Abstract

In a previous research (IPTC 14187) a new technique was introduced to characterize all kinds of naturally fractured reservoirs on the Megascopic scale of pressure transient analyses. The technique is optimized through application of pressure derivative methods to yield a very characteristic graphical representation (triangle) of each hydraulic "flow" unit in the fractured reservoir.

The graphical technique along with newly derived formulas yield the most important petrophysical and engineering parameters about the heterogeneous naturally fractured reservoir including effective fractures, matrix and skin systems volumes, partitioning coefficient, fracture intensity index, formation resistivity factor, formation tortuosity, effective drainage radius, damage radius, effective cementation exponent, fracture porosity, matrix porosity, storativity ratio, in addition to fracture permeability, matrix permeability, damaged permeability, average permeability, pressure drop across the damage area, skin factor, damage permeability, average/dimensionless diffusivity factor, flow efficiency, damage ratio/factor, economic implication of formation damage, average hydraulic "flow" unit quality index.

The technique is extended to derive the fracture partitioning coefficient and intensity index in terms of storativity ratio generated from the fractured triangle of pressure transient analyses along with new fracture/matrix permeability ratio and fracture/matrix porosity ratio are introduced to aid describing the degree of reservoir heteroginity. Again the graphical technique of the fractured triangle has proven to be successful for all kinds of fractured reservoirs including clastics, carbonates and basement rocks. This study will present the theory along with successful field application with the results.

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