A multi-channel downhole flow rate testing system and testing method

Abstract

The present invention discloses a multi-channel downhole flow test system and test method. The test system includes a downhole ultrasonic signal transceiver and a ground control terminal; the ultrasonic signal transceiver includes a first and a second ultrasonic transducer arranged axially symmetrically, and a third ultrasonic transducer centrally symmetrical with the first ultrasonic transducer; the first and the third ultrasonic transducers transmit ultrasonic signals alternately and cyclically; when the first ultrasonic transducer transmits an ultrasonic signal, the second ultrasonic transducer receives a first echo signal, and the third ultrasonic transducer receives a second echo signal; when the third ultrasonic transducer transmits an ultrasonic signal, the first ultrasonic transducer receives a third echo signal; the control terminal determines the solid particle content level based on a comparative analysis of the first flow rate of the time difference method and the second flow rate of the frequency difference method in each cycle within multiple consecutive cycles, and obtains a weighted average flow rate. The system can improve the adaptability of downhole flow test to the purity of fluid medium, and ensure the accuracy and reliability of downhole flow test.

Description

Technical Field

[0001] The invention relates to the technical field of ultrasonic measurement of oilfield water injection wells, and in particular to a multi-channel downhole flow rate testing system and a testing method. Background Art

[0002] As oil fields are continuously developed, formation energy is continuously consumed. At present, most oil fields have entered the middle and late stages of water injection development. Oil field water injection and production technology can maintain oil layer pressure and reduce the decline rate of crude oil production. It is the most economical and effective technical means to achieve long-term high and stable production of oil fields. In the stratified water injection process, how to accurately measure the flow rate of injected fluids in each layer of the well is the key to achieving precise injection and oil recovery. Due to the uneven management level of major oil fields, there are large differences in the purity of the injected fluid medium. The ultrasonic measurement method based on the time difference method or the phase difference method has good test accuracy for the case where the fluid contains less solid particle impurities. However, when the content of solid particle impurities in the fluid exceeds a certain range, the accuracy of the single-channel ultrasonic flow measurement drops rapidly, and the test results cannot meet the application requirements of precise water injection in oil fields, which has an adverse effect on the effect of water injection and oil recovery. In addition, when there are certain solid particle impurities in the injected fluid, in order to prevent sand accumulation from blocking the water injection channel of the downhole dispenser, the ground control system needs to regularly regulate the downhole injection according to the sand cleaning control logic. However, current downhole ultrasonic flowmeters usually use monophonic ultrasound for flow testing, which has relatively strict requirements for the purity of the test fluid medium, has certain deficiencies in environmental adaptability, and cannot effectively monitor the solid particle impurity content of the fluid medium injected downhole. Summary of the invention

[0003] In order to at least partially solve the technical problems existing in the prior art, the inventors have made the present invention, and through specific implementation methods, provide a multi-channel downhole flow testing system and testing method, which can improve the adaptability of downhole flow testing to the purity of fluid media and ensure the accuracy and reliability of downhole flow testing.

[0004] In a first aspect, an embodiment of the present invention provides a multi-channel downhole flow testing system, including a downhole ultrasonic signal transceiver and a ground control terminal;

[0005] The ultrasonic signal transceiver comprises a test flow guide tube and first, second and third ultrasonic transducers arranged on the test flow guide tube, wherein the first ultrasonic transducer is axially symmetrically arranged with the second ultrasonic transducer, and the first ultrasonic transducer is centrally symmetrically arranged with the third ultrasonic transducer;

[0006] The first ultrasonic transducer and the third ultrasonic transducer are used to transmit ultrasonic signals in an alternating cycle; when the first ultrasonic transducer transmits an ultrasonic signal, the second ultrasonic transducer is used to receive a first echo signal, and the third ultrasonic transducer is used to receive a second echo signal; when the third ultrasonic transducer transmits an ultrasonic signal, the first ultrasonic transducer is used to receive a third echo signal;

[0007] The control terminal is used to determine the first flow rate by using the time difference method based on the second echo signal and the third echo signal in the same period, and to determine the second flow rate by using the frequency difference method based on the first echo signal; determine the solid particle content level according to the fluctuation amplitude of the first flow rate and the second flow rate in multiple consecutive periods and the size of the second flow rate, determine the weights of the first flow rate and the second flow rate, and obtain the weighted average flow rate as the fluid flow rate in the corresponding time period.

