Basic Experiment And Numerical Model Study Of Low To Medium Temperature Oxidation Heating In Heavy Oil

The process of economic globalization has accelerated and the level of science and technology has been improved since the twenty-first century.Thus,the global energy problem has been caused and the reserves of coal and crude oil have been reduced rapidly.The continuous development of crude oil thermal recovery technology makes it possible for high viscous heavy oil as an important replacement energy.Based on the extensive distribution,abundant reserves and huge mining value in the worldwide,the heavy oil has gradually been paid attention by experts and enterprises in the field of petroleum.In-Situ Combustion(ISC)technology has shown great potential in the thermal recovery of heavy oil because of its green,high efficiency,high recovery and universality.However,the complex physical and chemical reaction mechanism in the process of fire flooding,especially the mechanism of middle and low temperature process is more complex,and the lacking of experiment,simulation and theoretical research lead to the mechanism of medium low temperature process is not clear.The commercialization and application of the technology of burning oil layer is also greatly hindered.In order to solve this problem,we carried out basic experiments and mechanism studies on the kinetics of middle and low temperature oxidation of heavy oil based on previous research results.In order to study the thermal exothermic characteristics of low temperature oxidation in heavy oil and obtain the corresponding thermodynamic parameters such as heat release rate and heat discharge,the study method of oxidation kinetics of heavy oil at home and abroad has been compared.At the same time,considering the high temperature and pressure environment of the oil reservoir,the high pressure differential scanning calorimeter is selected as the experimental equipment and a set of basic experimental methods for low temperature oxidation of heavy oil under controlled conditions is established.Also the thermal physical parameters of the target heavy oil has been analyzed.Based on the leading,widely applicable and advanced reservoir numerical simulation software CMG in the petroleum industry,a set of complete numerical simulation methods for exothermic process of the low and medium temperature oxidation is established innovatively,which contribute to the simulation of the low temperature oxidation and exothermic process in heavy oil and acquisition of the low temperature oxidation reaction kinetic parameters.In addition,the simulation method has been extended to the numerical simulation of low temperature oxidation of heavy oil under porous media scale.The two heavy oil(Z18-F3316 and Z18-FHW3076)in the Xinjiang oilfield is selected as the target heavy oil,and the experimental data of its viscosity,density,molecular weight and four component distribution have been obtained.Based on the PDSC experimental device,the heat release rate curves of 1,2 and 3MPa with the heating rate of 1,2,3 ℃/ min and the gas injection rate of 50ml/min are obtained.Based on the CMG numerical simulation software,establishing a numerical model of the low and medium temperature oxidation exothermic process with the STARS module,history matching the experimental thermal property parameters of the target heavy oil in the numerical model with the WINPROP module,and analyzing the sensitive parameters that influencing the reaction heat release greatly and history matching the cumulative heat released of the experiment with the CMOST model.The kinetic parameters of the medium and low temperature oxidation reaction model have been obtained finally.Based on the established simulation method,a numerical model for the “diffusion-reaction seepage” process of heavy oil at the porous media scale is established for the further research.The results of this study have a certain guiding significance for the numerical simulation of the low temperature oxidation process in the ISC process and also help to explore the start-up and control methods of the in-situ oxidation heat generation in the heavy oil reservoir.