Calculation Of Heat Loss During Steam Injection For Wellbore Of Heavy Oil Recovery

The main of heavy oil recovery is steam injection of thermal recovery in China and its output exceeds 80 percents. Based on the research object of the wellbore and the purpose which increasing the steam mass quality injected into bottom hole and improving energy utilization ratio of the steam, this paper has launched the basic theory and on-the-spot experimental study. The main research contents of the paper include:1.Study on the ways of the thermal recovery of heavy oil and the mechanism of steam stimulation recovery.The ways of the thermal recovery of heavy oil include hot water driving, steam driving and steam stimulation recovery. This paper recommends mainly to the steam stimulation on recovery, including three stages of steam injection, soaking time and recovery oil. Based on this and combined domestic and international relevant research results, this paper is discussed on the increasing production mechanism.2.Comparison of simulation calculation and experimental study of heat loss for wellbore.By using the subject knowledge obtained from heat transfer, thermodynamics and hydromechanics etc, the heat transfer processes in wellbore are analyzed. Based on these, the general computational model for wellbore heat transfer is set up, which gives more development through taking references from the existing domestic and foreign investigation results. Some calculation conditions in this model are as follows: the variable parameters are the evaporation temperature and the pressure; different structures of insulation tube are taken into consideration; the pressure drop is calculated by two-phase flow theory; the sectional correlations are used for different heat transfer process in this model, it is suitable to use the figure method to calculate. For the calculation of tD, Hasan formula is advised selecting and using while calculating. According to the practical computational results, the effects of well inlet steam injection parameters(speed, mass quality and time, etc)variability on the well bottom steam parameters(pressure, temperature, mass quality and heat loss)are discussed. The actual measurement of the well bottom steam mass quality is smaller than the simulation result. In response to the experimental study, the reason resulting in the error is analyzed and some modified methods are given. According to the theoretical and experimental investigation results, some suggestions about improving the performance of insulation tube are put forward.