塔中地区速度场建立及变速成图

The construction of the velocity field and the varying velocity mapping In Tazhong area

（中国石化石油勘探开发研究院西部分院，新疆乌鲁木齐 830011）

(Western Branch Institute of Exploration and Production Research SINOPEC,Urumchi Xinjiang)

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t0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 gives 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 basin.The main process is：Using the stacking and shifting velocity to construct the 3-D velocity field accurately. Transforming the figure of shifting time domain T0 into the nil shifting distance time domain. Then inversing the interval velocity of each layer step by step, in the use of the stacking velocity. Working out the interval velocity and drawing its plot. Thus getting the 3-D velocity motel and the model of the nil shifting distance time domain. Last, using the two data model to time-depth transforming. This paper gives an effective technique and method for the accurate description and studying of the low-amplitude structure and the lithology trapping, it improved the accuracy of the structural mapping.