微地震与井地电法联合探测系统的研究与设计

发布时间：2018-01-06 23:09

本文关键词：微地震与井地电法联合探测系统的研究与设计　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：水力压裂监测方法是指导油气田开采的重要技术手段,监测结果的准确程度将影响油气田采收率,当前的水力压裂监测方法以单一的地球物理探测方法为主,如微地震监测、井地电法等。但是,当压裂监测环境中干扰较多时,微地震方法很难获取准确的监测结果;而对于低电阻率储层压裂,由于储层和压裂液电阻率差异小,井地电法监测困难,因此,单一地球物理探测方法存在一定程度的局限性和多解性。本文针对单一地球物理探测方法在水力压裂裂缝监测中存在的不足,利用水力压裂中产生的微地震事件,与压裂前后电阻率的变化,采用震源定位技术与视差分电阻率成像方法,基于决策层数据融合技术研究了微地震与井地电法联合探测理论,同时设计完成了双参数联合监测系统,并通过黑龙江野外压裂监测实验,验证了微地震与井地电法联合监测的有效性。主要研究内容如下:1、采用逐步迭代射线追踪方法和三维有限差分法对微地震、井地电法进行数值模拟正演计算,为设计微地震与井地电法联合探测系统提供理论依据。2、根据联合系统的设计要求设计并实现了系统的接收单元和控制单元,其中以ARM为核心处理器,结合CF卡、FLASH、GPS、FPGA完成了四通道震电信号接收系统的设计,采用Wi-Fi通信技术实现了系统的无线控制功能,并根据信号特点完成了系统自测试功能设计,为微地震与井地电法联合探测方法的实现提供硬件基础。3、分析了微地震数据、电法数据的有效信号与噪声干扰的特点,采用小波变换技术消除微地震数据的噪声干扰;采用低通滤波、向后差分、数据平均、最小二乘多项式拟合等方法消除电法数据的工频干扰、尖峰干扰、随机噪声、偏置干扰,提高了数据的信噪比。利用射线追踪和比值法对微地震的速度模型与电法地质模型进行校正;利用震幅叠加方法对微地震数据进行震源定位,采用电法数据的视电阻率差值的变化对裂缝进行成像,并利用微地震方法拾取的震源点阵列和井地电法测量获得的裂缝成像结果进行融合得到更准确的异常信息,提高水力压裂中裂缝的监测精度。4、利用完成的微地震与井地电法联合探测系统进行了大量的对比和测试实验,其中在黑龙江省油田进行了实际的水力压裂监测实验,结果表明联合探测系统能够同时获取水力压裂过程中的微地震事件和电阻率异常信息,与单一地球物理方法的探测结果相比,利用两种数据联合反演能够获得更加准确的裂缝成像结果,提高水力压裂裂缝探测结果的可信度。
[Abstract]:Hydraulic fracturing monitoring method is an important technical means to guide oil and gas field production. The accuracy of monitoring results will affect oil and gas field recovery. The main method of hydraulic fracturing monitoring is single geophysical detection method. Such as microseismic monitoring, well geoelectric method and so on. However, when there is more interference in fracturing monitoring environment, it is difficult to obtain accurate monitoring results by micro-seismic method. For low resistivity reservoir fracturing, because of the small difference between reservoir and fracturing fluid resistivity, it is difficult to monitor well electrical method. Single geophysical detection method has some limitations and multiple solutions. This paper aims at the shortcomings of single geophysical detection method in hydraulic fracturing fracture monitoring. Based on the microseismic events produced by hydraulic fracturing and the changes of resistivity before and after fracturing, the focal location technique and apparent differential resistivity imaging method are used. Based on the decision layer data fusion technology, the theory of microseismic and borehole electrical joint detection is studied, and the two-parameter joint monitoring system is designed and completed, and the field fracturing monitoring experiment in Heilongjiang province is carried out. The effectiveness of the joint monitoring of microseismic and borehole geoelectric method is verified. The main contents of the research are as follows: 1. Step by step iterative ray tracing method and 3D finite difference method are used to study microearthquakes. In order to provide theoretical basis for the design of the joint detection system of micro-seismic and borehole geoelectric method, the numerical simulation forward calculation is carried out by the well geoelectric method. According to the design requirements of the joint system, the receiving unit and the control unit of the system are designed and implemented. The ARM is used as the core processor and the CF card flash GPS is used. FPGA has completed the design of the four-channel seismic signal receiving system, using the Wi-Fi communication technology to realize the wireless control function of the system, and has completed the system self-test function design according to the signal characteristic. This paper provides a hardware basis for the realization of the joint detection method of microseismic and borehole electrical method, and analyzes the characteristics of the effective signal and noise interference of the microseismic data and the electrical data. Wavelet transform technique is used to eliminate noise interference from microseismic data. Low pass filtering, backward difference, average data, least square polynomial fitting and other methods are used to eliminate power frequency interference, peak interference, random noise and bias interference of electrical data. The signal-to-noise ratio (SNR) of the data is improved. The velocity model of micro-earthquake and the geological model of electric method are corrected by ray tracing and ratio method. The seismic source location of microseismic data is carried out by using amplitude superposition method, and the fracture is imaged by the change of apparent resistivity difference of electrical data. Using the focal point array picked up by the micro-seismic method and the fracture imaging results obtained by the borehole geoelectric method, more accurate abnormal information can be obtained, and the monitoring accuracy of fractures in hydraulic fracturing can be improved by .4. A large number of contrast and test experiments have been carried out by using the combined detection system of microseismicity and borehole geoelectric method, among which the actual hydraulic fracturing monitoring experiment has been carried out in Heilongjiang oil field. The results show that the combined detection system can simultaneously obtain microseismic events and resistivity anomalies during hydraulic fracturing, which is compared with the results of single geophysical method. More accurate fracture imaging results can be obtained by combined inversion of two kinds of data, and the reliability of hydraulic fracturing fracture detection results can be improved.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE928

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