三角洲外前缘亚相储层井间连通性定量评价——以大庆长垣萨尔图油田南二区东部为例

发布时间：2018-07-29 15:15

【摘要】：三角洲外前缘亚相储层井间连通性研究对于高含水期油田井网优化和剩余油挖潜具有重要意义。以大庆长垣萨尔图油田南二区东部为靶区,利用122个时间单元的密井网资料,首先构建出三角洲外前缘亚相储层井间连通性定量评价模型,进而开展不同砂地比和井距条件下的三角洲外前缘亚相储层井间连通性定量评价。结果表明:(1)砂地比为评价储层井间连通性的宏观评价参数,即存在一个"渗流阈值",当砂地比低于渗流阈值时,井间连通性不超过20%变为不连通,当砂地比达到渗流阈值后,井间连通性迅速增长至80%以上变为完全连通,整个过程反映的砂地比和井间连通性函数图像呈S形曲线;(2)通过对砂体最大横截面面积沿垂直于井钻进方向的投影和井距的空间耦合关系分析,建立了以井距为变量的三角洲外前缘亚相储层井间连通概率模型,同时提出各微相砂体所占比例影响储层井间连通性整体变化趋势;(3)储层井间连通性渗流阈值与井距呈正相关,随着井距变小,砂地比与井间连通性的S形曲线函数图像趋于"线性",当平均井距为70 m(1倍井距)条件下三角洲外前缘亚相储层井间连通性的渗流阈值为0.20,平均井距为140 m(2倍井距)和210 m(3倍井距)条件下储层井间连通性的渗流阈值分别为0.24和0.30。
[Abstract]:The study of inter-well connectivity of subfacies reservoirs in the outer front of delta is of great significance for the optimization of well pattern and the exploitation of remaining oil potential in high water-cut oil fields. Taking the eastern part of the south second area of Daqing Changyuan Saltu Oilfield as the target area, using the data of the dense well pattern of 122 time units, a quantitative evaluation model of inter-well connectivity of the delta outer front subfacies reservoir is constructed. Furthermore, quantitative evaluation of inter-well connectivity of delta outer front subfacies reservoir is carried out under different sand / soil ratio and well spacing. The results show that: (1) the sand / ground ratio is a macroscopic evaluation parameter for evaluating the reservoir inter-well connectivity, that is, there exists a "seepage threshold". When the sand to ground ratio is below the seepage threshold, the inter-well connectivity does not exceed 20% and becomes disconnected, when the sand to ground ratio reaches the seepage threshold, Cross-well connectivity grew rapidly to more than 80% and became fully connected. The images of sand / ground ratio and inter-well connectivity function reflected by the whole process are S-shaped curves. (2) the projection of the maximum cross-section area of sand body along the direction perpendicular to well drilling and the spatial coupling of well spacing are analyzed. The interwell connectivity probability model of delta outer front subfacies reservoir is established, and it is proposed that the proportion of microfacies sand bodies affects the overall variation trend of inter-well connectivity. (3) the reservoir inter-well connectivity percolation threshold is positively correlated with well spacing. As the well spacing becomes smaller, The S-shape curve function image of sand to ground ratio to inter-well connectivity tends to be "linear". When the average well spacing is 70 m (1 double well spacing), the percolation threshold of inter-well connectivity in delta outer front subfacies reservoir is 0.20, and the average well spacing is 140 m (2 times). The percolation thresholds of interwell connectivity are 0.24 and 0.30 under the conditions of 210m and 210m (3 times interval), respectively.
【作者单位】：东北石油大学地球科学学院;大庆油田有限责任公司开发部;
【基金】：国家重大科技专项(2017ZX05001-003) 国家自然科学基金项目(No.41502136)资助
【分类号】：P618.13

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