Perspectives of Hydrogen Peroxide Injection to the Carbonate Reservoir for ISC Initiation

Abstract

Abstract As part of laboratory and numerical investigations, an assessment of hydrogen peroxide (H2O2) injection efficiency was performed to estimate the ability of H2O2 to increase the productivity of heavy oil field development. The combined effect can be observed, including heat release due to H2O2 decomposition and oxidative reactions with oil during the in situ combustion (ISC) process and increased oil mobility due to CO2 dissolution. Laboratory experiments were performed on an autoclave to study the decomposition of peroxide in conditions close to the reservoir (pressure and temperature) and obtain experimental values of the kinetic parameters of the H2O2 decomposition reaction. Further, these values and experimental parameters were integrated into a homogenous numerical model representing the target oil reservoir. Also, during the laboratory experiment, the optimal value of the H2O2 concentration was determined for subsequent sensitivity analysis. The numerical model was then used to build a Tornado diagram and to estimate the effects of preheating, operational parameters, reservoir properties and kinetic parameters with or without catalysts in the system. According to the results of the hydrodynamic modeling, efficient heating of the formation to high temperatures (over 100°C) during the injection and decomposition of H2O2 is possible only in the presence of a catalyst. The bottomhole formation zone temperature with a catalyst can reach up to 350°C. The most significant influence on the cumulative production is provided by the injection rate, reservoir permeability, initial temperature of the injecting fluid, as well as the thermal properties of the rock. When the temperature reaches 300°C, the reaction of peroxide decomposition begins to accompany the ISC of oil, which is self-initiated, since there is a sufficient amount of oxygen in the formation formed during the decomposition of H2O2. An effective application of the technology is possible during a sufficiently fast rate of the peroxide decomposition to avoid the dissipation of the released heat due to two possible mechanisms: heating (up to ~150°С) of injected agent (effective, but it is associated with additional costs for equipment and technological risks);use of widely available and cheap catalysts. As a result of the work, the most promising strategies of H2O2 injection technology for heating a carbonate reservoir were identified. The option of full-scale injection of the H2O2 is associated with high costs and limited development rates. This method can be applied to objects with specific conditions of elevated temperatures where the peroxide decomposition reaction will be the most active.