Physical and Chemical Processes During the Carbonated Water Flooding in the Oilfields

Abstract

Abstract Physical and chemical processes in oilfield reservoirs developed by carbonated water flooding were much more complex than previously thought. We have shown that these processes are directly related to the problem of hydrocarbons origin. Over the long time, this problem has not been solved in the debate between supporters of the "organic" and "inorganic" hypotheses. We adhere to the concept of biosphere origin of oil and gas, which allows to solve this problem differently. It considers the origin of oil and gas not only as long geological process, but also as a modern phenomenon, which is closely associated with the geochemical cycling of carbon through the Earth's surface with meteogenic waters. One of these processes is phenomenon of decomposition of carbonated water on surface of mechanically activated matrix of rocks, which occurs with formation of free hydrogen (H2) and low temperature synthesis of hydrocarbons from carbon dioxide (CO2) and water (H2O). In recent decades, it was accumulated many facts in support of the biosphere concept. However, some issues of hydrocarbon origin in this concept demanded special study. Our laboratory experiments performed in the dynamic and stationary modes allow to successfully solving this problem. We present the results of measurements of the rate decomposition of carbonated water under conditions simulating activated rocks of sedimentary cover. In our experiments, in a role "activator" of rocks we used an iron shaving. The experiments were performed at room temperature and atmospheric pressure. The research results are useful for technologies to improve oil recovery by maintaining reservoir pressure due to carbon dioxide (CO2) injection and recycling CO2 technologies, and storage of carbon dioxide in depleted oilfields, as well as technology to justify the production in oilfields with low-permeability reservoirs. Our research suggest that under certain conditions, injection of carbonated water (as well as CO2 in gas form) into reservoir beds, due to synthesis of hydrocarbons by the reaction CO2 + H2O, permits to increase oil recovery of depleted oil fields as well as increase the effectiveness of CO2 disposal in water-bearing stratum of the gas fields.