scholarly journals Influence of Formate Concentration on the Rheology and Thermal Degradation of Xanthan Gum

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3378
Author(s):  
María José Martín-Alfonso ◽  
Javier Mauricio Loaiza ◽  
Clara Delgado-Sánchez ◽  
Francisco José Martínez-Boza

Xanthan gum solutions have gained increasing interest for their use as environmentally friendly chemicals in the oil industry. Xanthan is compatible with most concentrate brines used for controlling formation damage and fluid loss. Particularly, formate brines reinforce the ordered structure of the biopolymer in solution, gel strength, and the specific gravity of the resulting fluid. In this paper, we studied the effect of thermal aging on the rheological behavior of xanthan solutions as a function of the concentration in potassium formate. Ionic strength below a threshold concentration does not prevent the degradation of the structure of xanthan after being submitted to aging at 165 °C. Aged solutions show an important loss of strength in their mechanical properties, lower pH, and higher content in furfural and hydroxymethylfurfural. Highly concentrated formate brines are necessary to maintain the strength of the rheological properties after exposure to high-temperature environments.

2021 ◽  
Author(s):  
Siti Humairah Abd Rahman ◽  
Anatoly Medvedev ◽  
Andrey Yakovlev ◽  
Yon Azwa Sazali ◽  
Bipin Jain ◽  
...  

Abstract With the development of new oil formations and with the advent of new directions in the global energy sector, new requirements for materials for well construction appear. With the close attention to environmental footprint and unique properties, one of the promising materials for well cementing is geopolymers. Being a relatively new material, they are characterized by low carbon footprint, high acid resistance and attractive mechanical properties. This article is aimed at developing new geopolymer slurries for the oil industry, their characterization and field implementation analysis. With the ultimate goal of developing a methodology for the analysis of raw materials and designing the geopolymer slurries, studies were carried out on various raw materials, including different types of fly ash. Based on the data obtained and rapid screening methods, an approach was developed to formulate a geopolymer composition recipe. Since not all cement additives directly work in geopolymers, special attention was paid to control the thickening time and fluid loss. The methods of XRD, XRF, ICP-MS, density, particle size distribution measurements as well as API methods of cement testing were used to understand the composition and structure of the materials obtained, their properties and design limitations. A special approach was applied to study the acid resistance of the materials obtained and to compare with conventional cements and slags. Using one of the most common sources of aluminosilicate, fly ash, formulations with a density of 13.5 – 16.5 lbm/galUS were tested. A sensitivity analysis showed that the type of activator and its composition play a critical role both in the mechanical properties of the final product and in the solidification time and rheological properties of the product. The use of several samples of fly ash, significantly different in composition, made it possible to formulate the basic rules for the design of geopolymers for the oil industry. An analysis was also carried out on 10 different agents for filtration and 7 moderators to find a working formulation for the temperature range up to 100°C. The samples were systematically examined for changes in composition, strength, and acid resistance was previously measured. Despite the emergence of examples of the use of geopolymers in the construction industry and examples of laboratory testing of geopolymers for the oil industry, to the best of our knowledge, there has been no evidence of pumping geopolymers into a well. Our work is an attempt to develop an adaptation of the construction industry knowledge to the unique high pressure, high temperature conditions of the oil and gas industry. The ambitions of this work go far beyond the laboratory tests and involve yard test experiments.


Author(s):  
Khalil Rehman Memon ◽  
Aftab Ahmed Mahesar ◽  
Shahzad Ali Baladi ◽  
Muhannad Talib Sukar

The experimental study was conducted on rheological properties in laboratory to measure the integrity of cement slurry. Three samples were used and analyzed at different parameters to check the elasticity of cement slurry. Additives with various concentrations, i.e. silica fume % BWOC (Present by Weight on Cement) (15, 17, 19 and 21), dispersant % Wt (Percent Weight) (0.21, 0.26 and 0.31) and additional 1; % Wt of fluid losscontrol were used to improve the performance of the cement slurry at the temperature of 123oC. The results have shown that increase in the concentration of dispersants that have caused to decrease in the Plastic Viscosity (PV), Yield Point (YP) and GS (Gel Strength). The rheological properties of cement were improved with the addition of fluid loss control additive in 21 % BWOC (Present by Weight on Cement) silica fume increase the water quantity in cement slurry that improve its durability and to reduce the strength retrogression in High Temperature High Pressure (HTHP) environment. Results were achieved through HTHP OFITE Viscometer (Model 1100).


