浅海区古生界海底电缆拟宽线地震采集方法

OBC Pseud Wide Line Acquisition Method for Paleozoic in Shallow Sea Area

南黄海中古生界盆地沉积厚度大,具有良好的油气勘探前景,是我国近海海域油气勘探的重要区域之一.但由于南黄海西侧海域水体浅,地震勘探目的层系时代老,地质背景复杂,浅层存在强屏蔽层等原因,传统海上拖揽地震采集方法在实际施工方式和地质要求上都不能充分满足该区的勘探需求.通过对其地震地质条件和已往采集技术手段的系统分析,针对实际地质情况和勘探要求,设计了针对南黄海西侧浅水区古生界地层的海底电缆地震采集方案,采用两炮三线的拟宽线观测系统和中间放炮递减排列滚动接收的作业方式.通过实际资料证实该种拟宽线海底电缆采集技术是适用于海域古生界地层的有效地震采集技术.

It is believed that Mesozoic-Paleozoic marine sedimentary strata is widely distributed and has a great thickness in South Yellow Sea basin,so it bears great hydrocarbon potential and is one of the most important areas in offshore oil exploration.However,due to shallow water,old target strata,large burial depth, complicated geological conditions and strong shielding layer in upper shallow depth,it is difficult to get high quality seismic data and meet the requirements of exploration by traditional hydrophone streamer methods in the westward of south yellow sea.Seismic data has become a bottleneck to the hydrocarbon exploration in this area.Aiming at this peculiar survey demand and solve actual geological problem,this paper analyses the special seismic and geological conditions in this area and compared previous seismic acquisition patterns,then presents the thought of pseud wide line ocean bottom cable acquisition method.By summarizing a suit of ocean bottom cable acquisition method and parameters which is suitable for the ancient strata in west shallow water area of South Yellow Sea,the specific data acquisition parameters and geometries are demonstrated and tested.The geometry is combined by two shot lines and three receiver lines,and the mode of operation is shot in middle and receiver scrolling in descending order.In addition,the real data verified that the OBC pseud wide line acquisition method has good effect in imaging of Paleozoic strata in South Yellow Sea.