An electro-pulse transient shock wave oil and water well resonance production enhancement method and system

Abstract

This application relates to the technical field of oil extraction, and specifically relates to a method and system for enhancing oil and water well production by resonance with an electric pulse transient shock wave. The method includes: determining an energy eigenvalue by analyzing the difference between the maximum amplitude and the average amplitude in each modal component, and combining the difference between the sum of energies within the 3dB bandwidth of each modal component and the total energy of the modal component; comparing the differences in energy eigenvalues between all high-energy components and all low-energy components to determine an energy concentration value; determining a natural frequency deviation value by measuring the difference in the fixed matching degree between each time period and the previous time period, and combining the minimum natural frequency matching degree of the vibration signals within all time periods, so as to determine the initial discharge frequency for fracture-induced plugging removal during the electric pulse plugging removal process. This application solves the problem that the transient shock wave formed by a fixed discharge frequency is not conducive to the formation and development of oil reservoir fractures, and improves the oil reservoir plugging removal efficiency and the resonance production enhancement effect.

Description

Technical Field

[0001] This application relates to the technical field of oil extraction, and particularly to a method and system for enhancing oil and water well production through resonance with an electric pulse transient shock wave. Background Art

[0002] After an oilfield is put into production, as oil and gas are produced, the reservoir pressure gradually decreases, and it is necessary to continuously supplement energy to the reservoir. Oil and water wells, as a very important production method in oilfield development, are an effective way to supplement reservoir energy and maintain long-term high and stable production in the oilfield. Water is injected into the reservoir through injection wells to maintain the reservoir pressure, increase the oil production rate, and improve the recovery factor. During the processes of drilling, completion, production, and implementation of production enhancement measures for oil and water wells, reservoir damage may occur, causing various contaminations to the reservoir, resulting in a significant reduction in the permeability of the near-wellbore zone, affecting the flow of bottom-hole fluid, and causing a decrease in the oil well production. Therefore, it is necessary to carry out plugging removal treatment on the reservoir to restore and improve the permeability of the reservoir to maintain stable and increased production in the oilfield.

[0003] As a commonly used physical oil production technology, the electric pulse plugging removal technology generates transient shock waves and cavitation effects by releasing high-voltage electric pulses at the position of the reservoir in the well, forming microcracks, increasing the seepage area, and thus achieving oilfield production enhancement. Currently, the discharge frequency of the electric pulse plugging removal technology is usually fixed. When plugging removal is carried out on reservoirs with different natural frequencies, the transient shock waves formed by the fixed discharge frequency are not conducive to the formation and development of reservoir cracks. At the same time, during the plugging removal process, as the transient shock waves change the crack structure of the reservoir, the natural frequency of the reservoir also changes accordingly, resulting in transient shock waves formed by the fixed electric discharge frequency, leading to a decrease in the plugging removal efficiency and rate of the reservoir and poor production enhancement effects of oil and water wells. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a method and system for enhancing oil and water well production through resonance with an electric pulse transient shock wave. The specific technical solutions adopted are as follows:

[0005] In a first aspect, an embodiment of this application provides a method for enhancing oil and water well production through resonance with an electric pulse transient shock wave. The method includes the following steps:

[0006] Divide the fixed-frequency detection and plugging removal process of electric pulse plugging removal into a preset number of time periods, set the discharge frequency for the electric pulse in each time period, and obtain the vibration signals in the oil and water well at the discharge frequency of the electric pulse in each time period;

[0007] Decompose the vibration signals of each time period into multiple modal components, determine the amplitude difference by analyzing the difference between the maximum amplitude and the average amplitude in each modal component, and determine the energy eigenvalue of each modal component in each time period by combining the difference between the sum of the energies within the 3dB bandwidth of each modal component and the total energy of the modal component.

[0008] Compare the difference between the energy eigenvalue of each modal component in each time period and the average energy eigenvalue of all modal components, divide all modal components into high-energy components and low-energy components, compare the difference in energy eigenvalues between all high-energy components and all low-energy components, and determine the energy concentration value of the vibration signal in each time period;

[0009] By comparing the difference between the discharge frequency in each time period and the maximum discharge frequency in all time periods, and combining the total energy and energy concentration value of the vibration signal in each time period, determine the fixed-frequency matching degree of the vibration signal in each time period; by measuring the difference in the fixed matching degree between each time period and its previous time period, and combining the minimum fixed-frequency matching degree of the vibration signal in all time periods, determine the fixed-frequency deviation value of the vibration signal in each time period;

[0010] Based on the difference in the natural frequencies of all high-energy components between the last time period and its previous time period during the fixed-frequency detection and plugging removal process, determine the high-energy deviation, and combine the discharge frequency and fixed-frequency deviation value in the last time period to determine the initial discharge frequency of crack-induced plugging removal during the electric pulse plugging removal process.

