Question

In a dual-porosity reservoir model, what distinct pressure behavior is observed on a log-log diagnostic plot during the transition between matrix and fracture flow?

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In a dual-porosity reservoir, which consists of a highly permeable fracture network and a low-permeability rock matrix that stores most of the fluid, the diagnostic log-log plot displays a characteristic dip during the transition period. This transition occurs when fluid begins to move from the matrix into the fractures to replenish the pressure drop created by production. On a log-log plot of the pressure derivative—a mathematical tool used to identify flow regimes—this phenomenon appears as a distinct &#x27;V-shaped&#x27; dip or trough. Think of this like a sponge inside a water-filled pipe: when you quickly pull water from the pipe, the pressure drops instantly, but then the water trapped in the sponge begins to seep out, temporarily slowing the rate at which the overall pressure falls. During this phase, the pressure derivative curve dips below the horizontal line that represents the fracture-only flow, eventually rising again to meet the final radial flow level once the matrix and fractures reach a state of pressure equilibrium.

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In a dual-porosity reservoir model, what distinct pressure behavior is observed on a log-log diagnostic plot during the transition between matrix and fracture flow?

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