scholarly journals Microscale Mineral and Pore Structure Characterization of the Low-Permeability Sandstone in the Ordos Basin, China

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jie Gao ◽  
Zhen Sun ◽  
Jianping Liu ◽  
Chenyang Zhao ◽  
Dazhong Ren ◽  
...  
Keyword(s):  
Pore Structure ◽  
Ordos Basin ◽  
Controlling Factors ◽  
Structure Characterization ◽  
Small Scale ◽  
Low Permeability ◽  
Pressure Curve ◽  
Capillary Pressure Curve ◽  
Average Porosity ◽  
The Ordos Basin

Given the insufficient understanding of the characteristics and controlling factors of the low-permeability sandstone reservoir in the Heshui area, the Ordos Basin, the present study examined the microscale mineral and pore structure of Chang 2 reservoir. It analyzed its major controlling factors using a series of methods, including imaging and indirect methods. The results show that the rocks of Chang 2 reservoir in the study area are dominated by lithic arkose and feldspathic detritus quartz sandstone. The reservoir space develops intragranular pores, feldspar dissolved pores, lithic dissolved pores, and intercrystallite pores. Microcracks can occasionally be found. The average porosity is 10.5%, and the average permeability is 2.2 mD, featuring a low-porosity-ultralow-permeability reservoir. During the reservoir development, traps formed by small-scale nose-shaped uplifts resulting from the tectonic effects provide opportunities for good reservoir space. Sedimentation and diagenetic processes control the degree of development and direction of the evolution of reservoir porosity to a certain degree. Multisegment capillary pressure curve and long missing zone were corresponding to relatively good pore-throat structures. Illite was the predominant diagenetic clay minerals that determine the reservoir quality. These three effects all contribute to the overall development of the reservoir.

PORE STRUCTURE OF TRANSITIONAL SHALES IN THE ORDOS BASIN, NW CHINA: EFFECTS OF COMPOSITION ON GAS STORAGE MECHANISM

2017 ◽  
Author(s):  
Fengyang Xiong ◽  
◽  
Zhenxue Jiang ◽  
Mohammad Amin Amooie ◽  
Mohamad Reza Soltanian ◽  
...  
Keyword(s):  
Pore Structure ◽  
Ordos Basin ◽  
Gas Storage ◽  
Nw China ◽  
Storage Mechanism ◽  
The Ordos Basin

scholarly journals Fractal Characterization of Nanopore Structure in Shale, Tight Sandstone and Mudstone from the Ordos Basin of China Using Nitrogen Adsorption

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 583 ◽  
Author(s):  
Xiaohong Li ◽  
Zhiyong Gao ◽  
Siyi Fang ◽  
Chao Ren ◽  
Kun Yang ◽  
...  
Keyword(s):  
Pore Structure ◽  
Pressure Range ◽  
Ordos Basin ◽  
Fractal Dimensions ◽  
Nitrogen Adsorption ◽  
Relative Pressure ◽  
Tight Sandstone ◽  
Porosity And Permeability ◽  
The Ordos Basin ◽  
Nanopore Structure

The characteristics of the nanopore structure in shale, tight sandstone and mudstone from the Ordos Basin of China were investigated by X-ray diffraction (XRD) analysis, porosity and permeability tests and low-pressure nitrogen adsorption experiments. Fractal dimensions D1 and D2 were determined from the low relative pressure range (0 < P/P0 < 0.4) and the high relative pressure range (0.4 < P/P0 < 1) of nitrogen adsorption data, respectively, using the Frenkel–Halsey–Hill (FHH) model. Relationships between pore structure parameters, mineral compositions and fractal dimensions were investigated. According to the International Union of Pure and Applied Chemistry (IUPAC) isotherm classification standard, the morphologies of the nitrogen adsorption curves of these 14 samples belong to the H2 and H3 types. Relationships among average pore diameter, Brunner-Emmet-Teller (BET) specific surface area, pore volume, porosity and permeability have been discussed. The heterogeneities of shale nanopore structures were verified, and nanopore size mainly concentrates under 30 nm. The average fractal dimension D1 of all the samples is 2.1187, varying from 1.1755 to 2.6122, and the average fractal dimension D2 is 2.4645, with the range from 2.2144 to 2.7362. Compared with D1, D2 has stronger relationships with pore structure parameters, and can be used for analyzing pore structure characteristics.

scholarly journals Pore Structure Characterization and the Controlling Factors of the Bakken Formation

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2879 ◽  
Author(s):  
Yuming Liu ◽  
Bo Shen ◽  
Zhiqiang Yang ◽  
Peiqiang Zhao
Keyword(s):  
Pore Structure ◽  
Oil And Gas ◽  
Vitrinite Reflectance ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Controlling Factors ◽  
Structure Characterization ◽  
Bakken Formation ◽  
Main Controlling Factors ◽  
Bakken Shale

The Bakken Formation is a typical tight oil reservoir and oil production formation in the world. Pore structure is one of the key factors that determine the accumulation and production of the hydrocarbon. In order to study the pore structures and main controlling factors of the Bakken Formation, 12 samples were selected from the Bakken Formation and conducted on a set of experiments including X-ray diffraction mineral analysis (XRD), total organic carbon (TOC), vitrinite reflectance (Ro), and low-temperature nitrogen adsorption experiments. Results showed that the average TOC and Ro of Upper and Lower Bakken shale is 10.72 wt% and 0.86%, respectively. The Bakken Formation develops micropores, mesopores, and macropores. However, the Upper and Lower Bakken shale are dominated by micropores, while the Middle Bakken tight reservoir is dominated by mesopores. The total pore volume and specific surface area of the Middle Bakken are significantly higher than those of the Upper and Lower Bakken, indicating that Middle Bakken is more conducive to the storage of oil and gas. Through analysis, the main controlling factors for the pore structure of the Upper and Lower Bakken shale are TOC and maturity, while those for Middle Bakken are clay and quartz contents.

Logging Identification Technology of Sedimentary Facies and Gas Layers within Low Pressure, Low Permeability and Low Abundance Gas Reservoirs: Example from SQW Block of the Sulige Gas Field, Ordos Basin, China

2012 ◽  
Vol 616-618 ◽  
pp. 96-99
Author(s):  
Fang Lu ◽  
Xin Jiang Du ◽  
Zhi Jun Mao ◽  
Yan Zhou ◽  
Yue Bin Cui ◽  
...  
Keyword(s):  
Ordos Basin ◽  
Sedimentary Facies ◽  
Low Pressure ◽  
Low Permeability ◽  
Braided River ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Exploration Target ◽  
The Ordos Basin ◽  
Gas Potential

Sulige Gas Field is located in the Suligemiao area, northwest of the Ordos Basin, with a prospecting area of about 4×104km2. Owing to the strong heterogeneity in the SQW Block, one of exploration blocks in the Sulige Gas Field, remains reservoir characteristics of the gas field: lithologic gas reservoirs with characteristics of “three low” (low pressure, low permeability and low abundance). The He8 member of the Shihezi formation, the major exploration target, is deposited in braided river environment. The conventional logging data is very useful to indentify different facies and to estimate gas potential. The technology of discrimination with sedimentary facies and gas layers using logging data is established in this paper. We use the technology combining with AVO and other exploration methods to pick out 4 favorable exploration target areas with the success rate of more than 80%.

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