Fracture Evaluation of Block P-0315, Point Arguello Field, Offshore California, Using Core, Outcrop, Seismic Data and Curved Space Analysis
M. J. Padgett, D. C. Nester, 1991. "Fracture Evaluation of Block P-0315, Point Arguello Field, Offshore California, Using Core, Outcrop, Seismic Data and Curved Space Analysis", The Integration of Geology, Geophysics, Petrophysics and Petroleum Engineering in Reservoir Delineation, Description and Management, Robert Sneider, Wulf Massell, Rob Mathis, Dennis Loren, Paul Wichmann
Download citation file:
The fracture system in the Miocene Monterey section at Point Arguello Field, was studied to find the relationship between fracture intensity and local tectonic structure. The analysis included five studies: seismic structural mapping, seismic amplitude, outcrop, core, and surface curvature. The goal was to develop a predictive and quantifying methodology for the exploitation and exploration of fractured reservoirs of the type found in the Point Arguello field.
A detailed structure map on the Monterey chert member was constructed from a 3D seismic survey on a Landmark workstation. The time structure map was depth converted with an accuracy of ±100 feet to the lithologic Monterey chert unit within existing well control. Seismic amplitude studies were performed to relate fracture intensity to a reduction in seismic amplitude across the field. An outcrop study was performed at Lion's Head fault to determine the relationship between the distance to a large fault and fracture density. A statistical evaluation of core analyses for 6 wells by Terra Tek (Salt Lake City) was performed to evaluate the variability of fracture intensity as a function of structure.
The surface curvature analysis consisted of treating each fault block as a 2 dimensional curved space (closed-compact 2D manifold in R3). At each point the distance to the boundary (faults) was determined as well as measures of the local curvature. The Gaussian curvature, ellipsoidal curvature and second derivative were used to characterize the curvature. The distances to faults and curvature measures were correlated to core analyses and to each other. Results are consistent with the outcrop and core studies, and indicate an ability to use the topology of a seismically derived structure map to predict fractured reservoir parameters.