OBN采集数据双基准面波动方程偏移研究

Research on wave equation migration on double datum planes for OBN acquisition data

双平方根方程(DSR)偏移需要炮检点同步沉降,要求炮检点在同一个基准面上。OBC/OBN采集数据炮点和检波点分别位于不同基准面,给双平方根方程偏移提出新的挑战。为此,提出了一种波场混合延拓方法,以解决双平方根方程对OBC/OBN数据的适应性。在水层,炮点波场往下延拓,到达海底后炮检点波场同步延拓,从而实现双基准面双平方根方程波场延拓,并在海底开始进行零时间零炮检距成像,实现双基准面下双平方根方程成像。所提方法较先静校正再成像的方法具有更高的精度和计算效率。OBN理论模拟资料和实际资料成像结果验证了方法的正确性和有效性。

The double square root(DSR)equation migration requires synchronous sinking of shot and receiver points,and the shot and receiver points need to be on the same datum plane.However,the shot and receiver points of OBC/OBN acquisition data are located on different datum planes,which poses a new challenge to the DSR equation migration.In this paper,a hybrid wave field extrapolation method is proposed to deal with the adaptability of the DSR equation to OBC/OBN data.In the water layer,the shot point wave field extrapolates downwards.After the wave field reaches the seabed,the wave fields of the shot and receiver points synchronously extrapolate,so as to realize the DSR equation wave field extrapolation on double datum planes.In addition,zero-time zero-offset imaging is carried out on the seabed,and the DSR equation imaging under the double datum planes is realized.The method in this paper has higher precision and computational efficiency than methods featuring first static correction and later imaging,and the theoretical simulation OBN data and the real data imaging verify the correctness and effectiveness of the method.