[0008] Optionally, the control terminal determines the solid particle content level and the weights of the first flow rate and the second flow rate according to the fluctuation amplitude of the first flow rate and the second flow rate in a plurality of consecutive cycles, and obtains a weighted average flow rate for:

[0009] When the fluctuation amplitude of the first flow in multiple consecutive cycles is less than the set amplitude threshold, if the fluctuation amplitude of the second flow is also less than the amplitude threshold, and the average value of the second flow is not less than the set flow threshold, it is determined that the solid particle content is normal, and the weights of the first flow and the second flow are both determined to be 0.5 to obtain a weighted average flow; otherwise, it is determined that the solid particle content is very small, and the weight of the first flow is determined to be 1, and the weight of the second flow is determined to be 0 to obtain a weighted average flow;

[0010] When the fluctuation amplitude of the first flow rate in a plurality of consecutive cycles is not less than the amplitude threshold, the fluctuation amplitude of the second flow rate is less than the amplitude threshold, and the average value of the second flow rate is not less than the flow rate threshold, it is determined that the solid particle content is extremely high, the weight of the first flow rate is determined to be 0, the weight of the second flow rate is determined to be 1, and a weighted average flow rate is obtained;

[0011] When the fluctuation amplitude of the first flow in multiple consecutive cycles is not less than the amplitude threshold, the fluctuation amplitude of the second flow is less than the amplitude threshold, and the average value of the second flow is less than the flow threshold, or when the fluctuation amplitudes of the first flow and the second flow in multiple consecutive cycles are not less than the amplitude threshold, an alarm message indicating possible transducer failure is issued.

[0012] Optionally, the control terminal determines the solid particle content level and the weights of the first flow rate and the second flow rate according to the fluctuation amplitude of the first flow rate and the second flow rate in a plurality of consecutive cycles, and obtains a weighted average flow rate for:

[0013] When the fluctuation amplitude of the first flow rate in multiple consecutive cycles is less than the set amplitude threshold, if the fluctuation amplitude of the second flow rate is also less than the amplitude threshold, and the average value of the second flow rate is not less than the set flow threshold, it is determined that the solid particle content is normal, and the weights of the first flow rate and the second flow rate are determined according to the difference amplitude between the two to obtain a weighted average flow rate; otherwise, it is determined that the solid particle content is very small, and the weight of the first flow rate is determined to be 1, and the weight of the second flow rate is determined to be 0 to obtain a weighted average flow rate;

[0014] When the fluctuation amplitude of the first flow rate in a plurality of consecutive cycles is not less than the amplitude threshold, the fluctuation amplitude of the second flow rate is less than the amplitude threshold, and the average value of the second flow rate is not less than the flow rate threshold, it is determined that the solid particle content is extremely high, the weight of the first flow rate is determined to be 0, the weight of the second flow rate is determined to be 1, and a weighted average flow rate is obtained;

[0015] When the fluctuation amplitude of the first flow in multiple consecutive cycles is not less than the amplitude threshold, the fluctuation amplitude of the second flow is less than the amplitude threshold, and the average value of the second flow is less than the flow threshold, or when the fluctuation amplitudes of the first flow and the second flow in multiple consecutive cycles are not less than the first threshold, an alarm message indicating possible transducer failure is issued.

[0016] Optionally, the control terminal determines the weights of the first flow and the second flow according to the difference between the first flow and the second flow, for:

[0017] If the absolute difference between the first flow rate and the second flow rate is less than a first flow rate difference threshold, it is determined that the solid particle content is medium, and the weights of the first flow rate and the second flow rate are both determined to be 0.5;

[0018] If the absolute difference between the first flow rate and the second flow rate is not less than the first flow rate difference threshold and not greater than the second flow rate difference threshold, it is determined that the solid particle content is too low, the first flow rate weight is determined to be 1, and the weight of the second flow rate is determined according to a first calibration result obtained in advance through experiments;

[0019] If the absolute difference between the first flow rate and the second flow rate is greater than a second flow rate difference threshold, it is determined that the solid particle content is too high, and a second flow rate weight 1 is determined. The weight of the first flow rate is determined according to a second calibration result obtained in advance through experiments.

[0020] Optionally, the first flow difference threshold is 0.05 to 0.1 times the system range, and the second flow difference threshold is 0.15 to 0.2 times the system range.

