The development of effective strategies for hydrocarbon extraction through unconventional shales requires a comprehensive understanding of shale petrophysical properties – specifically the variability of fabric, composition, matrix, porosity, permeability, and thermal maturity/organic content [1-5]. Unconventional resource extraction from shale can involve the injection of carbon dioxide (CO2) ...

China has vast reserves of shale gas. Currently, shale gas is one of the focuses of the unconventional reservoir. Well logs play an import role in shale gas production, and it is the bridge connecting geology, geophysics and petroleum engineering. In the exploration stage, well logs are used to identify lithology, evaluate the parameters of mineral types and compositions, total organic carbon (...

This study performs a comprehensive comparison of three key marine shale reservoirs in the southeastern margin of the Sichuan Basin, and explains why commercial gas production was only achieved in the Lower Silurian Longmaxi (LSL) and Upper Ordovician Wufeng (UOW) formations, but not in the Lower Cambrian Niutitang (LCN) formation. The experimental methods included in situ gas content and gas c...

Complexity in shale-gas reservoirs lies in the presence of multiscale networks of pores that vary from nanometer to micrometer scale. Scanning electron microscope (SEM) and atomic force microscope imaging are promising tools for a better understanding of such complex microstructures. Obtaining 3D shale images using focused ion beam-SEM for accurate reservoir forecasting and petrophysical assess...

Estonian shale oil contains about 25--30% phenols, and their action determines the toxicity of shale oils. The clinical symptoms of intoxication are rather similar, regardless of route of administration. Due to neurotropic action, the coordination of movements is impaired, and clonic and tetanic convulsions, paresis and paralysis of extremities, and narcosis are observed. In subacute and chroni...

The success of shale gas in North America has attracted increased interest in “unconventional” reservoirs. Two critical factors for shale-gas reservoirs are units amenable to hydrologic fracture stimulation and sufficient natural gas content. The effectiveness of hydrologic fracture stimulation is influenced by rock geomechanical properties, which are related to rock mineralogy. The natural gas...

Fine-grained sedimentary rocks (shale and mudstone) play important roles in global CO2 abatement efforts through their uses in carbon capture and storage (CCS), radioactive waste storage, and shale gas extraction. These different technologies, however, rely on seemingly conflicting premises regarding the sealing properties of shale and mudstone, suggesting that those rocks that lend themselves ...

Shale gas and oil are significant unconventional energy resources in the United States. Because of their low porosity and permeability, as well as the complex pore systems in organic rich shale formations, their petrophysical properties are not fully understood. Further, it is well known that wettability influences many aspects of reservoir characteristics, especially hydrocarbon storage and re...

During the hydraulic fracturing procedure in shale-gas exploitation, the poroelastic properties of shale formation can be altered significantly. However, it is difficult to evaluate these variations using microseismic field data. In this study, we conduct a hydro-fracturing experiment using Longmaxi shale, which is a major formation for shale-gas production in China, to simulate the water injec...

Shale formations show obvious anisotropic characteristics in their mechanical properties due to pronounced bedding planes and natural fractures. This anisotropic behavior generally creates complex fracturing networks and is crucial to gas shale stimulation. Although much research has been done to study the anisotropic compression behaviors of shale with static and quasi-static strain rates, the...