Application of multi-wavelet frequency division inversion technology in shale
Received date: 2024-05-13
Online published: 2025-01-14
Copyright
The shale gas exploration in Zhongmu area has a good prospect.However, the shale reservoirs in this area have the characteristics of strong heterogeneity, complex spatial distribution and vertical superposition.Due to the low accuracy of common inversion methods for thin reservoir lithology identification, the lithology identification problem in this area cannot be solved.Therefore, under the framework of frequency division inversion theory, this paper adds full-band information and explores a multi-wavelet frequency division inversion technique based on thin reservoir identification.Firstly, based on the theory of harmonic frequency extraction, the harmonic frequency extraction data is obtained, and the effect before and after denoising is compared. Secondly, the matching pursuit method is used to calculate the frequency division, and the high-precision frequency division data volume is obtained, which provides an important data basis for the subsequent heterogeneous characterization of thin reservoirs. The P-wave impedance-uranium-free gamma curve is reconstructed by rock physics relationship analysis to better distinguish shale. The low-frequency model obtained by Kriging interpolation algorithm, the medium-frequency model obtained by spectral inversion algorithm and the random high-frequency model based on wells are processed by frequency-division fusion, and a multi-scale fusion model suitable for thin reservoirs is established. Finally, the multi-wavelet frequency division inversion based on the constraint of reconstructed logging curve is carried out, and the effective identification of thin reservoirs is realized.The advantage of this method is that it can obtain a more accurate initial fusion model, highlighting the multi-wavelet and full-band information.
Cong LI , Dong ZHANG , QingSong YUAN , XinYuan ZHANG , ZhongMing LI , QingLun QIU , GuoGuo DONG , ZhiXun LI , Lei DAI , Tong JIAO . Application of multi-wavelet frequency division inversion technology in shale[J]. Progress in Geophysics, 2024 , 39(6) : 2306 -2317 . DOI: 10.6038/pg2024II0207
表1 不同尺度的模型计算方法Table 1 Model calculation methods of different scales |
| 频段 | 频率/Hz | 沉积旋回 | 计算方法 |
| 低频 | 3~10 | 长旋回地层 | 井插值 |
| 中频 | 10~40 | 中长旋回地层 | 谱反演 |
| 高频 | 40~80 | 短旋回地层 | 随机高频插值 |
图7 基于匹配追踪的分频剖面(a)15 Hz分频处理剖面;(b)27 Hz分频处理剖面;(c)39 Hz分频处理剖面;(d)52 Hz分频处理剖面. Fig 7 Frequency-division profile based on matching pursuit (a) 15 Hz frequency division processing profile; (b) 27 Hz frequency division processing profile; (c) 39 Hz frequency division processing profile; (d) 52 Hz frequency division processing profile. |
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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