[0011] Preferably, the method for determining the amplitude difference is as follows:

[0012] Take the ratio of the maximum amplitude to the average amplitude in each modal component as the amplitude difference of each modal component.

[0013] Preferably, the method for determining the energy eigenvalue of each modal component in each time period is as follows:

[0014] Calculate the ratio of the sum of the energies within the 3dB bandwidth of each modal component of the vibration signal in each time period to the total energy of the modal component, denoted as the energy ratio of each modal component, and take the product of the amplitude difference and the energy ratio of each modal component in each time period as the energy eigenvalue of each modal component in each time period.

[0015] Preferably, the division of all modal components into high-energy components and low-energy components includes:

[0016] Among all modal components in each time period, mark the modal components with energy eigenvalues greater than the average energy eigenvalue as high-energy components, and mark the remaining all modal components as low-energy components.

[0017] Preferably, the method for determining the energy concentration value of the vibration signal in each time period is as follows:

[0018] Sum the ratios of the energy eigenvalues between each high-energy component and all low-energy components in each time period, and take the cumulative result of the sums of all high-energy components as the energy concentration value of the vibration signal in each time period.

[0019] Preferably, the expression for the fixed-frequency matching degree of the vibration signal in each time period is: ; In the formula, represents the fixed-frequency matching degree of the vibration signal in time period i; represents the total energy of the vibration signal in time period i; represents the discharge frequency in time period i; represents the maximum discharge frequency in a preset number of time periods; represents the energy concentration value of the vibration signal in time period i; ln( ) represents the logarithmic function with the natural constant as the base; represents a preset value.

[0020] Preferably, the expression for the fixed-frequency deviation value of the vibration signal in each time period is: ; represents the fixed-frequency deviation value of the vibration signal in time period i; , respectively represent the fixed-frequency matching degrees in time periods i - 1 and i; max{} represents the maximum value function.

[0021] Preferably, the high-energy deviation is: the average value of the inherent frequency differences of all high-energy components between the last time period and the previous time period in the fixed-frequency detection and plugging removal process.

[0022] Preferably, the expression for the initial discharge frequency of fracture-induced plugging removal in the electric pulse plugging removal process is: ; In the formula, represents the initial discharge frequency of fracture-induced plugging removal in the electric pulse plugging removal process; represents the discharge frequency in the last time period of the fixed-frequency detection and plugging removal process; represents the high-energy deviation; represents the fixed-frequency deviation value in the last time period of the fixed-frequency detection and plugging removal process; ceil( ) represents the ceiling function. Second, the embodiment of the present application also provides an electric pulse transient shock wave oil and water well resonance production increase system, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of the electric pulse transient shock wave oil and water well resonance production increase method described in any one of the above.

[0023] The present application has at least the following beneficial effects:

[0024] By analyzing the modal component characteristics of vibration signals in each period during the fixed-frequency detection and plugging removal process, this application constructs energy eigenvalues, which can identify frequency components that match well with the natural frequency of the oil reservoir, providing a basis for adjusting the discharge frequency of the electric pulse in the subsequent stage to make it closer to the natural frequency of the oil reservoir and achieve more effective resonance. Further, by comparing the energy characteristic differences between high-energy components and low-energy components, an energy concentration value is constructed to optimize the discharge frequency, making the energy more concentrated in the weak parts of the oil reservoir, thereby more effectively inducing the generation and development of microcracks and improving the production increase effect of oil wells. Further, by comparing the differences in the fixed-frequency matching degrees in different periods, a fixed-frequency deviation value is constructed to timely detect the deviation degree between the discharge frequency of the electric pulse and the natural frequency of the oil reservoir, and the discharge frequency of the positive electric pulse can be dynamically increased to keep it in the best match with the actual natural frequency of the current oil reservoir, avoiding the weakening of the resonance effect caused by frequency deviation, and thus improving the plugging removal efficiency and resonance production increase effect of the oil reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a flowchart of the steps of a method for enhancing oil well production by resonance using electric pulse transient shock waves provided by an embodiment of this application;

[0027] Figure 2 It is a schematic diagram of the process for extracting the fixed-frequency matching degree provided by an embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] To further elaborate on the technical means and effects adopted by this application to achieve the intended invention purpose, the following, in combination with the drawings and preferred embodiments, details the specific implementation manners, structures, features, and effects of a method and system for enhancing oil well production by resonance using electric pulse transient shock waves proposed according to this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0030] The following specifically describes the specific solutions of an electro-pulse transient shock wave oil well resonance stimulation method and system provided by the present application in conjunction with the accompanying drawings.

