岩心污染表皮系数的计算
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摘要
评价岩心污染的主要方法有两种,一是通过矿场评价获取地层污染的表皮系数;二是通过室内岩心污染实验得到岩心渗透率分布和渗透率恢复值。目前还没有利用室内岩心污染试验结果直接计算表皮系数的方法。为了把室内评价结果与矿场评价结果挂钩,研究了利用岩心污染试验后岩心渗透率分布或渗透率恢复值计算表皮系数的方法。在单相不可压缩流体做单向达西渗流条件下推导出了不同岩心污染模式下污染表皮系数计算方法;揭示了均匀污染、污染区渗透率呈线性变化、污染区渗透率呈指数变化时污染表皮系数与污染深度之间的关系;得到了岩心均匀污染时污染表皮系数与渗透率恢复值之间呈反比关系的结论。研究表明:污染表皮系数随着污染深度的增加而增大,入口端岩心渗透率越小,污染表皮系数越大;污染区渗透率与未污染时渗透率比值越小,污染表皮系数越大。
There are two methods of evaluating core contamination: one is based on the skin factor of formation contamination obtained in the field evaluation;the other on the core permeability distribution and recovery values collected through an in-door core contamination test.However,there is still no method yet of calculating the skin factor with the data collected from the in-door core contamination test.In order to make the in-door test data related to the field evaluation,this paper explores the method of calculating the skin factor with the core permeability distribution and recovery values collected through an in-door core contamination test.Then,the method is deduced of calculating the skin factors of different core contamination patterns when the single phase and incompressible fluid moves as a single direction Darcy flow.Furthermore,different relationships are revealed between skin factor and contamination extensiveness when the permeability of contaminated area are changing in lineal and exponential manners respectively.On this basis,it is concluded that skin factor and permeability recovery values are inversely proportional to each other when cores are evenly contaminated.This study shows that the skin factor grows when contamination becomes more extensive;the smaller the core permeability of entry end or the ratio between the permeability of the contaminated area and that of the uncontaminated area,the bigger the skin factor will be.
There are two methods of evaluating core contamination: one is based on the skin factor of formation contamination obtained in the field evaluation;the other on the core permeability distribution and recovery values collected through an in-door core contamination test.However,there is still no method yet of calculating the skin factor with the data collected from the in-door core contamination test.In order to make the in-door test data related to the field evaluation,this paper explores the method of calculating the skin factor with the core permeability distribution and recovery values collected through an in-door core contamination test.Then,the method is deduced of calculating the skin factors of different core contamination patterns when the single phase and incompressible fluid moves as a single direction Darcy flow.Furthermore,different relationships are revealed between skin factor and contamination extensiveness when the permeability of contaminated area are changing in lineal and exponential manners respectively.On this basis,it is concluded that skin factor and permeability recovery values are inversely proportional to each other when cores are evenly contaminated.This study shows that the skin factor grows when contamination becomes more extensive;the smaller the core permeability of entry end or the ratio between the permeability of the contaminated area and that of the uncontaminated area,the bigger the skin factor will be.
引文
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[3]杨满平,李允.低渗透油气储层的应力敏感性表皮系数研究[J].天然气工业,2005,25(3):141-143.
[4]王新海,张冬丽,江山.储层压力敏感表皮系数的计算方法[J].油气井测试,2005,14(5):3-4.
[5]王新海,周国隆.渗透率间断与变产量的拟表皮系数[J].油气井测试,1998,7(4):14-17.
[6]王新海,吉玉林,钱春江.各向异性与不渗透直线边界的拟表皮系数[J].钻采工艺,1997,20(5):32-34.
[7]王新海,夏位荣,郭康良.径向非均质地层调查半径与表皮系数[J].大庆石油地质与开发,1995,14(3):23-26.
[8]李传亮.岩心分析过程中的表皮效应[J].天然气工业,2006,26(11):38-39.
[9]刘建军,程林松.表皮系数分解与油气层伤害定量评价[J].新疆石油科技,2004(4):6-8.
[10]王新海,夏位荣,陈立生.非均匀污染得污染深度计算方法[J].钻采工艺,1994,17(1):61-63.
[11]王新海,夏位荣.泥浆污染半径的计算和措施的增产率预测[J].油气井测试,1992,1(4):34-37.