Evaluation of Rock Mechanical Properties Alteration During Matrix Stimulation With Chelating Agents

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Assad Barri ◽  
Mohamed Mahmoud ◽  
Salaheldin Elkatatny
Keyword(s):  
Mechanical Properties ◽  
Elastic Properties ◽  
Carbonate Rocks ◽  
Chelating Agents ◽  
Ethylenediaminetetraacetic Acid ◽  
Chelating Agent ◽  
Well Stimulation ◽  
Before And After ◽  
Rock Mechanical Properties ◽  
Carbonate Formations

Well stimulation using acidic solutions is widely used to treat carbonate formations. The acidic fluids remove the near-wellbore damage and create channels around the wellbore by dissolving fraction of the carbonate rocks. Many stimulation fluids have been used such as hydrochloric acid (HCl) acid, organic acids, and chelating agents to stimulate carbonate reservoirs. Wormholes that are created by these fluids are very effective and will yield negative skin values and this will enhance the well productivity. In addition to the wormhole creation, the diffusion of these fluids inside the pores of the rock may create significant and permanent changes in the rock mechanical properties. These changes can eventually lead to weakening the rock strength, which may lead to future formation damage due to the wellbore instability. In this paper, the effect of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) chelating agents on the carbonate rocks elastic properties was investigated. The effect of wormholes created by chelating agent on the rock mechanical properties was investigated. Computed tomography (CT) scan and acoustic measurements were conducted on the core samples before and after matrix stimulation treatments. Experimental results showed that the mechanical properties of strong rocks such as Indiana limestone (IL) cores were not affected when chelating agents were used to stimulate those cores. On the other hand, less strong rocks such as Austin chalk (AC) show significant alteration on the rock elastic properties when chelating agents were used as stimulation fluids.

Evaluation of a New Environmentally Friendly Chelating Agent for High-Temperature Applications

SPE Journal ◽  
2011 ◽  
Vol 16 (03) ◽  
pp. 559-574 ◽  
Author(s):  
M.A.. A. Mahmoud ◽  
H.A.. A. Nasr-El-Din ◽  
C.A.. A. De Wolf ◽  
J.N.. N. LePage ◽  
J.H.. H. Bemelaar
Keyword(s):  
Carbonate Rocks ◽  
Chelating Agents ◽  
Oil And Gas ◽  
Environmentally Friendly ◽  
Chelating Agent ◽  
Reaction Rates ◽  
Acid Dissolution ◽  
Matrix Acidizing ◽  
Good Ability ◽  
Wide Range

Summary Matrix acidizing is used in carbonate formations to create wormholes that connect the formation to the wellbore. Hydrochloric acid (HCl), organic acids, or mixtures of these acids are typically used in matrix-acidizing treatments of carbonate reservoirs. However, the use of these acids in deep wells has some major drawbacks, including high and uncontrolled reaction rates and corrosion to well tubulars, especially those made of chromium-based tubulars (Cr-13 and duplex steel); and these problems become severe at high temperatures. To overcome problems associated with strong acids, chelating agents were introduced and used in the field. However, major concerns with most of these chemicals are their limited dissolving power and negative environmental impact. L-glutamic acid diacetic acid (GLDA), a newly developed environmentally friendly chelate, was examined as a replacement for acid treatments in deep oil and gas wells. The solubility of calcium carbonate (CaCO3) in the new chelate was measured over a wide range of parameters. Coreflood tests were conducted using long Indiana limestone cores 1.5 in. in diameter and 20 in. in length, which allowed better understanding of the propagation of this chemical in carbonate rocks. The cores were X-ray scanned before and after the injection of chelate solutions into the cores. The concentration of calcium (Ca) and chelate was measured in the core effluent samples. To the best of our knowledge, this is the first study to examine the fate and propagation of chelating agents in coreflood studies. GLDA has a very good ability to dissolve Ca from carbonate rocks over a wide pH range by a combination of acid dissolution and chelation. The addition of 5 wt% sodium chloride (NaCl) did not affect the GLDA performance at pH = 13 but significantly accelerated the reaction at pH = 1.7. Compared with other chelating agents, GLDA dissolved more Ca than ethanoldiglycinic acid (EDG) but less than hydroxyethyl ethylenediamine triacetic acid (HEDTA) at high pH values. GLDA of pH = 1.7 was able to form wormholes at 2 and 3 cm3/min. GLDA was found to be thermally stable at temperatures up to 350°F.

