The Spontaneous Imbibition of Micro/Nano Structures in Tight Matrix and the Influence on Imbibition Potential

Micromachines

Dandan Geng¹  Jun Wang²  Yinghao Shen³  Chenggang Xian³  Caoxiong Li³ 

[1] The No.6 Oil Production Company, Daqing Oilfield, CNPC, Daqing 163114, China;The No.7 Oil Production Plant Company, Changqing Oilfield, CNPC, Xi’an 710000, China;Unconventional Oil and Natural Gas Institute, China University of Petroleum, Beijing 102249, China;

关键词: tight matrix;    water imbibition;    pore structure;    fractal theory;   

DOI  :  10.3390/mi11090794

来源: DOAJ

【 摘 要 】

Tight matrix has relatively low permeability and porosity, with abundant micro/nano pores. The capillary force in these pores are relatively strong, making the wetting liquid easier to be imbibed in the matrix. This process is called spontaneous imbibition. The complexity of pore structure is identified as one of the key factors influencing the imbibition process, but the detailed mechanism is not clear. Thus, in this work, a method is proposed to evaluate the influence of pore structure on imbibition process. Pore structure has fractal properties in a specific scale. By using the fractal theory, an imbibition model is provided to analyze the influence of microscopic structures on spontaneous imbibition, considering the pore size distribution and pore connectivity. Also, based on this model, the influencing factors on dimensionless imbibition and diffusion rate are discussed. Results show that the pore structure has more branches, larger and shorter sub-throats has higher chance to gain a high imbibition rate. Finally, a 3D imbibition parameter cube is constructed to determine the parameter combinations in favor of strong water diffusion potential. By utilizing the analysis method based on the fractal theory, we can effectively evaluate the imbibition potential. It is helpful to provide a guidance to evaluate the water imbibition to gas production.

【 授权许可】

Unknown