宽频勘探技术在柴北缘深层侏罗系勘探中的应用

Wide-frequency prospecting technology and its application on deep-seated Jurassic exploration in northern margin of Qaidam Basin

柴北缘地区的主力产层位于中深层侏罗系及基岩顶部,受复杂地震地质条件的影响,地震资料信噪比和分辨率均较低,难以落实有利圈闭。在该区实施了以宽频勘探技术为核心的采集处理解释一体化勘探技术,新采集的地震资料中深层成像质量得到明显改善,构造落实,基岩反射清晰,对断层、断块和断点的刻画更为清楚。同时,低频信息丰富,有效频带得到拓宽,分辨率明显提高。该技术采用低频可控震源激发增强地震波下传能量,拓宽原始资料频带宽度;高密度宽方位观测保证波场连续、对称、均匀采样,提高资料信噪比;高精度层析初至静校正提高复杂构造成像精度;宽频补偿处理拓宽剖面频带,提高资料分辨率;宽频反演储层预测精确刻画有利砂体展布。应用成果表明,宽频地震勘探技术可以有效解决该区中深层成像问题,为油田勘探开发提供有效的技术支撑。

The targets are located in the deep Jurassic and basement in northern margin of Qaidam Basin. Under the influence of complex seismic geological conditions,the signal-to-noise ratio and resolution of seismic data are low,so it is difficult to implement favorable structural trap. Based on wide-frequency prospecting,a set of integrated seismic exploration technology of acquisition,processing and interpretation were carried out. The results show that deep imaging quality of the new acquisition seismic data is improved,and the reflection of Jurassic structure,fault and bedrock is clear,while the low frequency information is rich,effective bandwidth is broadened,and resolution is significantly improved. The integrated technology uses the low frequency vibroseis seismic excitation to enhance wave signal energy and broaden the original data bandwidth. High density wide azimuth observation ensures continuous,symmetric and uniform sampling of the wave field,and improves the signal-to-noise ratio.The precision of the complex structure imaging is improved by high precision chromatography first-break refrac-tion static correction. The wide frequency inversion reservoir prediction accurately depicts the favorable sand body. The application results show that broadband seismic exploration technology can effectively solve the deep imaging problems in this area,and it is an effective technical support for oilfield exploration and development.