碳酸盐岩储层井旁缝洞体反射横波提取方法

反射波信息提取是横波远探测测井资料处理的基础和关键，其提取精度直接影响井外异常反射体的成像质量。传统的反射波提取方法包括F-K滤波、Radon变换等，在一定程度上忽视了复杂井况和地层条件下产生的多种噪声信号，导致反射波提取精度较低，储层测井解释存在多解性。在大量分析横波远探测测井资料声学特征的基础上，系统梳理出影响反射波提取精度的2类噪声：相干噪声和不相干噪声。前者主要包括地层界面波和多次波；后者包括低频-高频噪声和坏道。通过深入探讨这4种噪声的产生原因、特征和判识方法，形成了噪声压制方法，提出了一套反射横波提取方法。现场实例应用表明，该方法可提高反射波的提取精度，使井外缝洞偏移图像更为清晰。这一研究可为油气层勘探和工程改造提供重要技术支撑。

Extraction method of reflected S-wave near borehole in carbonate fracture-cavity reservoirs

The extraction of reflected waves is a basic and key step during processing dipole acoustic reflection imaging data, and the extraction accuracy directly affects the imaging quality of near-borehole acoustical reflectors. The conventional extraction methods such as F-K filtering and Radon transformation generally ignore the noises generated under complex well and formation conditions, thus causing low extraction accuracy of reflectors and multi-solution of reservoir logging interpretation. Through analyzing the wave field characteristics of a large number of acoustic well logging data, this paper systematically determine two types of noises that affect the extraction accuracy of reflected waves:coherent noises and incoherent noises. The former mainly include formation interface wave and multiple wave, and the latter mainly include low- and high-frequency noise and bad channel. Through further research of the generation mechanisms, features, and identification methods of four kinds of noises, the noise suppression methods are developed, and S-wave reflected wave extraction method is proposed. Field application results indicate that the above method improves the extraction accuracy of reflected waves, makes the migration imaging of fractures and caves outside the borehole much clearer. This study can provide important technical support for oil-gas reservoir exploration and development.