectively, with the unit of Ω·m.

[0024] Preferably, in the step S2, in order to obtain the influence law of the fracture dip angle on the resistivity value of the array laterolog, and then obtain the parameters α1, α2, α3, α4, α5, n - 1 kinds of experiments on fractured rocks with different dip angles are set up.

[0025] Preferably, in the step S2, in order to obtain the quantitative change relationship between the different fracture widths of the cut rocks with different dip angles and the received values of the array acoustic wave and the array laterolog resistivity, 11 kinds of plastic partitions with widths of 1mm, 2mm, 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, and 20mm are made; at the same time, an uncut rock can obtain the array acoustic wave waveform and the array laterolog resistivity with a fracture width of 0mm as the standard background value.

[0026] Preferably, obtaining the waveforms and resistivity values of the cut rocks with different dip angles passing through fractures with different widths includes the following steps:

[0027] s21: First, place a rock with a certain dip angle and fracture width in a water tank and let the water submerge the rock.

[0028] s22: Then, put the array acoustic wave and the array laterolog instruments into the water tank for detection respectively, and record the array acoustic wave value through an oscilloscope and the resistivity value through a resistivity display.

[0029] s23: Change the fracture width and record the array acoustic wave value and the resistivity value at the fracture width under this dip angle.

[0030] S24: Replace the rock and repeat steps S21 to S23, and record the array acoustic wave values and resistivity values at different fracture dips.

[0031] Obtaining the background array acoustic wave and array lateral resistivity values of the uncut rock includes the following steps: First, fill the experimental water tank with brine and the water level submerges the uncut rock. Then, drag the array acoustic wave and array lateral scaled-down instrument at a uniform speed respectively to obtain the background array acoustic wave and array lateral resistivity values of the bedrock with a fracture width of 0 mm.

[0032] Preferably, in the step S21, the experimental water tank is filled with brine having a resistivity of 0.01 - 1 Ω·m and the water level submerges the rock.

[0033] Preferably, the step S5 specifically includes the following steps: Use the array lateral to identify the fracture position and dip, and then substitute the collected array lateral resistivity value and Stoneley wave attenuation coefficient at the target depth into the joint inversion calculation formula to obtain the fracture width at the target depth based on the joint inversion of acoustic and electric logging.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows: By conducting rock physics experiments, this method obtains the functional relationship between the instrument response and the fracture width, and can accurately and quickly obtain the fracture width of deep and ultra-deep fractured reservoirs using acoustic and electric logging data, improve the accuracy of interpretation and evaluation, and thus enhance the efficiency of oil and gas reservoir exploration and development, with strong versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a flowchart of the calculation method for joint inversion of fracture width by acoustic and electric logging of the present invention;

[0036] Figure 2 is a relationship diagram between the fracture width and Stoneley wave attenuation coefficient of rocks with different dips in the present invention;

[0037] Figure 3 is the processing effect diagram of the fracture width in the well section of 3620 m to 3745 m of Well Y1 in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The drawings are only for illustrative purposes and cannot be construed as a limitation to this patent; for better explaining this embodiment, some components in the drawings will be omitted, enlarged or reduced, and do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationships described in the drawings are only for illustrative purposes and cannot be construed as a limitation to this patent.

[0039] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "long", "short", etc. indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and cannot be construed as a limitation of this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0040] The technical solution of the present invention will be further specifically described below through specific embodiments in conjunction with the accompanying drawings:

[0041] Embodiment 1

[0042] As Figure 1 shown, a calculation method for jointly inverting the fracture width by acoustic-electric logging includes the following steps:

[0043] S1: Prepare no less than n pieces of dense rock with a certain length, drill holes at the center of one end of each piece of dense rock along the length direction, and then cut n - 1 pieces of dense rock into two halves from the center of the long side at different angles, completing the preparation of rocks meeting the experimental conditions, where n ≥ 3;

