4D Seismic Application To The Development Of Heavy Oil Thermal Recovery

4-D seismic(also called time-lapse seismic)is a modern technology used for reservoir dynamic monitoring and evaluation,which was produced in the middle of 70s in the 20th century and achieved a great development in the 90s.It is a very promising method used for researching the variations of reservoirs on the basis of the differences between kinematic and dynamic seismic of seismic wave field measured in different time.In recent years,the 4-D seismic reservoir dynamic monitoring technology has got a rapid development and become a new tool for reservoir dynamic monitoring and management.It has a great application result on the large offshore oilfields.This technology can be applied to more aspects and get more accurate results with the development of petrophysic and its associated technologies.Currently,this 4-D seismic technology plays an important role in monitoring oil recovery changes,oil displacement efficiency and fluid front in reservoirs,looking for dead oil areas,and predicting the remaining oil distributions.Taking Du 84 block in Liaohe oilfield as an example,this paper mainly analyzed the different forms of steam chamber in the phase of formation and expanding during the production process of SAGD.We have systematically analyzed the favorable conditions of reservoirs,injection-production and seismic for 4-D seismic monitoring.Based on the analysis results about the seismic data in Du 84 block,it can be concluded that these seismic data in this area is very suitable for 4-D seismic monitoring.The ranges of steam sweep can be described clearly through the seismic foundation profiles and combined with the developing dynamic curves.The causes for these differences in the ranges of steam sweep can be analyzed by seismic difference profiles.Furthermore,we can analyze the reasons for the numerous degrees of these differences in the ranges of steam sweep and explain the shafts in seismic profiles when combined with the production performance data,interlayer locations and steam cavity locations.All these analyses are helpful to promote the development of 4-D seismic differences explanation technology,get a better understanding of reservoirs and predict the distributions of remaining oil.This paper systematically summarized technologies for analyzing 4-D seismic attributes,and elected those preferred attributes for heavy oil thermal recovery by 4-D seismic monitoring.Our work can set the base for difference analyses of 4-D seismic attributes.Through analyzing the differences in seismic profiles and attributes,we predicted the distributions of remaining oil in reservoirs,and put forward new plans which are helpful to optimize the development and adjustment of infill wells and extension wells,and improve the reoperation of old wells.