Improving Long-Term Hydraulic Fracture Conductivity in Carbonate Formations by Substitution of Harder Minerals

2021 ◽  
Author(s):  
Yevgeniy Samarkin ◽  
Murtada Saleh Aljawad ◽  
Abduljamiu Olalekan Amao ◽  
Theis Ivan Sølling ◽  
Khalid Al-Ramadan ◽  
...  
Keyword(s):  
Fracture Surface ◽  
Petroleum Industry ◽  
Surface Hardness ◽  
Ion Concentration ◽  
Elemental Content ◽  
Sem Images ◽  
Fracture Conductivity ◽  
Rock Samples ◽  
Before And After ◽  
Proppant Embedment

Abstract Hydraulic fracturing is applied in tight formations to create conductive paths within the reservoir. However, the conductivity of the created fractures declines with time due to the closure stresses. The decline is sharp in soft formations because of proppant embedment and fracture surface asperities failure. The improvement in fracture surface hardness can mitigate the abovementioned challenges and sustain the fracture conductivity. This research targeted enhancing carbonate rock's hardness by forming minerals harder than calcite. Carbonate rocks, namely dolomite, limestone, and chalk, were treated at ambient temperature conditions by immersion into the aqueous solutions of NaF and ZnSO4 with a concentration of 0.1M. During treatment, the solution was sampled to monitor the changes in ion concentration and estimate the reaction kinetics by ICP - OES and IC devices. The hardness of rock samples was measured by impulse hammering technique before and after the treatment. The changes in rock's mineralogy and elemental content were studied by XRD and SEM imaging. The permeability of rocks was estimated by the steady-state gas injection method. The formation of smithsonite (ZnCO3, Mohs scale hardness - 4.5) and fluorite (CaF2, Mohs scale hardness - 4) was achieved in the reaction of calcite (CaCO3, Mohs scale hardness – 3) with ZnSO4 and NaF, respectively. Chalk and limestone reacted efficiently with both solutions; however, the dolomite reaction with solutions was feeble. XRD detected the newly formed smithsonite minerals, and it was observed in SEM images that minerals formed an interconnected net in chalk and limestone specimens. In dolomite samples, the minerals formed isolated gatherings that were sparsely located on the grains. The treatments caused the improvement of the rock specimen's hardness. 0.1M solution of NaF was not effective in strengthening the rock samples (only chalk sample experienced 6.7% improvement in hardness) because of low concentration of the solutions used; however, treatment resulted in negligible changes in permeability of the samples. In contrast, Young's modulus of limestone and chalk treated by ZnSO4 increased by 17% and 21%. Permeability of rocks treated by ZnSO4 reduced drastically, most likely due to the formation of gypsum as a byproduct of the reaction. This research presents a method for carbonate rock hardening via the transformation of parent calcite into harder minerals. It explains its possible application in the petroleum industry to sustain the conductivity of propped/acid fractures. The proposed technique will help to mitigate fracture conductivity decline due to proppant embedment and asperities failure issues that are especially severe in soft formations.

A New Method of Reproducing Rock Samples with Rough Surfaces for Testing Conductivity: A Case Study on Shale Propped Fractures

2021 ◽  
Author(s):  
Chi Chen ◽  
Shouxin Wang ◽  
Cong Lu ◽  
Kun Wang ◽  
Jie Lai ◽  
...  
Keyword(s):  
Fracture Surface ◽  
Surface Morphology ◽  
Shale Gas ◽  
Gas Production ◽  
New Method ◽  
Fracture Conductivity ◽  
Fracture Surface Roughness ◽  
Rock Samples ◽  
Fracture Surfaces ◽  
Effective Development

