井—地ERT水驱前缘数据处理、反演与解释

发布时间：2018-07-21 20:43

【摘要】：电法勘探种类多样，，适用性强，应用范围广，是应用地球物理学的一个重要的组成部分。自20世纪初视电阻率这一概念提出以来，电法勘探已被发展成很多种方法。电法勘探主要是依据岩层中介质不同的电磁性质，通过观测自然存在或人工建立的电场的分布，来研究地下介质，寻找有用的矿产资源、解决工程、环境等各种问题的一类重要的地球物理勘探方法。井地电法是目前在监测油田水力压裂的裂缝方位中比较成熟，应用比较广泛的一种方法。井地电法是将地表直流电法以及电测井法相结合的探测方法。井地电法的基本原理是在井中供电，通过套管向地下供入大功率的电流，供电同时在地表观测由于流入地层的“漏电流”而导致的非均匀地下介质在地表所形成的电位梯度异常分布，从分布情况来推断地下异常体的特征。井地电法的成本较低、操作较简单、实施较方便、场源实现比较容易、不易破坏井中情况等优势，所以本文对基于井地电阻率法的正反演以及水驱前缘的数据处理展开了研究。井地电阻率正演方法是井地电法在水驱前缘监测的理论基础，电阻率反演是对给定的模型以及正演的计算值来反映地下介质电阻率的分布情况。随着理论研究的深入以及实际的应用的广泛，许多问题需要进一步的完善，最主要的就是正反演算法的研究。论文主要讨论了有限差分法的电阻率正演算法，OCCAM正则化反演算法。本文根据任意线电流源在地下产生的电位以及有限差分方法进行研究，通过建立不同的地电模型和电位梯度法的观测方式，分析了高低异常体埋深不同对地表电位梯度的影响。建立一维的层状模型，采用Occam的反演方法对一维的层状模型进行深度电阻率的反演成像，得到电阻率和深度的光滑模型，Occam反演对层状模型的反演结果吻合，可以初步的对野外探测进行数据解释。本文进行野外实验的采集数据，并采用最小二乘法、低通滤波（中值滤波）和数字平均技术来提高信噪比。本文以大庆十厂压裂井以及山西煤矿井为例，说明野外的实验概况。
[Abstract]:Electrical exploration is an important part of applied geophysics because of its various types, strong applicability and wide range of application. Since the concept of apparent resistivity was put forward in the early 20th century, electrical prospecting has been developed into many methods. The electric exploration is mainly based on the electromagnetic properties of the medium in the strata, by observing the distribution of the electric field which exists naturally or artificially, to study the underground medium, to find the useful mineral resources, and to solve the project. A class of important geophysical exploration methods for various problems such as environment. Well-ground electrical method is a mature and widely used method in monitoring fracture azimuth of hydraulic fracturing in oil fields at present. Well-ground electrical method is a method that combines surface direct current method and electric logging method. The basic principle of the well-ground electrical method is to supply power in the well and supply the high power electric current to the ground through the casing At the same time, the distribution of potential gradient anomaly caused by the "leakage current" in the ground layer caused by the non-uniform medium is observed on the surface of the power supply, and the characteristics of the underground anomaly body are inferred from the distribution situation. The well ground electrical method has the advantages of low cost, simple operation, convenient implementation, easy field source realization and not easy to destroy the well situation. Therefore, the forward inversion based on well ground resistivity method and the data processing of the leading edge of water drive are studied in this paper. The forward modeling method of well-ground resistivity is the theoretical basis of well-to-ground electrical method in monitoring the leading edge of water drive. Resistivity inversion is to reflect the distribution of resistivity of underground medium by the given model and the forward calculated values. With the deepening of theoretical research and the wide application of practical applications, many problems need to be further improved, the most important is the research of forward and inverse algorithms. This paper mainly discusses the forward resistivity algorithm of finite difference method and the OCCAM regularization inversion algorithm. In this paper, based on the study of the potential generated by arbitrary line current sources underground and the finite difference method, the effects of different buried depths of high and low anomaly bodies on the surface potential gradient are analyzed through the establishment of different geoelectric models and the observation methods of the potential gradient method. A one-dimensional layered model is established, and the depth resistivity of the one-dimensional layered model is imaged by Occam inversion method. The inversion results of the resistivity and the depth smooth model are in agreement with the inversion results of the layered model. Preliminary data interpretation of field exploration can be carried out. In this paper, the data of field experiments are collected, and the signal-to-noise ratio (SNR) is improved by using least square method, low pass filter (median filter) and digital average technique. Taking the fracturing well of Daqing No. 10 Plant and the well of Shanxi Coal Mine as examples, this paper explains the general situation of field experiments.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.811

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