Present situation of the research and application of engineering multiwave seismic prospecting in China

In four aspects, which are the leading exploration of mine and tunnel f engineering geological hazard prospecting and engineering shock resistance; non-destructive testing of engineering quality 1 the measurement of rock physical properties, this pope gives a detailed summary and some comments on the present situation of the research and application of the ideas, theories and methods of engineering multiwave seismic prospecting. The content includes: the prospecting of coal field caved pillar, underground gallery, underground cavity and the fault ahead of tunnel; the exploration of earth surface Karst collapse, active fault, and shock resistance Of underground lifeline engineering; the dynamic non-destructive testing of quality and boring capacity of pile foundation, the non-destructive testing of strength, thickness and defects of concrete pavement, and the non-destructive testing of sub marine tunnel engineering quality ; the measurement of rock physical properties under high temperature and high pressure and the determination of physical properties of irregular rock samples. Some existing problems are discussed and the direction which should be developed in the future is proposed.

3D HIGH RESOLUTION SEISMIC PROSPECTING IN MINING AREAS,XIEQIAO COLLIERY

3D seismic prospecting in mining areas of Xieqiao Colliery is a successfulmodel for an advancement from the resource prospecting to mining prospecting stagein coal fields. Its results have proved that faults with a throw of 5-10 m can be detected in an area with good seismogeologic conditions by using 3D seismic technique.Detection of underground tunnels for the first time utilizing 3D seismic data indicates that subsided columns, gotten and mine goaf can be detected using 3D seismic technique, so it has a broad applied prospect.

3D HIGH RESOLUTION SEISMIC PROSPECTING IN COAL MINING AREAS

The production capacity and efficiency for mechanized coal faces of large-scale mines depend on the detecting degree of mining structures. It is a major task for geological exploration in coal fields to detect minor structures in district. 3D high resolution seismic prospecting is a effective measure for solving this problem.

The Practice of Forward Prospecting of Adverse Geology Applied to Hard Rock TBM Tunnel Construction： The Case of the Songhua River Water Conveyance Project in the Middle of Jilin Province

An increasing number of tunnels are being constructed with tunnel-boring machines （TBMs） due to the increased efficiency and shorter completion time resulting from their use. However, when a TBM encoun- ters adverse geological conditions in the course of tunnel construction （e.g., karst caves, faults, or frac- tured zones）, disasters such as water and mud inrush, collapse, or machine blockage may result, and may severely imperil construction safety. Therefore, the advance detection of adverse geology and water-bearing conditions in front of the tunnel face is of great importance. This paper uses the TBM tun- neling of the water conveyance project from Songhua River as a case study in order to propose a compre- hensive forward geological prospecting technical system that is suitable for TBM tunnel construction under complicated geological conditions. By combining geological analysis with forward geological prospecting using a three-dimensional （3D） induced polarization method and a 3D seismic method, a comprehensive forward geological prospecting technical system can accurately forecast water inrush geo-hazards or faults in front of the TBM tunnel face. In this way, disasters such as water and mud inrush, collapse, or machine blockage can be avoided. This prospecting technical system also has reference value for carrying out the forward prospecting of adverse geology for potential TBM tunneling and for ensuring that a TBM can work efficiently.

Integration of Well Logs and Seismic Data for Prospects Evaluation of an X Field, Onshore Niger Delta, Nigeria

Hydrocarbon reservoir beds have been delineated using direct hydrocarbon indicator on seismic sections as well as well logs data in X field, Onshore Niger Delta. The research methodology involved horizon interpretation to produce sub-surface structure map. Geophysical well log signatures were employed in identifying hydrocarbon bearing sand. The well-to-seismic tie revealed that the reservoir tied directly with hydrocarbon indicator (bright spot) on the seismic sections. The major structure responsible for the hydrocarbon entrapment is anticline. The crest of the anticline from the depth structural map occurs at 3450 metres.

