分频解释技术在川西砂岩储层预测中的应用

Application of seismic frequency division interpretation technology in predicting continental sandstone reservoir in the west of Sichuan province

（1.成都理工大学沉积地质研究院，四川成都610059；2.中国石油化工股份有限公司西南油气分公司勘探开发研究院德阳分院，四川德阳618000）

Institute of Sedimentary and Geology, Chengdu University of Technology, Chengdu 610059, China

分频解释技术是沿着储层或固定时窗对地震反射波各频率成分对应的调谐能量进行识别和成像，它避免了常规属性分析方法中的调谐陷阱，提高了识别薄储层的能力，能更客观地刻画地质体。在川西地区陆相隐蔽岩性气藏勘探中，存在调谐陷阱、波阻抗特征不明显、复杂地层结构中的有效薄储层不易识别等问题。为此，利用分频解释技术对川西地区侏罗系千佛崖组冲积扇相砾岩储层、上三叠统须四段河流三角洲相砂岩储层进行了描述。在多频率振幅叠加图上，冲积扇、三角洲水下分流河道等地质体形态和边界反映清晰；在单频振幅图上，清楚地显示出冲积扇内的辫状河道相薄层砾岩储层，与钻井结果相吻合，提高了储层预测精度。

Frequency division interpretation technology is used to identify and image the tuning energy corresponding to the seismic reflection frequency along a certain reservoir and fixed time-window. By doing so, we can avoid the tuning trap in conventional seismic attributes analysis and improve the capability of identifying thin bed reservoirs. In addition, the geologic bodies and thin reservoirs can be objectively characterized. In the subtle reservoir exploration of west Sichuan depression, there are some problems including tuning trap, poor impedance characteristics, and difficult in recognizing effective thin reservoirs in complex formation structure. Therefore, seismic frequency division interpretation technology was used to describe the alluvial fan conglomerate reservoir of Qianfoya formation of Jurassic and sandstone reservoir of river to delta facies in the fourth member of Xujiahe formation, Upper Triassic. On multi-frequency amplitude overlay chart, the shape and boundary of alluvial fan and delta submarine distributary channel deposited geologic bodies were clearly displayed. On singlefrequency amplitude chart, the thin cemented gravel reservoirs of braided channel facies in alluvial fan were clearly displayed, which avoided the prediction trap in conventional attribute analysis and decreased the exploration risk.