Conduits Characterization for Fractured Reservoirs Using Sub-Seismic Faults Convergence Intensities Mapping
El Fouly, Adel
The main objective of this study is to characterize the structurally related conduits in fractured reservoirs using 3-D seismic data. These conduits is identified and mapped by a three dimensional adaptive, multi-directional, multi-component logical operator seismic attribute. This operator is designed using total geologic concept, it is based on outlining the convergence of the sub-seismic faults as the main components of the damage zone that is distributed around the slip direction. This operator calculates gradients of the seismic abrupt change in amplitude values along 72 detection directions. It searches for the pattern where two sub-seismic faults angularly meet at a point. At these points the fluid and gas flow through the fracture network are most favorably integrated and focused. It is a decision supported operator. It recognizes the presence or absence of successive linear points sets on the detected sub-seismic faults and those that meet angularly at a convergence point. Mapping structurally related conduits, will lower exploration and development cost. It will help avoid the irreparable loss of recovery factor and the abnormal response in secondary recovery. It will help us drill only necessary in-fill wells and carry out more accurate assessment of economic prospects.
In this study examples are demonstrated for structurally related conduits characterization. The produced conduits map resolution depends on the seismic data grid size and velocity sampling interval. It shows different distribution and texture from one lithology to another. The conduits map will help understand the behavior and geometry of the faults damage zones. Their distribution and impact on fluid flow and the possibilities for compartments existence. Continuous and discontinuous connectivity of the conduits network can be identified. This technique can't detect primary sedimentary structures and random noises. It provides an output related to the variation of dual porosity and permeability and it can be considered a supporting input for more realistic reservoir simulation. The difference in conduits distribution in intensities, different texture coarseness, equally spaced, or with specific trends are adding remarkable knowledge for characterizing stress distribution, fluid flow directions and intensities. It is a good tool for reservoir top seal fracturing evaluation, and sweet spots in fractured reservoirs delineation.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013