Physical Simulation Study of In-Situ Combustion by a Chemical Self-Propagating Igniter

The technology of electric ignition and in-situ combustion for heavy oil reservoir suffers from the fact that it has a high ignition temperature and a low ignition success rate.A chemical self-propagating igniter was introduced to solve these problems.Its effect and influence factors were analyzed by physical simulation.According to the principle of self-propagating,the ignition agent was prepared with ammonium nitrate and citric acid as the main raw material,and the simulated core was prepared.The simulated ignition test was carried out on a simulated test device.The influence of the viscosity of crude oil,core porosity,oil saturation and water content of crude oil on the combustion of simulated core was analyzed through experiments.The results showed that the ignition temperature of self-propagating igniting agent was only 100-200℃,and the minimum temperature was 98℃.The ignition temperature of igniter increased with the increasing of viscosity of crude oil.The porosity of the core did not affect the ignition temperature,but the degree of combustion and the highest combustion temperature could increase with the increasing porosity of the core.The oil saturation did not affect the ignition temperature and the highest burning temperature of the crude oil,but the degree of the oil combustion would increase with the increasing of the oil saturation.The water content of crude oil had an effect on the ignition temperature,the oil’s highest temperature and the degree of combustion of the crude oil.The ignition temperature and the highest combustion temperature would lower with the declining water content of crude oil,but in contrast,the burning degree would increase.The result showed that self-propagating chemical ignition could ignite the crude oil safely and reliably and carry out thermal flooding.