Abstract: There are some problems in the prediction of fractured-vuggy reservoirs of granite bedrock buried hills, such as low imaging precision, strong multi-solutions and low resolution of fracture prediction results, and weak seismic response of caves, thus restricting the exploration efficiency of internal oil and gas reservoirs. Taking Baobab buried hill in Bongor Basin, Chad as an example and based on the depth migration processing method of full-azimuth local angle domain, angle domain decomposition and imaging was applied to obtain the true angle domain information of the formation, and the full-azimuth common reflection angle gathers and full-azimuth common dip angle gathers were extracted to improve the imaging precision of buried hills and the prediction accuracy of fractures and caves. Guided by the geological development mode of fractured-vuggy reservoirs of the buried hills, the fracture development intensity of Baobab buried hill was predicted using full-azimuth common reflection angle gathers, thus effectively improving the fracture prediction precision and reducing the multi-solutions for fracture prediction. Scattering imaging processing of full-azimuth common dip angle gathers can strengthen the geometrical characteristics beyond seismic resolution, highlight the discontinuity of small-scale geological bodies, and clearly identify karst caves on the seismic sections. The research method has achieved a good prediction result in Baobab buried hill and has certain application prospect and promotion significance in the fractured-vuggy reservoirs of granite bedrock buried hills.

Key words: full-azimuth angle domain imaging, scattering imaging, cave, fracture prediction, bedrock buried hill

摘要： 花岗岩基岩潜山缝洞型储层的预测存在成像精度低、裂缝预测结果多解性强且分辨率低、洞穴地震响应弱等问题，制约了其内部油气藏的勘探效率。以乍得Bongor盆地Baobab潜山为例，基于全方位局部角度域深度偏移处理方法，应用角度域分解与成像，获取地层真实角度域信息，提取全方位共反射角道集和全方位共倾角道集，以提高潜山成像的精度和裂缝、洞穴预测的准确率。以潜山缝洞型储层发育地质模式为指导，采用全方位共反射角道集预测Baobab潜山的裂缝发育强度，有效提高了裂缝的预测精度、降低了裂缝预测的多解性。对全方位共倾角道集资料进行散射成像处理，加强了超出地震分辨率的几何特征，突出了小尺度地质体的不连续性，可在地震剖面上较清楚地识别溶洞。研究方法在Baobab潜山取得了良好的预测效果，在缝洞型花岗岩基岩潜山储层预测方面具有一定的应用前景和推广意义。

关键词: 全方位角度域成像, 散射成像, 洞穴, 裂缝预测, 基岩潜山