纵波纯横波联合解释及应用

Joint interpretation and application of P-wave and pure S-wave

纯横波地震资料不受流体影响,故可以有效消除气云的影响进而实现地质构造的精确成像。在纯横波地震资料与纵波地震资料的频带宽度及主频相近的情况下,由于横波传播速度较低,故纯横波地震资料的纵向分辨率要大大高于纵波地震资料的纵向分辨率。为此,首先从恢复气云区成像、提高断层识别能力、提高纵向分辨率3个方面分析纯横波地震资料的优势;接着详细介绍了纵波、纯横波联合解释,主要包括纯横波叠前AVO同步反演的基本原理和纵波、纯横波联合解释关键技术;最后,以柴达木盆地三湖凹陷驼峰山地区纵波和纯横波地震资料为例,展示了纯横波地震资料的实际应用效果。结果表明,利用纯横波地震资料的优势在气云区开展纵、横波联合地震解释,能够准确识别气云区断裂的展布特征,实现气云区的地质构造精细解释;利用纵波和横波叠前AVO同步反演技术进行砂体储层描述和含气性预测,能够有效提升该区薄互储层预测的纵向分辨率及精度,岩性气藏地震识别成果突出。

With the development of seismic exploration technology,S-wave exploration technology has provided a new research direction for oilfield development and reserve increases.Pure S-wave seismic data,if not affected by fluid,can effectively eliminate the influence of gas cloud and help to produce a real image of geological structures.Moreover,when the frequency bandwidth and dominant frequency of pure S-wave seismic data are similar to those of P-waves,the vertical resolution of S-wave seismic data is much higher than that of P-wave seismic data owing to the low propagation speed of the S-wave.In this study,the advantages of pure shear wave seismic data were first analyzed from three aspects:restoration of gas cloud imaging,improvement of fault recognition ability,and improvement of vertical resolution.Thereafter,the P-wave and pure S-wave joint interpretation technology was introduced in detail,including the basic principle of S-wave prestack AVO synchronous inversion and the key technology of P-wave and pure S-wave joint interpretation.Finally,the P-wave and pure S-wave seismic data in the Tuofeng Mountain area in the Sanhu Depression of the Qaidam Basin were introduced to reveal the effect.The results showed that the advantages of pure S-wave seismic data in the joint interpretation application in the gas cloud area are that it can accurately identify the distribution characteristics of faults in the gas cloud area and present a fine interpretation of geological structures in the gas cloud area.In sand reservoir description and gas bearing prediction,the vertical resolution and prediction accuracy of thin interbed reservoirs in the area were effectively improved using P-wave and S-wave prestack AVO synchronous inversion technology.It also resulted in good geological effects in the identification of lithological gas reservoirs.In conclusion,the results of the study demonstrate that the joint seismic exploration of P-wave and pure S-wave has an outstanding geological effect and broad application prospects.