scholarly journals Demineralization, Collagen Modification and Remineralization Degree of Human Dentin after EDTA and Citric Acid Treatments

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 25 ◽  
Author(s):  
Maria Gandolfi ◽  
Paola Taddei ◽  
Anna Pondrelli ◽  
Fausto Zamparini ◽  
Carlo Prati ◽  
...  
Keyword(s):  
Citric Acid ◽  
Ethylenediaminetetraacetic Acid ◽  
Environmental Scanning Electron Microscopy ◽  
Chelating Agent ◽  
Environmental Scanning ◽  
X Ray ◽  
Before And After ◽  
Human Dentin ◽  
Mineral Components ◽  
Mineralization Degree

The aim of the study was to investigate the effects of several decalcifying agents used as irrigant solutions in endodontic treatment on collagen and mineral components of dentin. Coronal dentin discs from five caries-free human third molars with a smear layer were treated for one minute with a chelating solution (1% Ethylenediaminetetraacetic acid (EDTA), 10% EDTA, 17% EDTA, 10% citric acid). Mineralization degree (Ca/N and P/N atomic ratios, IR Iapatite/Iamide II and I1410(carbonate)/I554(phosphate) spectroscopic ratios) and possible collagen rearrangements (collagen infrared (IR) amide II e III shifts) were evaluated by environmental scanning electron microscopy (ESEM)/energy dispersive X-ray spectroscopy (EDX) and IR spectroscopy before and after treatment (T0) and after ageing (T24h and T2m) in simulated body fluid (SBF). At T0, analysis showed that the highest demineralizing effect was achieved using a 10% citric acid solution and 10% EDTA, while the smallest effect was observed when using 17% EDTA. No significant collagen modifications were detected upon treatment with 1% EDTA, while subtle changes were observed after the other treatments. At T24h or T2m, analyses showed the highest remineralization values for 1% EDTA and the lowest for 10% citric acid, mainly at T2m. The samples treated with 17% EDTA showed slight collagen rearrangements upon remineralization. In conclusion, the highest demineralizing effect was observed for 10% EDTA and 10% citric acid. Collagen rearrangement was found for all the treatments except for 1% EDTA. The highest remineralization capability in SBF values was recorded for 1% EDTA and the lowest for 10% citric acid. A slight collagen rearrangement upon remineralization was still present in 17% EDTA-treated samples. Clinical use as a chelating agent in the endodontic therapy of citric acid and concentrated EDTA solutions should be reconsidered.

scholarly journals Enhanced Degradation of Phenol by a Fenton-Like System (Fe/EDTA/H2O2) at Circumneutral pH

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 474 ◽  
Author(s):  
Selamawit Ashagre Messele ◽  
Christophe Bengoa ◽  
Frank Erich Stüber ◽  
Jaume Giralt ◽  
Agustí Fortuny ◽  
...  
Keyword(s):  
Chelating Agents ◽  
Ethylenediaminetetraacetic Acid ◽  
Chelating Agent ◽  
Nitrilotriacetic Acid ◽  
Molar Ratio ◽  
Phenol Removal ◽  
Stoichiometric Ratio ◽  
Initial Ph ◽  
Phenol Conversion ◽  
Circumneutral Ph

