scholarly journals Experimental Investigations of the Process of Carbonate Fracture Dissolution Enlargement under Reservoir Temperature and Pressure Conditions

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-19
Author(s):  
Jingxia Wang ◽  
Qingchun Yu
Keyword(s):  
Laser Scanning ◽  
Early Stage ◽  
Confining Pressure ◽  
Carbonate Reservoir ◽  
Dissolution Process ◽  
Experimental Investigations ◽  
Polynomial Type ◽  
Calcite Veins ◽  
Before And After ◽  
Logarithmic Type

Karst is a central focus in the field of carbonate reservoir geology. Fracture dissolution enlargement is an important mechanism for the formation of high-quality reservoirs. This study performed four carbonate fracture dissolution enlargement (CFDE) experiments under a confining pressure of 20 MPa, and temperatures ranged from 40 to 60°C. CO2-saturated deionized water was injected into artificial carbonate fractures at approximately 11.5 ml/h for 96, 208, 216, and 216 hours. The water flowing out of the fractures was sampled every 8 h to monitor the concentration of Ca2+. SEM photomicrographs and 3D laser scanning images were taken before and after the CFDE experiments to observe the dissolution process of the fracture surfaces. After the CFDE experiment, the hydraulic apertures (Bh) of sample 1 (S1), sample 3 (S3), and sample 4 (S4) were enlarged by 3.4, 1.4, and 1.2 times, respectively. The aperture of sample 2 (S2) was slightly reduced in the early stage of the experiment. The experimental results of this study demonstrate that Bh can be divided into three categories as a function of time: S type, logarithmic type, and polynomial type. The laboratory dissolution rate of S1, S2, S3, and S4 were 2.50 × 10−6, 3.11 × 10−6, 2.70 × 10−6, and 3.04 × 10−6 mol/m2/s. The pattern of fracture dissolution is closely related to the Peclet and Damkohler numbers. The dissolution processes of high Peclet and Damkohler numbers lead to a pattern of obvious channelization. The Peclet and Damkohler numbers of the S3 CFDE experiment were the highest, and the channelizing dissolution is the most notable in S3 of the four fractures. A dissolution process at low temperature has a higher Peclet number and thus leads to obvious channelizing dissolution. Mineral heterogeneities in the rock also play a significant role in channelizing dissolution. A preferential channel typically develops in places where bioclasts are accumulated or the calcite veins are distributed.

A Comparative Study of Amalaki Choorna along with Madhu and Vata Twak Kashaya Yoni Pichu Dharana in the Management of Shweta Pradara

2017 ◽  
Vol 2 (4) ◽  
Author(s):  
Renuka M. Tenahalli
Keyword(s):  
Vitamin C ◽  
Early Stage ◽  
Pathological Condition ◽  
Before And After ◽  
Group A ◽  
Phosphorus Iron ◽  
Group B ◽  
Busy Schedule ◽  
Iron And Calcium

Shweta Pradara (Leucorrhoea) is the disease which is characterized by vaginal white discharge. Vaginal white discharge this symptom is present in both physiological and pathological condition, when it becomes pathological it disturbs routine life style of the woman. Most of the women in the early stage will not express the symptoms because of hesitation and their busy schedule. If it is not treated it may leads to chronic diseases like PID (Garbhashaya Shotha etc.) Charaka mentioned Amalaki Choorna along with Madhu and Vata Twak Kashaya Yoni Pichu Dharana. This treatment is used in Shweta Pradara shown positive results, hence a study was under taken to assess its clinical efficacy. 30 diagnosed patients of Shweta Pradara were randomly selected, allocated in three groups. Group A and Group B received Amalaki Choorna with Madhu and Vata Twak Kashaya Yoni Pichu Dharana respectively and Group C received Amalaki Choorna with Madhu followed by Vata Twak Kashaya Yoni Pichu Dharana for 15 days. The patients were assessed for the severity of the symptoms subjectively and objectively before and after the treatment and at the end of the follow up. Data from each group were statistically analyzed and were compared. No side effects were noted and it may be considered as an effective alternative medicine in Shweta Pradara (leucorrhea). Amalaki is rich in natural source of vitamin C and contains phosphorus, iron and calcium. Honey contains carbohydrate, vitamin C, phosphorus iron and calcium. All together these help to increase Hb% and immunity. Vata Twak Kashaya contains tannin which helps to maintain normal pH of the vagina.

