Numerical Simulation Study Of CO₂ Huff And Puff About The Laws On The Control Of Water In The Horizontal Wells Of Heavy Oil

In view of heavy oil reservoirs for the high permeability,edge and bottom water sufficient energy,the use of horizontal wells,when production wells enter the high water cut stage,the simple use of natural capacity and the way of water injection can not meet the production needs,so CO₂ huff and puff test was carried out to study for controlling water and increasing oil.First of all,the case of CO₂ huff and puff in heavy oil horizontal well is analyzed by category.On the basis of understanding the actual case,175 typical schemes are designed by considering 19 different geological,development and technological factors,and the typical model was established by using the component modules of the numerical simulation software Eclipse.The regularity of each factor is studied,and the sensitivity of each factor in the process of the CO₂ huff and puff is evaluated,and the main control factors are selected.It bases on the increasing volume of CO₂ huff and puff to establish well selection methods and evaluation methods of well selection in heavy oil horizontal well,which provides technical support for the CO₂ huff and puff of the edge and bottom water heavy oil reservoir with horizontal well.The main research and achieved the following results and understanding:According to the statistics of CO₂ huff and puff case analysis in heavy oil horizontal well that the larger reservoir thickness,the interlayer,the high position of the structure,the horizontal section locating in the middle and higher the water cut before huff and puff factors are beneficial to control water and increase oil in the process of the CO₂ huff and puff.The huff and puff laws of different geological,development and technological factors are analyzed,and it evaluates the sensitivity of various factors on CO₂ huff and puff in heavy oil horizontal wells from the increased oil and the water cut after huff and puff.That heterogeneity,the time of huff and puff,parallel well distance,parallel wells producing liquid rate and the round of huff and puff is the main sensitive parameters,and determines the stimulation effect.A standard of reservoir screening on CO₂ huff and puff for horizontal wells in heavy oil reservoirs is presented.Based on the sensitive factors and the influence law of the 3 round CO₂ huff and puff of the 175 typical model in heavy oil,by using analytical hierarchy process and fuzzy comprehensive evaluation method,the selection method and evaluation method with quantitative index system of CO₂ huff and puff for heavy oil horizontal well are established.The research shows that the score of the evaluation method is higher than 0.7,and the production well can be carried out CO₂ huff and puff.