[0031] Please refer to Figure 1 , which shows a flowchart of the steps of an electro-pulse transient shock wave oil well resonance stimulation method provided by an embodiment of the present application. The method includes the following steps:

[0032] Step S1: Divide the fixed-frequency detection and plugging removal process of electro-pulse plugging removal into a preset number of time periods, set the discharge frequency for the electro-pulse in each time period, and obtain the vibration signals in the oil well under the discharge frequency of the electro-pulse in each time period.

[0033] The core of the electro-pulse plugging removal technology lies in using the transient shock wave to act on the oil layer, thereby forming new micro-fractures and improving the seepage conditions. However, the natural frequency of the oil layer varies due to geological characteristics, and during the plugging removal process, the natural frequency will change as the fractures expand. Therefore, if the discharge frequency is fixed, it is difficult to ensure that the transient shock wave always matches the natural frequency of the oil layer, resulting in a decrease in the plugging removal efficiency.

[0034] In this embodiment, an electro-pulse device is installed at the oil layer position, and a vibration sensor is installed inside the oil pipe of the same oil layer. Since this embodiment uses the electro-pulse plugging removal technology for oil well plugging removal, it is divided into two processes: fixed-frequency detection and plugging removal and fracture induction and plugging removal. The entire oil well plugging removal takes 30 minutes, of which the fixed-frequency detection and plugging removal takes 1 minute, and the fracture induction and plugging removal takes 29 minutes. Therefore, the fixed-frequency detection and plugging removal process of electro-pulse plugging removal is divided into a preset number of time periods. In this embodiment, the value of the preset number is 10, and the length of each time period is 6 seconds. The discharge frequencies of the electro-pulse device in each time period are set in chronological order as 50Hz, 45Hz, 40Hz, 35Hz, 30Hz, 25Hz, 20Hz, 15Hz, 10Hz, 5Hz; further, on the basis of the above, the vibration signals in the oil well under each time period are obtained.

[0035] It should be noted that the value of the preset number and the value of the length of each time period are both artificially set, and the implementer can also set them according to the specific situation by himself / herself. This embodiment does not make special restrictions.

[0036] In addition, it is supplemented that the sampling frequency of the vibration sensor used in this embodiment is 10kHz, the electro-pulse device uses three-phase AC power supply, the input frequency is 50Hz, the input phase voltage range is 210~230V, the discharge voltage level is 7~25kV, the discharge frequency is adjustable, and its adjustable range is 0~60Hz. In this embodiment, the discharge voltage of the electro-pulse device is set to 7.5kV.

[0037] Furthermore, due to the electromagnetic interference of high-frequency harmonics during the discharge process of the power pulse device on the vibration sensor and communication cable, there is some high-frequency noise in the collected vibration signal. Therefore, in this embodiment, the median filtering algorithm is used to filter the collected vibration signal to remove the high-frequency noise in the vibration signal. In the actual application process, as other implementation manners, the implementer can also adopt other denoising methods such as Gaussian filtering or mean filtering algorithm according to the specific situation. Regarding the selection of the denoising algorithm, this embodiment does not make special restrictions.

[0038] Among them, the median filtering algorithm is a well-known technology, and the specific principle process of denoising the signal will not be elaborated here.

[0039] Step S2: Decompose the vibration signals of each time period into multiple modal components, determine the amplitude difference by analyzing the difference between the maximum amplitude and the average amplitude in each modal component, and combine the difference between the sum of the energies within the 3dB bandwidth of each modal component and the total energy of the modal component to determine the energy eigenvalue of each modal component within each time period.

[0040] When the transient shock wave generated by the electric pulse resonates with the oil layer, the energy of the transient shock wave can be transmitted to the oil layer to the greatest extent without being reflected or dissipated. At the same time, in the resonance state, the energy of the transient shock wave is concentrated in the weak parts of the oil layer, inducing the generation and development of microcracks, improving the plugging removal efficiency and rate of the electric pulse device, and further enhancing the production increase effect of oil wells.

[0041] During the electric pulse plugging removal process, strong local pressure changes are generated by the high temperature, high pressure, and strong magnetic field in the oil layer. When the static pressure in the oil layer liquid is lower than the saturated vapor pressure of the liquid, the liquid will undergo local vaporization to form bubbles, resulting in cavitation. When the bubbles burst, the gas inside them is quickly compressed and releases a large amount of energy, and a secondary transient shock wave is generated. At the same time, the process of bubble rupture in cavitation is non-linear, and compared with the electric pulse period, the growth and rupture time of the bubbles are short. Therefore, the frequency of the transient shock wave is often higher than the discharge frequency of the electric pulse device. Measuring the natural frequency of the oil layer and adjusting the discharge frequency of the electric pulse device accordingly will cause the transient shock wave to deviate from the resonance state with the oil layer, affecting the effect of electric pulse plugging removal and resonance production increase of oil wells.

