Laboratory in situ combustion experiments were performed to determine the basic parameters prior to field projects, using a self-made combustion tube and S1-38-330 crude oil from Liaohe Oilfield. These basic parameters, the oil’s ignition temperature range from 340 to 360 °C, the apparent atomic H/C ratio of 1.044, the oxygen utilization of 52.15%, the oil recovery factor of 78.6%, the combustion front movement velocity of 0.20 cm/min, the maximum fuel consumption of 28.99 kg/m3, and the maximum air requirement of 298.6 N m3/m3, etc., were determined in the experiments. The gas chromatograms showed that the crude oil had undergone a series of pyrolysis reactions during combustion, and it could also be proved via the results of aromatics mass spectrometry that anthracene was generated during this process.

In order to investigate the catalytic effects of transition metal oxides submicro-particles on aquathermolysis of Liaohe extra-heavy crude oil, the catalysts NiO, α·Fe2O3 and Co3O4 are used and evaluated during the experiments. The optimum mass fraction of the catalyst and water was determined to be 5.0 wt% and 30 wt%, respectively. The optimum reaction time for aquathermolysis was 24 h, and the optimum reaction temperature was 240 °C. The analysis results showed the heavy oil was upgraded dramatically by addition of the catalysts based upon viscosity reduction, saturate/aromatics/resins/asphaltenes analyses, elemental analysis, Fourier transform infrared spectroscopy and gas chromatography. All results show the heavy oil is in situ updated dramatically by catalytic aquathermolysis under the optimum operating conditions. A five-lump model is proposed for estimating kinetic parameters of aquathermolysis and agrees well with the experimental data.

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The purpose of the research is to propose a novel method of mobility control of condensed water by melamine during steam flooding process. Melamine is working as water permeability modifier in a non-foaming manner to control mobility of condensed water, supported by the theoretic analysis. Wettability alternatation, water residual resistance factor, and oil displacement efficiecy by melamine addition were investigated in the experiments. The contact angle was decreased by 3.6° at 200 °C indicating that the core tends to be more water wet upon addition of melamine. Water residual resistance factor, approximately representing water/oil mobility ratio, increased in response to the temperature elevation and increased pore volume during melamine injection. Water residual resistance factor reached close to 1 after subsequent hot water flood, which indicated that the reduced water permeability by melamine precipitation could be restored. The oil recovery by saturated melamine injection was increasd by 11.7% when temperature dropped from 200 to 160 °C, in comparison with pure water flooding under the same condition. The results verify the feasibility of melamine to enhance oil recovery by controlling mobility of condensed water in a steam flooding process.