Fracture And Vug Evaluation Based On Resistivity Images

Fracture is not only a principal passway for hydrocarbon migration,but also an important storage space.Its distribution and shape in formation are quite complicated.Therefore the automatic detection and quantitative evaluation of fracture have always been the key points of oil and gas exploration and production.Resistivity images can visually show the shape and distribution of fractures around borehole.This paper has developed a set of computer programs including logging data pre-processing,resistivity image processing,fracture identification and quantitative evaluation.The pre-processing techniques can improve resistivity image resolution,image processing can improve signal-to-noise ratio and image segmentation can extract fracture features.What is more,Hough transformation and the least square method have been used to identify fractures.Thus,parameters of fractures and vugs could be derived.In addition,morphological component analysis has been applied to repair blank stripes,which helps interpreters have a better understanding of borehole circumstance.This set of programs has been tested by several field data and the results show that fractures can be effectively identified.It also has reduced interpreters' workload and generated key parameters,such as fracture aperture,dip,strike,etc.Finally,fracture and vug in formation have been quantitatively assessed.