Abstract Hydraulic fracturing technology provides a guarantee for effective production increase and economic exploitation of shale gas wells reservoirs. Propped fractures formed in the formation after fracturing are the key channels for shale gas production. Accurate evaluation of local propped fracture conductivity is of great significance to the effective development of shale gas. Due to the complex lithology and well-developed bedding of shale, the fracture surface morphology after fracturing is rougher than that of sandstone. This roughness will affect the placement of the proppant in the fracture and thus affect the conductivity. At present, fracture conductivity tests in laboratories are generally based on the standard/modified API/ISO method, ignoring the influence of fracture surface roughness. The inability to obtain the rock samples with the same rough morphology to carry out conductivity testing has always been a predicament in the experimental study on propped fracture conductivity. Herein, we propose a new method to reproduce the original fracture surface, and conductivity test samples with uniform surface morphology, consistent mechanical properties were produced. Then, we have carried out experimental research on shale-propped fracture conductivity. The results show that the fracture surfaces produced by the new method are basically the same as the original fracture surfaces, which fully meet the requirements of the conductivity test. The propped fracture conductivity is affected by proppant properties and fracture surface, especially at low proppant concentration. And increasing proppant concentration will help increase the predictability of conductivity. Due to the influence of the roughness of the fracture surface, there may be an optimal proppant concentration under a certain closure pressure.

scholarly journals Effect of Reaction Temperature on Adsorption Efficiency using Computer Mathematical Statistics Visible Spectorphotometer

2021 ◽  
Vol 2083 (3) ◽  
pp. 032072
Author(s):  
Yongli Zhang ◽  
Ruiting Li
Keyword(s):  
Reaction Temperature ◽  
Metal Ion ◽  
Adsorption Rate ◽  
Ion Concentration ◽  
Adsorption Efficiency ◽  
Optimum Temperature ◽  
Absorption Effect ◽  
Before And After ◽  
Measurement Experiment ◽  
Optimal Reaction

Abstract In this paper, waste shrimp shells extracted from the head of the chitosan material; static adsorption experiments manner by wastewater containing Fe(III) added chitosan, vis spectrophotometer absorbance before and after the measurement experiment was obtained by reacting the size of the metal ion concentration, adsorption conditions whereby chitosan Fe(III) and the ability to explore. Experiments show that. In the case where the reaction temperature is less than 55°C, chitosan has adsorption rate Fe(III) smaller rise, the optimum temperature was 55°C, but the effects on the reaction temperature adsorption rate is not large; Adsorption when control time 30 min to 50 min, the absorption effect is increased with increase in the time, to reach the optimal reaction time 50 min.

scholarly journals Research on Mechanical Performance & Behaviour of Geopolymer Concrete Subjected to Elevated Temperatures

2019 ◽  
Vol 8 (2S8) ◽  
pp. 883-887
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Geopolymer Concrete ◽  
Sem Images ◽  
Before And After ◽  
Alkaline Conditions ◽  
Compressive Strength Of Concrete

The investigative studies on mechanical performance & behaviour, of Geopolymer Concrete (GPC) before and after the exposure to elevated temperatures (of 200 0 C -1000 0 C with an increment of 100 0 C). Indicate that the GPC Specimens Exhibited better Compressive strength at higher temperatures than that of those made by regular OPC Concrete with M30 Grade. The chronological changes in the geopolymeric structure upon exposure to these temperatures and their reflections on the thermal behaviour have also been explored. The SEM images indicate GPC produced by fly ash , metakaolin and silica fume, under alkaline conditions form Mineral binders that are not only non-flammable and but are also non-combustible resins and binders. Further the Observations drawn disclose that the mass and compressive strength of concrete gets reduced with increase in temperatures.

scholarly journals A rapidly-dissolving silica-silver bioactive glass for cariostatic applications

2021 ◽  
Author(s):  
Saad Arshad
Keyword(s):  
Oral Cavity ◽  
Antibacterial Effect ◽  
Surface Hardness ◽  
Tris Buffer ◽  
Bacterial Strains ◽  
Buffer Solution ◽  
Solution Ph ◽  
Before And After ◽  
Knoop Microhardness ◽  
Tris Buffer Solution