[0044] S2: Obtain the waveforms and resistivity values of the cut rocks at different angles when passing through fractures of different widths, and obtain the background array acoustic wave values of the uncut rocks;

[0045] S3: According to the results obtained in step S2, respectively construct the inversion formulas for the array acoustic wave attenuation and fracture width, and the array lateral resistivity and fracture width:

[0046] S4: Based on the inversion formulas for the array acoustic wave attenuation and fracture width, and the array lateral resistivity and fracture width, construct the calculation formula for jointly inverting the fracture width by acoustic and electric methods;

[0047] S5: Obtain the fracture width at the target depth according to the calculation formula for jointly inverting the fracture width by acoustic and electric methods.

[0048] It should be noted that in this embodiment, the shape of the rock can be a cylinder or a cuboid, and a drill is used to drill holes at the end of the rock, and the diameter of the hole is 30 cm - 40 cm. Eight pieces of dense rock are obtained, and among them, 7 pieces of rock can be cut into two halves from the center in the length direction at 0°, 10°, 15°, 30°, 45°, 60°, and 75°.

[0049] Among them, in the step S3, the steps of constructing the inversion formula for the acoustic attenuation of the array acoustic wave and the fracture width are as follows: extract the average amplitude of the Stoneley wave of the waveforms received by multiple probes at different fracture widths and dips in the experimental records, calculate the Stoneley wave attenuation coefficient based on this, and construct the relationship between the Stoneley wave attenuation coefficient and the fracture width; in the step S3, the steps of constructing the inversion formula for the array lateral resistivity and the fracture width are as follows: after measuring the array resistivity values under different fracture widths and dips, construct the calculation relationship between the fracture width and the array resistivity.

[0050] In addition, in the step S4, the calculation formula for the acoustic and electrical joint inversion of the fracture width is as follows:

[0051]

[0052] Among them, H f is the fracture width obtained by acoustic and electrical joint inversion, with the unit of mm, and H f1 represents the fracture width calculated using the array acoustic wave, with the unit of mm, and H f2 is the fracture width calculated using the array lateral apparent resistivity, with the unit of mm.

[0053] Among them, in the step S3, the inversion formula for the acoustic attenuation of the array acoustic wave and the fracture width is as follows:

[0054]

[0055] Among them, the calculation formula for the Stoneley wave attenuation coefficient R n is as follows:

[0056]

[0057] Among them, L represents the source distance of different array acoustic wave instruments, with the unit of m, represents the average amplitude of the Stoneley wave received by the array acoustic wave instrument in the uncut dense rock, that is, the background array acoustic wave value, with the unit of mV, represents the average amplitude of the Stoneley wave of the waveforms received by multiple probes after passing through different fracture widths, with the unit of mV.

[0058] In addition, in the step S3, the inversion formula for the array lateral resistivity and the fracture width is as follows:

[0059]

[0060] Among them, α1, α2, α3, α4, α5 are all parameters obtained by solving the multi - variable linear equation with experimental values of different fracture widths, and R mis the mud resistivity, with the unit of Ω·m. MRL1, MRL2, MRL3, and MRL4 are the resistivity values under the four detection modes of the array laterolog, with the unit of Ω·m.

[0061] Among them, in the step S2, in order to obtain the influence law of the fracture dip angle on the resistivity values of the array laterolog, and then obtain the parameters α1, α2, α3, α4, and α5, n - 1 kinds of experiments of fractured rocks with different dip angles are set up.

[0062] In addition, in the step S2, in order to obtain the quantitative change relationship between the different fracture widths of the cut rocks with different dip angles and the received values of the array acoustic wave and the array laterolog resistivity, 11 kinds of plastic partitions with widths of 1mm, 2mm, 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, and 20mm are made; at the same time, an uncut rock can obtain the array acoustic wave waveform and the array laterolog resistivity with a fracture width of 0mm as the standard background value.

