弹性波CT软件设计及其在模型分析中的应用研究

发布时间：2018-12-26 15:36

【摘要】：随着我国经济的高速发展,煤炭作为最主要的能源消费品产量持续增涨,但是煤安生产安全状况一直不理想,煤矿中发生的瓦斯爆炸、断层的导水、严重透水等灾害,造成的人员伤亡和经济损失仍是十分惊人。国家相继出台了一系列加强煤炭生产安全的相关法规,加大了对安全生产的投入,一大批新型的工程地球物理技术被应用到了井下的煤炭开采当中。为工程地球物理勘探技术提供了十分广阔的施展空间。但是,由于煤炭生产安全的重要性以及井下地质情况的复杂加上连续生产的要求,对煤矿井下的勘探提出了严苛的要求。而目前在井下回采工作面的物探措施相对比较缺乏,物探效果不够理想。层析成像技术具有信息量大、分辨率高、形象直观的优点,今年来蓬勃发展,层析成像技术在医学上已经取得的跨时代的意义,也在科学技术各领域推广应用。弹性波CT技术在石油工业、土木、水电工程领域经过长时间的尝试和应用已经比较成熟。弹性波CT技术在井下回采工作面中将有较大的应用前景。目前国内仅进行过几次相关的井下实验,目前并无一套完整的系统也无相关专业软件。所以采用弹性波透视系统对煤矿回采工作面内地质异常的预测预报是必要的,对安全生产和提高经济效益都具有十分重大意义。与成熟的医学CT相比,井下回采区的层析成像条件更加复杂,投影数据大多不完全,探测对象与异常体间的相关性不够清楚,以及不适定等困难,造成成像不够精确,目前亟待开展CT技术在井下回采区应用中的基础理论研究。能有助于解决井下回采工作面地质异常体的探测,并推动弹性波CT技术在煤炭生产中的应用,为我国能源安全提供支持。弹性波CT技术主要包括“正演模拟”和“反演”两个关键技术。正演是由初始模型计算射线走时,反演是由实测走时计算模型的各项物理参数。正演一般都有比较稳定的模型和明确的解。而反演往往遇到多解的问题。本文开发了一套针对煤炭井下回采区的弹性波CT软件,应用“椭圆约束”算法实现快速弯曲射线追踪；应用SIRT联合迭代和阻尼系数“自动匹配”方法,实现快速高精度成像。通过数值模型分析和工程实例验证了这款软件的实际使用效果。并使用软件正反演功能对影响图像重建精度的因素做了一些探讨。
[Abstract]:With the rapid development of China's economy, the output of coal, as the most important energy consumer product, continues to increase, but the safety situation of coal production safety has not been ideal. The gas explosion in coal mines, the water conductivity of faults, serious water permeability and other disasters have occurred. The casualties and economic losses are still staggering. The state has issued a series of laws and regulations to strengthen the safety of coal production and increased the investment in safety production. A large number of new engineering geophysical techniques have been applied to underground coal mining. It provides a very broad application space for engineering geophysical exploration technology. However, due to the importance of coal production safety, the complexity of underground geological conditions and the requirement of continuous production, strict requirements have been put forward for underground exploration in coal mines. At present, the geophysical prospecting measures in the underground mining face are relatively lacking, and the geophysical exploration effect is not ideal. Tomography technology has the advantages of large amount of information, high resolution and visual image. It has developed vigorously this year. Tomography technology has made cross-epochal significance in medicine, and has also been popularized and applied in various fields of science and technology. Elastic wave CT technology has been used in petroleum industry, civil engineering and hydropower engineering for a long time. Elastic wave CT technology will have a great application prospect in underground mining face. At present, only a few related underground experiments have been carried out in China, and there is no complete system and no related professional software. Therefore, it is necessary to use elastic wave perspective system to predict geological anomalies in coal mining face, which is of great significance for safe production and improving economic benefits. Compared with the mature medical CT, the condition of tomography in underground mining area is more complex, the projection data is incomplete, the correlation between detecting object and abnormal body is not clear enough, and the difficulty of ill-posed, resulting in the imprecision of imaging. At present, it is urgent to develop the basic theory research of CT technology in underground recovery area. It can help to solve the problem of geological anomaly detection in underground mining face, promote the application of elastic wave CT technology in coal production, and provide support for energy security in China. Elastic wave CT technology includes two key techniques: forward modeling and inversion. The forward modeling is to calculate the ray travel time by the initial model, and the inversion is to calculate the physical parameters of the model by the measured travel time. In general, there are more stable models and definite solutions in forward modeling. The inversion often encounters the problem of multiple solutions. In this paper, a set of elastic wave CT software for coal mining area is developed. The fast bending ray tracing is realized by using "elliptical constraint" algorithm, and the fast and high precision imaging is realized by using SIRT combined iteration and damping coefficient "automatic matching" method. Through numerical model analysis and engineering examples, the actual application effect of this software is verified. The factors that affect the accuracy of image reconstruction are discussed by using the function of software forward and inverse.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.4

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