Polymer clay stabilizers, permeability

The first set of data is for oil production from 22 wells. A quaternary ammonium salt polymer clay stabilizer was utilized in five of the well treatments. Otherwise the 22 well treatment designs were identical. Use of the clay stabilizer in 5 well treatments resulted in a 131% production increase compared to a 156% increase after stimulation of 17 wells without clay stabilizer. Although the initial overall production response of the five clay stabilizer treated wells was less, the overall production decline rate was 4% per year compared to 16%/yr for the treatments which did not include the clay stabilizing polymer. This decline rate was determined for the period 4 to 24 months after well treatment. It is tempting to speculate that the lower initial production response of the five polymer treated wells was due to the formation of an adsorbed polymer layer which reduced formation permeability (particularly of the Wilcox Formation) significantly. 

Advances in clay-bearing formation treatment have led to the development of numerous clay-stabilizing treatments and additives. Most additives used are high-molecular-weight cationic organic polymers. However, it has been shown that these stabilizers are less effective in low-permeability formations [834]. 

Nanocomposites are a new class of particle-filled composites in which at least one dimension of the dispersed particles is within 100 nm. Because of the dispersion of nanosize clay particles, polymer-clay nanocomposites exhibit improved moduli and strength, decreased thermal expansion coefficient, decreased gas permeability, increased swelling resistance, better thermal stability and enhanced ionic conductivity when compared to the pristine polymers or microscale composites [149-151], They find increased applications in various fields such as automobile, packaging, electronic, coating and aerospace industries [152,153],... 

There have been many other reports on direct emulsion polymerizations involving nascent clays, either using clays as stabilizing agents or with the aim of preparing polymer-clay nanocomposites. In addition, organically modified clays have also been used in direct emulsion polymerization. Improved mechanical and thermal properties, reduced vapor permeability and improved flame retardancy for the prepared polymer-clay composites were reported. 

It is reasoned that the much better thermal stability is attributed to hindered out-diffusion of the volatile decomposition products, as a direct result of the usually observed decrease in permeability in polymer/clay nanocomposites. As improvements in the properties (such as thermal properties) of the nano-eomposites can be realized at very low filler content, it often makes the material... 

It is generally accepted that thermal stability of polymer nanocomposites is higher than that of pristine polymers, and that this gain is explained by the presence of anisotropic clay layers hindering diffusion of volatile products through the nanocomposite material. It is important to note that the exfoliated nanocomposites, prepared and investigated in this work, had much lower gas permeability in comparison with that of pristine unfilled PE [12], Thus, the study of purely thermal degradation process of PE nanocomposite seemed to be of interest in terms of estimation of the nanoclay barrier effects on thermal stability of polyolefin/clay nanocomposites. 

Biodegradable polymers can be mainly classified as agro-polymers (starch, protein, etc.) and biodegradable polyesters (polyhydroxyalkanoates, poly(lactic acid), etc.). These latter, also called biopolyesters, can be synthesized from fossil resources but main productions can be obtained from renewable resources (Bordes et al. 2009). However for certain applications, biopolyesters cannot be fully competitive with conventional thermoplastics since some of their properties are too weak. Therefore, to extend their applications, these biopolymers have been formulated and associated with nano-sized fillers, which could bring a large range of improved properties (stiffness, permeability, crystallinity, thermal stability). The resulting nano-biocomposites have been the subject of many recent publications. Bordes etal. (2009) analyzed this novel class of materials based on clays, which are nowadays the main nanoflllers used in nanocomposite systems. 

The positive effect on thermal stability of polymers due to polymers can be attributed to (i) high surface volume, (ii) improving barrier properties due to the clay contribution to tortuosity path, (iii) reduction of polymer molecular mobility, (iv) low permeability and decrease in the rate of evolution of the formed volatile products, (v) formation of high-performance carbonaceous silicate char on the nanoparticles surface that insulate the underline material and slows the escape of volatile products generated during the decomposition, (vi) absorption of formed gases into clay plates. 

Stabilization has been investigated for sodium containing byproducts. In some cases, clay and polymer mixtures have produced permeabilities as low as 10 cm/sec depending on the ash. The process is sensitive to the ratios of the various components and the requirements for proper mixing and compression, which become difficult when large quantities of byproduct have to be handled (Bennett and Nastri, 1990). 

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