This work deals with the degradation of phenol based on the classical Fenton process, which is enhanced by the presence of chelating agents. Several iron-chelating agents such as ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), diethylenetriamine pentaacetic acid (DTPA), and ethylenediamine-N,N’-diacetic acid (EDDA) were explored, although particular attention was given to EDTA. The effect of the molar ligand to iron ratio, EDTA:Fe, initial pH, and temperature on the oxidation process was studied. The results demonstrate that the proposed alternative approach allows the capacity for degrading phenol to be extended from the usual acidic pH (around 3.0) to circumneutral pH range (6.5–7.5). The overall feasibility of the process depends on the concentration of the chelating agent and the initial pH of the solution. The maximum phenol conversion, over 95%, is achieved using a 0.3 to 1 molar ratio of EDTA:Fe, stoichiometric ratio of H2O2 at an initial pH of 7.0, and a temperature of 30 °C after 2 hours of reaction, whereas only 10% of phenol conversion is obtained without EDTA. However, in excess of ligand (EDTA:Fe > 1), the generation of radicals seems to be strongly suppressed. Improvement of the phenol removal efficiency at neutral pH also occurs for the other chelating agents tested.

Long-Term Effects of CO2 Sequestration on Rock Mechanical Properties

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Wahbi Abdulqader AL-Ameri ◽  
Abdulazeez Abdulraheem ◽  
Mohamed Mahmoud
Keyword(s):  
Mechanical Properties ◽  
Carbonate Rocks ◽  
Co2 Sequestration ◽  
Carbonic Acid ◽  
Experimental Results ◽  
Geological Sequestration ◽  
Core Samples ◽  
Sequestration Of Co2 ◽  
Rock Mechanical Properties

The long-term geological sequestration of carbon dioxide (CO2) in underground formations (deep saline aquifers) is the most economically viable option to decrease the emissions of this greenhouse gas in the atmosphere. The injection of CO2 in carbonate aquifers dissolves some of the calcite rock due to the formation of carbonic acid as a result of the interaction between CO2 and brine. This rock dissolution may affect the rock integrity and in turn will affect the rock mechanical properties. The effect of CO2 on the rock mechanical properties is a key parameter to be studied to assess the aquifer performance in the process of geological sequestration and to get a safe and effective long-term storage. The main objective of this study is to address the impact of geological sequestration of CO2 on the mechanical properties of carbonate aquifer and caprocks. In addition, the effect of the storage time on these properties is investigated. In this study, CO2 was injected into the brine-soaked core samples under simulated downhole conditions of high pressure and high temperature (2000 psi and 100 °C). The mechanical properties of these core samples were analyzed using indirect tensile strength (ITS), unconfined compression, and acoustics testing machines. The effect of CO2 sequestration on the engineering operations such as well instability and aquifer compaction will be investigated based on the experimental results. Results showed that CO2 sequestration affected the mechanical properties of the carbonate rocks as well as the caprocks. Long time soaking of CO2 in brine allowed for the formation of enough carbonic acid to react with the cores and this greatly impacted the rock mechanical and acoustic properties. The significant impact of CO2 storage was noted on Khuff limestone (KL), and the good candidate among the carbonate rocks studied here for geological sequestration of CO2 is found to be Indiana limestone (IL). The stress calculations based on the experimental results showed that CO2 may affect the wellbore stability and care should be taken during drilling new wells in the sequestration area. Aquifer compaction based on KL measurements showed that the aquifer will compact 1.25 ft for a 500 ft thick carbonate formation due the CO2 sequestration for 90 days.

scholarly journals Improvement of Oxidative and Metabolic Parameters by Cellfood Administration in Patients Affected by Neurodegenerative Diseases on Chelation Treatment

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Alessandro Fulgenzi ◽  
Rachele De Giuseppe ◽  
Fabrizia Bamonti ◽  
Maria Elena Ferrero
Keyword(s):  
Neurodegenerative Diseases ◽  
Ethylenediaminetetraacetic Acid ◽  
Oxidized Ldl ◽  
Toxic Metal ◽  
Chelating Agent ◽  
Blood Parameters ◽  
Oxidative Status ◽  
Antioxidant Compounds ◽  
Before And After ◽  
Metabolic Conditions

