基于叠前分频振幅差异的溶洞识别技术及应用

Multi-scale cave detection based on amplitude difference of prestack frequency division

碳酸盐岩缝洞型储层中溶洞大小的识别是实际生产中一个较难解决的问题,为此,介绍了一种针对碳酸盐岩溶洞尺度识别与描述的技术。采用叠前分频偏移成像方法,分析了叠前分频对多尺度溶洞刻画的优势;然后对"串珠状"反射进行时频分析,研究溶洞的频率特征,确定合理的分频参数,对CMP道集开展叠前分频偏移成像;最后进行了基于分频振幅差异的多尺度溶洞识别研究,形成了一套基于叠前分频振幅响应差异的多尺度溶洞识别技术。该技术在塔河油田的实际应用结果表明,能够有效识别不同尺度的溶洞,溶洞识别的精度得到明显提高。

Identification of cave size in carbonate fracture-cavern reservoir is a challenge. A multi-scale cave detection method based on prestack frequency division and migration imaging is in troduced. At first, the advantages of prestack frequency division for multi-scale cave detection over poststack frequency division is discussed. After that,the time-frequency analysis for the ＂string beads＂ reflections is conducted to analyze the frequency characteristics of caves , and to determine the reasonable frequency division parameters. Then, frequency division and migration imaging are carried out on CMP gathers. Finally,the multi-scale cave detection is implemented based on the amplitude response difference of prestack frequency division Application results of the filed data in Tahe oilfield showed that this proposed technique is effective for multi-scale cave detection.