Experimental and numerical analysis of using thermochemical injection for preheating to improve in-situ combustion of bitumen

High production cost, inefficient energy utilization, high water requirement, and environmental pollution are the major challenges to heavy oil production through the conventional steam injection method. Thermochemical fluid injection is a novel and environmentally benign technology for in-situ generation of heat and nitrogen from the exothermic reaction of certain chemicals. Thermochemical stimulation offers several advantages including minimal heat loss and reduced emission of CO₂ compared with steam injection. This study aims at harnessing the potential of injecting thermochemical fluids (TCF) to preheat the reservoir for improved in-situ combustion of bitumen (TCF-ISC). Bitumen sample was preheated using TCF (ratio: 10 ml TCF: 5 g bitumen) or steam. Thermogravimetric Analysis (TGA) was conducted to compare the combustion characteristics of original bitumen sample (B₀), those pre-treated using steam (B₁) and TCF (B₂). In addition, numerical simulation studies were performed to evaluate the performance of the proposed process. The thermochemical reaction produced temperature and pressure of 67 °C and 1600 psi, respectively, and ΔH = 370 KJmol⁻¹. The SEM-EDX analysis show that TCF treatment created open cavities on the matrix of the bitumen sample (B₂) which strongly supports potential to increase thermal communication during the ISC process. The thermogravimetric analysis (TGA) show that the TCF treatment of bitumen sample improve combustion performance with higher exothermicity and reactivity. These results revealed higher combustion reactivity and higher potential for combustion front propagation with TCF. Moreover, numerical simulation confirms higher cumulative oil production (m³), oil recovery factor (%), and lower heat loss (GJ/m³) using TCF preheating before the ISC.