Keywords : Bentonite; characterization; clay.

Transcription

1 Materials Science Forum Vol 82 (215) pp 65-7 Submitted: (215) Trans Tech Publications, Switzerland Accepted: doi:1.428/ Clays Characterization in the Town of Sossego Paraiba State. I. D. S. Pereira 1, a ; V. N. F. Lisboa 2, b ; I. A. Silva 3, c ; J. M. R. Figueirêdo 4, d ; G. A. Neves 1 ; R. R. Menezes 1 1 Universidade Federal de Campina Grande 882, Aprígio Veloso Avenue, Bodocongó, Campina Grande City, PB, Zip code number: ivnadaniele@hotmail.com a, b neyonaraa@hotmail.com Keywords : ; characterization; clay. ABSTRACT: exhibt a range of industrial applications moving millions of dollars on the market per year. Among several applications if highlights it is use for petroleum drilling fluids. Thus, this work aims to characterize physical, mineralogical and technologically, the bentonitics clays of Sossego County, Paraíba, Brazil. Mineralogical characterization of clays was done through the following techniques: particle size analysis by laser diffraction, thermogravimetric and differential thermal analysis, chemical analysis and x-ray diffraction. The clays were turned in by treatment with sodium in Na 2 CO 3 and then determined whether the apparent viscosity, plastic and volume of filtrate of clay-water dispersions. The results showed that the samples are of polycationic, showing levels of MgO, CaO and K 2 O, similar to those from Boa Vista County, Paraíba, Brazil, and consist of clay mineral kaolinite, quartz and esmec. The clays showed rheological properties that indicate potential for use in drilling fluids. Introduction Betonites are formed predominantly by Clay materials belonging to the group of smectites with physical properties defined by the presence of the clay [2.3]. These clays possess the power to swell in the presence of water by expanding its volume up to twenty times its initial volume, reaching up to 1Å inter - planar spaces, high surface area (up to 8 m 2 g -1 ), cationic exchange capacity ranging from 6 to 17meq. 1 g -1 and thixotropic [4]. The ability to expand its volume is essentially important for applications that require rheological conditions, such as drilling fluids, given this feature check the viscosity of dispersion [5]. The drilling fluids consist of a continuous liquid phase, chemically treated so they can adapt their properties of drilling operations. These fluids in relation to the dispersant can be classified as water-based fluid or oil-based fluids [6]. Water-based fluids in the clays are used as seed disperser agent in Constitution of the drilling fluid of oil wells, and their rheological and physicochemical properties must be well monitored in order to ensure their proper functioning during drilling operations [7]. The drilling fluids present several physicochemical properties that must be taken into consideration during the implementation, among which we can highlight the rheological parameters that will influence directly in the calculation of the losses in the pipe and in the transport speed of the gravels. By doing certain rheological fluid measures, It is possible to determine how the fluid seeps under various conditions of temperature, pressure and shear rate. In rheological meaning, viscosity is the most well - known parameter being set to the resistance that a substance presents to the flow [8]. This way, the present work aims at the physical and mineralogical characterization of new occurrences of clays from the municipality of Sossego, PB for use in drilling fluids. Materials and Methods The materials used for the current research were three clay samples from deposits located in Sossego County - PB, which were known as DASL clay, RF clay and FDO clay. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: /4/15,15:48:31)

2 66 Brazilian Ceramic Conference 58 Each sample was taken to ball mill, with internal coating of ceramic material with high hardness, for commination. Then the material was sieved using sieve ABNT n o 2 (, 74mm). After the screening, the aliquots were removed for the different stages of characterization. The characterization of the samples was carried out through the following techniques: x-ray diffraction (DRX) (Shimadzu XRD6), with radiation Cuk (4 kv/3 ma) and goniometer speed of 2 the /min with step of.2, in the range of 2 to 6 to the natural samples and speed range from 2 to 3, for the samples treated with ethylene glycol; thermo-gravimetric analysis (ATG) and differential thermal analysis (DTA) (simultaneous thermal analysis system TA 6 h Shimadzu)with heating rate 12.5 o C/min under air atmosphere (the maximum temperature to both cases was 1 o C standard and used in ATD was aluminum oxide (Al 2 O 3 ) calcined);particle size analysis by laser diffraction (AG) (Cyprian, 164 Model equipment L/D) and chemical analysis by x-ray fluorescence (EDX 72 Shimadzu). After the tests of characterization, the polycationic was turned into green clay with sodium, by the use of concentrated solutions of sodium carbonate (Na2CO3) at the following levels: 75, 1, 125, 15 and 175 meq/1 g of dry clay to the samples. The rheological properties were determined: apparent viscosity (VA) and plastic viscosity (PV) using model 35A Fann viscometer. Volume of filtrate was held in filter press the Fann Mark. All trials were determined according to Petrobras standards [9]. Results and Discussions Table 1 shows the distribution of particle size sieve of DASL, RF and FDO. Table 1: Particle size distribution by particle size of clays Clay (%) ( ) Silt (%) ( ) Sand(%) ( ) DASL 22,24 76,86,9 RF 19,91 78,17 1,92 FDO 27,75 72,25 It is possible to observe in Table 1 that the accumulated average diameter volume below 2. μ m among and μ m. To the accumulated volume of silt, (diameter of particles larger than 2 µm and smaller than 2 µm) clays showed values between and μ m. The volumetric fraction below μ m 2 of DASL, of RF and FDO was and 27.75%, respectively, similar to the values found by Menezes et al [1]. Figure 1 shows the curves of thermo - gravimetric and thermal analysis differentials of the studied clays.

