Analysis and Modeling of Fractured Reservoirs

Abstract

Abstract The analysis and modeling of fracture and fault patterns on various scales has obtained a major role in hydrocarbon exploration and development. Mainefforts regard the optimization of well bore orientations with respect to fracture network characteristics, the identification of well site locations inorder to enhance productivity, and the improvement of the estimates ofgeometrical parameters such as matrix block sizes and shapes (sigma factor), representative elementary volumes (REV), and fracture porosity distribution forreservoir evaluation. A number of case studies will be presented regarding exploration and production activities in various types of naturally fractured reservoirs with poor primary matrix permeability. The new techniques developed relate to theissues of predicting parameters such as location, density, interrelation and orientation of fracture sets in complex tectono-stratigraphic settings. The optimum location and deviation of an exploration well to be drilled canbe established by applying Fracture Potential and Domain Mapping technologieson elaboration's of high quality 3D seismic datasets (amplitude, geometry, coherency), calibrated with available (oriented) core and log datasets(conventional logs, borehole viewers, borehole shape analysis, etc.). Theoutcome of these methodologies are a series of maps which predict fracturedensity and orientation throughout prospects and reservoirs, which can be used to choose optimum locations for exploration and development wells for which fracture and fault orientations can be predicted. Furthermore, strike domaininterference can help in the detection of fluid flow paths and can give clues to the interpretation of well behavior. Combinations of deterministic and probabilistic three-dimensional modeling of the subseismic fracture zone network provides a sophisticated tool to investigate the tectonic texture of the rocks to be drilled, for which fracture orientation can successfully bepredicted. The remarkable accuracy with which the texture of the fracture network can be analyzed, modeled and predicted applying a range of new technologies is highly encouraging and opens a whole new perspective for challenging future objectives related to the exploration and development of naturally fractured reservoirs. P. 31