[0042] Therefore, based on the above analysis, in this embodiment, the vibration signals of each time period are decomposed into multiple modal components. By analyzing the difference between the maximum amplitude and the average amplitude in each modal component, the amplitude difference is determined, and combined with the difference between the sum of the energies within the 3dB bandwidth of each modal component and the total energy of the modal component, the energy eigenvalue of each modal component within each time period is determined. The specific process is as follows:

[0043] An oil reservoir is usually composed of multiple media, including rocks, fluids (oil, water), pores, and fractures, etc. The elastic moduli, densities, and damping characteristics of these media are different, resulting in complex vibration behaviors of the oil reservoir. The coupling effect of multiphase media causes the oil reservoir to exhibit multiple natural frequencies when subjected to transient shock waves.

[0044] Therefore, in this embodiment, the vibration signals in each time period are used as the input of the modal decomposition algorithm, and all modal components are output. Among them, each modal component represents an inherent vibration frequency mode of the time period vibration signal.

[0045] It should be noted that there are many commonly used modal decomposition algorithms. In this embodiment, the Hilbert-Huang transform is used to decompose the vibration signal into multiple modal components. In the actual application process, as other implementation manners, the implementer can also adopt other modal decomposition algorithms such as empirical mode decomposition according to the specific situation. Regarding the selection of the modal decomposition algorithm, this embodiment does not make special restrictions.

[0046] Among them, the Hilbert-Huang transform is a well-known technology, and the specific process of decomposing the signal will not be elaborated here.

[0047] Furthermore, due to the multiple natural frequencies of the oil reservoir, when the oil reservoir is excited by transient shock waves, resonance will occur at multiple frequencies. The modal components of the vibration signal correspond to different vibration modes of the oil reservoir, reflecting the resonance state of the oil reservoir at multiple natural frequencies under the current discharge frequency. When the frequency of the vibration signal is close to the natural frequency of the oil reservoir, the oil reservoir will produce a strong resonance effect on the vibration signal, resulting in a significant increase in the energy of this frequency component.

[0048] Therefore, in this embodiment, by analyzing the difference between the maximum amplitude and the average amplitude in each modal component, the amplitude difference is determined. Specifically: the ratio of the maximum amplitude to the average amplitude in each modal component is used as the amplitude difference of each modal component. The larger the amplitude difference, the stronger the resonance effect caused by the transient shock wave generated by the current discharge frequency in this inherent vibration mode.

[0049] Furthermore, due to the influence of the coupling effect between different modes of the oil reservoir, the natural frequency is not a strictly single value in the marginal spectrum of the modal component, but usually appears as a frequency band. Therefore, in this embodiment, based on the difference between the sum of the energies within the 3dB bandwidth of each modal component and the total energy of the modal component, and combined with the amplitude difference, the energy eigenvalue of each modal component in each time period is determined. Specifically:

[0050] Calculate the ratio between the sum of the energies of each modal component of the vibration signal within the 3dB bandwidth and the total energy of the modal component during each time period, denoted as the energy ratio of each modal component. The higher the energy ratio of the corresponding modal component indicates a higher degree of energy concentration within the 3dB bandwidth, reflecting a stronger resonance effect under this natural vibration mode;

[0051] Furthermore, multiply the amplitude difference of each modal component during each time period by the energy ratio as the energy eigenvalue of each modal component during each time period.

[0052] Among them, the processes of obtaining the 3dB bandwidth and the energy of the modal component are both well-known technologies, and the specific concept of the 3dB bandwidth and the process of obtaining the energy of the modal component will not be elaborated here.

[0053] From the energy eigenvalues of each modal component during each time period, it can be understood that the energy eigenvalue reflects the resonance effect intensity at the corresponding discharge frequency. The larger the energy ratio, the higher the degree of energy concentration of the corresponding modal component within the 3dB bandwidth, and the stronger the resonance effect. This means that the energy of the transient shock wave is more effectively transmitted to the oil layer within this frequency range, promoting the plugging removal and production increase effects of the oil layer. Moreover, the larger the amplitude difference, the stronger the resonance effect caused by the transient shock wave generated at the current discharge frequency under this natural vibration mode, which helps to improve the plugging removal efficiency and rate. Therefore, the larger the energy ratio and the amplitude difference, the larger the finally obtained energy eigenvalue;

[0054] Conversely, the smaller the energy ratio, the lower the degree of energy concentration of the corresponding modal component within the 3dB bandwidth, and the weaker the resonance effect, which is not conducive to the plugging removal and production increase effects of the oil layer. Moreover, the smaller the amplitude difference, the weaker the resonance effect caused by the transient shock wave generated at the current discharge frequency under this natural vibration mode, which may reduce the plugging removal efficiency and rate. Therefore, the smaller the energy ratio and the amplitude difference, the smaller the finally obtained energy eigenvalue, reflecting a weaker resonance effect intensity at the corresponding discharge frequency.

