阅读说明：本技术 一种非常规储层固有频率原位测量系统 (Unconventional reservoir natural frequency in-situ measurement system ) 是由 高崇 康忠健 李雷 王聪 龚大建 于 2021-03-26 设计创作，主要内容包括：本发明公开了一种非常规储层固有频率原位测量系统,包括：金属壳体、振动监测模块、信号处理部分、数据传输部分、能量转换器。所述的信号处理部分包括信号预处理器与固有频率测定仪；所述数据传输部分包括通讯模块、信号转换器、数据线。该系统实现非常规储层固有频率原位测量,避免试样转移造成物性参数变化引起的误差问题,提高测量精度的同时达到实时监测的效果。(The invention discloses an unconventional reservoir natural frequency in-situ measurement system, which comprises: the device comprises a metal shell, a vibration monitoring module, a signal processing part, a data transmission part and an energy converter. The signal processing part comprises a signal preprocessor and a natural frequency determinator; the data transmission part comprises a communication module, a signal converter and a data line. The system realizes the in-situ measurement of the natural frequency of the unconventional reservoir, avoids the problem of errors caused by the change of physical property parameters due to sample transfer, improves the measurement precision and achieves the effect of real-time monitoring.)

1. An unconventional reservoir natural frequency in-situ measurement system, comprising: the device comprises a metal shell, a vibration monitoring module, a signal processing part, a data transmission part and an energy converter. The signal processing part comprises a signal preprocessor and a natural frequency determinator; the data transmission part comprises a communication module, a signal converter and a data line.

The shock wave generated by the energy converter induces the vibration of the reservoir through the well wall casing, the vibration response energy of the reservoir reaches the vibration monitoring module after penetrating through the well wall casing and the metal shell, the vibration monitoring module transmits the acquired data to the signal preprocessor, the signal preprocessor preprocesses the data acquired by the vibration monitoring module, the communication module transmits the digital signal sent by the signal preprocessor to the ground signal converter through the data wire, the signal converter completes the signal conversion and transmits the signal to the inherent frequency determinator through the data wire, and the inherent frequency determinator obtains the inherent frequency of the target reservoir under the current output power of the energy converter according to a filtering algorithm.

2. The unconventional reservoir natural frequency in-situ measurement system according to claim 1, wherein: the signal preprocessor carries out vibration signal spectrum analysis and feature extraction work based on the Hilbert-Huang transform theory, and finally obtains a plurality of Hilbert marginal spectrums.

3. The unconventional reservoir natural frequency in-situ measurement system according to claim 1, wherein: the soft core of the natural frequency determinator is an unconventional reservoir natural frequency filtering algorithm based on a maximum correlation coefficient method modal filtering theory, and the unconventional reservoir natural frequency and vibration energy numerical value solution under the ideal condition is used as a reference characteristic.

4. The unconventional reservoir natural frequency in-situ measurement system according to claim 1, wherein: the unconventional reservoir natural frequency in-situ measurement system can be coupled with the frequency spectrum resonance generation device, so that the reservoir natural frequency in-situ measurement is realized, and the timeliness and the accuracy of data are better ensured.

5. The unconventional reservoir natural frequency in-situ measurement system according to claim 1, wherein: the vibration signal detection has continuity, so the system can realize dynamic monitoring of the natural frequency of the target reservoir.

Technical Field

The invention relates to a geological data measurement technology, in particular to an unconventional reservoir natural frequency in-situ measurement system, and belongs to the technical field of well logging.

Background

Shale oil gas has gradually become an important alternative of conventional oil gas as an important component of unconventional oil gas resources, and the efficient large-scale development of the shale oil gas has important strategic significance for guaranteeing the safety of oil gas resources in China. The method is limited by the low-permeability and ultra-low-permeability characteristics of the shale reservoir, and has no commercial development value in the natural state. Therefore, the research of shale reservoir transformation technology becomes a key point for realizing the economic and effective development of unconventional oil and gas.

