地震油气储层的小样本卷积神经网络学习与预测   总被引：2，自引：0，他引：2       下载免费PDF全文

林年添  张栋  张凯  王守进  付超  张建彬  张冲 《地球物理学报》2018,61(10):4110-4125

地震储层预测是油气勘探的重要组成部分,但完成该项工作往往需要经历多个环节,而多工序或长周期的研究分析降低了勘探效率.基于油气藏分布规律及其在地震响应上所具有的特点,本文引入卷积神经网络深度学习方法,用于智能提取、分类并识别地震油气特征.卷积神经网络所具有的强适用性、强泛化能力,使之可以在小样本条件下,对未解释地震数据体进行全局优化提取特征并加以分类,即利用有限的已知含油气井段信息构建卷积核,以地震数据为驱动,借助卷积神经网络提取、识别蕴藏其中的地震油气特征.将本方案应用于模型数据及实际数据的验算,取得了预期效果.通过与实际钻井信息及基于多波地震数据机器学习所预测结果对比,本方案利用实际数据所演算结果与实际情况有较高的吻合度.表明本方案具有一定的可行性,为缩短相关环节的周期提供了一种新的途径.  相似文献   

Feasibility of signal enhancement with multiple grounded‐wire sources for a frequency‐domain electromagnetic survey          下载免费PDF全文

Haigen Zhou  Yao Yao  Changsheng Liu  Jun Lin  Lili Kang  Gang Li  Xinsen Zeng 《Geophysical Prospecting》2018,66(4):818-832

Frequency‐domain electromagnetic methods with a grounded‐wire source are powerful tools in geophysical exploration. However, the signal may be too weak to guarantee the quality of survey data in complex electromagnetic environments, especially when the receiver is located in the air for the newly developed grounded‐source airborne frequency‐domain electromagnetic method. In this paper, a signal enhancement method with multiple sources is proposed to solve this problem. To evaluate the signal enhancement effect, we compared the signals generated by a single source and multiple sources with equal electric moment. The signal differences caused by synchronisation error and separation distance between source elements were analysed, and the methods to achieve maximum signal were introduced. Besides, we discussed the interaction between adjacent source elements to ensure the system safety, including the changes in output current and the safe distance between two sources using a dual‐source model. Lastly, a comprehensive field experiment was designed and conducted to test the multiple‐source method. The data processing results are comparable for single and dual sources, and the signal‐to‐noise ratio of dual source is higher in the field test. The subsurface resistivity structure at the test site is consistent with the previous controlled‐source audio‐frequency magnetotellurics method. These results show that signal enhancement with multiple sources is feasible. This study provides guidance to the application of multiple sources in field surveys when the survey environment is complex and rigorous.  相似文献   

浙江象山港岛屿春、夏季潮间带大型底栖生物的群落结构特征     

刘颖  李进京  陈晨  刘懂  焦海峰  韩庆喜  王一农  尤仲杰 《海洋与湖沼》2021,52(3):685-696

基于2015年4月(春季)和6月(夏季)象山港主要岛屿潮间带大型底栖生物的生态调查数据,采用优势度、生物多样性指数、次级生产力、聚类、多维尺度排序及丰度/生物量比较曲线等方法,分析了主要岛屿潮间带大型底栖生物的群落特征和季节变化。结果表明:(1)春、夏季共鉴定出大型底栖生物52种,其中底栖动物与底栖藻类各有45和7种,春、夏季共有物种数为34种,短滨螺、中间拟滨螺、齿纹蜒螺、青蚶等11种为春、夏季共有优势种;(2)夏季平均丰度(2074.85g/m~2)高于春季(1505.01g/m~2),春季平均生物量和次级生产力(2373.75ind./m~2,16.31g/(m~2·a))高于夏季(2210.17ind./m~2,12.17g/(m~2·a));(3)春季Shannon-Weiner多样性指数和Pielou’sevenness均匀度指数(2.742,1.679)高于夏季(2.580, 1.623),夏季Margalef丰富度指数(0.716)高于春季(0.667);(4)熊本牡蛎、黑荞麦蛤、日本菊花螺等是引起春、夏季港口区(外干门岛、野龙山岛、大列山岛和小列山岛)和港中区(缸山岛、双德山岛、悬山岛、白石山岛和中央山岛)岛屿潮间带底栖生物群落结构差异的主要贡献种;春、夏季大型底栖生物群落结构受到人类活动和自然环境变化所引起的中度扰动,且港口区岛屿所受的扰动程度高于港中区。本研究可为象山港潮间带生物资源的保护和可持续利用以及港中区白石山人工渔礁区海洋牧场建设提供重要参考依据。  相似文献   

