Graded and Quantitative Technology and Application of Coal-Bearing Reservoir Based on Seismic Reflection Characteristics

Taiyuan formation is the main exploration strata in Ordos Basin, and coals are widely developed. Due to the interference of strong reflection of coals, we cannot completely identify the effective reservoir information of coal-bearing reservoir on seismic data. Previous researchers have studied the reservoir by stripping or weakening the strong reflection, but it is difficult to determine the effectiveness of the remaining reflection seismic data. In this paper, through the establishment of 2D forward model of coal-bearing strata, the corresponding geophysical characteristics of different reflection types of coal-bearing strata are analyzed, and then the favorable sedimentary facies zones for reservoir development are predicted. On this basis, combined with seismic properties, the coal-bearing reservoir is quantitatively characterized by seismic inversion. The above research shows that the Taiyuan formation in LS block of Ordos Basin is affected by coals and forms three or two peaks in different locations. The reservoir plane sedimentary facies zone is effectively characterized by seismic reflection structure. Based on the characteristics of sedimentary facies belt and petrophysical analysis, the reservoir is semi quantitatively characterized by attribute analysis and waveform indication, and quantitatively characterized by pre stack geostatistical inversion. Based on the forward analysis of coal measure strata, this technology characterizes the reservoir facies belt through seismic reflection characteristics, and describes coal measure reservoirs step by step. It effectively guides the exploration of LS block in Ordos Basin, and has achieved good practical application effect.

Time-domain characteristics of overlying strata failure under condition of longwall ascending mining

Ascending mining is one of the most effective ways to solve problems of water inrush, gas outburst and rock burst in coal seams mining. In order to reveal the law of motion and spatiotemporal relationship of overlaying strata, field measurement has been done in a mine. Long distance drillings were constructed from 4# coal seam to 6# coal seam at several certain typical positions, and movement and failure law of overlying strata after mining was analyzed by drilling video and observing the fluid leakage. Besides, we also analyzed the spatiotemporal development law of overlying strata failure with different mining heights and time intervals in the lower coal seam. The results show that: ascending mining is significantly affected by time-domain characteristics of overlaying strata failure after the lower coal seam's mining, height equations of caving zone and fractured zone are given in this paper, and the feasibility of ascending mining was compartmentalized concretely according to the spatiotemporal relationship. Research methods and conclusions of this paper have certain referential significance for the study of ascending mining, mining under water, mining under building, mining under railway and stress-relief mining.

Suppression of Pulse Interference in Partial Discharge Measurement Based on Phase Correlation and Waveform Characteristics

Partial discharge measurement is one of the most effective methods to find insulation defects and early failure of high voltage power equipments. The accuracy is significantly reduced by the interference in the partial discharge on-site detection or on-line monitoring, especially by the pulse interference. This paper studies the phase correlation of some types of typical partial discharge pulses and their characteristics in time domain and frequency domain. By collecting enough partial discharge pulse data, the correlation coefficient can be calculated based on both phase correlation and waveform similarity. The type of pulse will be determined by the scope of the calculated correlation coefficient. The pulses with very strong correlation will be identified as periodic pulse interference. The pulses with very weak correlation will be identified as random pulse interference. Only the pulses whose correlation coefficients fall into a specific range will be identified as partial discharge signals. In laboratory, simulated pulse interference is injected into measurement circuit, and typical partial discharge pulses are sampled by a high-speed acquisition system. The pulse interference can be effectively separated from partial discharge signals by correlation coefficient.

FAST COMPUTATION OF WIDEBAND RCS USING CHARACTERISTIC BASIS FUNCTION METHOD AND ASYMPTOTIC WAVEFORM EVALUATION TECHNIQUE

The Asymptotic Waveform Evaluation (AWE) technique is an extrapolation method that provides a reduced-order model of linear system and has already been successfully used to analyze wideband electromagnetic scattering problems. As the number of unknowns increases, the size of Method Of Moments (MOM) impedance matrix grows very rapidly, so it is a prohibitive task for the computation of wideband Radar Cross Section (RCS) from electrically large object or multi-objects using the traditional AWE technique that needs to solve directly matrix inversion. In this paper, an AWE technique based on the Characteristic Basis Function (CBF) method, which can reduce the matrix size to a manageable size for direct matrix inversion, is proposed to analyze electromagnetic scattering from multi-objects over a given frequency band. Numerical examples are presented to il-lustrate the computational accuracy and efficiency of the proposed method.