In this study, bioactive glasses were designed for the purposes of reducing the incidence of dental caries and lesion formation by supplying the teeth with therapeutic ions which may support remineralization and provide an antibacterial effect against oral cavity bacteria. Three glasses were synthesised through the melt quench method: Si-Control (SiO2-CaO-P2O5-Na2O), Si-02 and Si-05, where 0.2% and 0.5% Ag2O were substituted, respectively, for SiO2 in the control glass. The glasses were then ground, characterized and dissolved in tris buffer solution (pH=7.30) for 6, 12 and 24 hours, with the pH rise of the solution being recorded (7.48 for Si-Control, and 7.66 for both Si-02 and Si-05 after 24 hours) and the ions that were released into the tris buffer solution quantified. Samples of each glass were subsequently embedded into non-fluoridated toothpaste and samples of the paste were used to brush resin-mounted lamb molars after a 1.0M HCl overnight demineralization challenge. Knoop microhardness measurements were recorded before and after brushing to determine the presence of remineralization on the surface of the teeth (Percent Surface Hardness Loss of 37%, 35% and 34% for Si-Control, Si-02 and Si-05 respectively after 24 hours). Four oral cavity bacterial strains were isolated through swabs of the inner cheek, gums and teeth surfaces of three volunteers, and placed on agar discs. 0.5g of each glass were placed onto the discs and the resultant inhibition zones were measured after 6, 12 and 24 hours. Si-05 consistently performed better than Si-02 on all strains and timeframes, while Si-Control exhibited no antibacterial effect at any time point.

scholarly journals A rapidly-dissolving silica-silver bioactive glass for cariostatic applications

2021 ◽  
Author(s):  
Saad Arshad
Keyword(s):  
Oral Cavity ◽  
Antibacterial Effect ◽  
Surface Hardness ◽  
Tris Buffer ◽  
Bacterial Strains ◽  
Buffer Solution ◽  
Solution Ph ◽  
Before And After ◽  
Knoop Microhardness ◽  
Tris Buffer Solution

In this study, bioactive glasses were designed for the purposes of reducing the incidence of dental caries and lesion formation by supplying the teeth with therapeutic ions which may support remineralization and provide an antibacterial effect against oral cavity bacteria. Three glasses were synthesised through the melt quench method: Si-Control (SiO2-CaO-P2O5-Na2O), Si-02 and Si-05, where 0.2% and 0.5% Ag2O were substituted, respectively, for SiO2 in the control glass. The glasses were then ground, characterized and dissolved in tris buffer solution (pH=7.30) for 6, 12 and 24 hours, with the pH rise of the solution being recorded (7.48 for Si-Control, and 7.66 for both Si-02 and Si-05 after 24 hours) and the ions that were released into the tris buffer solution quantified. Samples of each glass were subsequently embedded into non-fluoridated toothpaste and samples of the paste were used to brush resin-mounted lamb molars after a 1.0M HCl overnight demineralization challenge. Knoop microhardness measurements were recorded before and after brushing to determine the presence of remineralization on the surface of the teeth (Percent Surface Hardness Loss of 37%, 35% and 34% for Si-Control, Si-02 and Si-05 respectively after 24 hours). Four oral cavity bacterial strains were isolated through swabs of the inner cheek, gums and teeth surfaces of three volunteers, and placed on agar discs. 0.5g of each glass were placed onto the discs and the resultant inhibition zones were measured after 6, 12 and 24 hours. Si-05 consistently performed better than Si-02 on all strains and timeframes, while Si-Control exhibited no antibacterial effect at any time point.

Microstructural and Fractographic Analysis of CuAlNi Shape Memory Alloy before and after Heat Treatment

2020 ◽  
Vol 405 ◽  
pp. 100-106
Author(s):  
Ivana Ivanić ◽  
Mirko Gojić ◽  
Stjepan Kožuh ◽  
Borut Kosec
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Fracture Surface ◽  
Shape Memory ◽  
Fractographic Analysis ◽  
Before And After ◽  
Different Temperatures ◽  
The Difference ◽  
Type Of Fracture ◽  
Scanning Electron

