Drilling fluids are multicomponent systems used to aid the removal of cuttings from a borehole, and subject to a number of requirements to ensure a safe drilling operation. One of the most important is to form a low permeability cake on the walls of the hole penetrated by the bit, to avoid excessive filtrate loss. To that end, carboxymethylcellulose (CMC) associated with calcite (CaCO 3) can be used. In this paper, the effect of carboxymethylcellulose on the colloidal properties of calcite suspensions in brine was systematically evaluated by rheological properties, filtrate volume and zeta potential. Higher viscosity fluids, lower filtrate loss and less negative zeta potential were obtained using small calcite particles with wide size distribution and CMC with high average molecular weight (Mw) and low average degree of substitution (DS), highlighting the importance of effective interactions between CMC and calcite to improve drilling fluid properties.
In this paper, the clay hydration inhibitive properties of carboxymethylcellulose (CMC) in drilling fluids systems were studied. The clay swelling degree was evaluated as a function of time in presence of different aqueous solutions containing sodium chloride, potassium chloride, CMC A (9 Â 10 4 g/mol À DS 0.7), CMC B (2.5 Â 10 5 g/mol À DS 0.7), CMC C (2.5 Â 10 5 g/mol À DS 1.2) and a commercial clay inhibitor based in quaternary amine, that was used as reference pattern. According to results obtained, the low molecular weight CMC showed slightly lower clay swelling degree compared to the high molecular weight along 180 minutes. In parallel, it was confirmed the higher efficiency of quaternary amine-based commercial inhibitor (QABCI) to control the clay swelling mechanism. Basically, this inhibition effect was attributed to the ability of cationic quaternary ammonium groups to form electrostatic interactions with negatively charged surfaces of the clay, enhancing associative interaction between their particles. Besides, it was visualized by microscopy that the highest molecular weight of CMC provided a reduction in formation and pores size compared to CMC of lower molecular weight after 1,000 minutes in aqueous medium. This behavior could be attributed to the dynamic of interactions between clay and high molecular weight CMC along the time, which is a result of strong contribution of electrostatic interactions between carboxylate groups located along the polymer backbone and positively charged clay layers edges as well as hydrogen bonds.
Despite the huge advances made in the petroleum sector regarding the innovation of its technological processes, there are still some troubling problems. An example of this refers to the water produced. Treatment and disposal has become one of the biggest challenges in the oil industry. The problem consists in the difficulty of degradation of the compounds to an adequate level that allows the safe disposal in the environment, ensuring the possibility of reuse or disposal in the standards established by the environmental agencies. This fact has encouraged researchers to direct studies to find alternatives capable of efficiently removing the contaminants present in this water at a lower cost compared to other existing technologies. Thus, the purpose of this work is to use adsorbent materials with high porosity and high silica content, such as sugarcane bagasse and rice, in order to remove the crude oil content present in the water produced. The adsorption process of the crude oil on the surface of each support occurred at predetermined intervals and with different concentrations of contaminant and adsorbent. A factorial modeling mapping (3²) was performed to evaluate the effect of the interactions between the concentrations of each support in relation to the contaminant. From the results obtained, it was verified that the calcination of sugarcane bagasse and rice was fundamental for the efficiency of the system. In all the systems an increase of the percentage of removal using these adsorbents was observed, suggesting that both represent a promising application in the advance of technologies responsible for the treatment of the water produced.
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