scholarly journals Rearing Drones in Queen Cells of Apis mellifera Honey Bees

2016 ◽  
Vol 60 (2) ◽  
pp. 119-128
Author(s):  
Georgios Goras ◽  
Chrysoula Tananaki ◽  
Sofia Gounari ◽  
Elissavet Lazaridou ◽  
Dimitrios Kanelis ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Larval Development ◽  
Honey Bees ◽  
Royal Jelly ◽  
Early Stage ◽  
Egg Laying ◽  
Horizontal Position ◽  
Before And After ◽  
Queen Larvae ◽  
As If

Abstract We investigated the rearing of drone larvae grafted in queen cells. From the 1200 drone larvae that were grafted during spring and autumn, 875 were accepted (72.9%) and reared as queens. Drone larvae in false queen cells received royal jelly of the same composition and of the same amounts as queen larvae. Workers capped the queen cells as if they were drones, 9-10 days after the egg laying. Out of 60 accepted false queen cells, 21 (35%) were capped. The shape of false queen cells with drone larvae is unusually long with a characteristically elongate tip which is probably due to the falling of larvae. Bees start the destruction of the cells when the larvae were 3 days old and maximised it before and after capping. Protecting false queen cells in the colony by wrapping, reversing them upside down, or placing in a horizontal position, did not help. The only adult drones that emerged from the false queen cells were those protected in an incubator and in push-in cages. Adult drones from false queen cells had smaller wings, legs, and proboscis than regular drones. The results of this study verify previous reports that the bees do not recognise the different sex of the larvae at least at the early stage of larval development. The late destruction of false queen cells, the similarity in quality and quantity of the produced royal jelly, and the bigger drone cells, allow for the use of drone larvae in cups for the production of royal jelly.

Antecedents of growth-oriented entrepreneurship before and during the Greek economic crisis

2017 ◽  
Vol 24 (3) ◽  
pp. 528-544 ◽  
Author(s):  
Ioannis Giotopoulos ◽  
Alexandra Kontolaimou ◽  
Aggelos Tsakanikas
Keyword(s):  
Work Experience ◽  
Early Stage ◽  
New Ventures ◽  
High Growth ◽  
Content Type ◽  
Crisis Period ◽  
Individual Level ◽  
Level Data ◽  
The Social ◽  
Before And After

Purpose The purpose of this paper is to explore potential drivers of high-growth intentions of early-stage entrepreneurs in Greece before and after the onset of the financial crisis of 2008. Design/methodology/approach To this end, the authors use individual-level data retrieved from Global Entrepreneurship Monitor annual surveys (2003-2015). Findings The results show that high-growth intentions of Greek entrepreneurs are driven by different factors in the crisis compared to the non-crisis period. Male entrepreneurs and entrepreneurs with significant work experience seem to be more likely to be engaged in growth-oriented new ventures during the crisis period. The same appears to hold for entrepreneurs who are motivated by an opportunity and also perceive future business opportunities in adverse economic conditions. On the other hand, the educational level and the social contacts of founders with other entrepreneurs are found to drive ambitious Greek entrepreneurship in the years before the crisis, while they were insignificant after the crisis outbreak. Originality/value Based on the concept of ambitious entrepreneurship, this study contributes to the literature by investigating the determinants of entrepreneurial high-growth expectations in the Greek context emphasizing the crisis period in comparison to the pre-crisis years.

