Coupling Relationship between Lithofacies and Brittleness of the Shale Oil Reservoir: A Case Study of the Shahejie Formation in the Raoyang Sag

Song, Zhaojing; Li, Junqian; Li, Xiaoyan; Chen, Ketong; Wang, Chengyun; Wei, Yongbo; Zhao, Rixin; Wang, Xiaocheng; Zhang, Shasha; Yan, Mengying; Geng, Haiyan

doi:10.1155/2022/2729597

Cited by 8 publications

(3 citation statements)

References 58 publications

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“…However, with the rapid development of the global shale oil and gas industries, shale and mudstone lithofacies analysis is increasingly valued [18][19][20]. Therefore, as an important target of unconventional oil and gas, there developed a series of machine learning methods to predict the identification and classification of shales and mudstones lithofacies [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Lithofacies and Source Rock Quality of Organic-Rich Shales in the Cretaceous Qingshankou Formation, Songliao Basin, NE China

et al. 2022

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The organic-rich shale of the Qingshankou Formation (K2qn) is the most important target in the Songliao Basin. The relationship between lithofacies and source rock quality, however, is still controversial. Core observation, thin section identification, X-ray diffraction, organic geochemistry, and other analytical methods were adopted to investigate the petrology and its effects on hydrocarbon potential of the Qingshankou shale. Based on the differences in minerals, bioclastic, and fabric of laminae, four main lithofacies were defined as: (i) felsic shale (FS), (ii) clay shale (CS), (iii) bio-bearing shale (BS), and (iv) mixed shale (MS). The clay minerals content in the CS (average: 46.72 wt%) and MS (average: 41.11 wt%) was higher than that in FS (average: 39.97 wt%) and BS (average: 35.48 wt%). This classification allows the following comparative quantification of total organic carbon (TOC) content to be differentiated: CS > BS > MS > FS. Geochemical analysis indicated that the oil generation potential of the CS was the best, and the hydrocarbons generated from CS might migrate and accumulate in other lithofacies. All this knowledge could shed light on the lithofacies classification in shale systems with high clay mineral content, and may provide references for sweet spotting of the Qingshankou Formation in the Songliao Basin.

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Section: Introductionmentioning

confidence: 99%

Lithofacies and Source Rock Quality of Organic-Rich Shales in the Cretaceous Qingshankou Formation, Songliao Basin, NE China

et al. 2022

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“…Feldspar is a brittle mineral 62 with strong compressive resistance, and the pores between particles are easily preserved during the burial process. Feldspar particle crystals are relatively regular, with mostly triangular, quadrilateral, or polygonal pores; these spaces are primarily classified as P mes (Figure 4c).…”

Section: Feldsparmentioning

confidence: 99%

Control of Physical Properties by the Matching between Rock Components and Pore Structure in Shale Reservoirs of the Permian Lucaogou Formation, Jimusar Sag

Song,

Li,

Sun

et al. 2024

Energy Fuels

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Shale oil reservoirs are extremely tight, making it fundamental to evaluate their physical properties for exploration and development efforts. These properties are closely linked to the rock components (RC) and pore structure (PS). The significant complexity and heterogeneity inherent in RC and PS pose considerable challenges for assessing the physical properties of these reservoirs. In specific depositional environments, a matching relationship between the RC and PS exists. Identifying this relationship and associating microscale PS attributes with macroscale physical properties can expose substantial variations within shale oil reservoirs, aiding in the selection of optimal layers for exploitation and improving the development efficiency. This study focuses on the shale oil reservoirs of the Lucaogou Formation in the Jimusar Sag, marked by mixed-source sedimentation. It employs experiments such as X-ray diffraction, total organic carbon measurement, low-temperature nitrogen adsorption, mercury injection capillary pressure, and scanning electron microscopy to characterize the RC and PS. Based on these experiments, the research analyzes the matching relationship between RC and PS in the shale oil reservoirs and the connection between microscale PS and macroscale physical properties, highlighting the control of physical properties, by RC and PS. The findings reveal that pore types in these shale oil reservoirs predominantly consist of small pores and mesopores. Small pores, developed within K-feldspar, quartz, and clay minerals, are chiefly dissolution pores; mesopores occur between dolomite or plagioclase grains and are characterized by a regular pore morphology. Porosity is governed by the presence of micro-, meso-, and macropores, while permeability is principally influenced by meso-and macropores. The study indicates that rocks with a higher content of dolomite and plagioclase, such as dolomitic siltstone, silty dolomite, and feldspar silt-fine sandstone, possess comparatively superior physical properties. This established relationship between RC and PS in this study offers a reference for the efficient development of the Lucaogou Formation shale oil reservoirs and can serve as a foundation for research into the fluid−solid interaction and flow characteristics in porous media.

