The reservoir-rocks contact rock contact surface limiting the size of the permeable petroleum reservoir where the practical fluid flow may occur.
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Most well tests can only detect the dynamic effect of the reservoir flow boundary or its absence (infinite acting reservoir flow boundary).
There are some production analysis techniques based on long-term production data readings which can reveal the size of the actual petroleum reservoir (see for example Multiwell Retrospective Testing)
The actual petroleum reservoir is always constrained in volume but in most practical applications the observation time is too short to see the effects of the reservoir boundaries (see ).
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[ Infinite reservoir boundary ] [ Reservoir flow boundary ] [ Multiwell Retrospective Testing (MRT) ]