Quantitative Characterization and Controlling Factors of Shallow Shale Reservoir in Taiyang Anticline, Zhaotong Area, China

Ma, Kai; Zhang, Bing; Wen, Siyu; Lin, Xin; Wang, Yan; Yang, Kai

doi:10.3390/min12080998

Cited by 5 publications

(4 citation statements)

References 28 publications

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“…Analytical techniques such as RTS observations, micro-CT analysis, and SEM have their own resolution ranges. Similar to the fact that pores of different scales in shale need to be characterized through comprehensive utilization of the CO 2 adsorption, N 2 adsorption, and high-pressure mercury intrusion techniques [53][54][55], the quantitative characterization of microfractures of different scales in shale requires the combined use of different analysis techniques. Full-scale quantitative characterization of microfractures, such as a combination of nuclear magnetic resonance and micro-CT analysis to obtain the microfractures of different scales in rocks, has been reported, but only microfractures with a fracture width greater than 50 µm can be characterized using previously reported methods [56].…”

Section: Performance Of Comprehensive Quantitative Characterization O...mentioning

confidence: 99%

A New Method for Comprehensive and Quantitative Characterization of Shale Microfractures: A Case Study of the Lacustrine Shale in the Yuanba Area, Northern Sichuan Basin

Li,

et al. 2023

Energies

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Microfractures can connect isolated pores within shale, significantly increasing the shale’s storage capacity and permeability, and benefiting shale gas exploitation. Therefore, the quantitative characteristics of microfractures are important parameters for shale reservoir evaluation. In this paper, taking the Jurassic Da’anzhai Member (J1z4) lacustrine shale in the Yuanba area of the northern Sichuan Basin as an example, we propose a method for comprehensive and quantitative characterization of shale microfractures that combines rock thin section (RTS) and scanning electron microscopy (SEM) observations. The different magnifications of RTSs and SEM images lead to the identification and characterization of microfractures of different scales using these two methods. RTSs are mainly used to characterize microfractures with widths larger than 10 μm, while SEM is mainly used to characterize microfractures with widths smaller than 10 μm. These techniques can be combined to comprehensively and quantitatively characterize microfractures of different scales in shale. The microfracture characterization results show that the average total porosity of the J1z4 shale is 4.46%, and the average microfracture surface porosity is 1.20% in the Yuanba area. The calculated average percentage of microfracture porosity to total porosity is 21.09%, indicating that the J1z4 shale reservoir space is dominated by pores and has the conditions for stable shale gas production and potential for shale gas exploration. However, the percentage of microfracture porosity to total porosity of shale near faults and fold zones approaches or exceeds 50%, which may lead to the loss of shale gas. The new method proposed in this study is also useful for quantitative characterization of shale microfractures in the Sichuan Basin and other basins.

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Section: Performance Of Comprehensive Quantitative Characterization O...mentioning

confidence: 99%

A New Method for Comprehensive and Quantitative Characterization of Shale Microfractures: A Case Study of the Lacustrine Shale in the Yuanba Area, Northern Sichuan Basin

Li,

et al. 2023

Energies

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“…Studies of shale diagenesis show that compaction, cementation, and mineral composition affect shale reservoir pores [10,11]. Shale reservoirs usually form interconnected pores systems under the interaction effects of diagenesis and the thermal evolution of organic matter (OM) [12]. In order to understand the evolution of pores in shale reservoirs, it is crucial to investigate the diagenesis of shale reservoirs [11,13].…”

Section: Introductionmentioning

confidence: 99%

“…At present, research on marine shale gas reservoirs in the Sichuan Basin is relatively mature [26][27][28][29], and research on the diagenesis and pore structure evolution of shale reservoirs mainly focuses on marine shale [30][31][32][33]. The Upper Permian Longtan Formation shale in the Sichuan Basin is a typical representative of MCFS in China, and it has a complex evolutionary process because of the organic-inorganic diagenesis, which has a significant impact on its reservoir space [12,15,34]. For the Longtan Formation shale in the Sichuan Basin, the related research still focuses on aspects of the sedimentary environment, reservoir distribution, reservoir-forming conditions, and hydrocarbon generation potential [35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Diagenetic Evolution Sequence and Pore Evolution Characteristics: Study on Marine-Continental Transitional Facies Shale in Southeastern Sichuan Basin