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“…Shale Oil Enrichment Model. Song et al used a BP (Back Propagation)neural network combined with X-ray diffraction (XRD) to predict the mineral components of 61 wells in the study area,76 got XiLiu3 -Liu490 lithofacies section (Figure15), corresponding to the section line in Figure1. Considering the microscopic characteristics and depositional environment, the shale oil enrichment model of the Raoyang sag has been established.…”

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confidence: 99%

Influence of Paleosedimentary Environment on Shale Oil Enrichment in the Raoyang Sag, Bohai Bay Basin

Wang

Huang

et al. 2022

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A set of high-quality hydrogen-rich shale was found in the upper third submember of the Shahejie Formation (Es3 U) in the Raoyang sag. After more than 40 years of exploration and development, oil and gas shows have been seen in many wells in this interval, and there are many wells to obtain industrial oil flow. However, the influencing factors of its shale oil enrichment are still unclear. Based on petrology, organic geochemistry, and elemental geochemistry analysis, the control effect of the characteristics of a paleosedimentary environment on lacustrine shale oil enrichment is revealed and the shale oil enrichment model is established in this paper through a comprehensive study of the occurrence and migration of elements in different sedimentary facies areas. The parameters of V/(V+Ni), δU, Sr/Cu, Rb/Sr, Zr/Rb, Zn/Al, and Sr/Ba indicate that lake water evaporates in hot and arid climate, and brief transgression events led to the increase of water salinity; the outburst of salt-eating organisms such as algae and nutrients from the provenance provided the material basis for the enrichment of organic matter. The quiet and strong reduction of paleowater provides good preservation conditions for the enrichment of organic matter. The Mg2+ provided by transgression moved toward the center of the lake basin under the action of gravity, and the low-magnesium and calcium-rich saline environment was conducive to the occurrence of carbonate minerals such as calcite. Calcite and aragonite laminae were generated in the center of the sedimentation of the lake basin and interbedded vertically with the organic matter carried by fine-grained materials. The areas where carbonate-rich, calcareous, and argillaceous shales with rich organic matter are relatively developed are sweet spot reservoir areas of shale oil, which are mainly located in the center of the lake basin. In addition, the total organic matter content is high enough to meet the shale oil enrichment standards. Through the above studies, shale oil enrichment is established, which can guide shale oil exploration and development in the Raoyang depression successfully.

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Coupling Relationship between Lithofacies and Brittleness of the Shale Oil Reservoir: A Case Study of the Shahejie Formation in the Raoyang Sag

Cited by 8 publications

References 58 publications

Lithofacies and Source Rock Quality of Organic-Rich Shales in the Cretaceous Qingshankou Formation, Songliao Basin, NE China

Lithofacies and Source Rock Quality of Organic-Rich Shales in the Cretaceous Qingshankou Formation, Songliao Basin, NE China

Control of Physical Properties by the Matching between Rock Components and Pore Structure in Shale Reservoirs of the Permian Lucaogou Formation, Jimusar Sag

Influence of Paleosedimentary Environment on Shale Oil Enrichment in the Raoyang Sag, Bohai Bay Basin

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