[0021] Optionally, the fluctuation amplitude is a standard deviation, and the amplitude threshold is 0.05 to 0.1;

[0022] The traffic threshold is 1 cubic meter per day.

[0023] Optionally, the first ultrasonic transducer and the third ultrasonic transducer have the same resonant frequency, and are both used to emit ultrasonic signals using their own resonant frequencies as excitation frequencies;

[0024] The first, second and third ultrasonic transducers are all used to collect echo signals at a sampling frequency greater than twice the resonance frequency.

[0025] Optionally, the first, second and third ultrasonic transducers are all used to collect echo signals with a sampling frequency of 15 to 25 times the resonant frequency.

[0026] Optionally, the first ultrasonic transducer and the third ultrasonic transducer are both used to directly collect the echo signal after amplifying and filtering it;

[0027] The second ultrasonic transducer is used to amplify and filter the echo signal, mix it with the excitation signal of the first ultrasonic transducer, and then collect it after low-pass filtering through a hardware circuit.

[0028] Optionally, the first, second and third ultrasonic transducers are arranged in the same plane.

[0029] In a second aspect, an embodiment of the present invention provides a multi-channel downhole flow rate testing method, comprising:

[0030] The ultrasonic signal transceiver of any of the above-mentioned multi-channel downhole flow test systems is lowered into the target position of the oil pipe of the target water injection well, and the flow rate of the fluid at the target position in each time period is obtained based on the output data of its control terminal.

[0031] Optionally, obtaining the flow rate of the fluid at the target position in each time period further includes:

[0032] The solid particle content level of the fluid at the target location at each time period is determined.

[0033] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0034] (1) The multi-channel downhole flow rate testing system provided by the embodiment of the present invention has a first ultrasonic transducer and a second ultrasonic transducer arranged axially symmetrically, and is used to transmit ultrasonic signals in an alternating cycle. The first ultrasonic transducer and the third ultrasonic transducer are arranged centrally symmetrically. The three ultrasonic transducers arranged axially symmetrically and centrally symmetrically realize multi-channel downhole flow rate testing, and can determine the first flow rate by using the time difference method and the second flow rate by using the frequency difference method. The control terminal is used to determine the solid particle content level and the weight of the first flow rate and the second flow rate according to the first flow rate and the second flow rate in multiple consecutive cycles, and obtain the weighted average flow rate as the fluid flow rate in the corresponding time period. The system effectively improves the adaptability of ultrasonic measurement to the purity of the fluid medium, and ensures the accuracy and reliability of downhole flow rate testing.

[0035] (2) The multi-channel downhole flow rate testing system provided in the embodiment of the present invention can effectively monitor the solid particle content level of the downhole injection fluid through the flow rate results tested by the time difference method and the frequency difference method, thereby preventing the problem of the downhole dispenser water channel being blocked by solid particle impurities.

[0036] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0037] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0039] Figure 1 Schematic diagram of the structure of a downhole ultrasonic signal transceiver in a multi-channel downhole flow testing system in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0041] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0042] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the invention belongs. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0043] In the description of the present invention, it should be noted that the terms "include", "including", "have", "contain" and the like are open terms, meaning including but not limited to.

[0044] In order to solve the problem of low flow test accuracy caused by high solid particle impurity content in the fluid during stratified water injection flow test and the problem of monitoring the solid particle impurity content of the fluid medium injected downhole, an embodiment of the present invention provides a multi-channel downhole flow test system and test method.

[0045] Example

[0046] An embodiment of the present invention provides a multi-channel downhole flow testing system, comprising a downhole ultrasonic signal transceiver and a ground control terminal.

[0047] See also Figure 1 As shown, it is a structural schematic diagram of the ultrasonic signal transceiver device, including a test flow guide tube 4 and a first ultrasonic transducer 1, a second ultrasonic transducer 2 and a third ultrasonic transducer 3 arranged on the test flow guide tube 4, the first ultrasonic transducer 1 and the second ultrasonic transducer 2 are axially symmetrically arranged, and the first ultrasonic transducer 1 and the third ultrasonic transducer 3 are centrally symmetrically arranged.

[0048] Furthermore, the first, second and third ultrasonic transducers are arranged in the same plane and fixedly installed on both sides of the test flow guide tube by contact installation. Each ultrasonic transducer is provided with an acoustic wedge.