Objective. This prospective pilot study aimed at evaluating the effects of therapy with antioxidant compounds (Cellfood, and other antioxidants) on patients affected by neurodegenerative diseases (ND), who displayed toxic metal burden and were subjected to chelation treatment with the chelating agent calcium disodium ethylenediaminetetraacetic acid (CaNa2EDTA or EDTA).Methods. Two groups of subjects were studied: (a) 39 patients affected by ND and (b) 11 subjects unaffected by ND (controls). The following blood parameters were analyzed before and after three months’ treatment with chelation + Cellfood or chelation + other antioxidants: oxidative status (reactive oxygen species, ROS; total antioxidant capacity, TAC; oxidized LDL, oxLDL; glutathione), homocysteine, vitamin B12, and folate.Results. After 3-months’ chelation + Cellfood administration oxLDL decreased, ROS levels were significantly lower, and TAC and glutathione levels were significantly higher than after chelation + other antioxidants treatment, both in ND patients and in controls. Moreover, homocysteine metabolism had also improved in both groups.Conclusions. Chelation + Cellfood treatment was more efficient than chelation + other antioxidants improving oxidative status and homocysteine metabolism significantly in ND patients and controls. Although limited to a small number of cases, this study showed how helpful antioxidant treatment with Cellfood was in improving the subjects’ metabolic conditions.

Atomic Force Microscopy of Removal of Dentin Smear Layers

2007 ◽  
Vol 13 (4) ◽  
pp. 245-250 ◽  
Author(s):  
Luiz Henrique Carvalho Batista ◽  
José Ginaldo da Silva Júnior ◽  
Milton Fernando Andrade Silva ◽  
Josealdo Tonholo
Keyword(s):  
Atomic Force Microscopy ◽  
Ethylenediaminetetraacetic Acid ◽  
Chelating Agent ◽  
Root Surface ◽  
Smear Layer ◽  
Alternative Methods ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Analysis ◽  
Before And After

The regular periodontal practice of scaling and root planing produces a smear layer on the root surface that is detrimental to the readhesion of tissues during subsequent regeneration therapy. Although it has been demonstrated that gels containing the chelating agent ethylenediaminetetraacetic acid (EDTA) can assist in the removal of this contaminating layer, no quantitative method is yet available by which to evaluate the efficiency of the treatment. In this article, the power of atomic force microscopy (AFM) as a technique for monitoring and mapping the surfaces of dentinal roots is demonstrated. Roughness parameters of teeth that had been scaled and root planed were determined from AFM images acquired both before and after treatment with EDTA. The results confirmed that EDTA is an efficient cleaning agent and that dentinal samples free from a smear layer are significantly rougher than the same samples covered by a contaminating layer. AFM analysis is superior to alternative methods involving scanning electron microscopy because the same sample section can be analyzed many times, thus permitting it to be used as both the control and the treatment surface.

scholarly journals Iron-[S,S′]-EDDS (FeEDDS) Chelate as an Iron Source for Horticultural Crop Production: Marigold Growth and Nutrition, Spectral Properties, and Photodegradation

HortScience ◽  
2011 ◽  
Vol 46 (8) ◽  
pp. 1148-1153 ◽  
Author(s):  
Joseph P. Albano
Keyword(s):  
Spectral Properties ◽  
Crop Production ◽  
Chelating Agents ◽  
Ethylenediaminetetraacetic Acid ◽  
Free Ligand ◽  
Chelating Agent ◽  
Dry Weight ◽  
Structural Isomer ◽  
Horticultural Crops ◽  
Significant Difference

