Water/Rock Interaction for Eagle Ford, Marcellus, Green River, and Barnett Shale Samples and Implications for Hydraulic-Fracturing-Fluid Engineering

SPE Journal ◽  
2016 ◽  
Vol 22 (01) ◽  
pp. 162-171 ◽  
Author(s):  
Maaz Ali ◽  
Berna Hascakir

Summary Knowledge of water/rock interactions on the surface of fractures is important to develop an understanding of the geological structures and changes within the formation, and to determine hydraulic-fracturing (HF) performance. To obtain this knowledge, this study investigates water/shale interactions in carbonate-rich (Eagle Ford), organic-rich (Green River), clay-rich (Barnett), and other-minerals-rich (Marcellus) shale samples. Crushed shale samples were exposed to water for 3 weeks at reservoir conditions. The water and rock samples before and after each static experiment were subjected to several analyses. The change in the rock mineralogy was defined by X-ray diffraction (XRD), the elemental composition of rock was determined by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy energy dispersive spectroscopy (SEM-EDS), and the organic content of rock samples was estimated by thermogravimetric analysis (TGA). The water was analyzed for its anions and cations, total dissolved solids (TDS), conductivity, pH, total organic carbon (TOC), and average particle sizes of colloids. The stability of the colloids was characterized by zeta-potential. We show that Barnett rock is high in illite content, and the greatest calcite concentration is determined for Eagle Ford. The sulfate content of water correlates with the atomic percent of the sulfur and oxygen elements determined through XPS analyses. The magnesium content of water correlates mainly with the illite amount in the rock, and calcium concentration associates with the calcite and gypsum content of the rock samples. The greatest dissolution rate belongs to the minerals that yield sulfate in the water; then, gypsum and calcite that yield calcium cation in the water come second; and the lowest dissolution rates are obtained from the magnesium-containing minerals (mainly, dolomite). TDS of the water samples shows that Green River has the least tendency to interact with water, and Barnett has the greatest tendency. Zeta-potential values indicate that particles in the water that interacted with Eagle Ford have the highest tendency for precipitation. The results of this study are used to make suggestions on the engineering of hydraulic-fracturing fluids (HFFs) in the context of water/rock interactions by considering the type and the concentration of ions along with colloidal stability determined through zeta-potential measurements.

SPE Journal ◽  
2020 ◽  
Vol 25 (02) ◽  
pp. 788-799 ◽  
Author(s):  
Lifu Zhang ◽  
Michael Tice ◽  
Berna Hascakir

Summary Reuse of flowback water in hydraulic fracturing is usually used by industry to reduce consumption, transportation, and disposal cost of water. However, because of complex interactions between injected water and reservoir rocks, induced fractures may be blocked by impurities carried by flowback and mineral precipitation by water/rock interactions, which causes formation damage. Therefore, knowledge of flowback water/rock interactions is important to understand the changes within the formation and effects on hydraulic fracturing performance. This study focuses on investigating flowback water/rock interactions during hydraulic fracturing in Marcellus Shale. Simple deionized water (DI)/rock interactions and complicated flowback water/rock interactions were studied under static and dynamic conditions. In static experiments, crushed reservoir rock samples were exposed to water for 3 weeks at room condition. In the dynamic experiment, continuous water flow interacted with rock samples through the coreflooding experimental system for 3 hours at reservoir condition. Before and after experiments, rock samples were characterized to determine the change on the rock surfaces. Water samples were analyzed to estimate the particle precipitation tendency and potential to modify flow pathway. Surface elemental concentrations, mineralogy, and scanning electron microscope (SEM) images of rock samples were characterized. Ion contents, particle size, total dissolved solids (TDS), and zeta-potential in the water samples were analyzed. After flowback water/rock interaction, the surface of the rock sample shows changes in the compositions and more particle attachment. In produced water, Na, Sr, and Cl concentrations are extremely high because of flowback water contamination. Water parameters show that produced water has the highest precipitation tendency relative to all water samples. Therefore, if flowback water without any treatment is reused in hydraulic fracturing, formation damage is more likely to occur from blockage of pores. Flowback water management is becoming very important due to volumes produced in every hydraulic fracturing operation. Deep well injection is no longer a favorable option because it results in disposal of high volumes of water that cannot be used for other purposes. A second option is the reuse of waste water for fracturing purposes, which reduces freshwater use significantly. However, the impurities present in flowback water may deteriorate the fracturing job and reduce or block the hydraulic fracturing apertures. This study shows that a simple filtration process applied to the flowback water allows for reinjection of the flowback water without further complication to the water/rock interaction, and does not cause significant formation damage in the fractures.


