Automatic pickup algorithm of shale bedding based on derivative characteristics of micro resistivity curve
Received date: 2023-07-19
Online published: 2024-09-29
Copyright
Bedding is one of the most typical and important characteristics of clastic rocks, and its development density (bedding density) reflects the changes of sedimentary environment and sediment to a certain extent. Aiming at the identification of shale bedding using micro resistivity scanning logging, first, the logging response of the bedding is extracted by trend filtering. Secondly, the quantitative relationship between the bedding interface and the first and second derivative of the logging curve is established. In other words, the bedding interface usually corresponds to the "half amplitude point" of the logging curve, which is approximately represented by the extreme point of the first derivative or the zero point of the second derivative in mathematics. Then the zero search algorithm is used to automatically pick up the bedding interface and calculate the bedding density. The method in this paper is applied to the bedding evaluation of the shale gas reservoir in Longmaxi formation, south Sichuan, and the calculated results are consistent with the bedding fractures observed in the core. Meanwhile, the comparison with the organic carbon content shows that the bedding density of the "sweet spot" segment with better source rock quality shows an obvious decreasing trend, indicating the effectiveness and feasibility of the bedding parameter evaluation in the shale gas reservoir evaluation.
ChaoWei DUAN , Yun RUI , PuLi WEI , FengSheng ZHANG , YaBin YAO , YangZhi SHI , Lei WANG . Automatic pickup algorithm of shale bedding based on derivative characteristics of micro resistivity curve[J]. Progress in Geophysics, 2024 , 39(4) : 1483 -1492 . DOI: 10.6038/pg2024HH0204
图8 Y区块与D区块五峰组-龙马溪组页岩储层层理密度连井对比图BD为层理密度,1和3为沿井轴对称的两个测量极板序号. Fig 8 Comparison of bedding density of shale reservoirs in the Wufeng formation and Longmaxi formation of Y block and D block by well connection BD is the bedding density, and 1 and 3 are the two measurement plate numbers symmetrically along the well axis. |
感谢审稿专家提出的修改意见和编辑部的大力支持!
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