Study On Three Dimensional Seepage Mechanism And Productivity Mode For SAGD Vertical Well And Horizontal Well Combination Of Heavy Oil Production

Steam-assisted gravity drainage technology(SAGD)is an advanced science technology of production super heavy oil.Compare SAGD with vertical wells steam flooding,the advances of SAGD is that the oil recovery and recovery rate are higher and quicker in thick layer,the disadvantage is the consumption of steam is great,in thinner layer and poor quality reservoir,the production technology demand is higher to use the single well SAGD production model.The spread of the steam chamber and the formation of hot connection in tradition steam flooding are important,which is the same in SAGD.However,the diversity of the well arrangement can take advantage of the steam expansion effected by the steam overlay,and take advantage of the hot fluid discharged by gravity and displacement pressure.Moreover,the synergy of overlap and discharge,make reservoir internal heat convection strength increase,and the heat reservoir connection effect is better.Therefore,depend on the combined action of gravity and displacement pressure to develop the heavy oil,the SAGD improving gradually became the perfect technology of thermal recovery.Besides,the current theory research in oil field about the percolation theory and the production of three-dimensional percolation mechanism are not clear,with the mainly aid of experience on-site management and application,the problem is exposed that theory and practice are not synchronized about the vertical-horizontal SAGD technology.The dissertation contrapose three-dimensional percolation mechanism research of vertical-horizontal SAGD technology,established a function of heavy starting pressure gradient and flow-degree by experimental study,using the results to analyze the condition of gravity drainage function.At the same time,by three dimensional physical model experiment,it reveals the theory of recovery degree and divide stages of production about the vertical-horizontal SAGD.In the perspective of theoretical research,using the potential establishment of a three-dimensional superposition method developed seepage mathematical model,it shows the three-dimensional visual flow field development trends,and analyzes the gravity effect on reservoir fluid particle movement direction.In three-dimensional seepage rule,considering the nature of the overlap of steam,it describes the development process of the morphology of the steam chamber,and then analyzes the mechanism about the combined action of gravity and the pressure.Studies have shown that there is a lag phenomenon between the migration of vapor phase and front liquid in vertical-horizontal SAGD production process,through the steam chamber mechanism of fluid phase behavior analysis,putting forward the productivity prediction model based on steam overlap assumptions,and comparing with the experimental results can validate that the productivity prediction model can be effectively used in oil field production process capacity trend prediction.The dissertation working on the new vertical-horizontal SAGD well group which proposed by oil field aimed at unused reserves in bottom layer for controlling the bottom water coning.The preliminary analysis confirms that the new well group can effectively explorate the bottom heavy oil and have a good control effect for bottom water.Also,it can confirm that the three-dimensional seepage mathematic field model has a certain extension.The study for vertical-horizontal SAGD production theory research provides the foundation and basis,also has a certain significance to enhance oil recovery in oil field.