2024年3月14日发(作者:诺基亚n85图片)
地震勘探中的速度概念
真速度:地震波在空间每一个点的实际传播速度
视速度(apparent v):某一个波相在地表观察到的速度,总是大于真速度
层速度(interval v):
1. The velocity of an interval in the subsurface measured by determining the
traveltime over a depth interval along some raypath. 1. In sonic log determinations
the interval may be 1 to 3 ft; in well surveys it may be 1000 ft or more. Usually
refers to P-wave velocity. 2. The average velocity of the interval in the subsurface
between two reflections. Often used for velocity calculated by the Dix Formula (q.v.)
from velocities measured from normal moveout, which implies horizontal
constant-velocity layers.
2.指在层状地层中地震波传播的速度。它直接反映地层的岩性,能用来划分地层。一
般是用地震测井或声波测井测得,并且指的是纵波的速度。也可以利用反射记录计算得到。
3. 做时深转换用的速度是层速度。
平均速度(average v):
1. 波延某个路径传播距离与时间的比
平均速度就是地震波垂直穿过一组水平层状介质各层的总厚度与总的传播时间之比。
2. 把t0图转化为深度图,就是把t0与速度相乘再除以2(因为t0是双程的),这个
速度就是平均速度,平均速度是基准面到目标层位之间的速度。
均方根速度(RMS v):
1.对某个射线而言的,对于水平层状地层
2.均方根速度,实际上就是把不是双曲线的时距曲线简化为双曲线的速度,处理做动
校正是就用到这个速度。
叠加速度(stacking v):
1. Velocity calculated from normal-moveout measurements and a
constant-velocity model. Used to maximize events in common-midpoint stacking.
2. Usually calculated for the best-fit hyperbola to gather data, the value thus
depending somewhat on the range of offsets involved. Fitting an NMO equation
to CMP data is equivalent to assuming an ellipsoidal wavefront, yielding the
stacking velocity of the horizontal component. Nonelliptical wavefronts yield
offset-variable stacking velocities.
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