The paper presents comparison of microstructure and fracture surface morphology of the CuAlNi shape memory alloy (SMA) after different heat treatment procedures. The investigation was performed on samples in as-cast state and heat treated states (solution annealing at temperatures of 850 °C / 60’ / H2O and 920 °C / 60’ / H2O along with tempering at two different temperature 150 °C / 60’ / H2O and 300 °C / 60’ / H2O). The microstructure of the samples was examined by optical (OM) and scanning electron microscope (SEM) equipped with device for EDS analysis. The obtained fracture surfaces were examined by SEM. Optical and scanning electron microscopy showed martensitic microstructure in all investigated samples. However, the fractographic analysis of samples after tensile testing reveals significant changes in fracture mechanism. In both solution annealed states the results shows transgranular type of fracture, but after tempering at two different temperatures the difference is obvious. After tempering at 150 °C, along with transgranular type of fracture appear some areas with intergranular type of fracture. After tempering at 300 °C, fracture surface reveals completely intergranular type of fracture.

scholarly journals Effect of Simulated Matches on Post-Exercise Biochemical Parameters in Women’s Indoor and Beach Handball

2020 ◽  
Vol 17 (14) ◽  
pp. 5046
Author(s):  
Joanna Kamińska ◽  
Tomasz Podgórski ◽  
Jakub Kryściak ◽  
Maciej Pawlak
Keyword(s):  
Blood Parameters ◽  
Ion Concentration ◽  
Electrolyte Balance ◽  
Acid Base Balance ◽  
Acid Base ◽  
Urine Ph ◽  
Physically Active ◽  
Post Exercise ◽  
Before And After ◽  
Base Balance

This study assesses the status of hydration and the acid-base balance in female handball players in the Polish Second League before and after simulated matches in both indoor (hall) and beach (outdoor) conditions. The values of biochemical indicators useful for describing water-electrolyte management, such as osmolality, hematocrit, aldosterone, sodium, potassium, calcium, chloride and magnesium, were determined in the players’ fingertip capillary blood. Furthermore, the blood parameters of the acid-base balance were analysed, including pH, standard base excess, lactate and bicarbonate ion concentration. Additionally, the pH and specific gravity of the players’ urine were determined. The level of significance was set at p < 0.05. It was found that both indoor and beach simulated matches caused post-exercise changes in the biochemical profiles of the players’ blood and urine in terms of water-electrolyte and acid-base balance. Interestingly, the location of a simulated match (indoors vs. beach) had a statistically significant effect on only two of the parameters measured post-exercise: concentration of calcium ions (lower indoors) and urine pH (lower on the beach). A single simulated game, regardless of its location, directly affected the acid-base balance and, to a smaller extent, the water-electrolyte balance, depending mostly on the time spent physically active during the match.

Preliminary investigations on reducing the high radiation risk level of TENORM scale waste from petroleum industry

2018 ◽  
Vol 106 (9) ◽  
pp. 793-800 ◽  
Author(s):  
Mohamed F. Attallah ◽  
Moustafa A. Hilal ◽  
Yasser T. Mohamed
Keyword(s):  
Radiation Risk ◽  
Petroleum Industry ◽  
Physicochemical Characteristics ◽  
Pilot Scale ◽  
Total Radioactivity ◽  
Risk Level ◽  
High Radiation ◽  
Economic Process ◽  
Before And After

Abstract The main objective of this study is directed to remove 226Ra, 228Ra radionuclides from TENORM scale waste without seriously degradation the physicochemical characteristics of soils or generating waste. It was found that 82, 87% removal of total radioactivity using successive washing by commercial and TX-100 solutions, respectively, after seven cycles. Some radiation risk before and after treatment with surfactants were determined. It is a promising and efficient as well as economic process. Our results from this task could provide a useful information for defining the establishing and operating on a pilot-scale plant for efficient and economic TENORM treatment.