[0055] So far, by using the modal decomposition algorithm to decompose the vibration signal into multiple modal components, each modal component represents a natural vibration frequency mode of the oil layer. By analyzing the amplitude difference and energy ratio of each modal component, the energy eigenvalue of each modal component during each time period can be determined, which reflects the resonance effect intensity at the corresponding discharge frequency, thereby helping to adjust the discharge frequency of the electric pulse device to match the natural frequency of the oil layer, achieving the best resonance state, and improving the plugging removal efficiency and the production increase effect of oil wells and water wells.

[0056] Step S3: Compare the differences between the energy eigenvalue of each modal component in each time period and the average energy eigenvalue of all modal components, divide all modal components into high-energy components and low-energy components, compare the differences in energy eigenvalues between all high-energy components and all low-energy components, and determine the energy concentration value of the vibration signal in each time period.

[0057] Considering that the frequency components of the transient shock wave generated by the electric pulse device are relatively fixed and it is difficult to match with multiple natural frequencies simultaneously. Therefore, in all modal components in each time period of this embodiment, the modal components with energy eigenvalues greater than the average energy eigenvalue are denoted as high-energy components, representing the natural vibration modes with stronger resonance effects, which have a stronger plugging removal effect on oil and water wells, and the remaining all modal components are denoted as low-energy components, representing the natural vibration modes with weaker resonance effects, which have a weaker plugging removal effect on oil and water wells.

[0058] Furthermore, in this embodiment, by comparing the differences in energy eigenvalues between all high-energy components and all low-energy components, the energy concentration value of the vibration signal in each time period is determined, specifically as follows:

[0059] As an implementation manner, in this embodiment, the sum of the ratios of the energy eigenvalues between each high-energy component and all low-energy components in each time period is taken, and the cumulative result of the sum values of all high-energy components is used as the energy concentration value of the vibration signal in each time period.

[0060] From the energy concentration value of the vibration signal in each time period, it can be understood that the energy concentration value reflects the degree of concentration of the energy generated by the transient shock wave near some natural frequencies at different discharge frequencies. The larger the energy concentration value, the larger the energy eigenvalue of the high-energy component compared to the energy eigenvalue of the low-frequency component, indicating that the energy generated by the transient shock wave at the current discharge frequency is more concentrated near some natural frequencies of the oil layer, and the stronger the promotion effect on the plugging removal of oil and water wells and the resonance production increase effect; on the contrary, the smaller the energy concentration value, the smaller the energy eigenvalue of the high-energy component compared to the energy eigenvalue of the low-frequency component, indicating that the degree of concentration of the energy generated by the transient shock wave at the current discharge frequency near some natural frequencies of the oil layer is lower, and the weaker the promotion effect on the plugging removal of oil and water wells and the resonance production increase effect.

[0061] So far, by comparing the differences in energy eigenvalues between high-energy components and low-energy components, the energy concentration value of the vibration signal in each time period is determined. The larger the energy concentration value, the more concentrated the energy of the transient shock wave near some natural frequencies of the oil layer, and the stronger the promotion effect on the plugging removal of oil and water wells and the resonance production increase effect. Based on the energy concentration value, it is helpful to optimize the discharge frequency of the electric pulse device and improve the plugging removal efficiency and the oil well production increase effect.

[0062] Step S4: Determine the natural frequency matching degree of the vibration signal in each time period by comparing the difference between the discharge frequency in each time period and the maximum discharge frequency in all time periods, and combining the total energy and the energy concentration value of the vibration signal in each time period; determine the natural frequency deviation value of the vibration signal in each time period by measuring the difference in the fixed matching degree between each time period and its previous time period, and combining the minimum natural frequency matching degree of the vibration signals in all time periods.

[0063] Due to the relatively fast discharge frequency, the energy of the released transient shock wave is too concentrated, resulting in a large amplitude of the vibration signal at a higher discharge frequency, but a smaller amplitude at the natural frequency of the oil layer. This is not conducive to the formation and development of microfractures in the oil layer, not only limiting the improvement of the oil layer plugging removal rate, but also having a large energy consumption at a higher discharge frequency, leading to a decrease in the plugging removal efficiency. At the same time, it affects the judgment of the resonance state between the transient shock wave generated by the current discharge frequency and the oil layer during the natural frequency detection and plugging removal process.

[0064] Therefore, based on the above analysis, in this embodiment, the natural frequency matching degree of the vibration signal in each time period is determined by comparing the difference between the discharge frequency in each time period and the maximum discharge frequency in all time periods, and combining the total energy and the energy concentration value of the vibration signal in each time period. Specifically:

[0065] As an implementation manner, in this embodiment, the natural frequency matching degree of the vibration signal in time period i is expressed as: ; in the formula, represents the total energy of the vibration signal in time period i; represents the discharge frequency in time period i; represents the maximum discharge frequency in the preset number of time periods; represents the energy concentration value of the vibration signal in time period i; ln( ) represents the logarithmic function with the natural constant as the base; represents a preset value.

