累积概率曲线在低渗透储层评价中的应用

APPLICATION OF CUMULATIVE PROBABILITY CURVE TO THE LOW-PERMEABILTIY RESERVOIR EVALUATION

为了对低渗透储层进行正确的分类和评价，探讨了累积概率曲线的分类意义。不同性质的储集层在累积概率曲线图上，其线段的数目、交切点位置和线段的斜率等性质不同，借助累积概率曲线可直观地比较不同性质的储集层之间的差别并对储层进行分类。在朝阳沟油田不同开发区块低渗透储层评价参数优选的基础上，采用灰色关联方法确定各评价参数的权系数，用综合评价方法计算评价指标，作出评价指标的累积概率曲线图，利用累积概率曲线图对朝阳沟油田低渗透储层进行了分类，可以明显地将朝阳沟油田不同开发区块分为3类，分类效果明显，其中Ⅰ类是相对较好的低渗透储集层，Ⅱ类次之，Ⅲ类最差。

In order to correctly classify and evaluate the low-permeability reservoirs, the paper discusses the classi- fication significance of cumulative probability curve. For the reservoirs with different properties, the properties such as the number of the line segments, the location of intersection points and the slope of line segments are also differ- ent in the cumulative probability curve. With the help of the cumulative probability curve, the differences among different properties＇reservoirs can be visually compared and thus the classification of these reservoirs can be engaged. Based on the optimization of the evaluation parameters of low-permeability reservoirs in different development blocks of Chaoyanggou Oilfield, gray correlation analysis is used to determine the weight coefficient of each e- valuation parameter, and the evaluation index has been calculated by comprehensive evaluation method, and fur- thermore, the cumulative probability curve diagram is drawn for index evaluation. Finally the classification of the low-permeability reservoirs in Chaoyanggou Oilfield has been conducted by the above diagram. Obviously the different development blocks in the oilfield can be divided into 3 categories, the classification results are evident. Type Ⅰ block is relatively much better low-permeability reservoirs, Type Ⅱ is second and Type Ⅲ is the worst.