An experimental investigation of the proportion of mortar components on physical and geomechanical characteristics of unconsolidated artificial reservoir sandstones

Physical properties of sedimentary rocks such as porosity, permeability, bulk density, and compression-tensile strengths are directly related to the features corresponding to the rock texture. The main characteristics of rock structure are principally grain size distribution, degree of sorting, type and amount of the cement located between the discrete particles in rock framework. In this study, three different types of sandstone core samples have been artificially prepared. From each type, two specimens were used to evaluate the physical properties and tests reliability. The samples utilized here represent two different grain sizes distribution with three different textural compositions. The results indicate that the grain size distribution and water-cement ratio (WCR) have considerable effects on the physical properties of artificial sandstone plugs. According to the experimental outcomes, an increment of cement content of 15% in mortar composition would lead to 9% rock porosity reduction. Less surface area in rock structure means lower rock volume unit indicating higher rock sample density. It was observed that there is a direct proportion between rock porosity and permeability. However, the functionality of rock permeability to cement content and consequently WCR is more intensive than the porosity. In this regard, results reveal that there is a critical point of WCR above which the rock permeability shows a sharp enhancement. The outcomes also indicated that the increase of cement content would result in higher uniaxial compression strength (UCS) of the core specimens as an increase in cement content of 50% would result in three times more UCS. Besides, the functionality of UCS and cement content and rock porosity have been investigated.