Abstract
Crossed dipole sonic logging data has been used to improve reservoir understanding in the Southern/Marine areas of Mexico. The anisotropy analysis of the in-line and cross-line dipole waveform data provides the fast and slow shear wave travel time data and their corresponding orientation. These slowness values provide the input to a model that calculates the minimum and maximum principal stresses and the far-field stress orientation. The far-field stress orientation and stress anisotropy combined with 3D hydraulic fracture modeling is used to optimize the stimulation treatment design. The far-field stress information is also used for optimizing the perforated interval and orientation of the perforations.
Natural fractures provide many challenges for drilling, zonal isolation, and production enhancement. The detection and orientation of natural fractures is a needed key for reservoir management, and can be determined from the cross dipole anisotropy analysis. Inflow analysis from production logs has verified that the fractures identified by anisotropy analysis are open and are a major source of production in the Cretaceous section in the Marine area and Cretaceous/Jurassic in the Southern area. Mapping of the fracture orientation obtained from the sonic anisotropy analysis is used for well planning. Crossed dipole log examples in carbonate formations in Mexico will be used to illustrate how reservoir understanding can be improved with the use of this interpretation process.
