Effect Of Chlorite Research Articles

Effect of chlorite on the flotation of pyrrhotite and its implications for elimination by different methods

ABSTRACTThe effect of chlorite on the flotation of pyrrhotite was systematically investigated through flotation tests, adsorption studies, optical microscopy experiments, inductively coupled plasma emission spectrometer tests, zeta potential measurements, and X-ray photoelectron spectroscopy analysis. Results showed that fine chlorite impaired the flotation of pyrrhotite due to slime coating. To eliminate the adverse effect of chlorite, two different methods were employed. Carboxymethyl cellulose and quartz could remove the slime coating of chlorite and improve the flotation recovery of pyrrhotite, whereas the addition of quartz provided better results. The key to eliminating the adverse effect of chlorite on the flotation of pyrrhotite is to remove the slime coating of chlorite by changing the surface charge of chlorite.

Origin of different chlorite occurrences and their effects on tight clastic reservoir porosity

The effects of chlorite on tight sandstone reservoirs have not been fully understood yet. In this paper, two different chlorite occurrences are observed in the Upper Triassic Xujiahe tight sandstones of Guang'an Area, Sichuan Basin (grain coating) and in the Permian Lucaogou tight sandstones of Jimusar Sag, Junggar Basin (pore filling), respectively. The effects these two chlorite occurrences having on reservoir quality are evaluated. Results show the influence of chlorite on porosity of tight clastic reservoir depends on its occurrences. Grain-coating chlorite has positive effect on porosity preservation, while pore-filling chlorite plays a negative role.Analysis of grain size indicates that grain-coating and pore-filling chlorites always occur in high-energy and low-energy environments, respectively. The water current carries an abundance of medium-grained saltating contents in strong hydrodynamic tractive current environment that leads to a relative motion between the saltating population and suspended clay in water. As indicated by Bernoulli's theory, the saltating grains are coated by clay on the surface because of the local flow pressure resulting from relative velocity. However, in the case of a weak hydrodynamic tractive current depositional environment, sand is entrained with clay, i.e., both sand grains and clays are in suspension and they have no relative velocity; thus, the clay cannot completely coat the grain surface. As the precursor of chlorite, occurrence of smectite-dominant clays determines the occurrence of chlorite during diagenesis, and therefore, determines whether the chlorite has a positive effect on porosity of tight clastic reservoirs.

A novel integrated approach to estimating hydrocarbon saturation in the presence of pore-lining chlorites

Pore-lining chlorites are often associated with a low-resistivity contrast between corresponding reservoir units, making the identification and quantitation of hydrocarbon-bearing intervals difficult. In many low-resistivity situations, the traditional approach of using Archie’s equation to determine saturation from electrical resistivity fails, and modified Archie equations derived specifically for ‘shaly sands’ have been developed. In chlorite-bearing intervals, however, the effect of chlorite can be such that both Archie and the so-called shaly-sand models are inappropriate. Under these circumstances, calculating saturation from electrical resistivity can be circumvented by detailed analysis of the sedimentology and petrophysics, enabling the construction of a saturation height model based on core data. In this novel study we integrate a detailed core-based sedimentological facies scheme with wireline log data and petrophysical core data to demonstrate a clear link between chlorite occurrence, petrophysical characteristics and saturation height. Through this innovative approach, saturation is estimated without recourse to resistivity logs and improves hydrocarbon saturation estimates in chlorite-bearing reservoirs.

Experimental Study on the Influence of Clay Minerals on the Yield Stress of Debris Flows

AbstractIt is common knowledge that a relationship exists between the volumetric sediment concentration, the percentage of clay mineral content, and the activity of clay minerals (which is related to the clay type) and the yield stress of a debris flow mass. In this paper, the effect of four types of common clay minerals (montmorillonite, illite, chlorite, and kaolin) on the yield stress of mixtures were investigated in a quantitative way. Laboratory experiments were carried out with single and mixed clay mineral types, various volumetric concentrations, and percentages of clay mineral content. For the same clay content and same volumetric concentration, a decreasing effect was found, respectively, of montmorillonite>illite>kaolin on the yield stress of the flow mixture, whereas the effect of chlorite was equal to that of kaolin. A concept of equivalent clay mineral percentage (P0) is introduced in this paper, in which the value of 1 is taken as the characteristic coefficient of kaolin in the experiments....