FRACTURE CHARACTERIZATION IN THE MIOCENE MONTEREY USING RESISTIVITY IMAGING, INTERVAL TESTING, AND DIPOLE SONIC TECHNIQUES

The Miocene age Monterey formation of coastal California is a prolific producer from extensive fracture systems. These zones were originally bypassed because there was no effective way to detect and evaluate fractured reservoirs. Modern day characterizations attempt to define spatial distributions to predict intersections of fracture sweet spots with oil columns in the reservoir. Fracture orientation and density are robustly defined by resistivity imaging methods. Detailed fracture identification and classification analyses provide reduction of fracture images to 1 or 2 dimensional vectors for inclusion in reservoir models. Relationships between faulting / folding and fracturing can also be observed with this methodology. Interval testing has been employed to identify the fluid content, permeability, and skin damage within fractured zones. Inflatable packers on a modular dynamics test tool, deployed with drillpipe conveyed logging techniques, have been used to evaluate intervals selected from the image logs. Dipole sonic data has been utilized to examine the anisotropy found in fractured and faulted zones. Low frequency sonic analysis has been used to evaluate relative permeability in fractured zones. Combining these methodologies provides for an understanding of the Monterey fracture systems previously not possible. Enhanced reservoir exploitation is the result.