川中地区侏罗系沙溪庙组致密气处理和解释关键技术与应用

四川盆地蕴含丰富的致密砂岩气资源,近期利用高精度三维资料开展侏罗系沙溪庙组河道砂体勘探取得突出成效。沙溪庙组河道砂体具有横向变化快、储层非均质性强的特点,因此提高河道砂体的边界识别及其含气性预测精度是致密气地震勘探的关键。通过开展AVO特征低频保护的“六分法”（分类、分频、分时、分域、分步和分区）高保真叠前去噪、近地表Q补偿和OVT域叠前时间偏移等技术攻关,形成了一套针对川中地区侏罗系沙溪庙组致密气藏的“双高”（高保真、高分辨率）地震处理技术,并创新应用“双亮点”属性及多波、多分量砂体含气性地震预测等解释技术,提高了含气砂体预测精度。该技术系列在川中沙溪庙组致密气预测应用成果显著,地震数据频带得到了拓宽,低频信息更加丰富,资料信噪比明显提升,河道边界及其含气性预测的精度大幅提高,钻井成功率超过83%,应用成果有力地支撑了该地区沙溪庙组致密气的增储上产。

Key technology and application of processing and interpretation of tight gas in Jurassic Shaximiao Formation in Central Sichuan Basin

Sichuan Basin is rich in tight sandstone gas resources, and the recent exploration of channel sandbodies by high-precision 3D data in Jurassic Shaximiao Formation has achieved certain results. Drilling shows that Shaximiao channel sandbody has the characteristics of fast lateral change and strong reservoir heterogeneity. Therefore, improving the boundary recognition and gas-bearing prediction accuracy of channel sandbody is the key to tight gas seismic exploration. By conducting "six division" (divided by type, frequency, time, domain, step, and zone) high-fidelity prestack denoising technology, near-surface Q compensation technology, and OVT domain prestack time migration (PreSTM) technology for AVO feature low frequency protection, sets of processing technology with high fidelity and high resolution was deve-loped for tight gas reservoir of Shaximiao Formation in Sichuan Basin. Meanwhile, the "double bright spot" attribute and multi-wave and multi-component seismic prediction technology are innovated and applied to improve the prediction accuracy of gas-bearing sandbody. The application of this technology series in the tight gas prediction in Central Sichuan has achieved remarkable results, such as expanded frequency band of seismic data, more abundant low-frequency information, significantly improved signal-to-noise ratio, and greatly improved accuracy of channel boundary and gas bearing prediction. In addition, the success rate of new wells has been more than 83%. The achievement strongly supports the increase in storage and production of Shaximiao tight gas in Central Sichuan.