[0049] Figure 1The arrow in the figure indicates the direction of fluid flow, and the position setting of the three ultrasonic transducers is only an example. Optionally, the first ultrasonic transducer may be located upstream, the third ultrasonic transducer may be located downstream, the second ultrasonic transducer may be axially symmetrical with the first ultrasonic transducer, or axially symmetrical with the third ultrasonic transducer, and so on, as long as the two ultrasonic transducers are axially symmetrical and centrally symmetrical.

[0050] The first ultrasonic transducer and the third ultrasonic transducer are used for emitting ultrasonic signals of a certain frequency in an alternating cycle.

[0051] When the first ultrasonic transducer transmits an ultrasonic signal, the second ultrasonic transducer is used to receive the first echo signal, and the third ultrasonic transducer is used to receive the second echo signal; when the third ultrasonic transducer transmits an ultrasonic signal, the first ultrasonic transducer is used to receive the third echo signal.

[0052] by Figure 1 The positions of the three ultrasonic transducers shown in the figure are set as an example for explanation. The specific working principles of the three ultrasonic transducers are as follows:

[0053] The first ultrasonic transducer is driven to emit an ultrasonic signal of a certain frequency, and the two ultrasonic transducers on the other side respectively receive the echo waveform signals and convert them into voltage signals recognizable by the circuit, wherein the third ultrasonic transducer at the central symmetrical position obtains a countercurrent echo signal (second echo signal), and the second ultrasonic transducer at the axially symmetrical position obtains a reflected or scattered echo signal (first echo signal); the third ultrasonic transducer at the central symmetrical position is driven to emit an ultrasonic wave, and the first ultrasonic transducer on the other side receives the echo waveform signal to obtain a downstream echo signal (third echo signal).

[0054] In some embodiments, the first ultrasonic transducer and the third ultrasonic transducer have the same resonant frequency f, and are both used to emit ultrasonic signals with their own resonant frequency f as the excitation frequency. In order to ensure that the sampled signal has the original signal and the characteristics are not distorted, the first, second and third ultrasonic transducers are all used to collect echo signals with a sampling frequency greater than 2×f. At the same time, in order to improve the flow test accuracy, the sampling frequency is selected to be (15 to 25)×f.

[0055] The first ultrasonic transducer and the third ultrasonic transducer are both used to directly collect the echo signal after amplifying and filtering it through the hardware circuit; the second ultrasonic transducer is used to amplify and filter the echo signal through the hardware circuit, mix it with the excitation signal of the first ultrasonic transducer, and then collect it after low-pass filtering through the acquisition circuit.

[0056] The control terminal is used to determine the first flow rate by using the time difference method based on the second echo signal and the third echo signal in the same period, and to determine the second flow rate by using the frequency difference method based on the first echo signal; determine the solid particle content level according to the fluctuation amplitude of the first flow rate and the second flow rate in multiple consecutive periods and the size of the second flow rate, determine the weights of the first flow rate and the second flow rate, and obtain the weighted average flow rate as the fluid flow rate in the corresponding time period.

[0057] Specifically, the following steps may be included:

[0058] 1. Perform filtering and noise reduction preprocessing on the upstream and downstream echo signals (the second echo signal and the third echo signal) in the same period, and use the adaptive threshold method to calculate the upstream and downstream time and the upstream and downstream time difference of the filtered signals, and then calculate the first flow rate Q1 of the fluid.

[0059] The original upstream and downstream echo signals are processed by sliding window mean filtering, the sliding window size is N, and the adaptive threshold method is used to find the first broadcast position of the echo signal after filtering. The position of the mean point after the first broadcast position is used as the characteristic point position for calculating the upstream and downstream transmission time of the sound wave, so as to calculate the upstream and downstream time. , Time difference between upstream and downstream , through the upstream and downstream time , , upstream and downstream time difference The first flow rate Q1 is obtained by calculating the installation structure parameters of the transducer guide tube.

[0060] 2. Perform filtering and noise reduction preprocessing on the obtained reflected and / or scattered echo signal (first echo signal), convert the filtered signal from the time domain to the frequency domain, obtain the frequency difference by analyzing its spectrum, and obtain the second flow Q2 by calculating the frequency difference.

