In situ steam and nitrogen gas generation by thermochemical fluid Injection: A new approach for heavy oil recovery

Thermal recovery techniques such as steam injection are very popular methods used for heavy oil recovery. However, several challenges including high cost of steam generation, low heat transfer efficiency and/or heat loss, geotechnical and environmental issues are threatening its sustainability. In-situ generation of steam and nitrogen gas through injection of certain exothermic chemical reactants (thermochemical fluids – TCF) can be employed to alleviate these challenges. The present investigation focuses on experimental, numerical simulation and economic studies to assess this novel technique, and to compare its performance with those of conventional steam injection methods. This comparison is based on the recovery factor (RF) and the net present value (NPV). It was generally observed that the proposed TCF injection performed better than the conventional steam injection method. From the core-flooding experiments, higher recovery was achieved through the TCF (RF: 82% of the oil in the core sample) compared with that of the steam injection (60% of the oil in the core sample) with 1.7 PV (pore volume) and 1.8 PV, respectively. In addition, from the field scale simulation over 10 years of production, the RF achieved using the proposed TCF injection method and the conventional steam injection methods are 50% and 40%, respectively; while the NPV are USD 9.8 × 10⁶ and 2.4 × 10⁶, respectively.