Fracture-cave reservoirs in carbonate rocks are characterized by a large difference in fracture and cavity size, and a sharp variation in lithology and velocity, thereby resulting in complex diffraction responses. Some small-scale fractures and caves cause weak diffraction energy and would be obscured by the continuous reflection layer in the imaging section, thereby making them difficult to identify. This paper develops a diffraction wave imaging method in the dip domain, which can improve the resolution of small-scale diffractors in the imaging section. Common imaging gathers (CIGs) in the dip domain are extracted by Gaussian beam migration. In accordance with the geometric differences of the diffraction being quasilinear and the reflection being quasiparabolic in the dip-domain CIGs, we use slope analysis technique to filter waves and use Hanning window function to improve the diffraction wave separation level. The diffraction dip-domain CIGs are stacked horizontally to obtain diffraction imaging results. Wavefield separation analysis and numerical modeling results show that the slope analysis method, together with Hanning window filtering, can better suppress noise to obtain the diffraction dip-domain CIGs, thereby improving the clarity of the diffractors in the diffraction imaging section.

中文翻译：

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基于斜率分析的倾角域中的衍射和成像衍射

碳酸盐岩中的缝洞型储层的特征是裂缝和腔体尺寸差异较大，岩性和速度变化剧烈，从而导致复杂的衍射响应。一些小规模的裂缝和溶洞会导致较弱的衍射能量，并且会被成像部分中的连续反射层遮挡，从而使其难以识别。本文提出了一种在倾角域中的衍射波成像方法，可以提高成像截面中小尺寸衍射器的分辨率。通过高斯光束偏移提取倾角域中的公共成像道集（CIG）。根据在倾斜域CIG中衍射为准线性和反射为准抛物线的几何差异，我们使用斜率分析技术对波进行滤波，并使用汉宁窗函数来提高衍射波的分离水平。水平地堆叠衍射浸入域CIG以获得衍射成像结果。波场分离分析和数值模拟结果表明，斜率分析方法结合汉宁窗滤波，可以更好地抑制噪声，获得衍射倾角域CIG，从而提高了衍射成像部分中衍射器的清晰度。