摘要
二、波及系数及其变化特点体积波及系数 E_v是指水驱油田水波及到的油藏体积与油藏总体积之比,它又可以分为厚度波及系数 E_z 和平面波及系数 E_p 两部分。它们之间的关系为:E_v=E_z×E_p (14)研究注水平面波及系数主要是利用油藏数值模拟和油层物理模型进行。文献[11]总结了戴斯(Dyes)等人所作的二维平面物理模型用 x
The displacement efficiency and the conformance factor in waterflooded sandstone reservoirs has been studied in this paper.Results of this study are: 1)The final displacement efficiency is mainly affected by oil water viscosity ratio and absolute permeability of layer.The correlations are consistent in oil field in China,Unit States and Soviet Union;2)The displacement efficiency, when production of waterflooding sandstone reservoirs is ended,may be the displacement efficiency calculated at 0.98 water cut by using oil water relative permeability curve;3)The production of waterflooded sandstone reservoir may be divided into two stages,depending on variation in the displacement efficie- ncy and the conformance factor with variatoin in water cut.Before 0.7—0.8 of water cut,increasing in the conformance factor is a main factor.After that increasing in the displacement efficiency is more important,and regularity of increasing is affected by Dykstra-Parsons permeability variation of the correspo- riding formation;4)Variation in the vertical coverage factor with increasing of water cut is faster in early and slower in late stage.The vertical coverage factor reaches a maximal value in watered cut layer.The higher effctive thickness of the sandstone,the less vertical coverage factor;5)Both filling in wells and sub- division of the oil bearing reservoir are efficient technique in the improvement of waterflooding.Regularity in the subdivision of oil bearing reservoir are that permeability of all layers in the same group is higher than certain permeability of water intake capability,Dykstra-Parsons permeability variation of formation is less than 0.5,and having a better injetiing and producting pattern;6)Acco- rding to a statistical study of 25 waterflooded sandstone reservoirs in China,the average oil displacement efficiency,when waterflooding is ended,would be 0.531. The average areal sweep efficiency factor would be 0.9.The average vertical coverage factor would be 0.77.The average volume conformance factor would be 0.693.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
1989年第3期46-54,共9页
Petroleum Exploration and Development