Zhang,

Wen,

Yang

et al. 2023

Minerals

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Diagenesis and pore structure are essential factors for reservoir evaluation. marine-continental transitional facies shale is a new shale gas reservoir of concern in the Sichuan Basin. The research on its diagenesis pore evolution model has important guiding significance in its later exploration and development. However, the current research on pore structure changes, diagenesis, and the evolution of marine-continental transitional facies shale is not sufficient and systematic. In order to reveal the internal relationship between pore structure changes and diagenesis, the evolution of marine-continental transitional facies shale was tested by X-ray diffraction, field emission scanning electron microscopy, low-pressure gas adsorption, nuclear magnetic resonance, and the diagenetic evolution sequence and nanopore system evolution of Longtan Formation shale was systematically studied. The results show that the Longtan Formation shale underwent short-term shallow after sedimentation, followed by long-term deep burial. The main diagenetic mechanisms of the Longtan Formation shale include compaction, dissolution, cementation, thermal maturation of organic matter, and transformation of clay minerals, which are generally in the middle-late diagenetic stage. The pore structure undergoes significant changes with increasing maturity, with the pore volumes of both micropores and mesopores reaching their minimum values at Ro = 1.43% and subsequently increasing. The change process of a specific surface area is similar to that of pore volumes. Finally, the diagenetic pore evolution model of Longtan Formation MCFS in Southeastern Sichuan was established.

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“…In previous research, many scholars have studied the shales of the Longmaxi Formation in the southern Sichuan Basin at a macroscopic level [7][8][9][10]. With the increase in shale gas exploration and development, the important role of shale microstructure characteristics for shale gas enrichment and seepage is gradually being recognized [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Micropore Structure of Deep Shales from the Wufeng–Longmaxi Formations, Southern Sichuan Basin, China: Insight into the Vertical Heterogeneity and Controlling Factors

Yang,

Zhao,

et al. 2023

Minerals

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The microscopic pore throat structure of shale reservoir rocks directly affects the reservoir seepage capacity. The occurrence and flow channels of shale gas are mainly micron–nanometer pore throats. Therefore, to clarify the microstructural characteristics and influencing factors of the deep organic-rich shales, a study is conducted on the marine shale from the Upper Silurian to Lower Ordovician Wufeng–Longmaxi Formation in the southern Sichuan Basin. Petrographic lithofacies division is carried out in combination with petro-mineralogical characteristics, and a high-resolution scanning electron microscope, low-temperature nitrogen and low-temperature carbon dioxide adsorption, and micron-computed tomography are used to characterize the mineral composition and pore structure qualitatively and quantitatively, upon which the influencing factors of the microstructure are further analyzed. The results show that with the increase in burial depth, the total organic carbon content and siliceous mineral content decrease in the Wufeng formation to Long-11 subsection deep shale, while clay mineral content increases, which corresponds to the change in sedimentary environment from anoxic to oxidizing environment. Unexpectedly, the total pore volume of deep shale does not decrease with the increase in burial depth but increases first and then decreases. Using total organic carbon (TOC), siliceous mineral content showed a good correlation with total pore volume and specific surface area, with correlation coefficients greater than 0.7, confirming the predominant role of these two factors in controlling the pore structure of deep shales. This is mainly because the Longmaxi shale is already in the late diagenetic stage, and organic matter pores are generated in large quantities. Clay minerals have a negative correlation with the total pore volume of shale, and the correlation coefficient is 0.7591. It could be that clay minerals are much more flexible and are easily deformed to block the pores under compaction. In addition, the longitudinal heterogeneity of the deep shale reservoir structure in southern Sichuan is also controlled by the thermal effect of the Emei mantle plume on hydrocarbon generation of organic matter and the development of natural microfractures promoted by multistage tectonic movement. Overall, the complex microstructure in the deep shales of the Longmaxi Formation in the southern Sichuan Basin is jointly controlled by multiple effects, and the results of this research provide strong support for the benefit development of deep shale gas in southern Sichuan Basin.

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Quantitative Characterization and Controlling Factors of Shallow Shale Reservoir in Taiyang Anticline, Zhaotong Area, China

Cited by 5 publications

References 28 publications

A New Method for Comprehensive and Quantitative Characterization of Shale Microfractures: A Case Study of the Lacustrine Shale in the Yuanba Area, Northern Sichuan Basin

A New Method for Comprehensive and Quantitative Characterization of Shale Microfractures: A Case Study of the Lacustrine Shale in the Yuanba Area, Northern Sichuan Basin

Diagenetic Evolution Sequence and Pore Evolution Characteristics: Study on Marine-Continental Transitional Facies Shale in Southeastern Sichuan Basin

Micropore Structure of Deep Shales from the Wufeng–Longmaxi Formations, Southern Sichuan Basin, China: Insight into the Vertical Heterogeneity and Controlling Factors

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