基于压汞实验的致密油储层孔隙分形特征分析--以鄂尔多斯盆地定边油田延长组长7油层为例  

Fractal analysis of pores in tight oil reservoirs based on mercury intrusion experiment:a case study of Chang 7 reservoir in Yanchang Formation,Dingbian oilfield,Ordos Basin

作　　者：白耀文[1] 张刚[1] 李春生[1] 任剑[2] 丁文龙[3] 尹帅 肖子亢 BAI Yao-wen;ZHANG Gang;LI Chun-sheng;REN Jian;DING Wen-long;YIN Shuai;XIAO Zi-kang(Dingbian Oil Production Plant of Yanchang Oilfield,Dingbian 718699,China;Yanchang Oilfield Co.,Ltd.,Yan'an 716000,China;School of Energy Resources,China University of Geosciences,Beijing 100083,China;.4.School of Eath Science and Engineering,Xi'an Shiyou University,Xi'an 710065,China).)

机构地区：[1]延长油田股份有限公司定边采油厂,陕西定边718699 [2]延长油田股份有限公司,延安716000 [3]中国地质大学(北京)能源学院,北京100083 [4]西安石油大学地球科学与工程学院,西安710065

出　　处：《桂林理工大学学报》2020年第1期60-67,共8页Journal of Guilin University of Technology

基　　金：国家自然科学基金项目(41372139,41072098);延长石油集团项目(ycsy2016ky-B-1-1)。

摘　　要：为准确评价致密油储层参数,为资源量评价及有效开发方式制定提供依据,以鄂尔多斯盆地定边油田延长组长7致密油储层为例,利用高压压汞实验和分形原理分析了目的层砂岩的分形特征,探讨了岩石分形特征参数对岩石渗透率的影响。结果表明:砂岩样品的分形维数(D_f)分布在2.759~2.987,平均2.890;毛细管平均迂曲度分维值(D_T)分布在1.194~1.553,平均1.391,D_f>D_T。D_f与D_T与岩样的渗透率间均存在较好的负相关性,致密砂岩的D_f和D_T值要大于中砂岩,表明与中砂岩相比,致密砂岩内部微孔的分布较为杂乱,孔隙间的连通性差,且其毛细管迂曲度较大。因此,致密砂岩中流体渗流所需通过的路径更长,这是造成其渗透率低的重要原因。利用分形模型对砂岩岩样的渗透率进行了预测,预测效果非常好,表明利用分形理论预测致密油储层渗透率是有效的。In order to accurately evaluate the tight oil reservoir parameters, and provide a resource evaluation and effective development method, based on the Chang 7 tight oil reservoir of Yanchang Formation in Dingbian oilfield of Ordos Basin as an example, the fractal characteristics of the sandstone in the target layer are analyzed by high pressure mercury intrusion and fractal principles. The influence of fractal characteristic parameters on rock permeability is discussed. The results show that the fractal dimension(D_f) of the sandstone samples is 2.759-2.987. The average is 2.890. The capillary mean fractal dimension(D_T) is 1.194-1.553, the average is 1.391, D_f>D_T. There is a good negative correlation between D_f or D_T and the permeability of rock samples. The D_f and D_T values of the tight sandstone are larger than the middle sandstone, which indicates that the distribution of micropores in the tight sandstone is more clutter than that of the middle sandstone, and the connectivity between the pores is poor. Thus, the path of fluid seepage in tight sandstone is longer, which is important for its low permeability. Finally, the fractal model is used to predict the permeability of sandstone samples, and the prediction is effective to predict the permeability of tight oil reservoirs by fractal theory.

关 键 词：孔隙分形 致密油储层 渗透率 压汞 

分 类 号：P618.130.21[天文地球—矿床学] TE311.2[天文地球—地质学]