Abstract

Study of key parameters of reservoir viz, porosity, water saturation, permeability and pore size distribution from well logging data is more complicated in carbonate reservoir due to geological heterogeneities than Clastic reservoir. In homogeneous reservoir, where the grains are regularly shaped and pore space may be complicated and intergranular, the evaluation and transformation of parameters can be done through empirical equations. But it is very difficult to evaluate these parameters in carbonate reservoir due to post depositional changes i.e. diagenesis, such as recrystallization, dolomitization, cementation, compaction, and dissolution. Crystallization & dolomitization may increase or decrease porosity and permeability, Cementation and compaction, reduces porosity to very low values because of pore size decreases as grain size and sorting decreases, while dissolution/leaching develops vugs and fractures, which may result in large variation in porosity and permeability of carbonate rock.