关键词: 高凝油油藏, 自生热压裂技术, 井筒温度场, 热平衡方程, 数学模型

Abstract: To enhance the effect of fracturing treatment for the high freezing point oil reservoirs,it is necessary to prevent the injection of cold fluid from cooling crude oil around the wellbore,because the cold fluid may cause the wax separated or solidified in the crude oil and plugging some flowing channels.The in-situ heat fracturing technique was applied to stimulation of the temperature of injected fluid in high freezing point oil well.The heat out of chemical reactions resulted from heat-generation agent can heat up the oil layer.Consequently,the damage of organism blocking can be removed,and the cold damage of injected fluid to reservoir can also be prevented,and the productivity of oil well can be improved greatly.However,the key for realizing this technology is to forecast the bottom hole temperature profiles during fracturing treatment.In view of this point,a mathematical model for wellbore temperature profiles based on heat-balance equation was established,and the numerical computation equations using implicit difference format were set up.Aiming at an example of Liaohe Oil Field,the effects of injecting temperature,injection rate of surface fluid and concentration of heat-generation agents on the change of the bottom temperature in wellbore were analyzed.This technique can improve the fracturing treatment effect.

Key words: high freezing point oil reservoir, in-situ heat fracturing treatment, wellbore temperature profile, heat balance equation, mathematical model