The Mechanism And Application Of SAGD In Heavy Oil Reservoir With Bottom Water

Heavy oil reservoir with bottom water is difficult to be developed.The production method with steam cannot do well in this situation.Steam Assisted Gravity Drainage(SAGD)is an effective method to decrease oil viscosity and control the coning of bottom water.For these reasons,SAGD becomes the important technology in heavy oil reservoir development.In this paper,author studies the mechanism and application of SAGD through physical simulation,numerical simulation and theoretical research.Reservoir pressure and bottom water volume are the two limitations in the physical simulation.Design the new experimental facilities which can be safe under 20 MPa.The new facilities can be used to study the Bohai oilfield which is deep burial.Get the experimental parameters through similarity criterion.Get the relationship among reservoir pressure,bottom water volume and gas volume to maintain pressure.It shows that there is a linear relationship between reservoir pressure and gas volume.This study provides the possibility to simulate the heavy oil reservoir with large bottom water and high pressure.Based on LD5-2N reservoir parameters,the experiments are carried out about cyclic-steam-stimulation(CSS)preheating stage and SAGD producing stage.Investigate the advantages and disadvantages of CSS to preheat the reservoir.Divide SAGD producing stage into more detailed stages.Extend the physical simulation with numerical simulation software.In the study,pay the attentions to the influences of bottom water volume,oil column height and vertical permeability on CSS and the influences of bottom water volume,oil column height and injection pressure on SAGD producing.Develop the new model about heat exchange near the steam chamber interface during steam chamber extension stage.In the new model,conduction heat transfer and convection heat transfer are considered.And the oil flow normal steam chamber interface is the point in this study.The results calculated through new model can match the UTF data well.For the reservoir with bottom water,the new productivity formula is got considering the oil loss in bottom water.The influences of injection pressure and velocity of steam chamber extension on production are studied.Develop the simulation model about Bohai oilfield.Protract the theoretic plate for reservoir screening,well spacing optimization and injection parameters optimization.Combing the characteristics of offshore oilfield and the plates,the heavy oil reservoirs with bottom water can be developed efficiently.Taking advantage of the results,the development of LD5-2N reservoir is studied.This study can be the guidance to exploit the heavy oil reservoir with bottom water with SAGD method.