oa Tectonic fracture network characterization in the giant Hassi-Messaoud oil field, Algeria

The objective of this presentation is to show the methodology used to characterize the tectonic fracture network in the giant Hassi Messaoud oil field located in Algeria. This field is characterized by a significant number of wells (One Thousand Five Hundred) and data of various origins and forms. The data includes borehole image logs in 100 horizontal wells, cores from 1,000 wells, 2,500 square km of 3-D seismic, as well as dynamic data (production, pressure and water/gas breakthrough) for most of the wells. The fractures are complex objects to analyze. Because their scale is greater than the diameter of the borehole, it is necessary to take into account all the indices (seismic, physical and dynamic) to characterize them. In the Hassi-Messaoud field, tectonic fractures are clustered and associated with faults, and/or organized in fracture swarms. When they are cemented and the matrix is damaged by silica, they behave as barriers. In contrast, when the fractures are open, they provide a preferential path for fluid flow. The fracture network induces anisotropy of permeability, which has a strong impact on the development of the field. A synthetic map, which combined all available information, was constructed to predict and model conductive and barrier trends. The fracture network characterization improved the development of this mature field.