Ultrasonic oscillations induced property development of water-bentonite suspension containing sulfonated wood coal

During drilling fluid preparation, ultrasonic oscillations were introduced into water-bentonite suspension incorporating sulfonated wood coal (SMC) by a specially designed device. The influences of ultrasonic oscillations on fluid loss and rheological performances of the drilling fluid as well as mechanism of ultrasonic action were investigated. The experimental results showed that the filtrate volume decreased with the increase of ultrasonic time till a certain extent and then leveled off. In the presence of ultrasound, shorter time of 15 min and mild intensity of 250 W could lead to a satisfactory result in fluid loss properties, including the reasonable filtrate volume and thin and compact filter cakes. With increasing ultrasonic intensity, the fluid loss properties changed relatively little but various rheological data of the drilling fluids always increased. Adsorption tests through total organic carbon, infrared spectrum and thermogravimetic analyses as well as clay particle size analysis confirmed that as compared with the conventional agitation, ultrasound-assisted mud preparation could not only increase adsorbed amount of SMC on bentonite but also decrease average clay particle diameter attributed to acoustic cavitation. A plausible mechanism based on sonochemical thermodynamics is proposed to explain the improvement of the colloidal structure and performances of drilling fluid.

Chain conformation of polymers adsorbed to clay particles: effects of charge and concentration

Schematic structure of PEO chains (red) adsorbed to a clay particle (blue) with increasing polymer concentration from (a) to (e).

A Qualitative Study of the Critical Conditions for the Initiation of Mine Waste Debris Flows

Mine waste debris flows are a type of man-made debris flow that commonly lead to major disasters. In this study, the Xiaotong Gully, which is located in the Xiaoqinling gold mining area in China and contains a typical mine waste debris flow gully, was selected as the study area. Since a debris flow can be classified as either a geotechnical debris flow or hydraulic debris flow based on its initiation mode, we conducted 46 experimental model tests to explore the initiation conditions of these two different types of debris flows. According to our tests, the initiation conditions of hydraulic debris flows were mainly affected by the flume gradient, the water content of the mine waste, the inflow discharge, the water supply modes, and the clay particle content. A larger flume gradient and higher mine waste water content were more conducive to initiating a hydraulic debris flow. However, the influence of the water supply mode on the initiation of a hydraulic debris flow was complex (influenced by factors such as water content of mine waste, runoff discharge rate and rainfall intensity). The critical runoff of a hydraulic debris flow, which starts with a parabolic relationship to the clay particle content of the mine waste, decreased with increasing clay particle content and then increased. There was a minimum critical runoff when the clay content of the mine waste was 30%. The initiation conditions of a geotechnical debris flow were mainly affected by the flume gradient, the water content, and the clay particle content. The critical gradient of a geotechnical debris flow decreased with increasing water content and had a parabolic relationship to the clay particle content. In tests 31–46 of this study, the second and third critical slopes both decreased and then increased with increasing clay particle content. These preliminary research results provide a scientific reference for subsequent research on the prevention and mitigation of mine waste debris flows.

Experimental and Development of Polymer-Clay based Hybrid Nanocomposites

The hybrid polymer was arranged by using of halloysite nano tubular particles in hand lay-up method. Natural polymer materials have nano-clay particles; the epoxy resin was a chemical reaction of bonding two materials. The polymer material and nano clay particles are bonding with the epoxy resin. The amount of benzyl peroxide-radical initiator was analyzed by X-Ray diffraction method. The polymer nano clay particle and glass fiber are reinforced with epoxy-resin hybrid composites. The weight fractions of nano clay particle are 1.5, 2.5, and 3.5 % (by weight.) and Halloysite Nano tubular (HNT) clay joined together with polymer clay. In this project work was carried out wear test, tensile Strength X-ray Diffraction and SEM. In this project work conducted by wear test by Varying the loads and percentage of nano clay particles can be studied

Stochastic modeling of kaolinite transport through a sand filter

Accurately modeling the transport of clay particles through coarse-grained porous media is essential to engineering applications ranging from filtration and drainage, groundwater flow modeling, to contaminant transport. However, predicting the retention and clogging behavior of clay particles within a coarse-grained soil matrix is extremely challenging because clay particles can aggregate and form clusters with a variety of fabrics depending on the prevailing geochemistry of the pore fluid (i.e., pH and ionic strength). The work performed in this study developed a stochastic model to investigate the uncertainty of clay particle transport in porous media using random sampling at a given grain-size distribution to account for inherent uncertainty of the size of clay clusters being transported. Results demonstrated that the model proposed in this work can evaluate upper and lower boundaries of retention profiles of clay particles in a sand medium at given mean and standard deviation of grain-size distributions. In addition, the deterministic approach (using median sizes of sand and clay particles in the simulation) underestimated the mass of retained particles at small size ratios of clay particle size/sand particle size when compared with the stochastic prediction, which would result in nonconservative design.

Experimental Study of Profile Control with Foam Stabilized by Clay Particle and Surfactant

Foam is a kind of ideal fluid for profile control in petroleum engineering, which has attracted intense interests of scholars globally in recent years. In this study, a foam system stabilized with anionic surfactants and clay particles was proposed for profile control in reservoirs, and the formulation was optimized experimentally. Moreover, flooding experiments in visible porous media models and in sandpacks were conducted to test the plugging effect of the foam system on reservoirs, and the effects of different factors such as gas–liquid ratio, temperature and permeability on profile control were also evaluated. According to the experimental results, the clay-HY-2 system was elected for its satisfactory foamability, stability, and salinity resistance, and the optimum concentrations of HY-2 and clay particle are 0.6 wt% and 5.0 wt%, respectively. Compared with traditional foam fluids, the clay-HY-2 system can form denser and smaller bubbles in high- and middle-permeable layers, enhancing the plugging effect there, while there are less bubbles in low-permeable layers, i.e., the restriction on the flow in narrow structures is slight. The clay-HY-2 foam can perform the efficient and uniform profile control effect on sandpacks when the foam quality is around 50%. The resistance factor of the foam decrease gradually with the increasing temperature, however, the resistance factor remains higher than 350.0 when the temperature reaches 80.0 °C. When the permeability exceeds 1502.0 mD, the clay-HY-2 foam can perform deep profile control in reservoirs, and the resistance factor are not sensitive to the change of permeability when it exceeds 3038.0 mD. Besides, the site application case shows that the clay-HY-2 foam do have good profile control effect on reservoirs, i.e., improving oil production and declining water cut.