In the research process of shale reservoir improvement and oilfield development technology, the researchers find the characteristics of resonance phenomena from other fields, namely the amplitude of a system or a unit vibrating at a specific frequency is the maximum value in the vibration frequency range, and the parameter equation is as follows:

when the target is in a resonance state, the energy converted from external excitation to the receptor is maximum and is mainly expressed in the form of kinetic energy, and the vibration amplitude of the receptor is sharply increased and reaches the maximum value before resonance, so that the yield limit of the receptor can be reached by applying a smaller loading force in the resonance state, the purposes of promoting crack development and rock fracture are further achieved, and the production efficiency is effectively improved. In the field of oil and gas exploitation, resonance-assisted rock breaking and unconventional reservoir spectrum resonance improvement technologies have been developed according to resonance characteristics, and the method does not need to add chemical agents, does not discharge waste liquid reversely, has high efficiency, and really achieves low pollution, zero emission and high efficiency.

In the application process of the resonance technology, the accurate determination of the natural frequency of the target reservoir is the key for inducing reservoir resonance. At present, the measurement of the natural frequency mainly depends on a hammering method and a frequency sweeping method, and is suitable for an environment in which vibration data are easy to collect indoors or outdoors. Because the shale reservoir is deeply buried, the direct application of the hammering method cannot cause the reservoir vibration and the collection of response signals. The sweep frequency method is developed for unconventional reservoir rock core samples, compared with the actual reservoir environment, the sample confining pressure, temperature, humidity and the like are changed, errors exist in the measured value of the natural frequency, and the method is not suitable for measurement of the natural frequency of the unconventional reservoir because the vibration amplitude suddenly drops in the neighborhood with smaller resonance and the influence on the resonance transformation effect is great, so that an unconventional reservoir natural frequency in-situ measurement system needs to be created.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides an unconventional natural frequency in-situ measurement system for a reservoir. The system is based on an unconventional reservoir natural frequency measurement algorithm of Hilbert-Huang transform and an eigenmode filtering theory, achieves the purpose of reservoir natural frequency in-situ measurement, avoids errors caused by physical property parameter changes in the sampling and transportation processes, guarantees the accuracy and timeliness of measured data, and meanwhile achieves dynamic monitoring of natural frequency.

The technical scheme adopted by the invention is as follows:

an unconventional reservoir natural frequency in-situ measurement system, comprising: the device comprises a metal shell, a vibration monitoring module, a signal processing part, a data transmission part and an energy converter. The signal processing part comprises a signal preprocessor and a natural frequency determinator; the data transmission part comprises a communication module, a signal converter and a data line.

The signal processing part comprises a signal preprocessor and a natural frequency determinator;

the data transmission part comprises a communication module, a signal converter and a data line;

the energy converter converts electric energy into kinetic energy and potential energy, and the kinetic energy and the potential energy act on an unconventional reservoir through a well wall sleeve and a cement sheath to induce the vibration of the reservoir;

the vibration monitoring module is fixed on the inner surface of the metal shell in a threaded connection mode, and transmits the acquired vibration data to the signal preprocessor by using a data line;

the signal preprocessor carries out spectrum analysis and feature extraction on the vibration signal based on the Hilbert-Huang transform theory, and transmits data to the signal converter by utilizing the communication module;

the signal converter converts the underground electric signal into a digital signal and transmits the digital signal to the natural frequency determinator through a data line;

preferably, the energy converter is made of alloy materials, so that the service life is effectively prolonged;

preferably, the metal shell is made of titanium steel alloy, so that the hardness is high, and the excessive loss when external energy is transmitted to the vibration monitoring module through the metal shell is prevented;

preferably, the communication module is an integrated chip with high anti-interference performance based on an AMP framework;

preferably, the signal converter has stronger data processing performance, and effectively avoids data loss;

compared with the prior art, the invention has the beneficial effects that:

(1) the natural frequency measurement system is coupled with the resonance excitation instrument, so that the natural frequency of the target reservoir is measured in situ under the well, the problem of sample physical property parameter change in a laboratory measurement mode is effectively solved, and the detection precision of the natural frequency is effectively improved.

(2) The natural frequency is influenced by physical parameters such as the structural strength of the reservoir, the quality of the target reservoir, the confining pressure and the like, but the related physical parameters change along with the moment of the resonance process. The invention can collect the dynamic response energy of the reservoir under the excitation of the complex frequency, and can change, namely measure, so as to achieve the aim of monitoring the natural frequency of the reservoir at any time.

