| Heavy oil is very abundant in reserve and it will be the main recovery target in China and all over the world.At present,the main recovery method for heavy oil is thermal recovery,which is decided by the high viscosity property of heavy oil.In recent years,with the development of horizontal well technology,it has been successfully applied in heavy oil recovery.Compared to vertical wells,horizontal wells could help the reservoir obtain more vapor injection and oil production,especially in thin heavy oil reservoir.With consideration of this tendency and in order to insure all the integrated treatment be effective,it is very worthy to study the well testing analysis method to precisely obtain heavy oil reservoir dynamic parameters.Due to the complexity of heavy oil recovery itself and horizontal well interference,it is very hard to build the interpretation model and the solving method is also difficult to get,thus the acknowledgement of the horizontal heavy oil recovery dynamics is limited.After lots of investigation,based on the combination of heavy oil reservoir thermal recovery model building method and conventional reservoir horizontal well model solving method,well testing interpretation models for horizontal well in two-section composite heavy oil reservoirs of single medium and dual porosity medium are established separately,through Laplace Transform and Fourier finite cosine integral transform,the vertical line source solution is achieved,then through the superposition integral along horizontal direction,the banding source solution formula is got,finally,the horizontal equivalent line source solution is deviated.Based on this,in order to stimulate the real reservoir more precisely,well testing interpretation models for horizontal wells in three-section composite heavy oil reservoirs of single medium and dual porosity medium are established separately with consideration of the transition characters of vapor zone and cold oil zone.At last,considering the effect on fluid viscosity in heating zone because of the temperature variation caused by heat carried by production fluid and heat conduction,well testing interpretation model for horizontal wells considering temperature variation in heavy oil thermal recovery is established,then the solution and the formation pressure distribution graphs in different moments are got with finite element software and the parameter sensitivity analysis are carried out. |
