???????????????????????????

随着各探区油气勘探工作的不断深入，复杂构造区成为新的油气有利远景区。而在复杂断裂区，常规时间偏移处理效果往往不好，这主要是由横向速度突变引起。为了得到精确的地下构造形态，必须利用叠前深度偏移能较好处理横向变速的优势对复杂断裂区进行精确成像。文中结合一个三维地震资料采集实例，给出了三维叠前深度偏移的处理方法和实现步骤，其中叠前深度偏移的关键是如何建立好层速度模型，并通过井资料和构造模型的约束来提高深度偏移的成像精度。由于叠前深度偏移能够提供精确的构造图象，这大大增加了复杂断裂区的解释可信度，从而降低了勘探与开发的风险。通过对成像效果进行分析，发现叠前深度偏移与钻井数据吻合较好，我们相信：叠前深度偏移成像技术必将成为一种解决复杂构造成像问题的有效手段。

Application of 3-D Prestack Depth Migration in Complicated Fault Areas

Along with the further oil and gas exploration in various regions, the complicated structural belts will become the new beneficial hydrocarbon prospective areas. In complicated fault areas, however, the effect of conventional time migration processing was poor, which was mainly caused by the big saltation of transverse velocities. In order to get a precise underground structural configuration, the prestack depth migration must be utilized for making an accurate imaging in the complicated fault areas because of its superiority of well processing the saltation of transverse velocities. In combination with an example of 3 D seismic acquisition, the processing method and working steps of 3 D prestack depth migration are put forward in the paper, in which the key of the prestack depth migration is how to set up the interval velocity model and to raise the imaging accuracy of the depth migration by the constraints of drilling data and structural model. Because the precise structural image can be provided by the prestack depth migration, the creditability of interpreting the complicated fault areas may be greatly increased, thus reducing the risks of exploration and development. Through the analysis of imaging results, it was found out that the prestack depth migration is well identical with the drilling data, therefore the imaging technique by the prestack depth migration will certainly become an effective means of solving the complicated structural imaging problem.