[0066] It should be noted that the preset value is used to prevent the denominator from being 0. In this embodiment, the preset value takes the value of 10. On the premise of ensuring that the denominator is not 0 and not overly affecting the calculation result, the implementer can also set it according to the specific situation by himself / herself. This embodiment does not make special restrictions.

[0067] Among them, the method for obtaining the total energy of the vibration signal is a well-known technology, and its specific acquisition process will not be elaborated here.

[0068] It can be understood from the fixed-frequency matching degree of the vibration signals in each time period that the fixed-frequency matching degree reflects the resonance matching degree between the transient shock wave generated by the current discharge frequency and the oil layer. The smaller the fixed-frequency matching degree of the discharge frequency, the larger the ratio between the discharge frequency in the current time period and the maximum discharge frequency, which may mean a higher discharge frequency, resulting in too concentrated energy, being unfavorable for the formation and development of oil layer fractures, and the energy concentration value and the total energy of the vibration signal being relatively small. The smaller the energy concentration value, the more dispersed the distribution of the energy of the vibration signal at the natural frequency of the oil layer, the weaker the resonance effect, and being unfavorable for the formation and unblocking of micro-fractures in the oil layer. The smaller the total energy, the less energy generated by the transient shock wave, the limited impact on the oil layer, and the unobvious unblocking and production increase effects may be caused;

[0069] On the contrary, the larger the fixed-frequency matching degree of the discharge frequency, the smaller the ratio between the discharge frequency in the current time period and the maximum discharge frequency, which may mean a relatively moderate discharge frequency and a more reasonable energy distribution, being favorable for the formation and development of oil layer fractures. At the same time, the energy concentration value and the total energy of the vibration signal are relatively large. The larger the energy concentration value, the more concentrated the distribution of the energy of the vibration signal at the natural frequency of the oil layer, the stronger the resonance effect, being favorable for the formation and unblocking of micro-fractures in the oil layer. The larger the total energy, the more energy generated by the transient shock wave, the significant impact on the oil layer, and the obvious unblocking and production increase effects may be caused.

[0070] Preferably, the schematic diagram of the extraction process of the fixed-frequency matching degree provided in this embodiment is as Figure 2 shown.

[0071] Furthermore, as the continuous unblocking of the oil layer by the electric pulse device, the blockage is removed, the porosity and permeability of the oil layer are improved, and the effective density of the medium is reduced. The combined action of the above factors leads to a relatively reduced elastic modulus and an increased internal damping of the oil layer, thereby causing the natural frequency of the oil layer to decrease. Therefore, in this embodiment, by measuring the difference in the fixed matching degree between each time period and its previous time period, and combining the minimum fixed-frequency matching degree of the vibration signals in all time periods, the fixed-frequency deviation value of the vibration signals in each time period is determined, specifically:

[0072] As an implementation manner, in this embodiment, the fixed-frequency deviation value of the vibration signal in time period i is expressed as: ; respectively represent the fixed-frequency matching degrees in time periods i-1 and i; max{} represents the maximum value function.

[0073] Particularly, for the first time period in the fixed-frequency detection and unblocking process, that is, when i = 1, The value of is the fixed-frequency matching degree corresponding to the maximum discharge frequency less than the optimal discharge frequency among the discharge frequencies in all periods of the fixed-frequency detection and plugging removal process. If there is no discharge frequency less than the optimal discharge frequency, the fixed-frequency matching degree of the optimal discharge frequency is used as

[0074] the value.

[0075] Among them, the method for obtaining the optimal discharge frequency is as follows: The binary groups composed of the fixed-frequency matching degrees and the corresponding discharge frequencies in each period of the fixed-frequency detection and plugging removal process are used to fit the binary groups in all periods of the fixed-frequency detection and plugging removal process to obtain a fitting curve. The discharge frequency corresponding to the maximum value on the fitting curve is used as the optimal discharge frequency. In this embodiment, a polynomial linear regression model is used to fit the binary groups in all periods. In the actual application process, as other implementation manners, the implementer can also use the least squares method to fit the binary groups according to the specific situation. Regarding the selection of the fitting method, this embodiment does not make special restrictions.

[0076] It can be understood from the fixed-frequency deviation values of the vibration signals in each period that it reflects the degree of decrease in the natural frequency of the oil layer. The larger the result of the ratio of the difference in the fixed-frequency matching degree between period i - 1 and period i to the fixed-frequency matching degree of period i - 1, the worse the matching degree between the discharge frequency and the natural frequency of the oil layer in period i, the more unreasonable the energy distribution, which may lead to a decrease in the plugging removal effect, and the corresponding fixed-frequency deviation value is larger; on the contrary, the smaller the result of the ratio of the difference in the fixed-frequency matching degree between period i - 1 and period i to the fixed-frequency matching degree of period i - 1, the better the matching degree between the discharge frequency and the natural frequency of the oil layer in period i, the more significant the plugging removal effect, and the corresponding fixed-frequency deviation value is smaller. Therefore, the discharge frequency is adjusted according to the size of the fixed-frequency deviation value.

