Characterization of Pore Structures and Implications for Flow Transport Property of Tight Reservoirs: A Case Study of the Lucaogou Formation, Jimsar Sag, Junggar Basin, Northwestern China

Energies

Jiehua Jin¹  Keyu Liu²  Jiangxiu Qu²  Xiujian Ding²  Yang Su²  Ming Zha² 

[1] Geophysical Research Institute, Shengli Oilfield Company of SINOPEC, Dongying 257022, China;School of Geosciences, China University of Petroleum, Qingdao 266580, China;

关键词: pore microstructure;    transport property;    tight reservoir;    digital core analysis;   

DOI  :  10.3390/en14051251

来源: DOAJ

【 摘 要 】

Quantitate characterization of pore structures is fundamental to elucidate fluid flow in the porous media. Pore structures of the Lucaogou Formation in the Jimsar Sag were investigated using petrography, mercury intrusion capillary porosimetry (MICP) and X-ray computed tomography (X-ray μ-CT). MICP analyses demonstrate that the pore topological structure is characterized by segmented fractal dimensions. Fractal dimension of small pores (r < R_apex) ranges from 2.05 to 2.37, whereas fractal dimension of large pores (r > R_apex) varies from 2.91 to 5.44, indicating that fractal theory is inappropriate for the topological characterization of large pores using MICP. Pore volume of tight reservoirs ranges over nine orders of magnitude (10⁻¹–10⁸ μm³), which follows a power-law distribution. Fractal dimensions of pores larger than a lower bound vary from 1.66 to 2.32. Their consistence with MICP results suggests that it is an appropriate indicator for the complex and heterogeneous pore network. Larger connected pores are primary conductive pathways regardless of lithologies. The storage capacity depends largely on pore complexity and heterogeneity, which is negatively correlated with fractal dimension of pore network. The less heterogeneous the pore network is, the higher storage capability it would have; however, the effect of pore network heterogeneity on the transport capability is much more complicated.

【 授权许可】

Unknown