[0061] The collected first echo signal, i.e. the frequency shift signal, is subjected to FIR filtering, noise reduction and smoothing processing, and the filtered signal is sampled to obtain the resampled signal, and then fast FFT frequency domain analysis is performed to obtain the final frequency difference. The second flow rate Q2 is calculated by combining the sound wedge sound velocity, the transducer installation structure parameters and the test guide tube structure.

[0062] 3. Determine the solid particle content level according to the fluctuation amplitude of the first flow rate and the second flow rate in multiple consecutive cycles and the size of the second flow rate, determine the weights of the first flow rate and the second flow rate, and obtain the weighted average flow rate as the fluid flow rate in the corresponding time period.

[0063] The implementation of step 3 above, as shown in Table 1, includes the following situations:

[0064] Table 1 Statistics of solid particle content levels

[0065]

[0066] 1. When the fluctuation amplitude of the first flow in multiple consecutive cycles is less than the set amplitude threshold L1

[0067] (1) If the fluctuation amplitude of the second flow rate is also less than L1, and the average value of the second flow rate is not less than the set flow rate threshold S1, it is determined that the solid particle content is normal, and the weight W1 of the first flow rate and the weight W2 of the second flow rate are both determined to be 0.5 to obtain the weighted average flow rate.

[0068] When the fluctuation amplitudes of the two flow rates are small, it means that the flow rates determined by the time difference method and the frequency difference method may be relatively accurate; at the same time, the average value of the second flow rate is not very small, indicating that the flow rate determined by the frequency difference method is relatively accurate. Therefore, it can be determined that the flow rates determined by the two methods are relatively accurate, and the solid particle content is determined to be medium, and the weights of the two flows are determined to be 0.5.

[0069] Optionally, in this case, instead of simply determining that the solid particle content is normal and determining that the weight W1 of the first flow and the weight W2 of the second flow are both 0.5, the normal solid particle content is further subdivided into three situations of high solid particle content, medium solid particle content and low solid particle content according to the difference between the first flow and the second flow, and the weights of the first flow and the second flow are determined for the three situations respectively. For details, see Table 2:

[0070] Table 2 Statistics of normal solid particle content

[0071]

[0072] ① If the absolute difference between the first flow rate and the second flow rate is less than the first flow rate difference threshold value K1, it is determined that the solid particle content is medium, and the weight W1 of the first flow rate and the weight W2 of the second flow rate are both determined to be 0.5.

[0073] When the fluctuation range of the two flows is small and the average value of the second flow is not very small, if It is small enough, indicating that the flow rates measured by the time difference method and the frequency difference method are similar, and the solid particle content is determined to be medium, so the weights of the two flow rates are determined to be 0.5.

[0074] ② If the absolute difference between the first flow rate and the second flow rate is not less than K1 and not greater than the second flow rate difference threshold K2, it is determined that the solid particle content is too little, and the first flow rate weight W1 is determined to be 1. The second flow rate weight W2 is determined based on the first calibration result obtained in advance through experiments.

[0075] When the fluctuation range of the two flows is small and the average value of the second flow is not very small, if It is neither small enough nor large enough, and it is determined that the solid particle content is too little. The flow rate measured by the time difference method is already close to the actual flow rate, but it is affected by certain solid particles. Therefore, the flow rate measured by the time difference method needs to be corrected using the flow rate measured by the frequency difference method.

[0076] ③ If the absolute difference between the first flow rate and the second flow rate is greater than K2, it is determined that the solid particle content is too high, and the weight W2 of the second flow rate is determined to be 1. The weight W1 of the first flow rate is determined based on the second calibration result obtained in advance through experiments.

[0077] When the fluctuation range of the two flows is small and the average value of the second flow is not very small, if It is large enough to determine that the solid particle content is too high. The flow rate measured by the frequency difference method is closer to the actual flow rate. Therefore, the flow rate measured by the frequency difference method needs to be corrected using the flow rate measured by the time difference method.

[0078] (2) If the average value of the second flow rate is not less than the set flow rate threshold S1, and the fluctuation amplitude of the second flow rate is not less than L1; or, the average value of the second flow rate is less than the set flow rate threshold S1, in both cases, it is determined that the solid particle content is extremely small, and the weight W1 of the first flow rate is determined to be 1, and the weight W2 of the second flow rate is determined to be 0, and the weighted average flow rate is obtained.