[0077] So far, by calculating the fixed-frequency matching degree and the fixed-frequency deviation value, the discharge frequency of the electric pulse device is dynamically adjusted to keep it in the best match with the natural frequency of the oil layer, optimizing the energy distribution and resonance effect, effectively improving the plugging removal efficiency and the oil well production increase effect, and at the same time avoiding the negative impact brought by too high frequency.

[0078] Step S5: Based on the difference in the natural frequencies of all high-energy components between the last period and the previous period in the fixed-frequency detection and plugging removal process, determine the high-energy deviation, and combine the discharge frequency and the fixed-frequency deviation value in the last period to determine the initial discharge frequency for fracture-induced plugging removal in the electric pulse plugging removal process.

[0079] Based on the fixed-frequency deviation value obtained in step S4, the discharge frequency during the fracture-induced plugging removal process is set. In this embodiment, based on the difference in the natural frequencies of all high-energy components between the last time period and the previous time period during the fixed-frequency detection plugging removal process, the high-energy deviation is determined, and in combination with the discharge frequency and the fixed-frequency deviation value within the last time period, the initial discharge frequency for fracture-induced plugging removal during the electric pulse plugging removal process is determined. The specific process is as follows:

[0080] In this embodiment, the average value of the differences in the natural frequencies of all high-energy components between the last time period and the previous time period during the fixed-frequency detection plugging removal process is used as the high-energy deviation.

[0081] It should be noted that there are many methods to measure the difference between data. In this embodiment, the absolute value of the difference in the natural frequencies of all high-energy components between the last time period and the previous time period is taken as the difference in the natural frequencies of all high-energy components between the last time period and the previous time period. In actual application processes, as other implementation manners, implementers can also use other methods to measure the difference, such as the square or ratio of the difference, depending on the specific situation. Regarding the selection of the method for measuring the difference, this embodiment does not make special restrictions.

[0082] Furthermore, the discharge frequency is corrected based on the high-energy deviation and the fixed-frequency deviation. Specifically:

[0083] As an implementation manner, in this embodiment, the initial discharge frequency for fracture-induced plugging removal during the electric pulse plugging removal process has the following expression: ; where represents the discharge frequency during the last time period of the fixed-frequency detection plugging removal process; represents the high-energy deviation; represents the fixed-frequency deviation value during the last time period of the fixed-frequency detection plugging removal process; ceil( ) represents the ceiling function.

[0084] The larger the fixed-frequency deviation value, the greater the change in the natural frequency of the oil layer in this time period. Therefore, reducing the discharge frequency of the electric pulse can keep the shock wave generated by the oil layer and the electric pulse device in an optimal resonance state, improving the effect of resonance production increase.

[0085] So far, in this embodiment, by analyzing the amplitude difference and energy ratio of each modal component of the vibration signal, the energy eigenvalue of each modal component in each time period is obtained, which reflects the resonance effect intensity at the corresponding discharge frequency. Further, by comparing the energy eigenvalue differences between the high-energy components and the low-energy components in each time period, the energy concentration value of the vibration signal is obtained. Combining the difference between the discharge frequency and the maximum discharge frequency, as well as the total energy and the energy concentration value of the vibration signal, the natural frequency matching degree and the natural frequency deviation value of the vibration signal in each time period are determined. By dynamically adjusting the discharge frequency of the electric pulse device to keep the best match with the natural frequency of the oil layer, the energy distribution and the resonance effect are optimized, so as to effectively improve the plugging removal efficiency and the oil well production increase effect, and at the same time avoid the negative impact brought by too high frequency.

[0086] Based on the same inventive concept as the above method, an embodiment of the present application further provides an electric pulse transient shock wave oil and water well resonance production increase system, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above methods of an electric pulse transient shock wave oil and water well resonance production increase method.

[0087] It should be noted that the above sequence of the embodiments of the present application is only for description and does not represent the advantages and disadvantages of the embodiments. And the above description of specific embodiments of this specification is given. In addition, the processes depicted in the drawings do not necessarily require the specific order or the continuous order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0088] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the key points of each embodiment are the differences from other embodiments.

