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

Abstract

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 < Rapex) ranges from 2.05 to 2.37, whereas fractal dimension of large pores (r > Rapex) 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.

Hydrocarbon Accumulation Process and Mode in Proterozoic Reservoir of Western Depression in Liaohe Basin, Northeast China: A Case Study of the Shuguang Oil Reservoir

“…The revolutionary success of tight oil in the USA has reversed the downward trend of oil production in North America at one stroke [1,2] and changed the world's traditional energy pattern to some extent. As a result, through active exploration, tight oil areas with large-scale reserves have been explored in several basins in China, such as the eastern Bohai Bay Basin [3,4], Ordos Basin [5,6], Sichuan Basin [7], and western Junggar Basin [8]. Therefore, tight oil has become a critical field.…”

Study on Micro-Nano Pore Characteristics and Classification of Tight Sandstone Reservoir Based on Q-Cluster

“…The technologies are mainly casting thin section, scanning electron microscopy (SEM), transmission electron microscopy (TEM), constant-speed mercury intrusion porosimetry (MIP), micro-nano CT, and unclear magnetic resonance (NMR) [26]. The research on different levels of pores has leaped from 2-D, qualitative to 3-D and quantitative, which provides favorable support for the study of pore characteristics of tight oil and gas reservoirs [4,14,15,[26][27][28][29][30][31][32]. However, all of these techniques have their strengths and limitations.…”