Article
Geosciences, Multidisciplinary
Siwei Meng, Dongxu Li, Qi Wang, Jiaping Tao, Jian Su, Hanqi Li, Xu Jin, Liu Yang
Summary: A new comprehensive evaluation method for shale fracturing was developed in this study, utilizing multiple factors and nanoindentation to determine fracturing and fracability coefficients that assess the overall fracturing performance of shale. The results were found to be consistent with actual performance.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Engineering, Petroleum
Yang Ju, Guangjie Wu, Yongliang Wang, Peng Liu, Yongming Yang
Summary: This paper introduces the entropy weight method (EWM) to establish a comprehensive evaluation model that quantifies the brittleness of reservoir rocks. A 3D model is used to simulate and compare hydraulic fracture propagation in different brittle and ductile reservoirs. A comprehensive evaluation index BIf is constructed to define the dominant factor of fracturing behavior based on simulation results.
Article
Energy & Fuels
Baicun Yang, Lei Xue, Yongting Duan, Miaomiao Wang
Summary: The study found a proportional relationship between the fracability and brittleness of shale gas reservoirs, with the ratio of fractal dimension and Weibull shape parameter close to a constant value of 2. This relationship is significant for the fracturing and recovery of shale-gas reservoirs, particularly in low-brittleness shale.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2021)
Article
Engineering, Chemical
Guangfu Zhang, Haibo Wang, Fengxia Li, Di Wang, Ning Li, Shiming He
Summary: Based on rock triaxial mechanical tests, this study developed a comprehensive evaluation method for the fracability of shale oil reservoirs that considers hydration, brittleness index, horizontal difference stress, fracture toughness, and water phase intrusion. The research findings provide insights into the mechanical properties and fracture behavior of hydrated shale rock.
Article
Geosciences, Multidisciplinary
Yapei Ye, Shuheng Tang, Zhaodong Xi, Renqi Lu, Zhongyao Zhang, Jintao Li
Summary: Studying the microscopic characteristics of shale can provide a theoretical basis for evaluating its macroscopic mechanical properties and fracturability. Different types of quartz in shale have different effects on the quality of shale oil/gas reservoirs. This study used finite element numerical simulation to set up different models based on the microscopic occurrence states of quartz, and found that the size and occurrence mode of quartz have a significant impact on shale compressive strength, while quartz content has the most significant influence on shale brittleness. The presence of quartz particles can enhance the compressive strength of shale and form complex fracture networks.
NATURAL RESOURCES RESEARCH
(2023)
Article
Energy & Fuels
Shanyong Liu, Nai Cao, Yishan Lou, Yuan Yuan
Summary: This study proposes a novel approach for post-fracturing evaluation by integrating geological and engineering parameters. Based on the reservoir fracability index (RFI), a production predicting model is built to assess the development potential of the H block in Zhaotong shale gas demonstration zone. The results show that a reservoir quality index (RQI) above 5.0 indicates good reservoir quality and potential, and the RFI of H Block, typically ranging from 4.0 to 6.0, can be used to identify sweet spots. This method not only serves as practical fracturing evaluation, but also provides productivity prediction and fracturing optimization methods, supporting the development of shale gas reservoirs.
JOURNAL OF PETROLEUM EXPLORATION AND PRODUCTION TECHNOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Wenjun Xu, Jinzhou Zhao, Jianguo Xu
Summary: This paper introduces a new Fracability Index (FI) model, which evaluates the potential candidate layers for hydraulic fracturing in unconventional reservoirs by considering the possibilities of complex hydraulic fracture network and large stimulation reservoir volume. The model takes into account essential factors like brittleness, fracture toughness, natural fractures, and in situ stresses, providing a useful tool for selecting the most suitable candidates for fracturing treatments.
NATURAL RESOURCES RESEARCH
(2021)
Article
Energy & Fuels
Jingfu Mu, Hongjun Qiao, Qing Guo
Summary: This paper establishes a preliminary model for evaluating the compressibility of shale reservoirs by considering the influence of fracture toughness and critical mechanical energy release rate, which provides ideas for accurately evaluating the compressibility of deep shale reservoirs.
