首页|基于语义分割的测井地层对比算法研究

基于语义分割的测井地层对比算法研究

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测井曲线可以从不同侧面反映地层岩层的属性变化,常用于地层的划分与对比.鉴于深度学习强大的特征提取能力,有学者不断将其应用到测井地层对比任务中来.然而,现有的深度学习算法不能很好地捕获曲线在层位边界的特征变化,此外,数据不平衡的情况下,神经网络难以拟合独热编码的曲线分层位置,导致预测结果和实际分层位置偏差较大.针对上述问题,本文提出了基于均匀分布软标签的测井曲线地层对比算法.在训练阶段,引入标签平滑损失函数,以充分考虑数据不平衡以及由于不同层位数据之间的相似性而产生的较大损失;同时,将空间注意力机制和通道注意力机制分别引入到U2-Net的浅层和深层编码器阶段,以更好地关注分层位置的变化.在预测阶段,提出了一种置信度阈值优化算法约束分层结果,解决偶发层位重复导致的预测精度下降问题.将本文方法应用于油田实际测井数据,定量评价结果表明,在1米、2米、3米的误差范围内,测井曲线地层划分的精度可以达到87.27%、92.68%、95.08%,验证了本文算法的有效性.
Well Logging Stratigraphic Correlation Algorithm Based on Semantic Segmentation
Well logging curves serve as indicators of strata attribute changes and are frequently utilized for stratigraphic analysis and comparison.Deep learning,known for its robust feature extraction capabilities,has seen continuous adoption by scholars in the realm of well logging stratigraphic correlation tasks.Nonetheless,current deep learning algorithms often struggle to accurately capture feature changes occurring at layer boundaries within the curves.Moreover,when faced with data imbalance issues,neural networks encounter challenges in accurately modeling the one-hot encoded curve stratification positions,resulting in significant deviations between predicted and actual stratification positions.Addressing these challenges,this study proposes a novel well logging curve stratigraphic comparison algorithm based on uniformly distributed soft labels.In the training phase,a label smoothing loss function is introduced to comprehensively account for the substantial loss stemming from data imbalance and to consider the similarity between different layer data.Concurrently,spatial attention and channel attention mechanisms are incorporated into the shallow and deep encoder stages of U2-Net,respectively,to better focus on changes in stratification positions.During the prediction phase,an optimized confidence threshold algorithm is proposed to constrain stratification results and solve the problem of reduced prediction accuracy because of occasional layer repetition.The proposed method is applied to real-world well logging data in oil fields.Quantitative evaluation results demonstrate that within error ranges of 1,2,and 3 m,the accuracy of well logging curve stratigraphic division reaches 87.27%,92.68%,and 95.08%,respectively,thus validating the effectiveness of the algorithm presented in this paper.

Well logging curve stratigraphic comparisonSemantic segmentationLabel smoothingAttention mechanism

王才志、魏兴云、潘海侠、韩林枫、王浩、王洪强、赵晗

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中国石油勘探开发研究院,北京 100083

北京航空航天大学软件学院,北京 100191

测井曲线地层对比 语义分割 标签平滑 注意力机制

2024

应用地球物理(英文版)
中国地球物理学会

应用地球物理(英文版)

影响因子:1.01
ISSN:1672-7975
年,卷(期):2024.21(4)