辫状河砂岩储层三维地质模型重构技术——以冀东油田高尚堡区块新近系馆陶组为例

Reconstruction of 3D geological model of braided river sandstone reservoirs:A case study of Neogene Guantao Formation in Gaoshangpu block,Jidong Oilfield

以冀东油田高尚堡区块新近系馆陶组Ⅳ油组的二维平面相和剖面相为训练图像,利用线性池化方法获得其三维沉积相的多点统计概率,通过蒙特卡洛抽样确定预测点的沉积相类型,建立了研究区辫状河三维精细地质模型,并采用抽稀井网的方法验证了其准确性。研究结果表明:(1)研究区主力生产层段馆陶组Ⅳ段12和13小层发育心滩、辫状河道与泛滥平原微相。心滩坝呈底平顶凸特征,辫状河道呈顶平底凸特征,河道与心滩规模均较小,宽度一般不超过600 m;辫状河道顶部发育泛滥平原沉积,整体上呈“砂包泥”特征;辫流带宽度为650~1 300 m,心滩平均长度为480 m,平均宽度为176 m,辫状河道平均宽度为71 m。(2)地质模型刻画出的储层砂体形态和空间分布准确,平面上心滩位置与地质分析结果吻合,心滩中间厚、两翼薄的特征显现;剖面上具有典型的底平顶凸的心滩特征;模型中泥岩相占比的误差为9.8%,心滩相占比的误差为3.4%,河道相占比的误差为6.4%,总体上看,建模误差均小于10.0%。

Taking two-dimensional plane facies and profile facies of oil group Ⅳ of Neogene Guantao Formation in Gaoshangpu block of Jidong Oilfield as training images,the multi-point geostatistics probability of three-dimensional sedimentary facies was obtained by linear pooling method,the sedimentary facies types of estimated points were determined by Monte Carlo sampling,the three-dimensional fine geological model of braided river was established,and its accuracy was verified by sparse well pattern method. The results show that:(1)The main production layer in the study area is the fifth member of Guantao Formation,and sublayers 12 and 13 mainly developed channel bar,braided channel and flood plain microfacies. The channel bar is characterized by flat bottom and convex top,and the braided channel is characterized by flat top and convex bottom. The scale of channel and channel bar is small,and the general width is less than 600 m. Flood plain developed at the top of braided channel,which is characterized by sand covered by mud as a whole. The width of braided channel belts is 650-1 300 m,the average length and width of channel bar are 480 m and 176 m respectively,and the average width of braided channel is 71 m.(2)The reservoir sand body shape and spatial distribution were accurately depicted by the geological model. On the plane,the position of the channel bar is consistent with geological analysis results,and the characteristics of the thick center and thin wings of the channel bar were shown. On profile,the channel bar has the characteristics of flat bottom and convex top. In the model,the error of mudstone proportion is 9.8%,the error of channel bar proportion is 3.4%,and the error of channel proportion is 6.4%. As a whole,the modeling error is less than 10.0%.