[0079] 2. When the fluctuation amplitude of the first flow rate in multiple consecutive cycles is not less than L1, the fluctuation amplitude of the second flow rate is less than L1, and the average value of the second flow rate is not less than S1, it is determined that the solid particle content is extremely high, and the weight W1 of the first flow rate is determined to be 0, and the weight W2 of the second flow rate is determined to be 1, and the weighted average flow rate is obtained.

[0080] 3. When the fluctuation amplitude of the first flow in multiple consecutive cycles is not less than L1, the fluctuation amplitude of the second flow is less than L1, and the average value of the second flow is less than S1, or when the fluctuation amplitude of the first flow and the second flow in multiple consecutive cycles is not less than L1, an alarm message indicating possible transducer failure is issued.

[0081] In some embodiments, the first flow difference threshold is determined to be 0.05 to 0.1 times of the system range, and the second flow difference threshold is determined to be 0.15 to 0.2 times of the system range; the flow threshold is determined to be 1 cubic meter / day.

[0082] The above fluctuation range can be represented by standard deviation, or optionally, other parameters can be used for representation. When the fluctuation range is represented by standard deviation, the amplitude threshold can be determined to be 0.05-0.1.

[0083] The specific number of the multiple continuous cycles is flexibly set according to the measurement accuracy. For example, it can be set to determine the flow rate once every 5 to 10 continuous cycles.

[0084] The multi-channel downhole flow rate testing system provided by the embodiment of the present invention has a first ultrasonic transducer and a second ultrasonic transducer arranged axially symmetrically, and used to transmit ultrasonic signals alternately and cyclically, and the first ultrasonic transducer and the third ultrasonic transducer are arranged centrally symmetrically; three ultrasonic transducers arranged axially symmetrically and centrally symmetrically realize multi-channel downhole flow rate testing, and can determine the first flow rate by the time difference method and the second flow rate by the frequency difference method; the control terminal is used to determine the solid particle content level according to the first flow rate and the second flow rate in multiple continuous cycles, determine the weights of the first flow rate and the second flow rate, and obtain the weighted average flow rate as the fluid flow rate in the corresponding time period. The system effectively improves the adaptability of ultrasonic measurement to the purity of the fluid medium, and ensures the accuracy and reliability of downhole flow rate testing.

[0085] The multi-channel downhole flow testing system provided in the embodiment of the present invention can effectively monitor the solid particle content level of the downhole injected fluid through the flow results tested by the time difference method and the frequency difference method, thereby preventing the problem of the downhole dispenser water channel being blocked by solid particle impurities.

[0086] Based on the inventive concept of the present invention, an embodiment of the present invention further provides a multi-channel downhole flow testing method, comprising:

[0087] The ultrasonic signal transceiver of any of the above-mentioned multi-channel downhole flow test systems is lowered into the target position of the oil pipe of the target water injection well, and the flow rate of the fluid at the target position in each time period is obtained based on the output data of its control terminal.

[0088] Optionally, obtaining the flow rate of the fluid at the target position in each time period further includes:

[0089] The solid particle content level of the fluid at the target location at each time period is determined.

[0090] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0091] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0092] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments can be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to represent "non-exclusive or". The terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

Claims

1. A multi-channel downhole flow testing system, characterized in that: It includes a downhole ultrasonic signal transceiver and a ground control terminal; The ultrasonic signal transceiver comprises a test flow guide tube and first, second and third ultrasonic transducers arranged on the test flow guide tube, wherein the first ultrasonic transducer is axially symmetrically arranged with the second ultrasonic transducer, and the first ultrasonic transducer is centrally symmetrically arranged with the third ultrasonic transducer; The first ultrasonic transducer and the third ultrasonic transducer are used to transmit ultrasonic signals in an alternating cycle; when the first ultrasonic transducer transmits an ultrasonic signal, the second ultrasonic transducer is used to receive a first echo signal, and the third ultrasonic transducer is used to receive a second echo signal; when the third ultrasonic transducer transmits an ultrasonic signal, the first ultrasonic transducer is used to receive a third echo signal; The control terminal is used to determine the first flow rate by using the time difference method based on the second echo signal and the third echo signal in the same period, and to determine the second flow rate by using the frequency difference method based on the first echo signal; according to the fluctuation amplitude of the first flow rate and the second flow rate in multiple consecutive periods and the size of the second flow rate, the solid particle content level and the weights of the first flow rate and the second flow rate are determined by the following steps to obtain a weighted average flow rate as the fluid flow rate in the corresponding time period: When the fluctuation amplitude of the first flow in multiple consecutive cycles is less than the set amplitude threshold, if the fluctuation amplitude of the second flow is also less than the amplitude threshold, and the average value of the second flow is not less than the set flow threshold, it is determined that the solid particle content is normal, and the weights of the first flow and the second flow are both determined to be 0.5 to obtain a weighted average flow; otherwise, it is determined that the solid particle content is very small, and the weight of the first flow is determined to be 1, and the weight of the second flow is 0; When the fluctuation amplitude of the first flow in multiple consecutive cycles is not less than the amplitude threshold, the fluctuation amplitude of the second flow is less than the amplitude threshold, and the average value of the second flow is not less than the flow threshold, it is determined that the solid particle content is extremely high, and the weight of the first flow is determined to be 0, and the weight of the second flow is determined to be 1.