3 Temperature Difference ( C) Loss of mass (%) Temperature Difference ( c) Loss of mass (%) Temperature Difference ( C) Loss of mass (%) Materials Science Forum Vol ,75 69,81 931,51 898, ,27 923,99 887, ,4 21% Temperature ( C) ,55 17,79% Temperature (%) (a) (b) 2 931, , , ,24 88,55 23,12% Temperature (%) (c) Figure 1: Thermo - gravimetric and thermal analysis curves differentials of DASL (a); FDO (b) and RF (c) Analyzing the DTA curves of the samples under study (Figure 1), the following points were observed: large thermal transformations endothermic peak around 95 C, featuring the presence of free water and adsorbed; exothermic peak between 95 C and 56 C, corresponding to the combustion of organic matter; endothermic peak around 56 C featuring the presence of hydroxyls of the octahedral sheet of smectite and kaolinite; for DASL, and RF was observed still an endothermic peak at roughly 71º C possibly related, magnesium carbonate endothermic peak with maximum at 9ºc characterizing the presence of calcium carbonate and exothermic peak with maximum in 93º C characteristic of mullite nucleation quartz releasing β. in relation to TG curves of the samples under study (Figure 1). We observe that the total mass loss ranged from %, corresponding to the loss of water, organic matter, hydroxyl and carbonates. When comparing the results of the thermograms with the values found by Menezes et al, [1], to the clays of Sossego-PB, it can be observed that are similar, showing a typical behavior of bentonite clay. Table 2 presents the chemical compositions of the three samples from Sossego-PB. Table 2: Chemical compositions of three of Sossego-PB. Oxides DASL Results FDO RF FL 12,1 1,5 13,8 SiO 2 46,1 47,5 46,1

4 68 Brazilian Ceramic Conference 58 FL fire loss Al 2 O 3 28, 28,6 25,7 Fe 2 O 3 3,7 5,9 3,5 MgO 5, 4,8 5,8 CaO 3,2,6 4,1 K 2 O 1, 1,1,4 TiO 2,5,6,4 Others,4,4,2 Analyzing the chart above, It is possible to verify that the samples showed loss of mass between 1.5 and 13.8%, which is probably related to the loss of water adsorbed and coordinated and hydroxyls of clay. It can be clearly observed that the chemical compositions of analyzed bentonites have high levels of silicon dioxide (SiO 2 ) and aluminum oxide (Al 2 O 3 ). It is observed that the content of Fe 2 O 3 samples stood around 3-5% while Menezes et.al, [1] obtained a range of 4.26 to 11.12%.MgO levels were similar showing the presence of magnesium in all samples as well as obtained by Menezes et.al, [1].For the CaO content, notes that of the DASL and RF presented a higher content highlighting the poly-cationic origin of the clay. Globally it had been found that the samples have typical chemical composition of bentonits, Menezes et al., [1]. The figure bellow presents the results of x-ray diffraction the samples studied. Fig. 2: x-ray Diffraction of RF, DASL and FDO Analyzing the figure above it can be observed that the samples have the following mineralogical phases: smectite, characterized by 15, 58Å, 4, 5Å, 2.57 Å; kaolinite, characterized by inter-planar distances of 7, 13Å, 4, 13Å, 3, 57Å, 2.51 Å, 2, 15Å, 2.8 Å and 2, Å, quartz, characterized by 3, 34Å, 1, 81Å, and 2, 26Å, calcium carbonate is characterized by 3, Å, and feldspar, characterized by 3.25 Å and 3.1.Quantitatively RF samples and showed high levels of DASL smectites similar to obtained in the samples studied by Menezes et.al.[1]. In all samples the presence of kaolinite, quartz and feldspar. Table 3 (see below) shows the results of apparent viscosity (VA), plastic viscosity (VP) and volume of the filtrate obtained with the Rheological characterization of clays in order to evaluate its suitability as a viscosificante agent in drilling fluids from oil wells.

