全地质构造格架模型约束下的速度建模技术研究及应用

Study and application of velocity modeling under the constraint of full geological structure framework

珠三坳陷文昌9、10区处于区域应力转换带,主要发育珠三南断裂及六号断裂,断裂系统复杂;本区近物源区,沉积体系复杂;复杂的构造运动及沉积作用导致本区地层速度纵横向变化大,速度规律复杂;目前常用速度研究方法在本区时深转换和深度预测误差均较大.本文以导致速度规律复杂的地质条件为切入点,分析速度研究面临的困难,以及常用速度研究方法的局限性,提出在地质模式约束下建立全地质构造格架模型,并以该模型作为速度建模的约束,得到与地下真实地层速度展布规律相符的速度模型.将该方法应用到文昌10-X区、阳江S区复杂断裂带的实际勘探中,与实钻井对比,该方法深度预测误差小,变速成图精度高.该方法的成功应用为断裂系统和沉积体系复杂地区的速度研究找到了一种行之有效的研究方法.

The Wenchang 9,10 area of the Zhu-3 Depression is in the regional tectonic stress conversion zone,the fault system is very complex,where developed the South Faults and the 6 th Faults. This area nears provenance,and the sedimentary system is complex.Complex tectonic movement and depositional system causes the strata velocity changes in vertically and horizontally large. With the current used time-depth conversion methods ＇in this area,it has huge error on time-depth conversion and depth prediction. Complex velocity is restricted the exploration in this area. Based on the complex velocity laws caused by various complex geological conditions,through analyzing the challenge of velocity research and the limitations of common velocity research methods,come up with build a full geological structure framework under the constraint of geological model,and use the full geological structure framework as a constraint of velocity modeling, a velocity model is obtained which agrees with the velocity distribution of underground real strata. This framework model contains faults framework,strata framework and multiple Zvalue 3 D anomaly; Faults framework and strata framework as a constraint of velocity interpolation,Through initial velocity of multiple Z-value 3 D anomaly,the Full Geological Structure Framework get the velocity anomaly information. With this three models,velocity modeling can get a well constraint. The method is applied to time-depth conversion,depth prediction,structure mapping and well trajectory design in the actual exploration on Wenchang 10-X zone and Yangjiang S zone,where has the complex fault system. Actual exploration indication,compared with commonly used method the new method can get a better velocity model,which has advantages of depths prediction and accuracy on structure map drawing. The successful application with this method has found an effective research method for the study of velocity in complex fault system and depositional system.