Geological Interpretation and Identification of Albian-Aged Petroleum Prospects in Block A, San Pedro Margin (Côte d’Ivoire)

The study aims to identify Albian-age oil prospects in Block A of the San Pedro margin, Côte d’Ivoire, by conducting a detailed geological interpretation. The objective is to confirm the presence of oil reservoirs trapped by favorable geological structures, identifiable through geophysical and seismic methods. The methodological approach is based on a combined analysis of studies and seismic data. Drilling data from well PA, including well logs and end-of-well reports, were used to characterize the lithological formations encountered, particularly those of the Albian. 3D seismic profiles were interpreted to identify structures conducive to hydrocarbon accumulation. Isochrone, isovelocity, and isobath maps were developed to refine the interpretation. Sedimentological analyses revealed five sandy/gritty levels between 2610 m and 3100 m, interspersed with clay, limestone, and siltstone beds. The seismic profiles highlighted two main prospects. These prospects exhibit favorable geological structures, including normal faults and structural traps that provide oil traps.

Seismic random noise suppression using an adaptive nonlocal means algorithm

Nonlocal means filtering is a noise attenuation method based on redundancies in image information. It is also a nonlocal denoising method that uses the self-similarity of an image, assuming that the valid structures of the image have a certain degree of repeatability that the random noise lacks. In this paper, we use nonlocal means filtering in seismic random noise suppression. To overcome the problems caused by expensive computational costs and improper filter parameters, this paper proposes a block-wise implementation of the nonlocal means method with adaptive filter parameter estimation. Tests with synthetic data and real 2D post-stack seismic data demonstrate that the proposed algorithm better preserves valid seismic information and has a higher accuracy when compared with traditional seismic denoising methods （e.g., f-x deconvolution）, which is important for subsequent seismic processing and interpretation.

Seismic safety of high concrete dams

China is a country of high seismicity with many hydropower resources. Recently,a series of high arch dams have either been completed or are being constructed in seismic regions,of which most are concrete dams. The evaluation of seismic safety often becomes a critical problem in dam design. In this paper,a brief introduction to major progress in the research on seismic aspects of large concrete dams,conducted mainly at the Institute of Water Resources and Hydropower Research(IWHR) during the past 60 years,is presented. The dam site-specific ground motion input,improved response analysis,dynamic model test verification,field experiment investigations,dynamic behavior of dam concrete,and seismic monitoring and observation are described. Methods to prevent collapse of high concrete dams under maximum credible earthquakes are discussed.

Research and Application of In-seam Seismic Survey Technology for Disaster-causing Potential Geology Anomalous Body in Coal Seam

In order to effectively detect potential geology anomalous bodies in coal bearing formation,such as coal seam thickness variation,small faults,goafs and collapse columns,and provide scientific guidance for safe and efficient mining,the SUMMIT-II EX explosion-proof seismic slot wave instrument,produced by German DMT Company,was used to detect the underground channel wave with the help of transmission method,reflection method and transflective method.Region area detection experiment in mining face had been carried out thanks to the advantage of channel wave,such as its great dispersion,abundant geology information,strong anti-interference ability and long-distance detecting.The experimental results showed that:(1)Coal seam thickness variation in extremely unstable coal seam has been quantitatively interpreted with an accuracy of more than 80%generally;(2)The faults,goafs and collapse columns could be detected and predicted accurately;(3)Experimental detection of gas enrichment areas,stress concentration regions and water inrush risk zone has been collated;(4)A research system of disaster-causing geology anomalous body detection by in-seam seismic survey has been built,valuable and innovative achievements have been got.Series of innovation obtained for the first time in this study indicated that it was more effective to detect disaster-causing potential geology anomalies by in-seam seismic survey than by ground seismic survey.It had significant scientific value and application prospect under complex coal seam conditions.

The application of ultrasonic seismic model experiment in quality test of cement mortar injection of Yongjiang river submarine tun－nel tube foundation

Ultrasonic seismic model experiment plays an important role in engineering multi wave seismic prospecting(EMSP), which has been used to do the complex engineering seismic exploration. It is introduced that the application of the technology in quality test of Yongjiang river submarine tunnel tube foundation in the paper. The material of the model was got from on the spot. The successful test has been made with results of the model experiment.

