Research On Injection-Production Relation Of In-Situ Combustion Based On Oxidation Kinetics

The kinetics of crude oil oxidation is the basic theory of in-situ combustion.It provides a basis for numerical simulation and reservoir engineering calculation.The study of the oxidation kinetics of crude oil can make the development scheme reliable and feasible,and promise a successful in-situ combustion project.In this paper,several common experiment methods of crude oil oxidation kinetics are compared and analyzed.The scope of application of each kinetic experiment is stated with advantages and disadvantages.The influence of reaction order and reaction mechanism function on the calculation of kinetic parameters is analyzed by the single scan rate method based on the data of thermogravimetric experiment.The results show that in the process of crude oil oxidation,reactions at different stages are distinct from one another.Thus the reaction kinetic parameters should be calculated according to the different reaction functions.Compared with the results of three different isoconversional methods,the kinetic parameters calculated by Friedman method are more accurate.Then from the perspective of oxidation kinetics,the formula of heat generation rate and heat exothermic rate of crude oil is derived,and the judge formula of combustion start is obtained.Furthermore,a calculation formula of reasonable air injection rate for fire flooding is derived.The advancing velocity of combustion front and oil production is calculated.At last,the CMG numerical simulation was used to establish a concept model of in-situ combustion,which for studying the influence of dynamic parameters on the injection production relationship.The influence of oxidation kinetic parameters of crude oil on the injection production relationship is mainly due to the change of coke combustion activation energy and the pre exponential factor of cracking reaction.This paper preliminarily explores the influence of oxidation kinetic parameters on the injection and production relationship of fire flooding.And it has a certain reference value for further development of the in-situ combustion theory.