[0063] Among them, obtaining the waveforms and resistivity values of the cut rocks with different dip angles passing through fractures with different widths includes the following steps:

[0064] s21: First, put the rock with a certain dip angle and fracture width into the water tank and let the water submerge the rock;

[0065] s22: Then, put the array acoustic wave and the array laterolog instrument into the water tank for detection respectively, and record the array acoustic wave values through the oscilloscope and the resistivity values through the resistivity display instrument;

[0066] s23: Change the fracture width and record the array acoustic wave values and resistivity values at this fracture width under this dip angle;

[0067] s24: Replace the rock and repeat steps s21 to s23, and record the array acoustic wave values and resistivity values at different fracture dip angles;

[0068] Obtaining the background array acoustic wave and array laterolog resistivity values of the uncut rock includes the following steps: First, fill the experimental water tank with brine and the water level submerges the uncut rock. Then, drag the array acoustic wave and the array laterolog scaled-down instrument at a uniform speed successively to obtain the background array acoustic wave and array laterolog resistivity values of the bedrock with a fracture width of 0mm.

[0069] Among them, the step S5 specifically includes the following steps: Use the array laterolog to identify the fracture position and dip angle, and then substitute the collected array laterolog resistivity value and Stoneley wave attenuation coefficient at the target depth into the joint inversion calculation formula to obtain the fracture width at the target depth based on the joint inversion of acoustic and electric logging.

[0070] Such as Figure 3As shown, in the depth section from 3620m to 3745m, first, the fracture location and dip angle of the target interval are obtained by using the fracture program based on array laterolog. Then, the Stoneley wave amplitude is extracted according to the fracture location, and the amplitude of the acoustic wave in the tight interval is selected as the background value to calculate the Stoneley wave attenuation coefficient and obtain the fracture width based on acoustic logging. Then, the mud salinity information is obtained by converting the wellhead mud resistivity data, and the mud resistivity value of 0.026 Ω·m is obtained by converting to the current interval depth. The parameters α1, α2, α3, α4, and α5 are calculated according to the two-dimensional chart obtained from the experimental results of the fracture dip angle. Then, the fracture width is calculated according to the acoustic-electric combined formula for calculating the fracture width Figure 3 As shown in the scatter data of the fracture width in the last column, the changing trends of the final acoustic and electric calculation results are in good agreement

[0071] Example 2

[0072] The difference between this example and Example 1 is that in step s21, the experimental water tank is filled with brine with a resistivity of 0.01 - 1 Ω·m and the water level submerges the rock

[0073] Example 3

[0074] Step 1: Prepare a cuboid of tight granite that meets the experimental conditions. After obtaining eight cuboid rocks of 30×30×260 cm, use a small drilling machine to drill a central hole in the center of the 30×30 cm side of the eight tight rocks to simulate the wellbore under actual well conditions. Then, cut seven rocks in half from the center of the long side at different dip angles to complete the preparation of the rocks that meet the experimental conditions

[0075] Step 2: Obtain the array acoustic wave and array lateral resistivity values of rocks with different dip angles passing through fractures of different widths. First, fill the experimental water tank with brine with a resistivity of 0.1 Ω·m and the water level submerges the uncut 30×30×260 cm cuboid rock. Drag the array acoustic wave and array lateral scaled-down instruments successively and uniformly in the water tank to obtain the array acoustic wave of the bedrock background with a fracture width of 0 mm, that is, the array lateral resistivity value. Then, use plastic partitions of 11 types with widths of 1 mm, 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, and 20 mm to fill the cut cuboid rocks respectively. After using the clamp to compact the two rocks and the plastic partition, drag the array acoustic wave and array lateral scaled-down instruments successively and uniformly in the experimental water tank to obtain the array acoustic wave waveforms and array lateral resistivity values passing through fractures of different widths. Then, measure 154 groups of data at dip angles of (0°, 10°, 15°, 30°, 45°, 60°, 75°) respectively according to the above steps. According to the experimental results Figure 2 It can be seen that under the same experimental conditions, as the fracture width increases, the relative amplitude of the Stoneley wave becomes smaller

