提高浅海OBC地震资料采集作业放缆点位精确度的理论计算方法

A theoretical computation method for improving the positioning precision of cable deployment in OBC seismic data acquisition

海底电缆地震资料采集过程中放缆的点位精度难以把握。在全面考虑影响海底电缆地震资料采集放缆过程的海水潮流、电缆下水后惯性、放缆力度不均匀等诸多因素的情况下,基于电缆下水后力学和运动学规律,对电缆进行受力分析和运动学分析,建立了一套较为完整的提高浅海OBC地震资料采集作业放缆点位精确度的理论计算方法,采用该方法可以较好地计算出浅海OBC地震资料采集作业时纵向和横向上电缆下水前抛点的预留长度,为电缆的抛点位置选择提供了理论依据。根据此算法可以建立工区放缆数据库,科学地指导实际放缆作业,从而大大提高放缆点位精确度,面元覆盖次数更为均匀,改善资料品质,整体上提高作业效率,降低勘探周期和勘探风险。

It is difficult to control the precision of deploying the cable at the accurate point in the Ocean Bottom Cable(OBC)seismic data acquisition.Considering all the aspects of influencing factors,such as tidal current,inertia of cable into water and uneven cable deployment strength,we carried out mechanical analysis and kinematics analysis on the cable after deployed into the water,and proposed a theoretical calculation methods to improve the positioning precision of cable deployment in OBC seismic data acquisition.The new method can well calculate the reservation length of throwing point in longitudinal and transverse direction,which provides data criteria for selecting throwing point of cables.By applying the method,we can establish cable-laying database of the work area to scientifically guide actual operation,which can increase the precision of cable deployment, obtain more even fold and improve the quality of seismic data.So the operation efficiency can be enhanced,and the exploration period and risk can be reduced.