BZ34油田亚地震断层定量预测技术

Quantitative prediction techniques of sub seismic faults in BZ34 Oilfield

亚地震断层是影响油田注水开发效果和剩余油分布的关键因素,由于其尺度较小,既不能从地震数据上识别,也不能从井资料上识别,定量预测难度极大。文中通过利用断层分形生长模式和三维地质力学模拟相结合的方法,对BZ34油田亚地震断层的断距、数量、长度、分布密度和平面位置进行了定量预测。首先,通过建立BZ34油田不同断裂系统断层长度和最大断距的分形生长模型,对不同尺度的亚地震断层的数量和长度进行预测。由于断裂系统的最大断距和断层长度之间均呈较好的线性关系,进而对断层断距进行预测。其次,通过三维地质力学模拟,建立研究区最大库伦剪切应力密度分布函数,定量表征断层密度,确定亚地震断层的平面发育位置。最后,通过获取的断层数据,建立随机模型,利用标值点方法来实现亚地震断层的定量预测。研究区典型井距断层距离与平均日产能关系表明,距离断层越近,平均日产能越大,后续可考虑应用在亚断层较发育地区且与注水井之间无遮挡区域部署开发井。研究技术可应用于类似油田开发井井位部署上,为油田亚地震断层精细刻画提供新思路。

Sub seismic fault is the key factor that influences the development of BZ34 Oilfield and the distribution of remaining oil.Because of its small size, it cannot be identified from seismic data or be identified from the well data, and the quantitative prediction is very difficult. In this paper, the fault distance, length, density and plane position of the sub earthquake fault in the study area are quantitatively predicted by the method of fractal growth model and 3 D geological mechanics simulation. Firstly, the fractal growth models of fault length and maximum fault distance of different fault system are established for BZ34 Oilfield, and the number and length of sub earthquake fault in different scales are predicted. Because there is a good linear relationship between the maximum fault length and the maximum length of the fault system, the fault distance is predicted. Then through the 3 D geomechanical simulation, this paper establishes the maximum Kulun shear stress distribution function of research area, gives a quantitative characterization of fault density, and determines the plane development location of sub seismic faults. Finally through fault data acquisition, a stochastic model is built to give a quantitative sub seismic fault prediction using marked point method. This technology research can be applied to the development of well deployment, which provides new ideas for fine description of sub seismic fault.