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过去的三维地震勘探排列多具直线性质,因而它不能提供正确解释所需的细节。从理论上讲,用同心圆三维地震技术可能是获得更大的、质量更高的数据覆盖范围的方法。在盐丘区用直线三维地震网采集时存在一些问题,故提出用同心圆三维地震采集技术做进一步研究。 用常规直线三维地震难以使盐丘翼部成象也许是由于我们尚不能精确预测盐岩和沉积岩附近的横向速度场变化之间的关系。盐岩和沉积岩层间速度差很大,因而返回射线严重偏离双曲线路径。这就妨碍了我们预测盐岩/沉积岩界面附近成象点的能力。用直线地震勘探成象最困难的地区可能是盐层檐突之下的区域。模拟结果认为,用同心圆方法可以有效地增加盐层檐突之下的射线数量。只有盐层檐突下大量的射线穿透沉积岩传播才能提高我们对盐岩/沉积岩界面附近成象点的预测能力。 本文论证了“圆形激发”在墨西哥湾盐丘型油气藏勘探中的应用。总共80个同心圆覆盖了该地区31000英亩范围。最终叠后数据分为25米×25米的面元。在同一地区对三维同心圆激发与三维直线激发方式做了对比,证明同心圆激发可改善数据质量和信噪比特征。
Past 3D seismic surveys were arranged in a linear fashion so that it did not provide the details needed to properly interpret it. In theory, using concentric 3D seismic techniques may be a way to obtain larger, higher quality data coverage. There are some problems when using the straight-line 3D seismic network in the saline region, so the concentric 3D seismic acquisition technology is proposed to do further research. It is perhaps due to the fact that it is difficult to predict saltwing wing formation with conventional straight-line 3D earthquakes because we are not yet able to accurately predict the relationship between changes in lateral velocity fields near the salt and sedimentary rocks. The velocity difference between salt rock and sedimentary rock is so great that the return ray deviates significantly from the hyperbolic path. This hindered our ability to predict the location of the image near the salt / sediment interface. The area most difficult to image with linear seismic exploration may be the area under the eaves of the salt cliff. The simulation results show that the concentric circle method can effectively increase the number of rays under the eaves of the salt layer. Only large amounts of radiation penetrating sedimentary rocks under the eaves of the salt layer can enhance our ability to predict the formation of the image near the salt / sediment interface. This paper demonstrates the application of “circular excitation” in the exploration of salt dome reservoirs in the Gulf of Mexico. A total of 80 concentric circles cover 31,000 acres in the area. The final stack data is divided into 25 meters × 25 meters of the surface element. In the same area, a comparison is made between the three-dimensional concentric excitation and the three-dimensional linear excitation, which proves that the concentric excitation can improve the data quality and signal-noise ratio characteristics.