Variable Rate Characteristic Waveform Interpolation Speech Coder Based on Phonetic Classification

A variable-bit-rate characteristic waveform interpolation （VBR-CWI） speech codec with about 1.8 kbit/s average bit rate which integrates phonetic classification into characteristic waveform （CW） decomposition is proposed. Each input frame is classified into one of 4 phonetic classes. Non-speech frames are represented with Bark-band noise model. The extracted CWs become rapidly evolving waveforms （REWs） or slowly evolving waveforms （SEWs） in the cases of unvoiced or stationary voiced frames respectively, while mixed voiced frames use the same CW decomposition as that in the conventional CWI. Experimental results show that the proposed codec can eliminate most buzzy and noisy artifacts existing in the fixed-bit-rate characteristic waveform interpolation （FBR-CWI） speech codec, the average bit rate can be much lower, and its reconstructed speech quality is much better than FS 1 016 CELP at 4.8 kbit/s and similar to G. 723.1 ACELP at 5.3 kbit/s.

考虑PWM波形特征的纳米晶磁心损耗模型的研究及验证

磁心损耗精确预测对于电力电子变压器的优化设计至关重要。然而,传统的磁心损耗模型在复杂激励下适用性较差,尤其对于占空比可调、高次谐波含量丰富的PWM波磁心损耗预测,计算精度显著下降。基于Jordan损耗分离模型,建立了一种考虑PWM波形特征的磁心损耗计算方法。首先,该方法根据激励波形特征,推导出相应的波形系数及等效频率来计算PWM波激励下的动态涡流损耗,将Jordan模型的适用范围从正弦拓展到PWM波激励下的磁心损耗计算;然后,分析了不同占空比激励下激励波形有效频率及高次谐波含量变化对损耗系数的影响,并对其进行数学表征,实现了整个占空比范围内磁心损耗的精确预测;最后,搭建了高频非正弦激励下软磁材料磁特性测量平台,针对1K107B纳米晶材料,测量了两种典型PWM波激励下的损耗数据。实验结果表明,所建立的磁心损耗模型具有较高的计算精度,相比于传统的Steinmetz改进公式,整体精度提高了25%。

10 kV电缆中间接头绝缘用硅橡胶内部典型缺陷的超声信号表征方法

电缆中间接头的绝缘状态对电缆安全稳定运行起重要作用。针对太赫兹成像技术的不成熟和有限元分析法的局限性,本文提出一种电缆附件硅橡胶内部典型缺陷的超声信号表征方法。首先通过仿真设计硅橡胶中不同类型的典型缺陷,然后对超声检测仿真中接收的反射回波进行时域特征量和相关性分析,得到时域波形特征量与缺陷尺寸、角度的相关系数。最后基于脉冲回波法搭建超声试验平台,对含缺陷的平板硅橡胶样品进行超声检测试验。结果表明:硅橡胶内部缺陷的尺寸、角度与一次回波的振幅峰值具有良好的相关性,且相较于气泡类缺陷,裂纹类缺陷检测结果受缺陷角度的影响更大,不同角度缺陷的振幅峰值差异较大。说明超声信号可以有效表征电缆附件硅橡胶内部典型缺陷。

