Papers by Keyword: Shale

Abstract: This research investigates the progressive substitution of natural aggregates, conventionally used in road construction, with alternative materials derived from industrial co-products. Specifically, the study focuses on developing an innovative material that combines shale aggregates and blast furnace slag for road construction applications. The experimental procedure involved preparing various mixtures with slag content ranging from 10% to 50%, followed by comprehensive laboratory characterization through standardized mechanical and road performance tests. The results demonstrate that these composite materials exhibit highly promising characteristics. Mixtures containing 30–50% slag meet all current standard requirements, showing particularly excellent performance in bearing capacity (with CBR values reaching 62.15 for the 50% slag mixtures), while maintaining outstanding water stability (with variations of less than 4% after immersion).These mechanical properties, combined with consistent dry density values above 2.1 g/cm³ and a maximum internal friction angle of 43.53°, make these materials especially suitable for pavement layers. Beyond their technical performance, the shale–slag composites offer a sustainable solution with dual benefits: they significantly reduce pressure on depleting alluvial deposits while effectively valorizing abundant industrial by-products.Based in these findings, it is strongly recommended that such materials be integrated into conventional pavement construction, particularly for low to medium traffic. This circular economy approach therefore represents both a high-performance and environmentally responsible alternative to traditional materials.

Abstract: In this paper, the nano flexible polymer was synthesized and the plugging property of the polymer in the drilling fluid was studied. The characterization and properties of nano flexible polymer were invested by Particle Size Analyzer and Transmission Electron Microscopy. The nano flexible polymer was synthesized successfully and it was flexible nano material both in water and in drilling fluid. The filtration ability of the polymer was studied by drilling fluid filter press and the results indicated that the filtration property was equal to commonly used fluid loss agent in drilling fluid. The plugging ability was studied by specific surface and porosity physical adsorption instrument (BET). The surface area reduced after treated with the polymer, indicating the nano flexible polymer entered into nanopores of shale formation due to the adsorption in the surface of shale. It was further exhibited that nanopores of shale were plugged by the nano flexible polymer.

Abstract: Maintaining the borehole stability while drilling oil and gas wells is a major problem when drilling through water sensitive formation. Drilling using oil-based drilling fluid is the most effective solution to control shale. Due to the increasing environmental constraints on the use of mineral oil-based drilling fluid system, expensive research has been studied to optimize oil well operations and minimize drilling cost using new water-based drilling fluid system. In this study, the effectiveness of three commonly used shale inhibitors were tested, where cationic polymer and KLA-Gard are cationic type inhibitors and PHPA is polymer type inhibitor. Two types of shale samples were used in this study, both were taken from Malaysia. Each shale sample represents different degree in swelling and dispersion characteristic. The testing procedures were employed for the shale reactivity evaluation, inhibitors’ performance evaluation, rheology and filtration loss effect evaluation as well as the character of the recovered shale from dispersion test. Result showed that the cationic type inhibitor is suitable to be used for swelling shale. For disperse shale, polymer type inhibitor is the best selection to be added in the drilling fluid system. The combination of cationic inhibitor used along with the polymer inhibitor showed reduction in dispersion and swelling tendency. It is also found that the cationic inhibitors showed well compatibility with other polymers in the ionic solution. Cationic inhibitors do not affect the rheology and filtration loss properties but polymer inhibitors affect these properties.

Abstract: The results of studies on the development of a new process of thermal cracking of tar oil as a slurry with crushed oil shale to obtain components of motor fuels. The results suggest doubtless advantages of the process before the industrial of thermo cracking, since the single-stage processing of raw materials in relatively in the mild conditions (5 MPa, 425 °C, volumetric feed rate 1.0 h^-1) is achieved deep destruction of tar oil (the yield petrol fraction with a bp amounts to up to 180 °C – ~12 mass % of middle distillates with a bp 180-360 °C – 43-44 mass %, of raw material for catalytic cracking of a bp 360-520 °C – ~15-16 %, based on the initial tar oil). Formed like coke products and raw materials contained in V and Ni is postponed on the mineral part of slate and removed from the reaction zone with the liquid products of the process.

