电成像孔隙度谱在砂砾岩有效储层识别的应用

Application of Electrical Imaging Logging Porosity Spectrum in Identification of Effective Reservoir in Sandy Conglomeratic Reservoirs

砂砾岩体储层非均值性强、孔隙结构复杂,测井识别储层有效性难度大。以红车断裂带佳木河组砂砾岩地层为研究对象,综合运用物性、岩石薄片、压汞等资料,将研究区储层孔隙结构划分为三种类型。鉴于中基性母岩顺磁矿物的影响,核磁共振测井对孔隙结构及储层有效性反应不灵敏,因此,充分利用电成像资料反映井壁砂砾岩体非均质性的优势,根据其电阻率值转化的孔隙度谱形态特征,将研究区孔隙度谱归为多峰宽谱型、变峰中谱型和单峰窄谱型,并提取出孔隙度谱几何平均值(P_(gm)),方差(φ^(2)_(v)),局部最大、最小孔隙度(φ_(max)、φ_(min)),变异系数(VK_(φ))等参数,明确了各个参数与压汞孔隙结构参数存在确定的关系后,建立了基于孔隙度谱参数的渗透率计算公式及储层分类综合评价指数,并结合试油资料,建立了适合本研究区的砂砾岩储层评价标准。将该方法应用至井筒剖面中,有效划分了有利储层,也为研究区砂砾岩油藏的高效开发提供了依据。

High heterogeneity and complex pore structure of conglomeratic sandstone makes it difficult to identify effective reservoir by logging.Based on data of physical properties,thin sections and mercury intrusion experiment from Jiamuhe formation in Hongche Fault Belt,the pore structure in this area was divided into 3 types.Affected by paramagnetic minerals in intermediate-basic volcanic rock,nuclear magnetic resonance(NMR)was insensitive to reflect pore structure and effective reservoir.Therefore,porosity-frequency spectrum was divided into multi-peak wide spectrum,variable peak medium spectral and unimodal narrow spectrum,the parameters,such as geometric mean,variance,local minimum porosity,local maximum porosity,variation coefficient,were also extracted.After defined the relationship between the various parameters and mercury intrusion parameters,the calculation formula of permeability and reservoir composite index were established.And combined with well testing data,the reservoir evaluation standard was established.Ultimately,the methods were applied in the hole,which effectively divide the favorable reservoirs and provides evidence for development in conglomerate reservoir.