初相捷变波形优化设计与信号处理方法研究

捷变波形具备一定的距离和速度模糊抑制能力,同时兼具优良的低截获和抗干扰性能,为雷达系统提供了新的信号处理维度。初相捷变波形相对简单,工程实现难度小,为实现波形设计和信号处理闭环,本文开展了初相捷变波形优化设计与信号处理方法研究。首先,介绍了初相捷变波形的距离选通特性,进而构建了基于距离选通特性的初相捷变波形优化设计模型,并通过Majorization-Minimization算法和牛顿法进行求解。所提算法可采用平方迭代法加快收敛速度,经仿真验证,与随机产生的初相捷变波形相比,所提算法可以显著改善优化后初相捷变波形的距离选通特性。其次,基于初相捷变波形的抗折叠杂波性能,探讨了基于距离选通特性的自适应杂波抑制算法,即利用初相捷变波形空时维导向矢量的距离选通特点,实现分距离段杂波抑制,使得近距主副瓣杂波不会折叠到远距离段,经仿真与实测数据验证,所提算法在强杂波环境下具备良好的远距低速目标探测能力。最后,研究了基于距离选通和交替反演的干扰抑制算法,利用远距支援干扰滞后于目标回波的特点,并基于初相捷变波形的距离选通特性,通过距离段间交替投影实现干扰与目标回波的分距离段重构,经仿真验证,所提算法可以实现对远距支援干扰的有效抑制。

板桥地区中浅层辫状河沉积储层预测研究

板南中浅层馆陶组油藏具有油层单一、底水发育的特点,准确刻画油层的位置、油层上下隔夹层的分布是有效开发的关键。通过开展沉积储层研究,认为板南馆陶组为辫状河沉积体系,主要发育心滩、辫状水道、水道间、泛滥平原泥4个微相。储层属高孔高渗储层,非均质性较强,油层分布比较稳定。分析认为常规反演方法分辨率较低,无法有效识别单砂体;而地震波形指示反演在单砂体的识别能力上具有明显的优势,可以满足水平井部署的需要。以储层反演成果为基础,完成油藏工程方案及实钻动态跟踪,并取得良好效果,证明了储层反演方法的可靠性。

基于超声反射法的环氧树脂复合材料内部缺陷检测与频谱分析研究

纤维增强树脂基复合材料被广泛地应用在电力设备中,其涉及多层介质,结构复杂,内部易产生缺陷,在长期电场作用下会引发局部放电甚至绝缘击穿。对绝缘内部缺陷进行早期检测,可以有效减少事故的发生。本文基于超声反射法搭建了复合材料超声检测系统,基于真空树脂传递模塑法人工制备了含裂纹、分层和金属杂质缺陷的玻璃纤维增强环氧树脂复合材料平板试样,然后分别对含缺陷的平板试样进行超声检测与频谱分析。结果表明:不同种类缺陷试样的超声反射波形存在明显差异。通过对超声回波进行频谱变换,得出归一化频谱特性曲线,根据曲线计算特征值可以实现对不同形态缺陷的识别。其中裂纹缺陷试样的特征值最小,分层缺陷试样的特征值最大。

变电站隔离开关操作产生的电磁暂态特征量研究

变电站隔离开关操作产生的电磁骚扰是电力系统二次设备防护的重要内容。基于真型实验场开展了一系列实验,在AIS和GIS内进行了一系列不同电压等级不同容性负载的隔离开关分合闸重复实验。由于隔离开关操作持续时间长,采样率高,采集得到的实测数据十分庞大,为了方便处理实测数据,设计了一种自动计算的模型既能实现隔离开关全过程多次放电脉冲群的特征量提取,也能实现单次击穿波形的分离和计算。计算结果显示AIS隔离开关操作产生的电磁骚扰主频在300~600 kHz,有些文献中测量结果高达几MHz,GIS产生的电磁骚扰在17~20 MHz。暂态电流及其耦合的电磁骚扰主频仅受变电站结构和参数影响,相同实验条件下GIS产生的地电波比AIS幅值更高主频更大振荡更强烈。该实验结果为电力系统开展针对二次设备的电磁防护试验提供了量化参数。

电压电流能量信息融合的低压交流电弧故障检测

针对串联电弧故障检测判据选择难、阈值设置难的问题,本文在传统基于电流检测方法的基础上融合使用电压信息,提出了一种电压电流能量信息融合的交流电弧故障检测方法。以分析开关电源和非开关电源类负荷下的各自故障特征为基础,提出了利用电压半波总能量的开关电源类电弧故障直接判定方法,并融合使用电压电流特征能量波形相关性实现故障线路的选择;提出了基于敏感域电压电流最大瞬时特征能量相位匹配的适用于非开关电源类负荷下的故障检测方法,以特征能量相位信息构建判据,克服了传统检测方法的阈值设定困难问题。本文检测方法判据虽利用了负荷分类思想,但由于开关电源类负荷下的故障检测可利用电压半波总能量幅值实现故障直接判定,因此实际应用中无需辨识负荷类型。相较传统利用电流特征的检测方法,本文方法具有判据简单、易于阈值设定的优势。试验结果表明,本文方法可有效用于多种类型负荷的电弧故障检测,检测时间满足相关标准规定。

