Identifying And Modeling Research Of Structural Fracture

Along with ever increasing assured quantity of fractured reservoirs over the whole world, Fracture research has became a hot issues in petroleum geology currently. Meanwhile, Owing to the complexity of fracture itself, it also turns into a worldwide problem.This article takes the Triassic Yanchang formation in Dingbian-Huachi region of central-west Ordos Basin as a case study, and applies a variety of technical means of multi-discipline which proceed cooperatively to launch the research about identification and qualitative,quantitative description of structural fracture, the means include that the investigation and description of fracture through outcrop,observation and description of fracture through drilling core,identification and characterization of fracture through borehole wall electrical and acoustic imaging logging as well as identification and appraisement of fracture through conventional logging. Finally, Basically figuring out a variety of structural fracture's developmental features of Yanchang formation in the region of interest, consisting of the following fracture parameters:geologic genetic type,mechanical character,attitude,dimension or scale,density,width,poroperm characteristics and longitudinal developmental pattern, etc. In the course of using the conventional logging data to research structural fracture, especially leading in the R/S analytic technique which is the most maturity in the field of fractal geometry, its results show that this method can preferably distinguish the developmental grade of fracture when the well sections or regions relatively lack of borehole wall imaging logging and drilling core data.It is the newest quantitative description technology of fracture currently that applying the Discrete Fracture Network model to conduct fracture stochastic modeling, the Discrete Fracture Network model can better approach the actual existing condition of underground fracture, and the application of random analogy method can meet the statistical characteristics of the given fracture information while it's able to fully reflect the objective fact that the distribution of fracture has stochasticity. This paper selectes "Zhai Zi Shan block" as a key studying object, and carries out the DFN model fracture stochastic modeling research of structural fracture system in Chang6 of Yanchang formation. Its results show that the fracture geometric model established through above-mentioned technology can intuitively demonstrate the three-dimensional developmental features of underground fracture, and the fracture parameter model calculated based on it can effectively quantitatively describe the three-dimensional distribution of various fracture parameters, thereby better reveal the improvement of reservoir poroperm characteristics which results from fracture. Meanwhile, this reserch provides a new and practical technical means for three-dimensional quantitative description of fracture as well as its parameters.