The Xihu sag is the largest oil-bearing sag in the East China Sea.The main reservoir of the Xihu sag is located in the middle and deep strata.Adding low frequency information is one of the core issues for solving the main geological problems in the Xihu sag.The variable-depth streamer acquisition technology can effectively suppress ghost waves,broaden the frequency band,especially the low frequency,and has the advantages of simple field operation and low cost,which is beneficial to solving the geological problems of the Xihu sag.Based on the average ghost filter of variable-depth streamer,the key acquisition parameters are theoretically analyzed,such as streamer mode and the streamer depth range.Through 2D field test,a further comparative study was carried out on the raw shot and PSTM record.It is concluded that,for the deep reservoirs of the Xihu sag,the variable-depth streamer is more clearly structured than the conventional horizontal streamer data,and the frequency band has been broadened. Among the two commonly used streamer modes,the linear streamer has better notch compensation effect,and the parabolic streamer has higher low frequency energy.When the shallowest depth of the variable-depth streamer is fixed,increasing the depth range is beneficial to obtaining more low frequency information.
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