几种典型近地表有限导体瞬变电磁特征响应研究          下载免费PDF全文

陈曙东  郭树旭  张爽  袁志文  朱俊  张海洋  方东 《地球物理学报》2017,60(1):403-412

近地表有限导体的瞬变电磁响应中包含其形状、结构特征,如何建立这些特征与其响应之间的关系是近地表有限导体探测与识别的核心问题.本文建立了几种典型有限导体响应的三维感应偶极子模型,通过有限导体早期幂函数衰减的幅度与速率、晚期指数衰减的幅度与时间常数共四个模型参数表征有限导体的形状和结构特征,利用最小二乘拟合算法提取这些模型参数,揭示有限导体的形状、结构特征与模型参数之间的内在联系.理论与实验研究结果表明:具有绕球心旋转对称性的球形目标体,其三维感应偶极子响应完全相同,早期响应呈幂函数衰减,晚期呈e指数衰减,信号幅度和时间常数均能很好反映球体半径与材料特性;具有绕轴旋转对称性目标体,其三维感应偶极子响应部分相同,早期幂函数衰减的幅度与速率主要体现目标体的长度特征,晚期e指数衰减的时间常数体现了目标体的外径与壁厚特征;非轴对称性目标体,其三维感应偶极子响应均不相同,各个感应偶极子参数差异较大.本文的研究对提高瞬变电磁系统区分轴对称目标体与金属碎片能力,降低系统探测虚警率具有重要意义.  相似文献   

Frequency‐domain waveform modelling and inversion for coupled media using a symmetric impedance matrix          下载免费PDF全文

Jungkyun Shin  Hyunggu Jun  Dong‐Joo Min  Changsoo Shin 《Geophysical Prospecting》2017,65(1):170-183

To simulate the seismic signals that are obtained in a marine environment, a coupled system of both acoustic and elastic wave equations is solved. The acoustic wave equation for the fluid region simulates the pressure field while minimizing the number of degrees of freedom of the impedance matrix, and the elastic wave equation for the solid region simulates several elastic events, such as shear waves and surface waves. Moreover, by combining this coupled approach with the waveform inversion technique, the elastic properties of the earth can be inverted using the pressure data obtained from the acoustic region. However, in contrast to the pure acoustic and elastic cases, the complex impedance matrix for the coupled media does not have a symmetric form because of the boundary (continuity) condition at the interface between the acoustic and elastic elements. In this study, we propose a manipulation scheme that makes the complex impedance matrix for acoustic–elastic coupled media to take a symmetric form. Using the proposed symmetric matrix, forward and backward wavefields are identical to those generated by the conventional approach; thus, we do not lose any accuracy in the waveform inversion results. However, to solve the modified symmetric matrix, LDLT factorization is used instead of LU factorization for a matrix of the same size; this method can mitigate issues related to severe memory insufficiency and long computation times, particularly for large‐scale problems.  相似文献   

晚更新世以来台湾浅滩西北近岸沉积特征与古环境演化     

赵东波  孙荣涛  蒋恒毅  李董 《海洋地质与第四纪地质》2021,41(2):53-63

对取自台湾浅滩西北部福建东山岛外的浅钻ZK2孔进行了包括AMS14C测年、粒度、微体古生物、碎屑矿物和黏土矿物等分析。结果表明该孔地层中存在两个明显的海相层和其间的两个陆相层,顶部的海相层为全新世高海平面以来形成的被现代潮流作用改造的现代沉积和残留沉积混合体;底部陆相层为MIS4期低海平面时期形成的河流沉积;中间的细粒沉积层又可划分为下部形成于MIS3期的以潟湖、潮坪和盐沼交替出现的海相沉积层,以及上部形成于MIS3期末到盛冰期出露水面之前的陆上沟谷充填沉积;台湾海峡南部在MIS3期之后发生了明显的构造沉降过程,但是在末次盛冰期海峡南部仍然出露水面之上形成了沉积间断面。本文研究内容为今后在台湾浅滩西北边缘到福建东南近岸区深入开展沉积学、地层学及古环境演化研究提供了新的参考。  相似文献   

Effect of compressive strength on the performance of the NEMO-LIM model in Arctic Sea ice simulation     

Dong  Chunming  Luo  Xiaofan  Nie  Hongtao  Zhao  Wei  Wei  Hao 《中国海洋湖沼学报》2023,41(1):1-16