Hydrocarbon Prospectivity and Risk Assessment of “Bob” Field Central Swamp Depobelt, Onshore Niger Delta Basin, Nigeria

This paper evaluates the hydrocarbon prospectivity and play risks of “Bob” field in Niger Delta Basin, Nigeria. The aim is to enhance exploration success through improved approach/technique by incorporating risk analysis that previous studies have not fully considered. This approach combines a set of analyses including stratigraphic/structural, amplitude, petrophysical parameter, volumetric and play risk using a suite of well logs and 3D seismic data. Maximum amplitude anomaly map extracted on the surfaces of delineated 3 reservoirs revealed 6 prospects, namely: Dippers, Cranes, Turacos, Nicators, Jacanas and Pelicans with hydrocarbon accumulation. Petrophysical analysis showed ranges of values for porosity, permeability and water saturation of 0.21 to 0.23, 158.96 to 882.39 mD, and 0.07 to 0.11, respectively. The various prospects yielded the following stock tank volumes 12.73, 6.84, 3.84, 11.32, 7.42 and 4.76 Million barrels (Mbls) each respectively in a column of 66 ft reservoir sand in the study area. Play risk analysis results gave: Pelicans and Nicators (low), Turacos and Dippers (moderate), while Jacanas and Cranes show high risk with minimal promise for good oil accumulation. The prospects possess good reservoir petrophysical properties with low to moderate risk, thus, viable for commercial hydrocarbon production, which increases confidence in management decisions for production.

Techniques for Surveying Urban Active Faults by Seismic Methods

Using the seismic method to detect active faults directly below cities is an irreplaceable prospecting technique. The seismic method can precisely determine the fault position. Seismic method itself can hardly determine the geological age of fault. However, by considering in connection with the borehole data and the standard geological cross-section of the surveyed area, the geological age of reflected wave group can be qualitatively (or semi-quantitatively) determined from the seismic depth profile. To determine the upper terminal point of active faults directly below city, it is necessary to use the high-resolution seismic reflection technique. To effectively determine the geometric feature of deep faults, especially to determine the relation between deep and shallow fracture structures, the seismic reflection method is better than the seismic refraction method.

当前研究生教学实践中存在的问题与对策——以地震波成像与反演课程为例

研究生课程教学是研究生培养的重要途径,地震波成像与反演是一门介绍地质资源与地质工程专业地震勘探理论与前沿技术进展的课程。在当前国内高校推动研究生教育迈上新台阶的背景下,该文根据近些年的教学实践,总结高校研究生课程教学中存在的一些问题,并认为提升研究生教学成效的对策主要体现在三个方面,即在教学中突出学科专业知识所蕴含的思想、精神、文化等育人元素,增强研究生课程内容的前沿性,同时还要创新教学和考核方式。

基于VMD和GA-SVM的矿井地震自适应噪声压制方法

煤矿井下地震信号往往呈现出复杂的波场特性且伴随着大量噪音干扰,导致地震信号的初至拾取精度降低,从而影响地震数据的反演与解释。针对复杂干扰环境下采集的低信噪比地震信号,提出了基于变分模态分解(VMD)和遗传算法优化支持向量机(GA-SVM)的地震噪声压制与初至提取方法,以提高煤矿井下复杂噪声条件下的地震信号质量。采用变分模态分解对含噪地震信号进行自适应分解,得到数个的变分模态分量(IMF);对VMD分解得到的IMF分量进行特征提取,将提取所得的信号特征作为信号有效性判别的依据;利用遗传算法对支持向量机模型进行优化,得到最优的惩罚因子c与核函数参数g;利用优化后的支持向量机模型对IMF分量进行有效性判别并将有效分量重构成高信噪比信号;通过对人工加噪的地震信号应用噪声压制算法,煤矿井下常见的不同类型噪声被有效地压制,验证了算法的可行性;对矿井巷道实采的地震记录进行噪声压制处理,有效地压制了数据中的干扰噪声,极大程度地提高了地震记录的信噪比,使初至拾取得更加准确。结果表明,基于VMD和GA-SVM的地震噪声压制方法可以很好地提取含噪地震记录中的有效信号,提高初至拾取精度,在矿井复杂干扰条件下具有显著的应用潜力,对解决矿井复杂干扰条件下的地震勘探问题有重要意义。

智能化地震队系统的设计及应用

针对当前地震勘探面临作业环境复杂、项目管理难度大、作业成本压力激增等难题,提出了智能化地震队系统“云边端”一体化架构解决方案,按照“一平台两体系”模式开发建设。实现了地震勘探生产智能化任务分发、生产数据智能化采集、多维度全方位生产进度统计及可视化、车辆和作业人员位置的实时监控、风险信息数据的采集加载及安全预警。该系统的推广应用,提高了地震勘探生产效率和质量,降低了生产成本,保障了作业安全。

