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| 各向同性地层地应力作用下倾斜井眼弯曲波声场特征研究———以Berea砂岩为例 |
| Investigation on the effects of stress and borehole deviation on flexural dispersions in an isotropic formation using numerical simulation: An example of Berea sandstone |
| 投稿时间：2024-07-12 修订日期：2025-01-14 |
| 中文摘要: |
| 地应力信息在油气勘探开发过程中具有重要应用价值和意义。以Berea砂岩为例，本文采用时间域三维直角坐标有限差分算法模拟了各向同性地层应力作用下井孔中正交偶极子阵列声波测井波形，利用频率域各向异性反演算法研究了井斜角对弯曲波声场特征的影响。研究结果表明，对于最大最小水平主应力作用力不相等地层，井眼倾斜程度会对井中偶极声场影响较大。对于小角度倾斜井孔，快慢弯曲波频散曲线呈交叉状态，快慢弯曲波振幅比在反演频段不连续，低频快弯曲波方位与最大水平主应力方位一致，随着井斜角逐渐增加，交叉点向低频方向移动，快慢弯曲波频散曲线之间差异逐渐减小。对于大角度倾斜井孔，与传统观点不同，快慢弯曲波频散曲线不交叉，低频快弯曲波方位与最大水平主应力方位相反，随着井斜角逐渐增加，快慢弯曲波频散曲线之间差异逐渐减小，快慢弯曲波振幅比在反演频段连续。 |
| 英文摘要: |
| In-situ stress information is very important in petroleum exploration and development. In this paper, the three-dimensional Cartesian coordinate finite difference time domain algorithm is used to simulate the cross-dipole waveforms in a borehole surrounded by the pressurized Berea sandtone, and the influence of the well inclination on the acoustic field characteristics is investigated by an anisotropy inversion algorithm in the frequency domain. The results show that for the formations where the maximum and minimum horizontal principal stresses are not equal, the well inclination has a great influence on the borehole wavefield. For the small inclined wellbore, the fast and slow flexural wave dispersion curves are crossed, the amplitude ratio of fast and slow flexural waves is not continuous in the frequency domain, the orientation of low-frequency fast flexural wave is consistent with the orientation of the maximum horizontal principal stress, and as the inclination of the well gradually increases, the crossover points move to the low-frequency, and the difference between the fast and slow flexural wave dispersion curves gradually decreases. For the large inclined wellbore, the fast and slow flexural wave dispersion curves do not cross, the orientation of the low-frequency fast flexural wave is normal to the maximum horizontal principal stress orientation, and the difference between the fast and slow flexural wave dispersion curves gradually decreases as the inclination of the well gradually increases, and the amplitude ratio of the fast and slow bending waves is continuous in the frequency domain. |
| DOI： |
| 中文关键词: 有限差分，频散曲线，地应力，声弹性理论，斜井 |
| 英文关键词: Dispersion curves, Stresses, Acoustoelastic theory, Deviated well |
| 基金项目: |
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