利用分形几何定量评价克拉2气田裂缝

摘要

According to the relationship between faults and structural fractures, this paper processed fault system with fractal geometry, and set up the relationship of dimension value with fracture density in combination with log interpretation, performed fractal statistics of faults on top of the dolomite interval in the Kumugeliemu Group ( Paleogene) , and the second and third lithologic intervals of the Bashijiqike Formation ( Lower Cretaceous) , built relationship between fractural dimension values of faults at well point and the fracture density, and predicted interwell fracture distribution. The fractal dimension value of faults increases with fault density and length increase. Statistical values of fractal dimension of faults at well point show positive correlation with the linear density of fractures obtained by well logging interpretation. Fracture growth is significantly influenced by the geometry of anticlines. Fractures are commonly well developed in areas close to the axis of anticline and having a fractal dimension value over 1. 25. The fracture density of three reservoir intervals near the A3 well is relatively large. Furthermore, some of the fractures may penetrate through the barriers, causing the watering of gas well. The study indicates that quantitative evaluation of fractures by using fractal geometry can guide exploration and development planning,and can be used to evaluate fractured reservoirs in oil/gas fields.%根据断层与构造裂缝存在的关系,利用分形几何方法处理断裂系统,并结合测井解释结果建立分维值大小与裂缝密度的对应关系,对古近系库姆格列木群白云岩段、下白垩统巴什基奇克组第二、第三岩性段顶面断层进行分形统计,建立井点断层分维值与裂缝线密度的关系,在此基础上对井间裂缝分布进行了预测.研究认为,断层分维值随着断层密度、延伸长度的增加而增大,井点处断层分维统计值与测井解释得到的裂缝线密度呈正相关关系；平面上,裂缝发育受背斜形态影响明显,靠近背斜轴部、断层分维值大于1.25的区域最有利于裂缝发育；A3井附近,3个储层段裂缝发育密度偏大,部分裂缝可能穿透了中间的隔层,造成附近气井出水.研究结果表明,利用分形几何定量评价裂缝对勘探开发方案部署有指导意义,可以用来对油气田裂缝性储层进行评价.