联合VMD和Shearlet变换的去噪方法研究

地震数据中的噪声信号会很大程度上降低地震数据的信噪比,对后续的处理和解释工作造成一定的难度,因此研究一种去噪方法具有十分重要的意义。本文构建一种变分模态分解(Variational Mode Decomposition,VMD)和Shearlet变换联合去噪的方法,首先通过VMD将地震数据分解为一系列不同中心频率分布的模态分量(Intrinsic Mode Function,IMF),然后使用Shearlet变换对含噪的IMF分量进行去噪并对处理后的分量进行重构,最终达到去噪目的。该方法引入基于稀疏表示的地震数据去噪方法,兼顾VMD和Shearlet变换的优点,可以有效去除噪声。经过合成信号、模型及实际数据测试结果表明,本文方法处理合成信号结果显示,与VMD和小波变换方法相比,信噪比分别提高1.69、1.87,均方误差数值上减少近一半,在去除噪声的同时能更好地保留地震数据特征,提高地震资料的信噪比。

Present status and prospective on the seismic hazard studies of major seismic gaps in the Sichuan-Yunnan region

Several seismic gaps have been identified along the Xianshuihe-Xiaojiang fault zone and the Longmenshan fault zone in the Sichuan-Yunnan region, including the Daofu-Shimian gap on the Xianshuihe Fault, the Anninghe-Zemuhe gap, parts of the Xiaojiang Fault, and the Dayi gap between the Wenchuan and Lushan earthquakes. The seismic hazards of the Daofu-Shimian and Dayi gaps have aroused great concern and caused considerable debate. This paper reviews the recent geophysical observations and multidisciplinary studies conducted by domestic and international researchers in these areas, focusing on seismogenic structures, seismic activity, fault locking, stress fields, as well as earthquake triggering, and further analyzes the current controversial viewpoints about the seismic hazards in these regions. Based on the comprehensive analysis, we argue that the kinematic status along the Daofu-Shimian segment may vary significantly along the fault strike. Due to limitations in data and models, there is no consensus on the seismogenic potential of this area. Conversely, the Dayi seismic gap presents a high seismic potential. Furthermore, we delve into the scientific problems associated with major seismic gaps in the Sichuan-Yunnan region and make prospects for the strategy of future work. We propose a research framework that combines dense array and distributed acoustic sensing, artificial intelligence and big data technologies, joint inversion of multiple geophysical fields, as well as numerical simulation techniques for comprehensive seismic hazard analysis in seismic gaps.

鄂尔多斯盆地黄土塬三维地震勘探进展、难点及技术需求

针对黄土塬地震勘探这一世界级难题,回顾了黄土塬地震勘探历程,介绍了黄土塬地震采集、处理、解释关键技术,总结了长庆油田分公司在鄂尔多斯盆地黄土塬三维地震勘探成效和取得的主要油气勘探成果,梳理了鄂尔多斯盆地不同探区、不同类型油气藏勘探开发对黄土塬地震勘探的技术需求。长庆油田油气勘探开发实践结果表明,经过几代人50年攻关形成的黄土塬特色的“两宽一高一单点”三维地震勘探技术,有力支撑了长庆油田油气勘探重大发现、大规模增储和高效建产。下一步将以油气需求驱动为目标,瞄准三维地震“高精度、高效率、低成本、智能化”发展方向,持续攻关完善黄土塬地震技术系列,坚持原创技术引领与适用成熟技术推广结合,更有效支撑长庆油田分公司6600×10^(4) t上产稳产。

综合物探方法和检测技术在大坝渗漏检测中的应用

伪随机流场法在大坝渗漏检测中应用广泛,也取得了极为突出的效果,但单一使用该方法往往无法精准找到大坝渗漏点和渗漏通道。本文在使用伪随机流场法的基础上,结合水下机器人、钻孔全景图像、地震波CT等多种物探方法和检测技术,以实现对大坝渗漏点和渗漏通道的全面、精准检测。首先,使用伪随机流场法,圈定大坝渗漏的隐患区;其次,对已检测得的大坝水下渗漏区,使用水下机器人搭载设备进行摄影拍照、二维声纳成像、喷墨示踪剂追踪检测,确定水下大坝渗漏点;最后,在地面钻孔开展地震波CT成像和钻孔全景图像,找出大坝发育的结构面、渗漏点。本文方法应用在川西某大坝渗漏检测中,精准找到了大坝渗漏点,确定了大坝存在的多条渗漏通道,在实际应用中取得了良好的效果。该应用成果对同类大坝渗漏检测具有借鉴意义。