Mineral compositions and microstructural characteristics of the tight sandstone reservoir in the Sulige area and their potential influence on hydraulic fracturing

Peiyue LI; Xiaodong HE; Changjing ZHOU; Yonggang XIE; Hua SHI

doi:10.16030/j.cnki.issn.1000-3665.202211048

Shuiwen dizhi gongcheng dizhi (May 2023)

Mineral compositions and microstructural characteristics of the tight sandstone reservoir in the Sulige area and their potential influence on hydraulic fracturing

Peiyue LI,
Xiaodong HE,
Changjing ZHOU,
Yonggang XIE,
Hua SHI

Affiliations

Peiyue LI: School of Water and Environment, Chang’an University, Xi’an, Shaanxi　710054, China
Xiaodong HE: School of Water and Environment, Chang’an University, Xi’an, Shaanxi　710054, China
Changjing ZHOU: National Engineering Laboratory for Exploration and Development of Low-Permeability Oil & Gas Fields, Xi’an, Shaanxi　710018, China
Yonggang XIE: National Engineering Laboratory for Exploration and Development of Low-Permeability Oil & Gas Fields, Xi’an, Shaanxi　710018, China
Hua SHI: National Engineering Laboratory for Exploration and Development of Low-Permeability Oil & Gas Fields, Xi’an, Shaanxi　710018, China

DOI: https://doi.org/10.16030/j.cnki.issn.1000-3665.202211048
Journal volume & issue: Vol. 50, no. 3
pp. 1 – 11

Abstract

Read online

Tight sandstone gas is an important unconventional natural gas resource. Mineral characteristics of the tight sandstone not only affect the occurrence of gas, but also have a significant impact on the hydraulic fracturing effectiveness. The potential influence of tight sandstone mineral compositions and microscopic morphology on gas reservoir during hydraulic fracturing was seldom examined. In this study, five tight sandstone gas wells in the Sulige gasfield located in the Ordos Basin were drilled. The core samples of the 8th formation of the lower member of the Permian Shihezi Group (He 8) were collected. The mineral characteristics, microstructure and pore feature of the tight sandstone are systematically analyzed by using XRF, XRD, casting thin section, SEM and EDS technologies and the potential effects of the above factors on hydraulic fracturing are discussed. The results show that the tight sandstone is mainly composed of lithic sandstone and lithic quartz sandstone. The density of the tight sandstone ranges from 2.44 to 2.56 g/cm3, the porosity from 7.7% to 12.6%, and the permeability from 0.16 to 1.42 mD. The mineral compositions are mainly quartz and clay minerals (16.5%−47.4%), and feldspar and carbonate are absent. Kaolinite, illite and chlorite are the main clay minerals. Kaolinite is widely developed, filling the intergranular pores and surface in the forms of “booklets” and worm-like. The intergranular pores, intragranular solution voids, intergranular and intragranular fractures occur in the tight sandstone, which provide basic reservoir space for natural gas. The results of mineral analysis and fracturing fluid-tight sandstone interactions reveal that the stability of clay minerals, especially kaolinite and illite, are crucial for hydraulic fracturing in the Sulige gasfield. It is necessary to understand the mineral compositions and formation water of the tight reservoir and select the appropriate clay stabilizer to optimize hydraulic fracturing.

Published in Shuiwen dizhi gongcheng dizhi

ISSN: 1000-3665 (Print)
Publisher: Editorial Office of Hydrogeology & Engineering Geology
Country of publisher: China
LCC subjects: Science: Geology
Website: https://www.swdzgcdz.com/indexen.htm

About the journal

Abstract

Keywords