西非深水目标高密度三维地震勘探效果

High-density 3D seismic exploration of deep-water targets in West Africa

西非深水A区块三维地震勘探经历了20年的发展。随着复杂目标与油气田评价工作的不断深入,常规三维地震勘探已无法满足精细研究的要求。对比分析了研究区高密度三维与常规三维地震的采集参数、频谱信息、成像剖面,明确了高密度三维地震勘探的优势。采用地震方差属性技术、地震相识别技术、平点技术以及甜点单元多因素分析技术,对复杂断裂、沉积相带、储层流体界面以及甜点单元进行了识别与预测。对比高密度三维和常规三维地震资料解释结果可知,高密度三维地震资料成像剖面上断点及断面更加清晰,对小规模断层的识别和对平面交切关系的解释更为精确、合理;横向连续性更好,在识别沉积体内部反射特征及边界刻画方面优势明显;具有更高的纵向和横向分辨率,提高了流体界面的识别能力。研究表明,高密度三维地震勘探在深水复杂构造精细评价中具有很好的适用性。

The 3D seismic exploration of Block A in West Africa has been ongoing for 20 years.As targets become more complex,conventional 3D seismic cannot meet the requirements of high-resolution exploration.A comprehensive comparative analysis has been conducted on the acquisition parameters,spectral information,and profile imaging of high-density and conventional 3D seismic exploration,highlighting the advantages of high-density 3D seismic exploration.Complex fault identification,sedimentary facies prediction,reservoir fluid interface identification,and sweet unit identification were implemented using seismic variance attributes,seismic phase identification,flat point,and multi-factor analysis for sweet units,all based on high-density 3D seismic data.Section interpretation and plane combination of the faults were more accurate and consistent when based on high-density 3D seismic.Further,improved lateral continuity and wave group characteristics were conducive to identifying the internal reflection characteristics of sedimentary bodies and depositional boundaries.The higher vertical and horizontal resolution of high-density 3D seismic led to the observation of a group of flat spot reflections at the fluid interface,thus improving the ability to recognize the fluid interface.The study demonstrates that high-density 3D seismic exploration has superior applicability and potential in the evaluation of complex structures in deep water.