Reservoir effectiveness is a key factor restricting the efficient development and also one of the difficulties in reservoir evaluation. Formation C and J of the T oilfield in Syria are carbonate fractured reservoirs. The diversified storing space

complex lithology

pore structure and other reservoir characteristics lead to high porosity and low permeability of matrix pore. Although fractures formed by tectonic action have improved reservoir’s seepage capacity significantly

there still have great ambiguity in fracture effectiveness well logging interpretation. It is urgent to establish a criterion for the effectiveness of matrix-fracture complex carbonate reservoirs. According to the above problem

geology and rock physics analysis such as core observation

scanning electron microscopy（SEM） and mercury injection data are used to calibrate well logging. In combination with multivariate statistical method

the comprehensive evaluation standard of reservoir effectiveness

including the lithology

physical properties

pore structure characteristics

logging response and reservoir parameters like reservoir quality factor and flow index of different reservoir storing space

has been established. This study provides technical support for comprehensive evaluation and efficient development of such complex carbonate reservoirs.