基于非均匀间隔采样的光幕过靶信号波形获取

为确保光幕阵列的测量精度,提出一种基于非均匀采样的过靶信号波形获取方法。首先分析光幕过靶弹丸信号特性,得出该信号具有瞬态性、非周期性、大频带宽等特性;其次,对非均匀分数采样原理进行阐述;再次,设计相应信号采集系统并介绍系统组成及其工作原理;最后,通过试验验证与传统方法相比,系统测量精度满足要求,同时可降低测量成本。

直流充电桩快速变化的电流和电压波形模态特性分析

针对电动汽车充电桩输出电流和电压呈现出“随机性、波动性、时变性”的快速变化特性,引发电能计量较大超差问题,文章建立充电桩快速变化直流电流和电压的随机信号数学模型及其时频域表征模型;提出快速变化波形模态提取方法,提取了6类12种快速变化直流波形模态,提出并构建了幅度域8个特征参量数学模型,表征影响电能计量的电流和电压特征;提取了典型特征参量数值和重要特性,该特征参量数值和特性可为制定直流电能表动态误差的测试评价试验条件提供理论依据。

新疆乌鲁木齐及周边地区非天然地震特征与识别

选取2017—2023年M L2.4~3.8新疆地震台网记录的20个爆破、5个塌陷、25个地震事件,采用波形记录特征、垂直向P波初动方向、振幅比、时频分析方法开展非天然地震特征研究。分析结果表明,非天然地震和天然地震在时域和频域方面存在明显不同,爆破事件垂直向P波向上发育、周期小、S波的振幅和周期变化不明显、容易与面波混淆;塌陷事件垂直向P波向下、P波S波成组出现且接近、波形较爆破简单;两者震动衰减较快,面波发育。爆破Pc/Sm的值大于0.42、地震小于0.42、塌陷Pc/Sm的值大于0.62。爆破Pm/Sm的值大于0.70、地震小于0.70、集中在0.40左右、塌陷Pm/Sm的值在0.55左右;时频分析方面爆破和塌陷频率成分简单,能量峰值在4 Hz以下,频域较窄,以低频面波为主,衰减较快,呈现出“少峰”特征。地震频率成分复杂,分布在4~16 Hz之间,频域较宽,主频不固定,呈现“多峰”特征,能量分布在S波。以上识别判据为今后区分研究区内非天然地震特征提供有效参考。

基于地震波形驱动层序格架建立及页岩岩相特征研究--以松辽盆地古龙页岩油5号试验区为例

松辽盆地古龙凹陷页岩油具有良好的富集条件和勘探开发潜力,已开展规模开发试验。目前,青山口组内部的细分层序地层研究还不够深入,影响古龙页岩油地质综合研究、甜点预测及部署。以松辽盆地古龙页岩油5号试验区为例,以地震层序地层学理论为指导,针对页岩型页岩油横向沉积相对稳定的特点,采用各向异性扩散滤波、层序识别与选取等手段,地震处理、解释及地质结合,使得地震波形可指示地质层位,形成基于地震波形驱动的层序格架建立技术。该技术实现了地震波形向沉积地层地质含义的快速转化,在研究区青山口组识别出1个二级、1个三级及8个四级层序界面,划分为Q1—Q9共9个小层,分析了各小层的格架特征,为页岩油岩相和甜点精细预测奠定基础。基于细分层地层格架,通过分析TOC、沉积构造、矿物成分、页理密度4个评价参数,建立了古龙页岩油页岩型岩相划分标准,划分为10类亚相。以研究区Q1—Q4小层为例,页岩岩相划分为3类亚相,描述了其平面分布特征。基于以上研究,结合含油性、脆性及物性等6个页岩油甜点参数的预测成果,在5号试验区优化布井11口,单井平均日产油在10t以上,有效支撑了松辽盆地古龙页岩油的效益勘探开发。