Aminopolycarboxylic acid (APCA) complexones, commonly referred to as ligands or chelating agents, like ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA), are commonly used in soluble fertilizers to supply copper (Cu), iron (Fe), manganese (Mn), and/or zinc (Zn) to plants. Offsite runoff and contamination of surface waters with these chelating agents is of increasing concern as a result of their reported ability to remobilize heavy metals in sediments and their low susceptibility to biodegradation. The APCA ethylenediaminedisuccinic acid (EDDS) is a structural isomer of EDTA with the [S,S′] stereoisomer of the complexone, a compound naturally produced by actinomycetes, and is biodegradable. Information on the use of [S,S′]-EDDS as a chelating agent in formulating soluble fertilizers for the production of horticultural crops is limited. Therefore, a series of studies were conducted with the objectives of evaluating Fe[S,S′]-EDDS as an Fe-chelate fertilizer agent in the production of marigold and [S,S′]-EDDS (free ligand) and/or Fe[S,S′]-EDDS spectral properties and vulnerability to photodegrdation. Marigold grown in peat-based media were fertilized with complete nutrient solution containing 1 mg·L−1 Fe from FeEDDS, FeEDTA, or FeDTPA. There was no significant difference in foliar Fe or Mn between Fe-chelate treatments, averaging 140 μg·g−1 and 88 μg·g−1, respectively, nor were there significant differences in leaf dry weight (2.30 g) between Fe treatments. Spectra of [S,S′]-EDDS and Fe[S,S′]-EDDS produced from ferrous or ferric sources of Fe absorbed maximally in the 210 to 230 nm and 238 to 240-nm range, respectively. The [S,S′]-EDDS complexone used in the current study, a 30% assay solution, had chromaphoric properties, appearing light yellow in color. When exposed to light, Fe[S,S′]-EDDS quickly degraded at a rate at least twice that of FeEDTA.

The Migration of DNA Into a DNA-Crosslinked Gel Using Electrophoresis

2003 ◽  
Author(s):  
David C. Lin ◽  
Noshir A. Langrana ◽  
Bernard Yurke
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Elastic Properties ◽  
Polyacrylamide Gels ◽  
Single Stranded Dna ◽  
Before And After ◽  
Polymeric Electrolytes ◽  
Osmotic Effects

DNA-crosslinked polyacrylamide gels are polymeric electrolytes by virtue of the fact that DNA is negatively charged in an aqueous solution. As such, their mechanical properties can be altered by electrophoretic and electro-osmotic effects. Hybridization of single-stranded DNA with single-stranded sections of the crosslinks provides a novel means of altering gel mechanical properties. As a step toward exploring this means of altering gel mechanical properties, we report here on a study of the use of electrophoresis to introduce single stranded DNA into DNA crosslinked gels. Changes in elastic properties of the gel, before and after electrophoresis, were measured.

Effect of Cryogenic Treatment Thermal Shock on Rock Dynamic Elastic Properties and Permeability of Wolfcamp Core Samples – An Experimental Study

2021 ◽  
Author(s):  
Mahdi Ramezanian ◽  
Hossein Emadi
Keyword(s):  
Mechanical Properties ◽  
Thermal Shock ◽  
Elastic Properties ◽  
Cryogenic Treatment ◽  
Xrd Analysis ◽  
Rock Properties ◽  
Core Samples ◽  
Permeability Enhancement ◽  
Rock Mechanical Properties ◽  
Dynamic Elastic Properties

Abstract A few researches have been conducted to study effects of cryogenic treatment (known as thermal shocking) on unconventional rock properties, while they have been extensively studied in geothermal projects. The results show that cryogenic treatment significantly alters the rock mechanical properties by creation of new cracks owing to thermally induced stresses resulting in the permeability enhancement. In this laboratory study, effects of cryogenic treatment (thermal shocking) on permeability and dynamic elastic properties of three Wolfcamp core samples (one outcrop and two downhole samples) at downhole conditions were experimentally evaluated. Permeability and dynamic rock mechanical properties were measured before and after conducting each cycle of thermal shock. Using X-ray powder diffraction (XRD) analysis, the mineral compositions of the cores were determined. The results demonstrate that implementing the thermal shock technique on the core samples results in increasing their permeability and ductility.

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