叠前道集优化处理在浅层气预测中的应用

Application of prestack gather optimization preprocessing to prediction of shallow gas

荆雅莉

Jing Yali

中国石油大庆油田有限责任公司勘探开发研究院，黑龙江 大庆 163712

Research Institute of Exploration and Development, Daqing Oilfield Company Ltd., PetroChina, Daqing 163712, China

叠前AVO属性分析技术在浅层气地震预测中应用广泛，叠前道集作为AVO属性分析的主要输入数据，道集资料品质对气藏的预测结果影响较大。文中以ALX工区为例，针对常规道集处理中存在的信噪比低、道集不平、远偏移距频率低等问题，在AVO正演的指导下，应用均值滤波、无速度道集拉平、远近道频谱能量补偿的道集优化处理技术，提高叠前CRP道集资料品质，并运用优化处理前后的道集对比、气层顶面AVO曲线对比、叠加剖面对比及平面属性对比的方式，对优化处理后的道集进行质控。实际资料应用效果表明，优化后道集气层处AVO曲线与正演道集曲线更加接近，叠加剖面上气藏低频“亮点”特征更加明显，应用优化后道集提取的叠前AVO属性预测气藏的精度较优化前有明显提高。

Prestack AVO attribute analysis technology has been widely applied to the prediction of shallow gas, but the quality of prestack gather which is the main input data of AVO affects the prediction results of gas reservoir. Taking ALX seismic survey as an example in this paper, there are some problems of processing in prestack gather, such as the low signal-to-noise ratio, the event uneven, and the low frequency in far offset. Under the guidance of AVO forward modeling, the technology of gather preprocessing is used to improve the quality of prestack gather data, e.g. the mean filtering, the flatten event, the energy compensation of near or far gather. Four kinds of evaluation methods (preprocessing gather comparison with raw gather, the AVO curve comparison of gas top, the prestack section comparison and the map attribute comparison) are used to control the quality of the preprocessing gather. The actual application indicates that AVO curve of gas top which is extracted from the preprocessing gather is more similar to the forward curve, the "bright spot" features of gas are more obvious on the prestack profile, and the prediction accuracy of gas with the preprocessing gather is better than that of the raw gather.

10.6056/dkyqt201506008