Effects Of Non-hydrocarbon Gases On Physical And Chemical Properties Of Heavy Oil

Qi 40 heavy oil of Liaohe Oil field has nearly 30 years history of thermal recovery processes.After years of exploitation,its oil reservoir formation pressure has been reduced to about 3MPa,which greatly increases the difficulty to mine the remaining heavy oil.On gases medium optimization,Non-hydrocarbon gases(except hydrocarbon gases)are extensive sources and more easy accessibility.For gas injection production heavy oil,it is lower cost.However,there are many unknown effects on physical and chemical properties of Qi 40 heavy oil.So this paper carried out the laboratory study on effects of nonhydrocarbon gases on physical and chemical properties of Qi 40 heavy oil.This paper firstly researches the PVT data,including solubility,volume factor and so on under different temperatures and 5 kinds of non-hydrocarbon gases.And then,this paper continues to carry out modification test analysis for further exploring effects of 3 kinds of non-hydrocarbon gases on heavy oil compositions under different temperatures.In the end,the pyrolysis reactions and kinetics character of heavy oil is analyzed by integrated thermal analyzer.PVT analysis under non-hydrocarbon gases howed that the solubility of CO2,N2 and fire-flood exhaust gas in heavy oil decreased,but oxygen-poor air and flue gas increased at first and then decreased,with he increase of temperature.As a whole,the volume factor of Qi 40 block heavy oil after saturation 5 kinds of non-hydrocarbon gases increases with the increase of temperature,and which of carbon dioxide is the biggest and the nitrogen is the smallest.The mechanisms of non-hydrocarbon gases on effects of Qi 40 heavy oil on physical and chemical properties mainly contain heating oil reducing viscosity mechanism and gas dissolving mechanism.When below 100℃,the major factor on the amount of gas dissolved,namely gas dissolving mechanism.But above this temperature,it is mainly dependent on the heating by this gases carried,that is heating oil reducing viscosity mechanism.It also found that the higher content of CO2 in non-hydrocarbon gases,the greater solubility in the same conditions and the larger the volume factor of this heavy oil after the saturated gases.The results of modification analysis in CO2,flue gas and oxygen-poor air show that the content of saturated hydrocarbon and aromatic in heavy oil decreases,while resin and asphaltene increases.The greater oxygen content of non-hydrocarbon gases and temperature,this trend is clearer.Due to CO2 is an inert gas,there is no significant effects on heavy oil besides dissolution.But the heavy oil is oxidated obviously by flue gas and oxygen-poor air to produce CO2 and resin,asphaltene and other substances,which play negative effects for heavy oil viscosity reduction.The results of TG analysis show that the presence of oxygen,regardless of the concentration,will react with the heavy oil during the heating process,and the residual weight increases with the increase of the oxygen content in the gas.For CO2 and N2,the heavy oil mainly occur pyrolysis reaction;but the others,besides pyrolysis reaction,there are a few oxidation reaction.