Pore-scale imaging of asphaltene-induced pore clogging in carbonate rocks

FUEL

卷:283

Article

Lin, Qingyang¹  Akai, Takashi^1,3  Blunt, Martin J.¹  Bijeljic, Branko¹  Iwama, Hiroki²  Takabayashi, Katsumo²  Onaka, Yutaka³  Yonebayashi, Hideharu² 

[1] Imperial Coll London, Dept Earth Sci & Engn, London SW7 2BP, England

[2] INPEX Corp, Tech Res Ctr, Setagaya Ku, 9-23-30 Kitakarasuyama, Tokyo 1570061, Japan

[3] Japan Oil Gas & Met Natl Corp, Minato Ku, Toranomon Twin Bldg 2-10-1 Toranomon, Tokyo 1050001, Japan

关键词: Asphaltene;    X-ray microtomography;    Pore-scale imaging;    Formation damage;   

DOI  :  10.1016/j.fuel.2020.118871

来源: Elsevier

【 摘 要 】

We propose an experimental methodology to visualize asphaltene precipitation in the pore space of rocks and assess the reduction in permeability. We perform core flooding experiments integrated with X-ray micro tomography (micro-CT). The simultaneous injection of pure heptane and crude oil containing asphaltene induces the precipitation of asphaltene in the pore space. The degree of precipitation is controlled by the measurement of differential pressure across the sample. After precipitation, doped heptane is injected to replace the fluid to enhance the contrast between precipitated asphaltene and doped heptane. The micro-CT images are segmented into three phases: void, precipitated asphaltene, and rock. In the experiment, we observed that the precipitated asphaltene which occupied 39.1% of the pore volume caused a 29-fold reduction in permeability. Furthermore, we analyze the spatial distribution of precipitated asphaltene which showed that the asphaltene tended to clog the larger pores. We also computed the flow field numerically on the images and obtained good agreement between simulated and measured permeability. The distribution of local velocity showed that after precipitation the flow was confined to narrow channels in the pore space. This method can be applied to any type of porous system with precipitation.

【 授权许可】

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