2. The system according to claim 1, characterized in that The control terminal, the determining of the solid particle content level and the weights of the first flow rate and the second flow rate, is further used for: When the fluctuation amplitude of the first flow in multiple consecutive cycles is not less than the amplitude threshold, the fluctuation amplitude of the second flow is less than the amplitude threshold, and the average value of the second flow is less than the flow threshold, or when the fluctuation amplitudes of the first flow and the second flow in multiple consecutive cycles are not less than the amplitude threshold, an alarm message indicating possible transducer failure is issued.

3. The system according to claim 1, characterized in that The control terminal determines that the weights of the first flow and the second flow are both 0.5, and is further used to: The weights of the first flow rate and the second flow rate are determined according to the difference between the first flow rate and the second flow rate.

4. The system according to claim 3, characterized in that The control terminal determines the weights of the first flow rate and the second flow rate according to the difference between the first flow rate and the second flow rate, for: If the absolute difference between the first flow rate and the second flow rate is less than a first flow rate difference threshold, it is determined that the solid particle content is medium, and the weights of the first flow rate and the second flow rate are both determined to be 0.5; If the absolute difference between the first flow rate and the second flow rate is not less than the first flow rate difference threshold and not greater than the second flow rate difference threshold, it is determined that the solid particle content is too low, the first flow rate weight is determined to be 1, and the weight of the second flow rate is determined according to a first calibration result obtained in advance through experiments; If the absolute difference between the first flow rate and the second flow rate is greater than a second flow rate difference threshold, it is determined that the solid particle content is too high, and a second flow rate weight 1 is determined. The weight of the first flow rate is determined according to a second calibration result obtained in advance through experiments.

5. The system according to claim 4, characterized in that The first flow difference threshold is 0.05 to 0.1 times of the system range, and the second flow difference threshold is 0.15 to 0.2 times of the system range.

6. The system according to any one of claims 1 to 5, characterized in that: The fluctuation amplitude is the standard deviation, and the amplitude threshold is 0.05 to 0.1; The traffic threshold is 1 cubic meter per day.

7. The system according to claim 1, characterized in that The first ultrasonic transducer and the third ultrasonic transducer have the same resonant frequency, and are both used to emit ultrasonic signals using their own resonant frequency as the excitation frequency; The first, second and third ultrasonic transducers are all used to collect echo signals at a sampling frequency greater than twice the resonance frequency.

8. The system according to claim 7, characterized in that The first, second and third ultrasonic transducers are all used to collect echo signals at a sampling frequency of 15 to 25 times the resonance frequency.

9. The system according to claim 1, characterized in that The first ultrasonic transducer and the third ultrasonic transducer are both used to directly collect the echo signal after amplifying and filtering; The second ultrasonic transducer is used to amplify and filter the echo signal, mix it with the excitation signal of the first ultrasonic transducer, and then collect it after low-pass filtering through a hardware circuit.

10. The system according to claim 1, wherein: The first, second and third ultrasonic transducers are arranged in the same plane.

11. A multi-channel downhole flow testing method, characterized in that: include: The ultrasonic signal transceiver of the multi-channel downhole flow test system according to any one of claims 1 to 10 is lowered into the target position of the oil pipe of the target water injection well, and the flow rate of the fluid at the target position in each time period is obtained based on the output data of its control terminal.

12. The method according to claim 11, characterized in that The step of obtaining the flow rate of the fluid at the target position in each time period further includes: The solid particle content level of the fluid at the target location at each time period is determined.

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