2019 ◽  
Vol 32 (2) ◽  
pp. 471-476
Author(s):  
G. Bhagavanth Reddy ◽  
B. Rajkumar ◽  
K. Girija Mangatayaru ◽  
T.V.D. Prasad Rao

In the present investigation, synthesis of gold nanoparticles (AuNPs) was carried out with microwave irradiation of HAuCl4 and the extract of ginger waste. Synthesized AuNPs were characterized by various techniques including UV-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). The TEM images revealed that the nanoparticles were spherical in shape and the average particle size of the AuNPs was found to be approximately 6 ± 2 nm. The stability of gold nanoparticles was analyzed by zeta potential measurements. A negative zeta potential value of -18.4 mV indicates the stability of the AuNPs. Further, gold nanoparticles exhibited the excellent catalytic activity in reducing 4-nitrophenol to 4-aminophenol in the presence of NaBH4 (reducing agent), and it was found to depend on the amount of AuNPs and temperature. Gold nanoparticles did not show any significant antibacterial activity against the pathogenic bacteria studied.


2018 ◽  
Vol 58 (2) ◽  
pp. 104 ◽  
Author(s):  
Jana Kavuličová ◽  
Anna Mražíková ◽  
Oksana Velgosová ◽  
Dana Ivánová ◽  
Martina Kubovčíková

The study focuses on an investigation of the influence of both citrate and mixed gelatin/citrate as a reductant and stabilizer on the colloidal stability of silver nanoparticles (AgNPs)synthesized by a chemical reduction of Ag<sup>+</sup> ions after a short - (7th day) - and long - (118th day) - term storage. Formed AgNPs were characterized by a UV–vis Spectroscopy, Transmission Electron Microscope (TEM), Dynamic light scattering (DLS) and Zeta-potential (ZP). The obtained results revealed that a short-term stability of the synthesized AgNPs was greatly influenced by a citrate stabilizer with the absence of gelatin. Smaller-sized AgNPs (average particle diameter of 3 nm), roughly spherical in a shape, were obtained with a narrow size distribution. The very negative value of the Zeta-potential confirmed a strong stability of the citrate capped AgNPs. However, a surface coating of the AgNPs by a gelatin/citrate stabilizer was found to be a dominant contributor in improving a long-term stability of the AgNPs (average particle diameter of 26 nm). The use of gelatin in mixed stabilizer solution provided the AgNPs with higher monodispersity and a controllable size after both the short and long-term storage.


2016 ◽  
Vol 40 ◽  
pp. 146-157 ◽  
Author(s):  
Cyril O. Ehi-Eromosele ◽  
Benedict I. Ita ◽  
Emeka E.J. Iweala ◽  
Kehinde O. Ogunniran ◽  
Joseph A. Adekoya ◽  
...  

Magnetic nanocomposite material composed of silica coated MgFe2O4 for potential biomedical applications were synthesized by a two-step chemical method including solution combustion synthesis, followed by silica coatings of the ferrite nanoparticles. The effects of silica coatings on the structural, morphological and magnetic properties were comprehensively investigated using powder X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), energy dispersive absorption x-ray (EDAX), Fourier Transform Infrared spectroscopy (FTIR), thermogravimetric analysis and differential thermal analysis (TG–DTA) and vibrating sample magnetometer (VSM). The colloidal behaviour of coated MNPs in physiological saline medium like water or phosphate buffer saline (PBS) was also studied by zeta potential measurements. The XRD patterns indicate that the crystalline structure is single cubic spinel phase and the spinel structure is retained after silica coating. Also, after silica coating, the crystallite size (from Scherrer formula) decreases from 53 to 47 nm. The magnetic results show that MgFe2O4 MNPs (bare and silica coated) is ferrimagnetic at room temperature. Zeta potential studies revealed that there is enhanced colloidal stability of MgFe2O4 MNPs after silica coating in aqueous media which is an applicable potential in biomedical applications.