CHEMISTRY AND TECHNOLOGY OF FUELS AND OILS
(2022)
Article
Energy & Fuels
Qamar Yasin, Ghulam Mohyuddin Sohail, Ke-Yu Liu, Qi-Zhen Du, Cyril D. Boateng
Summary: It is crucial to differentiate between brittle and ductile zones in low permeability shale formations for effective hydraulic fracturing stimulation. This study constructed brittleness templates and utilized an improved brittleness index model to classify the Longmaxi shale gas reservoir in China. The results demonstrate the significance of the brittleness templates in identifying favorable zones for hydraulic fracturing and enhancing shale characterization.
Article
Energy & Fuels
Alexandra Scerbacova, Elena Mukhina, Denis Bakulin, Alexander Burukhin, Anastasia Ivanova, Alexander Cheremisin, Margarita Spivakova, Alexandra Ushakova, Alexey Cheremisin
Summary: The combination of horizontal well drilling and multistage hydraulic fracturing is the leading method for developing shale reservoirs. However, oil recovery from these techniques is low, which has led to the exploration of supporting technologies. This study investigates the use of water-based compositions and nanofluid boosters to enhance oil recovery from low-permeability shale cores through huff-n-puff treatment. Experimental and numerical investigations were conducted, showing that oil recovery using brine was around 50%, decreasing to 31% after nanofluid injection.
Article
Energy & Fuels
H. Samara, T. Ostrowski, F. Ayad Abdulkareem, E. Padmanabhan, P. Jaeger
Summary: The study shows that utilizing carbon dioxide in shales can enhance oil recovery and climate storage, but success depends on controlling various mechanisms in rock pores. Results indicate that operating pressure significantly affects interfacial properties, and gas adsorption on rock surfaces is directly related to contact angle of the gas.
JOURNAL OF PETROLEUM EXPLORATION AND PRODUCTION TECHNOLOGY
(2022)
Article
Engineering, Geological
Daniel Fraser, Raoof Gholami, Mohammad Sarmadivaleh
Summary: Magnitude and direction of in-situ stresses are crucial inputs for geomechanical analysis, with Deformation Rate Analysis (DRA) being an effective method for unconventional shale gas reservoirs. However, the elapsed time between sample extraction and testing, as well as the impact of loading cycles on results, should not be ignored during laboratory measurements.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2021)
Article
Energy & Fuels
M. Akbarabadi, A. H. Alizadeh, M. Piri, N. Nagarajan
Summary: The significant amount of gas produced from unconventional reservoirs in the US in recent years has created an opportunity for using low-cost gas in enhanced oil recovery projects. Experimental and numerical studies have shown the great potential of using produced gas as an injectant for enhanced oil recovery from tight shale resources. The objective of this study is to investigate the feasibility of produced gas huff-and-puff operations in a major oil-producing shale formation in North America.
Article
Energy & Fuels
Ning Sun, Yang Gu, Xiaolong Zhang, Hao Zhang, Zhongyang Zhai, Xuezhu Qi
Summary: This study introduces the fracturability index (FI) based on shale brittleness, fracture toughness, and stress decay rate for the exploration and development of shale gas in the lower Paleozoic marine organic shale strata of the upper Yangtze region in South China. The fracturability index of the Longmaxi Formation shale in the study area ranges from 0.34 to 0.72, with the middle and lower parts showing better fracturability than the upper part. Shale reservoirs with high brittleness index, low fracture toughness, and low critical strain energy release rate tend to have high fracturability.
ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS
(2022)
Article
Geosciences, Multidisciplinary
Hongyan Qi, Jing Su, Xuan Hu, Aiyu Ma, Yuqing Dong, Ang Li
Summary: This study focuses on the characterization and evaluation method of shale oil reservoirs in the Lucaogou Formation in the Jimsar Sag, Junggar Basin. By analyzing the logging response characteristics of complex lithologies, a multilevel, multi-logging parameter combination shale oil logging evaluation model is proposed and successfully applied to interpret the data in the study area. This model effectively solves the evaluation problems of shale oil source rock quality, reservoir quality, and engineering quality, and clarifies the sweet spot of shale oil.
FRONTIERS IN EARTH SCIENCE
(2022)