SPE Journal ◽  
2020 ◽  
pp. 1-19 ◽  
Author(s):  
Ahmed Hanafy ◽  
Faisal Najem ◽  
Hisham A. Nasr-El-Din

Summary Viscoelastic surfactants (VESs) have been used for acid diversion and fracturing fluids. VESs were introduced because they are less damaging than polymers. VESs’ high cost, low thermal stability, and incompatibility with several additives (e.g., corrosion inhibitors) limit their use. The goal of this study is to investigate the interaction of VES micelles with different nanoparticle shapes to reduce VES loadings and enhance their thermal stability. This work examined spherical and rod-shaped nanoparticles of silica and iron oxides. The effects of particle size, shape, and surface charge on a zwitterionic VES micellization were conducted. The physical properties were measured using zeta-potential, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The rheological performances of VES solutions were evaluated at 280 and 350°F using a high-pressure/high-temperature rotational rheometer. The proppant-carrying capacity of the fracturing fluids was evaluated using a high-pressure/high-temperature see-through cell and dynamic oscillatory viscometer. The fluid loss and formation damage were determined using corefloods and computed-tomography scans. The interaction between nanoparticles and VES is strongly dependent on the VES concentration, temperature, nanoparticle characteristics, and concentration. The spherical particles at 7-lbm/1,000 gal loading extended the VES-based-fluid thermal stability at VES loading of 4 wt% up to 350°F. The nanorods effectively enhanced and extended the thermal-stability range of the VES system at VES concentration of only 2 wt%. Both particle shapes performed similarly at 4 wt% VES and 280°F. The addition of silica nanorods extended the thermal stability of the 4 wt% VES aqueous fluid, which resulted in an apparent viscosity of 200 cp for 2 hours. The addition of rod-shaped particles enhanced the micelle to micelle entanglement, especially at VES loading of 2 wt%. The use of nanoparticles enhanced the micelle/micelle networking, boosting the fluid-storage modulus and enhancing the proppant-carrying capacity. The addition of nanoparticles to the VES lowered its fluid-loss rate and minimized formation damage caused by VES-fluid invasion. This research gives guidelines to synthesize nanoparticles to accommodate the chemistry of surfactants for higher-temperature applications. It highlights the importance of the selected nanoparticles on the rheological performance of VES.


2016 ◽  
Vol 864 ◽  
pp. 189-193 ◽  
Author(s):  
Abdul Razak Ismail ◽  
Wan Rosli Wan Sulaiman ◽  
Mohd Zaidi Jaafar ◽  
Issham Ismail ◽  
Elisabet Sabu Hera

Nanoparticles are used to study the rheological characteristics of drilling fluids. Nanoparticles have high surface to volume ratio, therefore only small quantity is required to blend in the drilling fluid. This research evaluates the performance of nanosilica and multi walled carbon nanotubes (MWCNT) as fluid loss additives in water based drilling fluid with various nanoparticles concentration and temperature. The results show that plastic viscosity, yield point and gel strength of drilling fluid increases as the concentration of nanoparticles increased. Drilling fluid with nanosilica gives the highest filtrate loss of 12 ml and mudcake thickness of 10 inch at 1 g concentration at 300°F. However, drilling fluid with MWCNT shows a decreasing trend in fluid loss and mudcake thickness. The results also show that xanthan gum containing 1 g of MWCNT gives 4.9 ml fluid loss and mudcake thickness of 4 inch at 200°F. After aging, plastic viscosity, yield point and gel strength of mud containing nanoparticles decrease significantly especially for 1 g of nanosilica and 0.01 g MWCNT. Fluid loss and mudcake thickness increased when the mud is exposed to temperature above 250°F. The results showed that xanthan gum with MWCNT gives a better rheological performance.


