增长曲线的分类与优选

Classification and Optimization of Increase curves.

对提出的用于预测油田开发指标的增长曲线进行了分类 ,根据曲线中常数的数目和含有的bt 和tb 项以及对应 (tQt) max和Qtmax的准数 ,将增长曲线分为 4种类型 ,并分别列出了它们的Np～t、Qt～t、 NpNRmax (tQt) max准数、 QtNRmax Qtmax准数以及参数求取的关系式。通过对随机抽取的试样———庆祖集油田用上述增长曲线计算的相关系数R、最大可采储量NRmax值、以及曲线初始产量R、最大可采储量NRmax值、曲线初始产量Qi、 NPNRmax Qtmax准数的最大变化范围、参数求解的方便程度等 5方面的研究和分析 ,从中筛选出一种最优的增长曲线——— 3常数bt 型不定准数俞启泰增长曲线Ⅰ (3Y1增长曲线 ) :Np=NRmaxbt-1bt+a;而 3常数tb 型定准数Weibull增长曲线 (3W增长曲线 ) :Np=NRmax(1 -e-tb/a) ,可作为当 NpNRmax Qtmax>0 .5时的补充曲线。对增长曲线的研究和应用表明 ,提出的增长曲线法是和递减曲线、水驱特征曲线法具有同等重要地位的一种新的油藏工程方法。

The proposed increase curves for predicting oil field development indexes have been classified.In terms of number of constants,term of containing b t or t b,and criterion corresponding(tQ t) max and Q tmax ,the increase curves are divided into four types:(1)the increase curves of b t type with non fixing criterion and 3 constants;(2)the increase curves of t b type with fixing criterion and 3 constants;(3)the increase curves or b t type with non fixing criterion and 4 constants;(4)the increase curves of t b type with non fixing criterion and 4 constants.The relationships of N p t,Q t t,and N pN Rmax (tQ t) max criterion,and N pN Rmax Q tmax criterion,and formulas for obtaining parameters of these increase curves are listed.According studies and analyses for calculating maximum recoverable reserves N Rmax and correlation coefficient of a actual oilfield,Qingzuji Oilfield,sampled randomly by using above mentioned increase curves and their initial production Q i,maximum range of N pN Rmax Q tmax criterion and easy level obtaining parameters,the best increase curve,Yu Qitai increase curve of b t type with non fixing criterion and 3 constants(3Y1 increase curve),N p=N Rmax b t-1b t+a,have been screended in them.And Weibull increase curve of t b type with fixing criterion and 3 constants(3W increase curve),N p=N Rmax (1-e -t b/a ),can regard as a additional curve whileN pN Rmax Q tmax >0.5.Studies and application of increase curves show that the proposed increase curve method is a new reservoir engineering method as important as decline curve method and water drive curve method.