基于模糊数学理论的储层评价——以鄂尔多斯盆地富黄地区延长组长9油层为例

Evaluation of Reservoirs Based on Fuzzy Mathematics: a Case Study from Chang 9 Formation in Fuhuang Area,Ordos Basin

鄂尔多斯盆地延长组中下部组合油气勘探开发程度相对较低,超低渗储层分类与评价是制约该组合层系油气勘探开发的关键。选取可动流体百分数、主流孔喉半径均值、启动压力梯度、黏土矿物含量以及原油黏度作为低渗储层评价指标,建立评价体系,运用模糊数学理论,建立模糊数学模型,对长9储层进行定量评价,进而建立储层评价体系。研究表明,富黄地区长9储层主要为Ⅰ类、Ⅱ类和Ⅲ类储层,不含Ⅳ类储层。通过对富黄地区长9储层和沉积相平面图对比分析,储层分级结果与有利沉积相储层展布有较高的契合度,以期为延长组超低渗油气勘探和开发提供指导。

The exploration and development of the middle and lower parts of the Yanchang formation in the Ordos basin is relatively low,and the classification and evaluation of ultra-low permeability reservoirs are the key to the exploration and development of oil and gas in this composite formation. Taking the percentage of movable fluid,the mean of the main throat radius,the starting pressure gradient,the content of the clay minerals and the crude oil viscosity were selected as the evaluation indexes. Based on the model of fuzzy mathematics,the evaluation system was established accordingly. With this evaluation system,the oil layer of Chang 9 in the Ordos Basin was assessed.The results show that the Chang 9 reservoirs in Fuhuang area are mainly class Ⅰ,Ⅱ and Ⅲ reservoirs,excluding class IV reservoirs. Through comparative analysis of Chang 9 reservoir and distribution of sedimentary facies in Fuhuang area,the reservoir classification and sedimentary facies favorable reservoir distribution have a high degree of correspondence,in order to provide exploration and development of ultra-low permeability oil and gas in the Yanchang formation.