(3) Aiming at the characteristic that the vibration amplitude of the reservoir in the natural frequency neighborhood is sharply reduced, the natural frequency function of the reservoir can be monitored, reliable reference is provided for a frequency spectrum excitation system, and the resonant transformation operation efficiency of the unconventional reservoir is effectively guaranteed.

Drawings

FIG. 1 is a diagram of an unconventional reservoir natural frequency in-situ measurement system;

FIG. 2 is a schematic diagram of an unconventional reservoir natural frequency in-situ measurement system;

in the figure: the device comprises a natural frequency tester (1), a signal converter (2), a data line (3), a metal shell (4), a communication module (5), a signal preprocessor (6), a vibration monitoring module (7), an energy converter (8), an unconventional reservoir (9-1), a cement sheath (9-2), a well wall casing (9-3) and a perforation (9-4).

Detailed Description

The embodiments of the present invention will now be described in terms of conventional practice, and those skilled in the relevant art can appreciate advantages and effects of the present invention through the description of the embodiments. The embodiments are partial embodiments of the invention, so that all other embodiments obtained by others without creative efforts are within the protection scope of the invention.

As shown in figure 2, the invention provides an unconventional reservoir natural frequency in-situ measurement system, which comprises an external excitation generation structure energy converter (8), a vibration monitoring module (7) sealed inside a metal shell (4) and used for acquiring rock mass response signals of an unconventional reservoir (9-1), a signal preprocessor (6) and a communication module (5), wherein signal data are transmitted to a natural frequency determinator (1) through a signal converter (2) to complete natural frequency determination.

Example 1

The underground part of the system works as follows: the energy converter (8) converts electric energy into kinetic energy and potential energy based on a liquid electricity effect, and the generated shock waves act on the unconventional reservoir (9-1) through the well wall casing (9-3) and the cement sheath (9-2) to induce the target area of the unconventional reservoir (9-1) to vibrate; the unconventional reservoir (9-1) vibrates an internal structure and a medium under the action of external excitation, and vibration energy reaches the metal shell (4) through the cement sheath (9-2), the well wall casing (9-3) and the well medium; the vibration monitoring module (7) is fixed on the inner surface of the metal shell (4) in a threaded connection mode, the reservoir vibration and energy converter (8) releases energy to disturb the vibration monitoring module (7), and the vibration monitoring module (7) sends acquired data to the signal preprocessor (6) by using the data wire (3); the signal preprocessor (6) decomposes the data collected by the vibration monitoring module (7) into a plurality of marginal spectrums based on the Hilbert-Huang transform theory, and transmits the marginal spectrums to the signal converter (2) by using the communication module (5);

the system comprises the following working processes of an aboveground part: the signal converter (2) converts the received underground electric signal into a digital signal and transmits the digital signal to the natural frequency determinator (1) through a data line (3); the soft core of the natural frequency determinator (1) is a natural frequency determination algorithm based on an eigenmode filtering theory, and is characterized by time-frequency characteristics, vibration energy and natural frequency numerical solution, marginal spectrum data uploaded by a signal preprocessor (6) are screened, disturbance signals generated when forced vibration response energy of a well wall casing (9-3) and a cement sheath (9-2) acts on a vibration monitoring module (7) are filtered, and the natural frequency of a target reservoir is obtained;

the method overcomes the difficulty that the existing laboratory natural frequency measurement technologies such as a hammering method, a frequency sweep method and the like are not suitable for the in-situ measurement of the unconventional reservoir stratum, directly carries out the measurement in situ under the condition of ensuring the original physical property parameters of the target reservoir stratum, and achieves the dynamic monitoring effect of the natural frequency of the reservoir stratum.

Example 2

The structure of the embodiment is basically the same as that of the embodiment 1, except that the vibration energy of the reservoir directly acts on the surface of the metal shell (4) through the perforation (9-4) and the medium in the well.

Example 3

The structure of the embodiment is basically the same as that of the embodiment 1, except that the energy converter (8) generates impact on the vibration sensor in the process of releasing energy, a disturbance signal caused by the impact is identified by the characteristic analysis process of the natural frequency detector (1) and is identified as a noise signal to be filtered, and the natural frequency is measured.

The above-described embodiments are merely conventional examples of the present invention and are not intended to limit the present invention in any manner. Therefore, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the scope of the technical solution of the present invention without departing from the technical solution of the present invention.