虚拟井技术在无井或少井条件下时深转换中的应用

The application of virtual well technique to time-depth conversion under the condition of no or few wells

针对海外新区新领域勘探时面临的地质条件复杂、水深变化大、钻井稀缺且分布不均、速度资料缺乏等问题,常规的方法往往难以进行精细的时深转换。为了有效落实构造,笔者提出借用地震资料和仅有的井资料来构建虚拟井进行无井区域的定量化表征,合理构建虚拟井,有效降低速度场建立的不确定性。利用虚拟井约束速度场建立,为无井或少井、水深变化大、地层变化剧烈地区的时深转换提供了一种切实可行的选择,有效地提高了时深转换的精度,为圈闭优选以及有利目标评价奠定坚实的基础,从而降低勘探风险。

In the light of the geological conditions of the new exploration field abroad characterized by complexity,varying water depth, scarcity and uneven distribution of drill holes,and lack of velocity data,it is often difficult for conventional methods to carry out fine time depth conversion.In order to effectively detect the structure,this paper proposes using seismic data and the available well data to build virtual wells for quantitative characterization in nowell area.The reasonable construction of virtual wells can effectively reduce the uncertainty of the velocity field＇s establishment,ultimately improve the timedepth conversion accuracy of the study area,and lay a solid foundation for the optimization of traps and evaluation of favorable targets,so as to reduce the risk of exploration.Using the establishment of virtual well constrained velocity field,such a means provides a feasible choice of time depth conversion in the area characterized by no or few wells,remarkable varying water depth,and drastic stratigraphic change,thus effectively improving the accuracy of timedepth conversion.