Developed Correlations Between Sound Wave Velocity and Porosity, Permeability and Mechanical Properties of Sandstone Core Samples

Abstract

Abstract In the evaluation of a petroleum reserve, it is necessary to accurately determine certain petrophysical properties such as porosity and permeability of the reservoir rocks and rock mechanical properties. Petrophysical properties are key factors in the reservoir description and geomechanical properties are determining parameters in drilling operations and in stimulation and hydraulic fracturing jobs and also the development plans for given reservoir. It is more convenient to use homogenous rock samples with nearly constant initial permeability; however, obtaining such cores is very difficult. In this paper a simulated natural and homogeneous compacted sandstone rock with known physical and petrophysical properties were used. Physical properties of reservoir rocks include pore size distribution; grain size, cementing material concentration, and confining pressure affect rock porosity and permeability. Sound wave velocity was measured using an ultra sound tool on different sandstone core samples. Good correlations have been developed between sound wave velocity (VP and VS) the petrophysical properties mainly porosity and permeability. Significant correlations have been found between seismic wave velocity (VP, VS and VP/VS) and mechanical parameters namely Young’s modulus, shear modulus, bulk modulus and Poison’s ratio for sandstone core samples. This study has been carried out on dry core samples and core samples with different water saturations and results showed that there are changes in the correlation between seismic wave velocity and mechanical and petrophysical properties as function of water saturation change from dry rock to water wet rock.