准噶尔盆地石炭系火山岩地震勘探关键技术

Key technologies for seismic exploration of Carboniferous volcanic rocks in Junggar Basin

以准噶尔盆地腹部石炭系原生韵律型和西北缘风化壳型火山岩为例,针对地震勘探难点,论述了地震勘探关键技术。研究认为,对于原生韵律型火山岩,按照岩性油气藏的思路,采用低频可控震源采集、井控低频补偿以及层间多次波压制处理技术可以大幅度提高深层地震资料的保真度与空间分辨率;以多属性融合技术预测的火山岩相为约束,再通过叠后相控反演,可以实现优势储层的定量预测。对于风化壳型火山岩,按照后期改造型油气藏的思路,强反射界面续至波压制、“真”地表TTI叠前深度偏移等技术可以实现构造、地层和断裂精细成像;古地貌恢复与多属性断裂精细识别技术可以落实有利目标区。通过关键技术的应用,准噶尔盆地腹部火山岩地震资料频带由3~25Hz拓宽到8~46Hz,储层的钻探平均符合率由65%提高至81%。该方法可为国内外类似火山岩油气藏的勘探提供参考。

Taking the Carboniferous primary rhythmic igneous rocks in the center and the weathered volcanic rocks at the northwestern margin of Junggar Basin as examples,this study discusses the key techniques for solving difficulties in seismic exploration.According to the research,for primary rhythmic volcanic rocks,the use of low-frequency vibroseis acquisition,well-controlled low-frequency compensation,and interlayer multiple suppression can greatly improve the fidelity and spatial resolution of deep seismic data with the idea of lithologic oil and gas reservoirs.Quantitative prediction of superior reservoirs can be achieved by poststack facies-driven inversion with the constraints of volcanic lithofacies predicted by multi-attribute fusion.For weathered volcanic rocks,according to the idea of later stimulated reservoirs,the continuous wave suppression of strong reflection interfaces and the TTI pre-stack depth migration technology of the“true”surface can realize fine imaging of structure,formations,and faults.Ancient landform restoration and fine identification of multi-attribute faults are conducive to identifying favorable target areas.The bandwidth of seismic data for volcanic rocks in the central Junggar Basin is increased from 3~25 Hz to 8~46 Hz,and the average coincidence rate of reservoir drilling is raised from 65%to 81%.This method can provide a reference for the exploration of similar volcanic rock reservoirs at home and abroad.