Micro scale fractures play a crucial role in facilitating the migration of oil and gas low permeability shale reservoirs. However, identification such is complex task. The efficacy dual lateral log physical field changes as means identifying micro remains uncertain. To address this issue, three-layer bedding fracture model was developed using finite element method core conventional logging data...

The outcropping Cretaceous siliciclastic sediments in the Al Bauga area in Northern Sudan reach a maximum thickness of about 30 meter. They rest with angular unconformity on tilted Precambrian basement rocks and are capped by Tertiary-Quaternary basalts forming a type of nonconformity. The sedimentary sequence was subdivided into three major units separated by two disconformities. The lower uni...

SUMMARY Crack nucleation and rock failure processes in a fine-grained siltstone (Montney Formation) under triaxial compression are investigated using combined diagnostic techniques, including ultrasonic-wave measurement, acoustic-emission (AE) monitoring, computed tomography (CT) scanning, thin-section imaging. The sample displays weak-to-moderate inherent seismic anisotropy noticeable stress-i...

In this paper, the needle penetrometer test was utilized to explore the reliability of the Needle Penetration Index (NPI) for estimating the Unconfined Compressive Strength (UCS) of sedimentary rocks including gypsum, marl, siltstone and sandstone collected from the Qom Formation. Following the UCS and NP test, regression analyses were carried out to control the predictive performances of NPI. ...

   The study area is located in the northeast of Iran. Miankuhi Formation is 500m thick and comprises homogeneous shales, brown granular sandstone and siltstone. In this study, 45 samples were taken from Miankuhi shales and sandstones in order to determine their tectonic origin by using a polarizing microscope. Samples were analysed by X-Ray Fluorescence (XRF) method to determine their chemical...

Detailed knowledge of chemical, petrographic and mineralogical compositions as well the effects applying rock powder on soil chemical properties plant production are required for classifying these materials remineralizers (SR), according to Brazilian legislation in force. This study aimed evaluate potential powders siltstone, tephrite olivine melilitite, pure or mixed, improving fertility a Cam...

Early Palaeoproterozoic (2.5-2.0 billion years ago) was a critical phase in Earth's history, characterized by multiple severe glaciations and a rise in atmospheric O(2) (the Great Oxidation Event). Although glaciations occurred at the time of O(2) increase, the relationship between climatic and atmospheric transitions remains poorly understood. Here we report high concentrations of the redox-se...