Transmission cable fault detector based on waveform reconstruction

In order to improve the accuracy of cable fault position location at a low cost and make the testing results intuitive, a cable fault detector based on wave form reconstruction is designed. In this detector, the cable fault position is located based on the time-domain pulse reflection （TDR） principle. A pulse waveform is injected in the tested cable, and a high-speed comparator with changeable reference voltages is used to binarize the test pulse waveform to a binary sequence on a certain voltage. Through scanning the reference voltage in a full voltage range, multi-sequences are acquired to reconstruct the pulse waveform transmission in the cable, and then the pulse attenuation feature, electrical open circuit fault, electrical short circuit fault, and the fault position of the cable are diagnosed. Experimental results show that the designed cable fault detector can determine the fault type and its position of the cable being tested, and the testing results are intuitive.

计及燃弧频次的配电网单相接地故障分类与辨识

尽管采用小电流接地方式的配电网发生单相接地故障时短路电流较小,但若故障发生后燃弧现象长时间存在,将会显著增加火灾发生风险。为减小火灾隐患,已有多数研究从燃弧现象发生与否角度对故障进行辨识,但并未计及燃弧频次的影响。为此,针对某地配电网实际单相接地故障案例,通过系统分析不同故障场景下零序电流变化特性与燃弧之间的关联规律,从火灾隐患程度角度提出了计及燃弧频次的单相接地故障分类方法;进一步挖掘出不同种类故障发生后零序电流波形分别呈现“平肩畸变”、“瞬态值”等特征,并利用不同频带能量占比、谐波重心和燃弧周期数对波形畸变特征进行了数学描述;以前述数学特征量作为输入,研究建立了基于长短期记忆(long short-term memory, LSTM)网络的故障种类辨识模型,经某电力公司现场收集的223组现场典型故障案例验证,模型识别准确率达96.4%,可有效识别燃弧故障种类,对于减小森林火灾隐患、节约配电网运维成本意义重大。

基于脉间码型捷变波形的距离-多普勒二维干扰重构算法

密集假目标干扰通过在真实目标周围产生大量假目标,形成欺骗和压制双重干扰效果,严重影响雷达的目标探测能力。为此,该文提出一种基于脉间码型捷变波形的距离-多普勒二维干扰重构算法来抑制密集假目标干扰。该算法基于脉间码型捷变波形的距离选通性,在距离-多普勒域通过交替反演实现干扰和目标重构,并从回波中对消干扰来实现干扰剔除。首先,通过构造不同距离段的接收滤波器组来实现干扰和目标回波的分距离段处理;其次,采用联合失配滤波器组使各脉冲滤波输出的距离旁瓣结构近似相同,减小脉间码型捷变波形经脉冲多普勒处理后沿多普勒维的散布能量;然后,利用干扰和目标回波在不同距离-多普勒平面上的能量分布特性构造滤波矩阵;最后,通过交替反演实现干扰和目标的精准重构,进而实现密集假目标干扰的抑制。仿真结果表明,与传统方法相比,该文所提算法在干扰抑制和运行时间方面展现出优越的性能,显著提升了雷达在强干扰环境中的目标检测能力。

大同煤田矿区微震记录特征与识别方法研究

为了更好地了解大同煤田矿震的特点,以山西矿震监测研究中心在山西北部设立的矿震监测研究试验区,以及山西地震监测台网在大同煤田及周边区域持续开展的近3年(2021年1月至2023年9月)的非天然地震监测所获取的数据为基础,进行大同煤田矿震记录特征与识别方法研究。结果表明:大同煤田及周边区域矿震活动发生较频繁,活动特征以M_(L)<2.0的微震或小震为主,最大矿震震级为M_(L)=2.8级;具有空间上集中分布的特征,主要集中在煤矿开采区域,特别是深部矿井附近;相比于天然地震和其他非天然地震事件,矿震震相中往往含有较多高频部分,其优势频率一般在10 Hz以上,但易受震源与传播路径(距离和介质)衰减影响;波形记录形态上往往表现为波形的快速上升和迅速衰减,波形持续时间较短;初动向上和向下都有,当记录台站较多时有四象限分布特征。