Small-Scale Faults and Fractures Identification Using Image Enhancement Techniques

Summary It is difficult to identify small scale faults and fractured zones using post stack seismic data. Traditional techniques such as coherence and ants tracking are difficult to highlight the scale effect and directional effect of post stack data at the same time. The image enhancement technique based on contourlet transform has the characteristics of multi-scale decomposition and multi-directional filtering, and can well highlight the directional anisotropy in post-stack seismic data. First of all, we introduce the principle of image enhancement based on contourlet transform. Secondly, to analyze the results of different methods, we designe a physical model and apply this proposed new technique as well as traditional coherence and ants tracking techniques to the obtained post-stack seismic data. It is found that the image enhancement technique based on contourlet transform has obvious advantages in highlighting the distribution of small-scale faults and structural fractures. Finally, we present the applications of this technique in predicting fracture zones of carbonate reservoirs and in characterizing small-scale fractures of tight sandstone and mudstone reservoirs. This technique has been successfully applied to the well site deployment in a number of oilfields of PetroChina.