塔中地区速度场建立及变速成图

The construction of the velocity field and the varying veloc- ity mapping in Tazhong area.

对塔里木盆地塔中地区构造成图采用了有别于常规方法的时深转换。其主要流程是:①首先利用叠加、偏移速度精确建立三维速度场,将偏移时间域t0图转换到零偏移距时间域内;②利用叠加速度由浅至深逐层进行反演,分别反演出沿该反射层的层速度,计算并绘制出层速度平面图;③最终得到三维速度模型和零偏移距时间模型,并利用2种数据模型作时深转换。将该方法应用于塔中地区低幅度构造、岩性圈闭精细描述和研究,提高了构造成图的精度。

This paper present the unconventional method to time-depth transform with the software explorer (PG2) while the structural mapping in the Ka-1 zone of the central part of Tarim Basia The main process is: 1) using the stack and migration velocity to construct the 3-D velocity field accurately, Transforming the figure of shifting time domain to into the nil shifting distance time domains; 2)Inversing the interval velocity of each layer u-sing of the stacking velocity, and draw the interval velocity plot; 3) Thus getting the 3-D velocity model and the model of the zero shifting distance time domains,finally, using the two data model to time-depth transforming. This paper gives an effective method for the accurate description and studying of the low-amplitude structure and the lithology trapp, it improved the accuracy of the structural mapping.