The Influence of Purification of Ethyl Acrylate on the Properties of Cement Matrix

2010 ◽  
Vol 150-151 ◽  
pp. 1143-1151
Author(s):  
Chau Lee ◽  
Nian Fu Wang ◽  
Meng Xun Xiem
Keyword(s):  
Hydrogen Peroxide ◽  
Early Stage ◽  
Setting Time ◽  
Ethyl Acrylate ◽  
Cement Matrix ◽  
Strength Development ◽  
Final Setting Time ◽  
Before And After ◽  
Analysis Of Performance ◽  
Acrylate Polymer

This research mainly probes into the analysis of performance and assessment that ethyl acrylate polymer is applied to the cement matrix. The result shows that, before and after the purification, ethyl acrylate can increase the flowability of modified mortar, and with the increasing the dosage of polymer, the flowability is getting better. But if the dosage of hydrogen peroxide used to remove the residua alcohol is excessive, it is easy to cause high mortar viscosity, and that is unfavorable to the flowability. According to the setting time of the mortar under normal consistency, the result shows that the ethyl acrylate before the purification, has retarding effects on both initial and final setting time. With the increasing the dosage of polymer, it takes longer for both setting time. Besides, because hydrogen peroxide has accelerative effect, the purified ethyl acrylate can shorten the setting time of initial and final setting time. However, over dosage of hydrogen peroxide can easily lead to poor strength development in later stage. Using purified ethyl acrylate can overcome the shortcoming of lower strength of 3、7- day early stage. when hydrogen peroxide consumption is 0.5% of the total amount of acid and alcohol, the ethyl acrylate has the positive effect on improving the compressive strength. Finally, among the comprehensive assessments of the mortar testing results, EH0.5-0.1 has the significant effect of modification.

scholarly journals Experimental investigations of CO2 seepage behaviorin naturally fractured coal under hydro-thermal-mechanical conditions

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4651-4658
Author(s):  
Teng Teng ◽  
Xiaoyan Zhu ◽  
Yu-Ming Wang ◽  
Chao-Yang Ren
Keyword(s):  
Gas Flow ◽  
Confining Pressure ◽  
Gas Pressure ◽  
Experimental Investigations ◽  
Permeability Evolution ◽  
Coal Permeability ◽  
Naturally Fractured ◽  
Series Of Experiments ◽  
Fractured Coal ◽  
Increasing Temperature

Gas-flow in coal or rock is hypersensitive to the changes of temperature, confin?ing pressure and gas pressure. This paper implemented a series of experiments to observe the seepage behavior, especially the permeability evolution of CO2 in naturally fractured coal sample under coupled hydro-thermal-mechanical conditions. The experimental results show that coal permeability increases exponentially with the increasing gas pressure, and tends to be linear when the confining pressure is high. Coal permeability decreases exponentially with the increasing confining pressure. Coal permeability decreases with the increasing temperature generally, but it may bounce up when the temperature rises to high. The results provide reference for the projects of coal gas extraction and carbon dioxide geological sequestration.

scholarly journals Features of biochemical indices and content of enzymes in the serum of syphilis patients with viral hepatites B and C in the course of treatment

2021 ◽  
Vol 26 (3) ◽  
pp. 107-113
Author(s):  
S.V. Zakharov ◽  
V.K. Zakharov ◽  
V.V. Gorbuntsov
Keyword(s):  
Functional State ◽  
Biochemical Parameters ◽  
Early Stage ◽  
Serum Levels ◽  
Test Methods ◽  
Comprehensive Examination ◽  
Before And After ◽  
Biochemical Indices ◽  
Increased Activity ◽  
Latent Syphilis