5 Materials Science Forum Vol Table 3: Results of apparent viscosity (AV), plastic viscosity (PV), volume of filtrate, degree of fineness and moisture of the analyzed clays. SAMPLES RF CLAY FDO Clay Clay DASL(YC) Na 2 CO 3 meq/1g AV (cp) PV (cp) ph Filtered (milliliters) 75 21, 2, 1,69 24,4 1 26,5 3, 1,68 25, , 3, 1,82 24, ,5 2, 1,78 29, 75 4, 2, 1,72 32, 1 6, 2, 1,83 27, 125 5,5 3, 1,92 29, 15 6, 1, 1,97 32, 75 1, 4, 1,42 29, 1 11,5 3, 1,71 26, , 13 1,91 22, 15 11, 3, 1,78 2, From the chart above it is noticeable that the clays showed apparent viscosity (AV) ranging from 4. to 32.5 Cp and plastic viscosity (PV) ranging from 2. to 13cP and volume of filtrate (VF) ranging from 24.4 to 32. About ph values were obtained samples next. Doing a comparison of these results with standard specifications for water-based fluid Petrobrás, observed that the RF samples showed a value of plastic viscosity higher than the minimum value specified for the standardization (15Cp for clay activated).on the other hand the samples FDO and DASL (YC) presented below the values specified by the Petrobras. With respect to the parameter, only plastic viscosity dispersions prepared with FDO to 15meq/1 g and DASL (YC) to 125meq/1 g presented a value greater than the minimum value specified by the norm of Petrobras (4Cp).Analyzing the filtered values all samples showed a value greater than the maximum value established by specification of Petrobras (18 ml). Dispersions prepared with FDO, DASL (YC) and RF had magnitudes of ph exceeding the maximum limit value indicated by the normalization of Petrobras (ph 1). Conclusion Through the study of characterization and rheological properties of clays of new deposits from Sossego County, we can conclude that the samples studied showed in mineralogical composition of smectite, kaolin and quartz. Regarding to rheological properties, it was discovered that the analyzed samples satisfy partially Petrobras standards specifications [9] for the use in water-based drilling fluids.

6 7 Brazilian Ceramic Conference 58 References [1] R.R. Menezes, M.M. Ávila Júnior, L.N.L. Santana, G.A. Neves, H.C. Ferreira: Revista Cerâmica Vol. 54 (33) (28), p [2] L.V. Amorim, K.V. Farias, J.D. Viana, M.I.R. Barbosa, E. Pereira, K.B. França, H.L. Lira, H C. Ferreira: Revista Cerâmica Vol.51 (318) (25), p [3] F.K.A Sousa: Estudo de composições de argilas organofílicas para fluidos de perfuração de poços de petróleo em águas ultraprofundas. Doutorado. (Tese). Campina Grande, 21. Universidade Federal de Campina Grande (UFCG). (PB). [4] K.C. Melo: Avaliação e Modelagem Reológica de Fluidos deperfuração Base Água. Mestrado (Dissertação). Natal, 28. Universidade Federal do Rio Grande do Norte (UFRGN). (RN). [5] L.A. Silva: Desenvolvimento do Processo de Obtenção da Bentonita Organofílica de Moçambique: Síntese e Caracterização. Mestrado (Dissertação). Florianópolis, 21. Universidade Federal de Santa Catarina (UFSC/EQ). (SC) [6]F.K.A. Sousa, A.P. Ramos, L.F.A. Campos, R.R. Menezes, H.S. Ferreira, G.A Neves: Revista Cerâmica Vol. 57 (342) (211), p [7] H.S. Ferreira, G.A. Neves, H.C. Ferreira: Uso de bentonitas organofilicas em fluídos de perfuração base óleo. II Simpósio de Minerais Industriais do Nordeste, Campina Grande, PB, (21). [8] E.L.F. Vidal, T.F. Félix, R.B. Garcia, M. Costa, J.H.S Girão, Aplicação de novos polímeros catiônicos como inibidores de argila em fluidos de perfuração à base de água. 4 PDPETRO, Campinas, SP (27), p. 21. [9] Petrobras: Ensaio de viscosificante para fluidos base água na exploração e produção de petróleo. Código: EP-1EP-11-A, 211. [1] R.R. Menezes, P.M. Souto, L.N.L. Santana, G.A. Neves, R.H.G.A. Kiminami, H C. Ferreira: Revista Cerâmica Vol. 55 (334) (29), p. 163.