scholarly journals Experimental study on the pore structure characteristics of tight sandstone reservoirs in Upper Triassic Ordos Basin China

2016 ◽  
Vol 34 (3) ◽  
pp. 418-439 ◽  
Author(s):  
Zhiqiang Zhang ◽  
Yongmin Shi ◽  
He Li ◽  
Wenqi Jin
Keyword(s):  
Experimental Study ◽  
Pore Structure ◽  
Ordos Basin ◽  
Upper Triassic ◽  
Tight Sandstone ◽  
Structure Characteristics ◽  
Sandstone Reservoirs

Micro-Nanopore Structure and Fractal Characteristics of Tight Sandstone Gas Reservoirs in the Eastern Ordos Basin, China

2021 ◽  
Vol 21 (1) ◽  
pp. 234-245
Author(s):  
Peng Qiao ◽  
Yiwen Ju ◽  
Jianchao Cai ◽  
Jun Zhao ◽  
Hongjian Zhu ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Pore Structure ◽  
Ordos Basin ◽  
Gas Storage ◽  
Main Peak ◽  
Storage Space ◽  
Tight Sandstone ◽  
Fractal Characteristics ◽  
Sandstone Reservoirs ◽  
Nanopore Structure

The complex pore system in tight sandstone reservoirs controls the storage and transport of natural gas. Thus, quantitatively characterizing the micro-nanopore structure of tight sandstone reservoirs is of great significance to determining the accumulation and distribution of tight gas. The pore structure of reservoirs was determined through polarizing microscopy, scanning electron microscopy (SEM), and the combination of mercury injection capillary pressure (MICP) and nuclear magnetic resonance (NMR) experiments on Late Paleozoic conventional and tight sandstone samples from the Linxing Block, Ordos Basin. The results show that in contrast to conventional sandstone, dissolution pores, with diameters less than 8 μm, are the main contributors to the gas storage space of tight sandstone reservoirs. The pore size distribution derived from the MICP experiment demonstrates that the main peak of tight sandstones corresponds to a pore radius in the range of 247 nm to 371 nm, while the secondary peak usually corresponds to 18 nm. The results of the NMR test illustrate that the T2 spectra of tight sandstones are unimodal, bimodal and multimodal, and the main NMR peak is highly related to the MICP peak. Fractal theory was proposed to quantitatively characterize the complex pore structure and rough porous surface. The sandstones show fractal characteristics including nanopore fractal dimension DN obtained from the MICP and large pore fractal dimension DL obtained from the NMR experiment. Both DN and DL are positively correlated with porosity and negatively correlated with permeability, demonstrating that complex and heterogeneous pore structure could increase the gas storage space and reduce the connectivity.

Pore structure and fractal characteristics of ultra-low permeability sandstone reservoirs in Upper Triassic Yanchang Formation, Ordos Basin

2021 ◽  
pp. 1-59
Author(s):  
Quanpei Zhang ◽  
Tao Jiao ◽  
Hao Huang ◽  
Zhao Qi ◽  
Tao Jiang ◽  
...  
Keyword(s):  
Pore Structure ◽  
Quality Evaluation ◽  
Pore Space ◽  
Ordos Basin ◽  
Upper Triassic ◽  
Reservoir Quality ◽  
Low Permeability ◽  
Yanchang Formation ◽  
Fractal Characteristics ◽  
Sandstone Reservoirs

The complex pore structure and high heterogeneity of ultra-low permeability sandstone reservoirs have a significant effect on reservoir quality evaluation and hydrocarbon resource assessment. We collected 10 reservoir samples from the Upper Triassic Yanchang Formation Chang 8 in the Zhenbei area of the Ordos Basin. We measured the pore size distribution (PSD) and fluid occurrence characteristics of the reservoir by Pressure-controlled porosimetry (PCP), rate-controlled porosimetry (RCP) and nuclear magnetic resonance (NMR), and then analyzed the results via the fractal theory to determine the pore space fractal characteristics. Our analysis indicates that the three major pore types of these reservoirs are residual intergranular pores, dissolution pores and intercrystalline pores. The pore structure of the ultra-low permeability sandstone reservoirs is highly heterogeneous with pore throats of various scales, and the corresponding fractal characteristics are notably different, exhibiting multi-fractal features. Compared to macropores and mesopores, micropores are more uniform and regular in terms of their PSD and thus only slightly influence the reservoir quality. The complexity of the throat distribution and whole pore space is attributed to the development of dissolution pores and the content of feldspar minerals. Fractal features depend on the movable fluid pore space and effective pores, whose fractal dimensions reflect the complexity of interconnected pores and correlate well with the porosity and permeability. The development of different types and sizes of pore throats in these ultra-low permeability sandstone reservoirs resulted in the observed pore structure heterogeneity. The difference in mineral composition and content of these reservoirs aggravates the pore structure complexity and affects reservoir quality evaluation and further oilfield development.

Experimental Study on the Two-Phase Seepage Law of Tight Sandstone Reservoirs in Ordos Basin

2021 ◽  
Vol 147 (6) ◽  
Author(s):  
Jie He ◽  
Xiaodong Liu ◽  
Xinyu Zhu ◽  
Tao Jiang ◽  
Hui He ◽  
...  
Keyword(s):  
Experimental Study ◽  
Ordos Basin ◽  
Tight Sandstone ◽  
Two Phase ◽  
Sandstone Reservoirs ◽  
Seepage Law

scholarly journals Binary pore structure characteristics of tight sandstone reservoirs

2019 ◽  
Vol 46 (6) ◽  
pp. 1297-1306 ◽  
Author(s):  
Haihua ZHU ◽  
Tingshan ZHANG ◽  
Dakang ZHONG ◽  
Yaoyu LI ◽  
Jingxuan ZHANG ◽  
...  
Keyword(s):  
Pore Structure ◽  
Tight Sandstone ◽  
Structure Characteristics ◽  
Sandstone Reservoirs

Diagenesis of tight sandstone reservoirs in the Upper Triassic Yanchang Formation, southwestern Ordos Basin, China

2019 ◽  
Vol 99 ◽  
pp. 548-562 ◽  
Author(s):  
Kelai Xi ◽  
Yingchang Cao ◽  
Keyu Liu ◽  
Songtao Wu ◽  
Guanghui Yuan ◽  
...  
Keyword(s):  
Ordos Basin ◽  
Upper Triassic ◽  
Tight Sandstone ◽  
Yanchang Formation ◽  
Sandstone Reservoirs
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