Objective – before and after the treatment to determine the functional state of the liver, serum levels of enzymes and biochemical indices in syphilis patients with viral hepatites B and C. The results of the study are based on the data from a comprehensive examination of 35 patients with syphilis alone and 127 patients with syphilis co-infected with viral hepatites B and C before and after treatment. Test methods: hepatology, rheogeopathography, enzyme content and biochemical parameters determined in the serum. According to the results of radionuclide hepatology it has been established that disorders of the functional capacity of the liver already occur in the early stages of the disease. The most significant disorders have been in the patients with the prescription of infection for more than 12 months and in the patients co-infected with viral hepatites B and C. A disorder of pigment metabolism and increased activity of trans­aminases have been revealed in early latent syphilis. In co-infection with viral hepatites B and C an increase in total bilirubin, Lactate dehydrogenase, Alanine transaminase, Aspartate aminotransferase and albumin has been revealed. Dysproteinemia has been revealed in patients with early latent syphilis co-infected with hepatitis C. Patients with early latent syphilis treated with immunomodulators tend to normalize these indices. In patients with syphilis a disorder of the functional state of the liver have been revealed already at an early stage of the disease. The most pronounced disorder of biochemical parameters and activity of liver enzymes are observed in syphilis patients with viral hepatites B and C, as well as in patients with early latent syphilis only with the prescription of the infection for more than 12 months; in such a case it is advisable to use drugs affecting the immune system.

Determination of oil charge timing in the Ordovician carbonate reservoir of the Tahe Oilfield, Tarim Basin, NW China

2021 ◽  
Author(s):  
Jiaxu Chen ◽  
Xiaowen Guo
Keyword(s):  
Tarim Basin ◽  
Sedimentary Basins ◽  
Carbonate Reservoir ◽  
Rock Interaction ◽  
Tahe Oilfield ◽  
Petroleum Systems ◽  
Calcite Veins ◽  
Homogenization Temperatures ◽  
Two Phases ◽  
Northern Tarim Basin

<p>Determining the timings of oil charge in sedimentary basins are essential to understand the evolutionary histories of petroleum systems, especially in sedimentary basins with complicated tectonic evolution and thermal histories. The Ordovician carbonate reservoir in the Tahe Oilfield, which is located in the northern Tarim Basin, comprises the largest marine reservoirs in China with reserves up to 3.2×10<sup>8</sup> t. This study aims to determine the timings of oil charge in the Ordovician carbonate reservoir in the Tahe Oilfield, Tarim Basin, which basin is subjected to multiple phases of tectonic deformations and oil charge. The phases of calcite veins that contain oil inclusions were systematically investigated by cathodoluminescence observation, in situ rare earth element, C, O, and Sr isotope analyses. The homogenization temperatures of aqueous inclusions that are coeval with oil inclusions were measured to determine the timings of oil charge by combining the burial and geothermal histories. Two phases of calcite veins were judged by the differences in cathodoluminescence color, Ce anomaly, δ<sup>18</sup>O, and <sup>87</sup>Sr/<sup>86</sup>Sr values, which might be caused by variations in the water-rock interaction processes during different calcite phases. Primary oil inclusions with yellow fluorescence were observed in the two phases of calcite veins, suggesting two phases of oil charge. By combining the homogenization temperatures of aqueous inclusions with the burial and geothermal histories, the timing of phase I oil charge was inferred to be 336–312 Ma, and the timing of phase II oil charge was inferred to be 237–217 Ma.</p>

Triacrylamide-Based Adhesives Stabilize Bonds in Physiologic Conditions

2022 ◽  
pp. 002203452110617
Author(s):  
F.S. de Lucena ◽  
S.H. Lewis ◽  
A.P.P. Fugolin ◽  
A.Y. Furuse ◽  
J.L. Ferracane ◽  
...  
Keyword(s):  
Bond Strength ◽  
Cross Sections ◽  
Laser Scanning ◽  
Adhesive System ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Gap Formation ◽  
Bond Stability ◽  
Occlusal Surfaces ◽  
Before And After