Abstract: Based on continuum damage mechanics, by defining the initial and critical damage value, because of the plastic volumetric strain of the specimen, we established the calculation methods of the rock specimen’s damage value. Through the conventional triaxial compression test of the shale, we find that damage value D changes as axial strain changes during compression, and summarizes its variation.

Abstract: The possible ways of shale destruction under electrophysical treatment were discussed. The products destruction were analyzed by GC-MS, DTA-TG and elemental analysis. The pyrolysis products formation was shown.

Abstract: Attention to oil shale processing as unconventional energy source grows significantly. Electrical discharge phenomena application allows creating new efficient technology. Dynamics of PD basic characteristics of voltage in oil shale is described in this paper. Thermodestruction with abnormally high rate is occurred and caused by PD activity. Critical PD incept under low electrical intensity due to oil shale porosity, anisotropy and heterogeneity. PD induce treeing with following electrothermal breakdown. Organic content has influence on electrical discharges phenomena in oil shale. Therefore, the detailed study of PD, treeing and breakdown in oil shale allows developing an efficient method of inferior solid fossil fuels processing.

Abstract: Serious borehole collapse has occurred in shale below salt formation of Fauqi oilfield in Iraq. The Lots of bedding shale cavings returned to ground. The strength of bedding shale cores with different bedding dip angle are tested, which changes along in a high degree with the dip angle and reach the minimum in 50°-60°. The experimental results are regressed by different strength criterion, which demonstrate that McLamore strength criterion is more accurate. The collapse pressure of shale below salt formation is calculated by Mohr-Coulomb criterion and McLamore criterion respectively. The maximum collapse pressure by Mohr-Coulomb criterion occurs in the maximum in-stress orientations and 90° deviation angle, and that by McLamore criterion occurs in the maximum in-stress orientations and 50°-60° deviation angle. By analyzing the actual drilling situation, McLamore criterion is proved to be more accurate and can be used in Fauqi oilfield.

Abstract: Theoretical studies have shown that the generation of the hydraulic fractures reduces or even reverses the stress anisotropy near the fractures and results in increasing the complexity of fractures. A finite element model was established in which the pore pressure elements were used to simulate the behavior of porous media and the pore pressure cohesive elements were adopted to catch the characters of hydraulic fractures. A special fracturing manner was adopted to create complicated fracture networks by reducing or even reversing the stress anisotropy between fractures. The geometries of hydraulic fractures, strains, stresses, pore pressure distributions and fluid pressures within the fractures are obtained. The results of the model are fit well with the corresponding theoretical data. The simulation results show that the stress anisotropy is reduced by the generation of the hydraulic fractures, multiple parallel transverse fractures of horizontal well even reverse the stress anisotropy in some place of the reservoir. The simulation results validate the feasibility of the theoretical studies and the expected complex network fractures could be created by adopting special fracturing manner.

Abstract: During the drilling process of shale gas horizontal well, wellbore instability problem happens frequently. Especially in the horizontal interval, shale which has high levels of gamma is more likely to collapse which lead to delays, and exist certainly collapse period. The development of shale gas is restricted seriously. Research on the formation process of cracks network around the wellbore by CT chromatographic technique. The result reveals that under the condition of uniaxial compression, the cracks initiated inside the shale formation around the wellbore, with the propagation of cracks, between the orientation of cracks and the maximum stress direction will emerge a certain deviated angle. The drilling fluid filtrates into the formation and reduce the strength of rock which will prompt crack propagation and form crack network. Finally the wellbore will collapse with drilling fluid continuous invasion, because the invasion have altered the stress intensity factor at fracture tip, and changed the propagating direction of crack and the friction coefficient of fracture plane, which will reduce the strength of rock and the effective stress of the rock around the wellbore. Crack network dominates the mechanism of instability; mud weight increases do not necessarily lead to a more stable borehole and can further destabilize the wellbore.