Satellite records show that the extent and thickness of sea ice in the Arctic Ocean have significantly decreased since the early 1970s. The prediction of sea ice is highly important, but accurate simulation of sea ice variations remains highly challenging. For improving model performance, sensitivity experiments were conducted using the coupled ocean and sea ice model (NEMO-LIM), and the simulation results were compared against satellite observations. Moreover, the contribution ratios of dynamic and thermodynamic processes to sea ice variations were analyzed. The results show that the performance of the model in reconstructing the spatial distribution of Arctic sea ice is highly sensitive to ice strength decay constant (C^rhg). By reducing the C^rhg constant, the sea ice compressive strength increases, leading to improved simulated sea ice states. The contribution of thermodynamic processes to sea ice melting was reduced due to less deformation and fracture of sea ice with increased compressive strength. Meanwhile, dynamic processes constrained more sea ice to the central Arctic Ocean and contributed to the increases in ice concentration, reducing the simulation bias in the central Arctic Ocean in summer. The root mean square error (RMSE) between modeled and the CryoSat-2/SMOS satellite observed ice thickness was reduced in the compressive strength-enhanced model solution. The ice thickness, especially of multiyear thick ice, was also reduced and matched with the satellite observation better in the freezing season. These provide an essential foundation on exploring the response of the marine ecosystem and biogeochemical cycling to sea ice changes.

  相似文献   

Numerical Analysis of Groundwater Ridging Processes Considering Water‐Air Flow in a Hillslope          下载免费PDF全文

Yong Ge Zang  Dong Mei Sun  Ping Feng  Stephan Semprich 《Ground water》2018,56(4):594-609

In this study, a water‐air two‐phase flow model was employed to investigate the formation, extension, and dissipation of groundwater ridging induced by recharge events in a hypothetical hillslope‐riparian zone, considering interactions between the liquid and gas phases in soil voids. The simulation results show that, after a rain begins, the groundwater table near the stream is elevated instantaneously and significantly, thereby generating a pressure gradient driving water toward both the stream (the discharge of groundwater to the stream) and upslope (the extension of groundwater ridging into upslope). Meanwhile, the airflow upslope triggered by the advancing wetting front moves downward gradually. Therefore, the extension of groundwater ridging into upslope and the downward airflow interact within a certain region. After the rain stops, groundwater ridging near the stream declines quickly while the airflow in the lower part of upslope is still moving into the hillslope. Thus, the airflow upslope mitigates the dissipation of groundwater ridging. Additionally, the development of groundwater ridging under different conditions, including rain intensity, intrinsic permeability, capillary fringe height, and initial groundwater table, was analyzed. Changes in intrinsic permeability affect the magnitude of groundwater ridging near the stream, as well as the downward speed of airflow, thereby generating highly complex responses. The capillary fringe is not a controlling factor but an influence factor on the formation of groundwater ridging, which is mainly related to the antecedent moisture. It was demonstrated that groundwater ridging also occurs where an unsaturated zone occurs above the capillary fringe with a subsurface lateral flow.  相似文献   

震后建筑进度BIM估计模型改进   总被引：1，自引：0，他引：1       下载免费PDF全文

武炜  崔邯龙  张丽丽 《地震工程学报》2018,40(4):841-847

传统震后建筑进度BIM估计模型,未考虑精益管理对建筑施工的影响,造成建筑成本浪费较多,影响后期建筑施工进度。本文构建基于BIM和精益管理的震后建筑进度评估模型,根据模型细分震后建筑进度评估过程,在此基础上根据BIM实施三维算量,采用进度计划编制子模型获取各分项工程量,确定建筑施工的主要进度计划,实现对建筑进度计划的编制;通过虚拟施工和现实施工两条主线,利用进度控制子模型实现对施工状态的模拟和精益管理。以此为基础,进行挣值分析比较计划施工成本、实际施工成本和挣值曲线,获取震后建筑的施工进度与成本情况。实验结果说明,本文构建的模型可对震后建筑进度和工程成本进行精准估计,能够减少成本浪费。  相似文献   

强震临震微波动现象初步研究(二)   总被引：1，自引：0，他引：1  

杨立明  郝臻  王建军  张淑珍  姚家俊  董蕾 《中国地震》2018,34(2):234-243

为了验证和检验强震临震微波动现象及其主要特征,利用甘、青、川、滇、藏等区域台网200余个宽频带数字地震台站的波形资料,建立了实时监控技术系统。通过对2012~2014年间青藏块体发生的24次5级以上地震及部分无震区域台站观测的全程实时跟踪、动态监控,检验和验证了临震微波动现象的重现性和客观性,验证了临震微波动现象的频谱、时间、空间、方向性等特征,进一步得出了临震微波动现象可能与地震强度有关,且震级越大,震前出现持续临震微波动的可能性越大的结论。  相似文献