SPE Journal ◽  
2020 ◽  
Vol 25 (06) ◽  
pp. 2853-2866 ◽  
Author(s):  
Hu Jia ◽  
Hao Chen ◽  
Jin-Zhou Zhao

Summary Effective mitigation of fluid loss and prevention of formation damage are substantial concerns during well completion and workover in low-pressure, high-permeability, and/or fractured reservoirs, especially with high temperature (HT). In this paper, a highly elastic composite gel is developed on the basis of the solution blending for “intercalated crosslinking.” The mechanism is the intercalation of polymer and crosslinker into layered silicate material (LSM) using a specific procedure. The gel is composed of HT resistant copolymer, crosslinker polyethyleneimine (PEI), LSM, and antioxidant in freshwater. The effects of main variables on the gelation performance are investigated. The mature composite gel strength is noticeably improved with increasing temperature. The elastic modulus (G′) of the mature composite gel prepared at 160°C can reach up to 15 000 Pa, while only a value of 6000 Pa is obtained for the gel at 130°C. The composite gel remains robust after aging 10 days at 160°C. The pressure-bearing capacity and rigidity of the mature composite gel are noticeably improved with increasing layered silicate concentration. This unique feature can benefit stress buffering when the sealing operation is conducted under high differential pressure such as the case with a long hydrostatic column. Scanning electron microscope (SEM) is used to further reveal the intercalated crosslinking mechanism of the composite gel. A temporary plugging experiment for a fractured limestone core also supports the gel's high-pressure (HP) resistance and low adsorption and retention to alleviate formation damage. The composite gel is promising for fluid loss mitigation that could be extended to other related near-wellbore operations in HT wells.


Author(s):  
D. R. Clarke ◽  
G. Thomas

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.


Author(s):  
H.-J. Kleebe ◽  
J.S. Vetrano ◽  
J. Bruley ◽  
M. Rühle

It is expected that silicon nitride based ceramics will be used as high-temperature structural components. Though much progress has been made in both processing techniques and microstructural control, the mechanical properties required have not yet been achieved. It is thought that the high-temperature mechanical properties of Si3N4 are limited largely by the secondary glassy phases present at triple points. These are due to various oxide additives used to promote liquid-phase sintering. Therefore, many attempts have been performed to crystallize these second phase glassy pockets in order to improve high temperature properties. In addition to the glassy or crystallized second phases at triple points a thin amorphous film exists at two-grain junctions. This thin film is found even in silicon nitride formed by hot isostatic pressing (HIPing) without additives. It has been proposed by Clarke that an amorphous film can exist at two-grain junctions with an equilibrium thickness.


Author(s):  
K Das Chowdhury ◽  
R. W. Carpenter ◽  
W. Braue

Research on reaction-bonded SiC (RBSiC) is aimed at developing a reliable structural ceramic with improved mechanical properties. The starting materials for RBSiC were Si,C and α-SiC powder. The formation of the complex microstructure of RBSiC involves (i) solution of carbon in liquid silicon, (ii) nucleation and epitaxial growth of secondary β-SiC on the original α-SiC grains followed by (iii) β>α-SiC phase transformation of newly formed SiC. Due to their coherent nature, epitaxial SiC/SiC interfaces are considered to be segregation-free and “strong” with respect to their effect on the mechanical properties of RBSiC. But the “weak” Si/SiC interface limits its use in high temperature situations. However, few data exist on the structure and chemistry of these interfaces. Microanalytical results obtained by parallel EELS and HREM imaging are reported here.


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