[0076] Step 3: Based on the physical experiment results, respectively establish the inversion formulas for the acoustic attenuation of the array acoustic wave and the fracture width, and the resistivity of the array laterolog and the fracture width:

[0077] 1) Extract the average amplitude of the Stoneley wave received by multiple probes at different fracture widths and dips in the physical experiment records, calculate the Stoneley wave attenuation coefficient based on this, and establish the relationship between the Stoneley wave attenuation coefficient and the fracture width.

[0078] 2) After measuring the array resistivity values under different fracture widths and dips, establish the calculation relationship between the fracture width and the array resistivity.

[0079] The specific steps are as follows: During the actual measurement process, the acoustic wave waveform will be affected by the surrounding environmental noise. To eliminate this influence, a band-pass filter is used to suppress the surrounding noise and the longitudinal and transverse waves, extract the low-frequency Stoneley wave, and then extract the Stoneley wave amplitude. Through the analysis of the experimental results, it can be seen that different fracture widths correspond to different Stoneley wave amplitudes and array laterolog resistivity values. To more accurately represent this correspondence, directly establish the crossplot relationship between the fracture width and the Stoneley wave amplitude, and obtain the relationship formula for calculating the fracture width using the Stoneley wave attenuation coefficient. Based on the understanding of the influence of the fracture width and dip on the array laterolog apparent resistivity, establish a two-dimensional chart of the fracture dip and the apparent resistivity, and then combine the variation relationship between the apparent resistivity and the fracture width to directly establish the quantitative calculation relationship formula for the fracture width based on the array laterolog.

[0080] Step 4: Establish the joint inversion formula for the fracture width based on acoustic and electric logging: Based on the separately established inversion formulas for the fracture width of acoustic and electric methods, considering the differences in the characteristic responses of acoustic and electric logging fractures, establish the calculation formula for jointly inverting the fracture width of acoustic and electric methods;

[0081] Step 5: Jointly invert the acoustic and electric methods to obtain the fracture width at the target depth: First, based on the response characteristic of the decrease in the array laterolog resistivity at the fracture, program to realize the identification of the fracture position and dip. After obtaining the array acoustic wave and array laterolog data collected in the actual formation, substitute the apparent resistivity value and the Stoneley wave attenuation coefficient into the joint inversion calculation formula to obtain the fracture width at the target depth.

[0082] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A calculation method for jointly inverting the fracture width by acoustic and electric logging, characterized in that It includes the following steps: S1: Prepare no less than n dense rocks with a certain length, drill holes along the length direction at the center of one end of each dense rock, and then cut n - 1 dense rocks into two halves respectively from the center of the long side at different angles to complete the preparation of rocks meeting the experimental conditions, where n≥3; S2: Obtain the waveforms and resistivity values of the rocks with different cut angles passing through cracks of different widths, and obtain the background array acoustic wave values of the uncut rocks; In order to obtain the influence law of crack angle on the resistivity value of the array laterolog, and further obtain the parameters α1, α2, α3, α4, α5, set up experiments on rocks with cracks at n - 1 kinds of angles; S3: According to the results obtained in step S2, respectively construct the inversion formulas of array acoustic wave attenuation and crack width, and array laterolog resistivity and crack width; The inversion formula of the array laterolog resistivity and crack width is as follows: Among them, α1, α2, α3, α4, and α5 are all parameters obtained by solving a multiple linear equation through experimental values of different crack widths, and R m is the resistivity of the mud, with the unit of Ω·m. MRL1, MRL2, MRL3, and MRL4 are the resistivity values in the four detection modes of the array laterolog, respectively, with the unit of Ω·m; S4: Based on the inversion formulas of array acoustic wave attenuation and crack width, and array laterolog resistivity and crack width, construct the calculation formula for joint acoustic and electrical inversion of crack width, as follows: Among them, H f is the fracture width obtained by acoustic-electric joint inversion, with the unit of mm. H f1 represents the fracture width calculated by using array acoustic waves, with the unit of mm. H f2 is the fracture width calculated by using array laterolog apparent resistivity, with the unit of mm; S5: Obtain the crack width at the target depth according to the calculation formula for joint acoustic and electrical inversion of crack width.

