| The transition zone three and four strips of zone A were put into development in 1971,and after 50 years of water injection and development,the comprehensive water content rate was as high as 96.0%,which was influenced by high crude oil viscosity,strong formation inhomogeneity and high oil-water well number ratio,resulting in low water drive control,uneven plane pressure,poor injection and recovery condition and low recovery degree in this zone.Due to the above problems,the study area was encrypted and adjusted in 2019,in which the south area was encrypted with 150m five-point method area well network;the north area was encrypted with 150m inverse nine-point method area well network.Therefore,the evaluation of the water drive development effect of the encrypted reservoir,the study of the remaining oil distribution characteristics and the study of the reasonable injection and extraction parameter boundaries on the basis of a renewed understanding are the keys to improve the recovery rate of the reservoir.This paper takes the transition zone of area A as the research object,firstly,based on the analysis of reservoir geological condition and production and development dynamics,a three-dimensional fine geological model is established,the geological reserves and water content rate are fitted historically and the remaining oil is studied,then reservoir engineering methods and numerical simulation techniques are applied to evaluate the production,oil recovery rate,integrated water content rate,water drive index,water storage rate,water consumption,recoverable reserves and The factors affecting the development effect were determined to be crude oil viscosity,reservoir inhomogeneity,well network density and the number of injection and extraction wells ratio,water drive control degree and well spacing,water drive index and water storage rate,etc.Finally,the reservoir engineering method was applied to determine the reasonable injection and extraction ratio in the north and south zone,the The reasonable injection and extraction ratio of the north and south zones,the reasonable injection and extraction intensity of the whole zone,new wells,old wells and each formation system,the transition period of injection intensity and the reasonable extraction intensity of the whole zone were determined by numerical simulation technology.The study showed that the recoverable reserves in the north zone increased by13.87×10~4t and the recovery rate increased by 3.05 percentage points after encryption,while the recoverable reserves in the south zone increased by 26.25×10~4t and the recovery rate increased by 4.76 percentage points.The numerical simulation study came up with a reasonable injection-to-recovery ratio of 0.9-1.1 for the north zone,1.5-1.7 for the south zone,6.80-7.37 m~3/d.m for the whole zone,7.35-8.08 m~3/d.m for the old wells and6.10-6.67 m~3/d.m for the new wells,and determined a reasonable injection intensity for the old and new wells The transition period is 24 months,and the reasonable fluid production intensity for the whole area is 4.27-4.62m~3/d.m.The fluid production intensity for the north area(anti-nine point)is 2.32-2.56m~3/d.m,and for the south area(five point method)is6.07-6.71m~3/d.m. |
