ABSTRACT The paper illustrates, using a field example, how well test data can be used to evaluate matrix block size and fissure volume in fissured reservoirs. The method is based on type-curve analysis with a recently published type-curve for double porosity reservoirs, and is applied to two tests on the same well, performed at a few years interval, with reservoir pressure above and below the bubble point, respectively. Detailed analysis of the two tests is presented, that yields consistent values for fissuration parameters, ω and λ, although pressure behavior during the tests is very different. Interpretation results were used as inputs to a numerical reservoir simulator, which was then calibrated against actual performance history to yield the size of the matrix blocks. The result was in excellent agreement with that obtained from λ, and with available geological, information.