[0089] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for enhancing oil and water well production by resonance using electrical pulse transient shock waves, characterized in that, The method includes the following steps: Divide the fixed-frequency detection and plugging removal process of electric pulse plugging removal into a preset number of time periods, set the discharge frequency for the electric pulse in each time period, and obtain the vibration signals in the oil well under the discharge frequency of the electric pulse in each time period; Decompose the vibration signals of each time period into multiple modal components, determine the amplitude difference by analyzing the difference between the maximum amplitude and the average amplitude in each modal component, and combine the difference between the sum of the energies within the 3dB bandwidth of each modal component and the total energy of the modal component to determine the energy eigenvalue of each modal component in each time period; Compare the difference between the energy eigenvalue of each modal component in each time period and the average energy eigenvalue of all modal components, divide all modal components into high-energy components and low-energy components, compare the difference in energy eigenvalues between all high-energy components and all low-energy components, and determine the energy concentration value of the vibration signal in each time period; Determine the fixed-frequency matching degree of the vibration signal in each time period by comparing the difference between the discharge frequency in each time period and the maximum discharge frequency in all time periods, and combining the total energy and the energy concentration value of the vibration signal in each time period; determine the fixed-frequency deviation value of the vibration signal in each time period by measuring the difference in the fixed matching degree between each time period and its previous time period, and combining the minimum fixed-frequency matching degree of the vibration signals in all time periods; Based on the difference in the natural frequencies of all high-energy components between the last time period and its previous time period in the fixed-frequency detection and plugging removal process, determine the high-energy deviation, and combine the discharge frequency and the fixed-frequency deviation value in the last time period to determine the initial discharge frequency of fracture-induced plugging removal in the electric pulse plugging removal process.

2. The method for enhancing oil and water well production by resonance using an electro-pulse transient shock wave according to claim 1, characterized in that, The method for determining the amplitude difference is: Take the ratio of the maximum amplitude to the average amplitude in each modal component as the amplitude difference of each modal component.

3. A method for enhancing oil and water well production by resonance using an electric pulse transient shock wave, as described in claim 1, characterized in that The method for determining the energy eigenvalue of each modal component in each time period is: Calculate the ratio of the sum of the energies within the 3dB bandwidth of each modal component of the vibration signal in each time period to the total energy of the modal component, denoted as the energy ratio of each modal component, and take the product of the amplitude difference and the energy ratio of each modal component in each time period as the energy eigenvalue of each modal component in each time period.

4. A method for enhancing oil and water well production by resonance using an electrical pulse transient shock wave, as described in claim 1, wherein The division of all modal components into high-energy components and low-energy components includes: Among all modal components in each time period, mark the modal components with energy eigenvalues greater than the average energy eigenvalue as high-energy components, and mark the remaining all modal components as low-energy components.

5. The method for enhancing oil and water well production by resonance with an electric pulse transient shock wave according to claim 1, characterized in that, The method for determining the energy concentration value of the vibration signal in each time period is: Take the sum of the ratios of the energy eigenvalues between each high-energy component and all low-energy components in each time period, and take the cumulative result of the sum values of all high-energy components as the energy concentration value of the vibration signal in each time period.

6. The method for enhancing oil and water well production by resonance with electric pulse transient shock wave according to claim 1, characterized in that, The expression for the fixed-frequency matching degree of the vibration signals in each time period is as follows: ; in the formula, represents the fixed-frequency matching degree of the vibration signal in time period i; represents the total energy of the vibration signal in time period i; represents the discharge frequency in time period i; represents the maximum discharge frequency in a preset number of time periods; represents the energy concentration value of the vibration signal in time period i; ln( ) represents the logarithmic function with the natural constant as the base; represents a preset value.

7. A method for enhancing oil and water well production by resonance with an electric pulse transient shock wave according to claim 1, characterized in that, The expression for the fixed-frequency deviation value of the vibration signal in each time period is as follows: ; represents the fixed-frequency deviation value of the vibration signal in time period i; and represent the fixed-frequency matching degrees in time periods i - 1 and i respectively; max{} represents the maximum value function.

8. A method for enhancing oil and water well production by resonance using an electric pulse transient shock wave, as described in claim 1, wherein The high-energy deviation is: the average value of the differences in the natural frequencies of all high-energy components between the last time period and its previous time period in the fixed-frequency detection and plugging removal process.

9. A method for enhancing oil and water well production by resonance using an electric pulse transient shock wave, as described in claim 1, wherein The expression for the initial discharge frequency of fracture-induced plugging removal during the electric pulse plugging removal process is as follows: ; where represents the initial discharge frequency of fracture-induced plugging removal during the electric pulse plugging removal process; represents the discharge frequency in the last period during the fixed-frequency detection plugging removal process; represents the high-energy deviation; represents the fixed-frequency deviation value in the last period during the fixed-frequency detection plugging removal process; ceil( ) represents the ceiling function.

10. An electric pulse transient shock wave oil and water well resonance production enhancement system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method for enhancing production by resonance of oil wells with electric pulse transient shock waves according to any one of claims 1-9.

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