溢出点约束速度场法──提高低幅度构造成图精度的方法

AN APPROACH OF SPILL POINT CONSTRAINED VELOCITY FIELD:A METHOD FOR IMPROVING IMAGE ACCURICY OF LOW CLOSURE STRUCTURES

尽管影响低幅度构造成图精度的因素很多，但在消除了闭合差和实现了准确的层位标定与追踪情况下，真实合理的变速速度场的建立则成为最为重要的因素。用深度经基准面校正后的钻井资料确定的油水界面和圈闭溢出点深度与等ｔ０图上的溢出点位置及对应的ｔ０值，可推算一个溢出点平均速度。在钻井平均速度控制点少或分布不匀的情况下，由溢出点平均速度和井点平均速度对地震叠加速度推导出的平均速度约束校正可得到一个较合理的变速速度场，由此所做的构造图将比无溢出点约束作出的构造图具有更精确的圈闭形态和闭合高度，为储量计算和开发井布置提供更可靠的依据。

AbstractThough there are many factors offecting the image accuricy of low closure structures,the building up of a real and reasonable variable speed velocity field is the most important one ofter eliminating mistie and calibrating and tracing exactly the horizon.A t o value can be found at the spill point in isot o map,and the spill point depth can be obtained from base level corrected oil or gas wells.Then the spill point constrained average velocity can be derived.When well control point are rare or distributed unevenly,the seismic stacking derived average velocity should be constraint corrected with spill point average velocity and well point average velocity,then a reasonable varying speed velocity field could be obtained.Structural maps made in this way will have more accurate trap configuration and closure,and could provide more reliable basis for reserve calculation and development well allocation.