Macroscale Mechanical and Microscale Structural Changes in Chinese Wufeng Shale With Supercritical Carbon Dioxide Fracturing

SPE Journal ◽  
2017 ◽  
Vol 23 (03) ◽  
pp. 691-703 ◽  
Author(s):  
Qing-You Liu ◽  
Lei Tao ◽  
Hai-Yan Zhu ◽  
Zheng-Dong Lei ◽  
Shu Jiang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Shale Gas ◽  
Structural Changes ◽  
Triaxial Tests ◽  
Upper Ordovician ◽  
Sem Images ◽  
Bedding Planes ◽  
Before And After ◽  
Supercritical Carbon

Summary Waterless fracturing for shale-gas exploitation using supercritical carbon dioxide (scCO2) is both effective and environmentally friendly, and has become an extensive research topic. Previous researchers have focused on the chemical and physical properties and microstructure of sandstone, carbonate, and shale caprock, rather than on the properties of shale-gas formations. The macroscale mechanical properties and microscale fracture characteristics of Wufeng Shale exposed to scCO2 (at greater than 31.8°C and 7.29 MPa) are still not well-understood. To study the macroscale and microscale changes of shale subjected to scCO2, we obtained Chinese Wufeng Shale crops (Upper Ordovician Formation) from Yibin, Sichuan Basin, China. The shale samples were divided into two groups. The first group was exposed to scCO2, and the second group was exposed to nitrogen (N2). Scanning-electron-microscope (SEM) and X-ray-diffraction (XRD) images were taken to study the original microstructure and mineral content of the shale. To study the macroscale mechanical changes of Wufeng Shale immersed in scCO2 or N2 for 10 hours, triaxial tests with controlled coring angles were conducted. SEM and XRD images were taken after the triaxial tests. In the SEM images, tight bedding planes and undamaged minerals (with sharp edges and smooth surfaces) were found in N2-treated samples both before and after testing, indicating that exposure to N2 did not affect the microstructures. However, the SEM images for the microstructure scCO2-treated samples before and after testing were quite different. The bedding planes were damaged, which left some connected microfractures and corrosion holes, and some mineral types were broken into small particles and left with uneven mineral surfaces. This shows that scCO2 can change rock microstructures and make some minerals (e.g., calcite) fracture more easily. The complex microscale fractures and the decrease in strength for scCO2-treated shale aid the seepage and gathering of gas, enhancing shale-gas recovery. Knowledge of the multiscale physical and chemical changes of shale exposed to scCO2 is not only essential for scCO2 fracturing, but it is also important for scCO2 jets used to break rock and for the geological storage of CO2.

Inhibitive Effect of a New Dental Resin Composite on Enamel Artificial Caries

2014 ◽  
Vol 1058 ◽  
pp. 323-328
Author(s):  
Xin Yi Zhao ◽  
Shao Jie Hou ◽  
Shi Bao Li
Keyword(s):  
Resin Composite ◽  
Surface Hardness ◽  
Filling Material ◽  
Dental Resin ◽  
Buffer Solution ◽  
Partially Saturated ◽  
Enamel Demineralization ◽  
Restorative Materials ◽  
Before And After

Purpose To investigate the cariostatic effect of six restorative materials in vitro. Method Enamel blocks of bovine incisors were restored with six restorative materials (a conventional GIC, FujiIILC, Compoglass F, BeautifilII,Charisma and an experimental fluoride releasing resin composite) respectively with a gap of 270μm in width between each filling material and enamel. Then all restorations were immersed in a partially saturated acidic buffer solution at 37C for 3days. The surface enamel microhardness of the enamel blocks were measured before and after demineralization and the depth of enamel demineralization was measured using polarization microscope for each restoration.Results Enamel surface hardness of all restorations demonstrated significant reduced after demineralization ( p<0.05), and the order of hardness reduction is as follows: Charisma >BeautifilII≈Compoglass F≈Experimental Resin>FujiIILC>GIC ( p> 0.05). The order of the depth of enamel demineralization along the surface and the interface near the gap for the 5 materials is as follows: Charisma >BeautifilII≈Compoglass F ≈Experimental Resin>FujiIILC>GIC (P > 0.05). Conclusion The new fluoride releasing and recharging composite resin has the ability to prevent recurrent caries around the restoration and its ability is comparable to compomer materials.

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