煤炭全数字高密度三维地震勘探关键技术研究

发布时间：2018-03-31 19:15

本文选题：高密度　切入点：数字检波器　出处：《煤炭科学研究总院》2016年博士论文

【摘要】：常规三维地震勘探的精度已不能完全满足煤矿安全高效开采对地质条件查明程度的要求,全数字高密度三维地震勘探技术在石油天然气高精度地震勘探中取得成功。该技术能否实现煤矿采区三维地震精细勘探的地质目标,尚缺少相关的基础研究和针对性的处理技术。本文首先设计了典型的地震地质模型,对高密度地震采集效果进行了2D/3D正演模拟分析,从定性、定量的角度讨论了空间采样间隔与地震分辨率之间的关系；其次,从实验室测试和现场数据分析两方面,对比分析了数字检波器与模拟检波器在机械结构、工作原理及其性能参数等方面的差异；然后,针对高密度地震数据单点采集、信噪比低等问题,重点开展了室内组合、信噪分离、弱信号增强等处理方法研究,理论模型和实际资料的处理效果验证了上述方法的有效性；最后,以赵固二矿全数字高密度三维地震试验项目为例,对比分析了全数字高密度三维地震与常规三维地震勘探的实际应用效果。主要创新性成果如下：(1)揭示了空间采样间隔与地震纵、横向分辨率之间的内在关系。地震水平分辨极限是以空间波场连续采样为默认前提,空间采样间隔越小越有利于提高水平分辨率；而地震垂向分辨极限是以零炮检距为前提,实际上叠加或偏移剖面的垂向分辨率是不同炮检距条件下单道垂向分辨率的积分,其表达式的凹函数性质表明空间采样间隔越小,垂向分辨率越高。(2)理论上数字检波器具有诸多优势,实际测试结果不尽如此。实验室测定表明数字检波器幅频响应与理论响应存在偏差；由于数字检波器灵敏度高,它对各种噪声与信号“兼蓄并收”,导致野外采集资料的信噪比偏低；现场实测数据表明：数字检波器的动态范围达不到预期的目标。(3)引入了矢量中值滤波方法,并将矢量由梯度结构张量来估计,避免了常规中值滤波对倾斜、弯曲同相轴的损伤,提高了随机去噪的保真度；扩展了十字排列域中三维锥形滤波法的适应性,实际资料处理中在面波压制上效果良好。(4)提出了Curvelet域自适应阈值函数,在压制背景噪声的同时,可以明显增强弱信号的识别度。今后,煤炭全数字高密度三维地震还应加强观测系统优化设计、复杂构造成像、全三维解释方法等研究,以推动煤矿采区全数字高密度三维地震勘探早日得到推广应用。
[Abstract]:The accuracy of conventional 3D seismic exploration can not fully meet the requirements of geological conditions for safe and efficient mining of coal mines. The full digital high density 3D seismic exploration technology has been successfully used in high precision seismic exploration of petroleum and natural gas.Whether this technology can realize the geological target of 3D seismic fine exploration in coal mining area is still lack of relevant basic research and targeted processing technology.In this paper, a typical seismogeological model is designed, and the forward modeling of high-density seismic acquisition is analyzed by 2D/3D. The relationship between spatial sampling interval and seismic resolution is discussed qualitatively and quantitatively; secondly, the relationship between spatial sampling interval and seismic resolution is discussed.The differences between digital geophone and analog geophone in mechanical structure, working principle and performance parameters are compared and analyzed from two aspects of laboratory test and field data analysis.The problems of low signal-to-noise ratio (SNR), such as indoor combination, separation of signal and noise, weak signal enhancement and so on, are emphasized. The effectiveness of the above methods is verified by the theoretical model and the actual data processing results.Taking the full digital high density 3D seismic test project in Zhaogu No.2 Mine as an example, the practical application results of the full digital high density 3D seismic exploration and the conventional 3D seismic exploration are compared and analyzed.The main innovative results are as follows: 1) the relationship between spatial sampling interval and seismic vertical and lateral resolution is revealed.The seismic horizontal resolution limit is based on continuous sampling of spatial wave field. The smaller the spatial sampling interval is, the better the horizontal resolution is, while the vertical seismic resolution limit is based on zero offset.In fact, the vertical resolution of stacking or migration profile is an integral of the vertical resolution of the order track issued by different offset conditions. The concave function of its expression shows that the smaller the spatial sampling interval, the smaller the spatial sampling interval.The higher the vertical resolution is, the higher the vertical resolution.) the digital geophone has many advantages in theory, but the actual test results are not the same.The experimental results show that the amplitude response of digital geophone deviates from the theoretical response, because of the high sensitivity of digital geophone, it "accumulates and receives all kinds of noises and signals", which leads to the low signal-to-noise ratio of field data.The field measured data show that the dynamic range of the digital geophone can not reach the expected target. The vector median filtering method is introduced, and the vector is estimated by the gradient structure Zhang Liang, which avoids the damage caused by the conventional median filter to the oblique and bending cophase axis.The fidelity of random denoising is improved, and the adaptability of three-dimensional conical filtering in cross permutation domain is extended. In practical data processing, the effect of surface wave suppression is good. (4) the adaptive threshold function in Curvelet domain is proposed, which can suppress background noise at the same time.It can obviously enhance the recognition degree of weak signal.In the future, it is necessary to strengthen the research on the optimization design of observation system, the imaging of complex structures and the method of full 3D interpretation, so as to promote the application of full digital high density 3D seismic exploration in coal mining area as soon as possible.
【学位授予单位】：煤炭科学研究总院
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P631.4

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