2003 ◽  
Vol 762 ◽  
Author(s):  
C. Smit ◽  
D.L. Williamson ◽  
M.C.M. van de Sanden ◽  
R.A.C.M.M. van Swaaij

AbstractExpanding thermal plasma CVD (ETP CVD) has been used to deposit thin microcrystalline silicon films. In this study we varied the position at which the silane is injected in the expanding hydrogen plasma: relatively far from the substrate and close to the plasma source, giving a long interaction time of the plasma with the silane, and close to the substrate, resulting in a short interaction time. The material structure is studied extensively. The crystalline fractions as obtained from Raman spectroscopy as well as from X-ray diffraction (XRD) vary from 0 to 67%. The average particle sizes vary from 6 to 17 nm as estimated from the (111) XRD peak using the Scherrer formula. Small angle X-ray scattering (SAXS) and flotation density measurements indicate void volume fractions of about 4 to 6%. When the samples are tilted the SAXS signal is lower than for the untilted case, indicating elongated objects parallel to the growth direction in the films. We show that the material properties are influenced by the position of silane injection in the reactor, indicating a change in the plasma chemistry.


Author(s):  
R. Preethi ◽  
P. Padma

The study focused on the green synthesis of silver nanobioconjugates (AgNPs) from phenolic-rich fruit source, Vitis vinifera seed extract and its major component phenolic, resveratrol respectively. Sunlight exposure for 20 minutes was the method of choice for the synthesis of AgNPs of the extract as well as the phenolic, resveratrol. The synthesized nanobioconjugates were characterized using UV-Visible spectroscopy, Transmission electron microscopy (TEM), Energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), Polydispersity index, Zeta potential and Fourier transform infrared spectroscopy (FTIR). The reduction of silver ions was confirmed by UV-visible spectroscopy with peaks at 440nm for both nanobioconjugates synthesized from seed extract and compound. The nanobioconjugates showed the spherical in shape with 14-35nm in size and crystalline in nature. The conjugates are well dispersed with 0.301 and 0.287 polydispersity index and the zeta potential range at -13.6 and -14.3mV for stability. The FTRI data proved that the components in grape seeds act as good reductants and stabilizers for the silver nanobioconjugate synthesis. All the synthesized nanobioconjugates exhibited steady and sustained release of the medicinal components conjugated, proving their druggability, and were biocompatible with human cells, demonstrating their safety. The findings of the study validate the anticancer properties of silver nanobioconjugates of Vitis vinifera and its active component resveratrol.


Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 97
Author(s):  
Suresh V. Chinni ◽  
Subash C. B. Gopinath ◽  
Periasamy Anbu ◽  
Neeraj Kumar Fuloria ◽  
Shivkanya Fuloria ◽  
...  

The present study was planned to characterize and analyze the antimicrobial activity of silver nanoparticles (AgNP) biosynthesized using a Coccinia indica leaf (CIL) ethanolic extract. The present study included the preparation of CIL ethanolic extract using the maceration process, which was further used for AgNP biosynthesis by silver nitrate reduction. Biosynthetic AgNPs were characterized using UV–Visible spectrometry, zeta potential analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX) spectrometry. The biogenic AgNP and CIL extracts were further investigated against different bacterial strains for their antimicrobial activity. The surface plasmon resonance (SPR) signal at 425 nm confirmed AgNP formation. The SEM and TEM data revealed the spherical shape of biogenic AgNPs and size in the range of 8 to 48 nm. The EDX results verified the presence of Ag. The AgNPs displayed a zeta potential of −55.46 mV, suggesting mild AgNP stability. Compared to Gram-positive bacteria, the biogenic AgNPs demonstrated high antibacterial potential against Gram-negative bacteria. Based on the results, the current study concluded that AgNPs based on CIL extract have strong antibacterial potential, and it established that AgNP biosynthesis using CIL ethanol extract is an effective process.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
K. A. Athmaselvi ◽  
C. Kumar ◽  
M. Balasubramanian ◽  
Ishita Roy

This study evaluates the physical properties of freeze dried tropical (guava, sapota, and papaya) fruit powders. Thermal stability and weight loss were evaluated using TGA-DSC and IR, which showed pectin as the main solid constituent. LCR meter measured electrical conductivity, dielectric constant, and dielectric loss factor. Functional groups assessed by FTIR showed presence of chlorides, and O–H and N–H bonds in guava, chloride and C–H bond in papaya, and chlorides, and C=O and C–H bonds in sapota. Particle size and type of starch were evaluated by X-ray diffraction and microstructure through scanning electronic microscopy. A semicrystalline profile and average particle size of the fruit powders were evidenced by X-ray diffraction and lamellar/spherical morphologies by SEM. Presence of A-type starch was observed in all three fruits. Dependence of electric and dielectric properties on frequency and temperature was observed.


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