Relationship Between Grain Size and Physical Properties of Dolomites in Order to Geomechanics Study of Dolomite Reservoirs

Based on the extensive studies which have been done, undoubtedly, the role of the wave velocity data of rocks in hydrocarbon reservoir evaluation is absolutely vital. Within, it is important to study the wave velocities in the Dolomites, which often make up one of the best parts of hydrocarbon reservoirs in the carbonate system. Certainly, the texture of rocks, mineralogical composition, grain size, percent of quartz in rocks, and many microstructure properties affect the Engineering and Physical Behavior of rocks. According with previous studies and to better understanding this relationship, a comprehensive program of tests on the three categories of dolomite with fine, medium and coarse grained were designed. In this paper, the results related to the measurement of compressive (Vp) and shear wave velocity (Vs) for 32 samples are given. According to the results, with increasing in grain size, density of rock decreases. The compressive and shear wave velocity for fine grain and coarse grain samples were found to be %9 and %12 lower, respectively, than those for the medium grain samples. The results showed that for fine, medium and coarse grain samples; moreover, the ratio of Vp/Vs is 1.78, 1.81, and 1.77 respectively. It was also observed that the dynamic Young›s modulus for the medium grain samples approximately 15% of the fine grain samples and approximately 27% of the coarse grain samples is more. In addition, it was found that a significant change does not occur in Poisson›s ratio of the studied rocks with an increase in grain size.