Artificial carbonate rocks: Synthesis and petrophysical characterization

Carbonate rocks are important for rock properties research because they are linked to significant oil and gas reserves around the world. The goal of synthesizing carbonate rocks in laboratory is to simulate the natural carbonate rock matrix regarding the main factors of lithification such as grain size and shape, concentration of cementing material and compaction pressure, and allowing the production of rock specimens that can be used for tests in extreme conditions in replacement of the high cost natural cores. The reproduction of rocks in laboratory also allows to access samples with predetermined characteristics enabling a better understanding of the relationship between their physical properties. In this work, samples of synthetic carbonate rocks were made by mixing a fixed amount of calcite and sand, and varying the amount of cement material (Portland cement and water) aiming to reproduce a primary interparticle por system. The behavior of the main petrophysical characteristics of these samples was investigated, such as porosity, permeability and P- and S-wave velocities versus the amount of cementing material. The results were compared with natural carbonate samples and showed a high similarity to the petrophysical behavior of mudstones rocks. That similarity points out the feasibility of those synthetic rocks to be used as analogous of mudstones, specifically those exhibiting only primary porosity, in experiments regarding rock physics, core flooding or rock mechanics.