2. The calculation method for jointly inversely determining the fracture width by acoustic-electric logging according to claim 1, wherein In step S3, the steps of constructing the inversion formula of array acoustic wave attenuation and crack width are: extract the average amplitude of the Stoneley wave received by multiple probes at different crack widths and angles in the experimental records, calculate the Stoneley wave attenuation coefficient based on this, and construct the relationship between the Stoneley wave attenuation coefficient and crack width; in step S3, the steps of constructing the inversion formula of array laterolog resistivity and crack width are: after measuring the array resistivity values under different crack widths and angles, construct the calculation relationship between crack width and array resistivity.

3. The calculation method for jointly inversing the fracture width by acoustic-electric logging according to claim 1, characterized in that, In step S3, the inversion formula of the array acoustic wave attenuation and crack width is as follows: Among them, the Stoneley wave attenuation coefficient R n has the following calculation formula: Among them, L represents the source distance of different array acoustic wave instruments, with the unit of m. It represents the average amplitude of the Stoneley wave received by the array acoustic wave instrument in the uncut rock, that is, the background array acoustic wave value, with the unit of mV. It represents the average amplitude of the Stoneley wave of the waveforms received by multiple probes when passing through different crack widths, with the unit of mV.

4. The calculation method for jointly inversing the fracture width by acoustic-electric logging according to claim 1, wherein, In step S2, in order to obtain the quantitative change relationship between different crack widths of each cut rock at each angle and the received values of array acoustic wave and array laterolog resistivity, make 11 kinds of plastic partitions with widths of 1mm, 2mm, 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, and 20mm; at the same time, for the uncut rock, the array acoustic wave waveform and array laterolog resistivity with a crack width of 0mm can be obtained as the standard background value.

5. The calculation method for jointly inversing the fracture width by acoustic-electric logging according to claim 1, wherein, Obtaining the waveforms and resistivity values of the rocks with different cut angles passing through cracks of different widths includes the following steps: s21: First, put the rock with a certain angle and crack width into a water tank and let the water submerge the rock; s22: Then, put the array acoustic wave and array laterolog instruments into the water tank for detection respectively, record the array acoustic wave values through an oscilloscope, and record the resistivity values through a resistivity display; s23: Change the crack width and record the array acoustic wave values and resistivity values at this crack width under this angle; s24: Replace the rock and repeat steps s21 to s23 to record the array acoustic wave values and resistivity values at different crack angles; Obtaining the array acoustic wave and array laterolog resistivity values of the uncut rock background includes the following steps: First, fill the experimental water tank with brine and the water level submerges the uncut rock. Then, drag the array acoustic wave and array laterolog scaled-down instrument at a constant speed successively to obtain the array acoustic wave and array laterolog resistivity values of the bedrock background with a fracture width of 0 mm.

6. The calculation method for jointly inversing the fracture width by acoustic-electric logging according to claim 5, characterized in that, In the step s21, the experimental water tank is filled with brine having a resistivity of 0.01 - 1 Ω·m and the water level submerges the rock.

7. The calculation method for jointly inversing the fracture width by acoustic-electric logging according to any one of claims 1 to 6, characterized in that The step S5 specifically includes the following steps: Use the array laterolog to identify the fracture position and dip angle, and then substitute the array laterolog resistivity value and Stoneley wave attenuation coefficient at the target depth collected into the joint inversion calculation formula to obtain the fracture width at the target depth based on the joint inversion of acoustic and electric logging.

Images