In this study, an acrylamide-based adhesive was combined with a thiourethane-based composite to improve bond stability and reduce polymerization stress, respectively, of simulated composite restorations. The stability testing was conducted under physiologic conditions, combining mechanical and bacterial challenges. Urethane dimethacrylate was combined with a newly synthesized triacrylamide (TMAAEA) or HEMA (2-hydroxyethyl-methacrylate; control) to produce a 2-step total-etch adhesive system. Methacrylate-based composites (70 wt% silanized filler) were formulated, containing thiourethane oligomers at 0 (control) or 20 wt%. Standardized preparations in human third molars were restored; then, epoxy replicas were obtained from the occlusal surfaces before and after 7-d storage in water or with Streptococcus mutans biofilm, which was tested after storage in an incubator (static) or the bioreactor (mechanical challenge). Images were obtained from the replicas (scanning electron microscopy) and cross sections of the samples (confocal laser scanning microscopy) and then analyzed to obtain measurements of gap, bacterial infiltration, and demineralization. Microtensile bond strength of specimens stored in water or biofilm was assessed in 1-mm2 stick specimens. Data were analyzed with analysis of variance and Tukey’s test (α = 0.05). HEMA-based materials had greater initial gap measurements, indicating more efficient bonding for the acrylamide materials. When tested in water, the triacrylamide-based adhesive had smaller gaps in the incubator or bioreactor. In the presence of biofilm, there was less difference among materials, but the acrylamide/thiourethane combination led to statistically lower gap formation in the bioreactor. HEMA and TMAAEA-based adhesives produced statistically similar microtensile bond strengths after being stored in water for 7 d, but after the same period with biofilm-challenged specimens, the TMAAEA-based adhesives were the only ones to retain the initial bond strength values. The use of a stable multiacrylamide-based adhesive led to the preservation of the resin-dentin bonded interface after a physiologically relevant challenge. Future studies will include a multispecies biofilm model.

Experimental Methods for the Evaluation of the Efficiency of an Innovative Sulfur-Dissolving Product in HP-HT Conditions

2021 ◽  
Author(s):  
Ivan Maffeis ◽  
Alberto Renato de Angelis ◽  
Riccardo Guernelli ◽  
Ettore Croce ◽  
Luigi Romano
Keyword(s):  
Elemental Sulfur ◽  
Liquid Product ◽  
Active Phase ◽  
Crystal Form ◽  
Experimental Investigations ◽  
Physical Interaction ◽  
Laboratory Equipment ◽  
Complete Representation ◽  
Before And After ◽  
Dissolution Efficiency

Abstract During production from sour gas reservoirs, precipitation of elemental sulfur can take place in production tubing, resulting in plugging of the well and stop of production. Injection in tubing of products devoted to dissolving sulfur can be an efficient solution for plug removal and production restoring. Traditionally, organic solvents (like toluene) are employed for solid sulfur dissolution. In the present work, experimental investigations have been performed on a particular innovative liquid product designed as active phase for wellbore injection or near wellbore applications. The analyses about the behavior of the considered product were conducted at HP-HT conditions. For this purpose, PVT laboratory equipment was employed, being able to reproduce the conditions of interest for the formation of elemental sulfur plug in well. An important preliminary optimization phase on the experimental setup was necessary to assure the correct management of studied liquid substance and solid sulfur. Integration of main outcomes with other kind of analyses allowed to depict a complete representation of the behavior: microscopy analysis of the liquid phase and high-resolution tomography of solid sulfur before and after the interaction were employed. A key point of the experimental characterization is the reproduction of significant involved phenomena. A preliminary effort was necessary for reproducing the realistic crystal form expected during the precipitation of solid sulfur in well. The dissolution efficiency of the liquid product is evaluated by observing its physical interaction with sulfur in a HP-HT cell. Particular attention was paid to correctly handling employed substances at the considered pressure and temperature conditions. A detailed description of the optimized equipment used in laboratory is provided. Several dissolution tests have been conducted at different temperature and pressure conditions, aiming to observe the dependence of the dissolution efficiency on the thermodynamic parameters. A visual qualitative analysis was performed on both the liquid product and the solid plug, before and after the interaction in cell. This allowed to deepen the comprehension of the dynamics of sulfur dissolution, which takes place not only from the top face of the plug, but also from preferential paths (fractures) present inside the plug itself. The presence of sulfur crystals dispersed in the liquid product after sampling from the cell is also evident at the end of the tests. The studied novel sulfur-dissolving liquid active phase is a candidate for remedial job injection at well in case of plugging due to solid elemental sulfur precipitation. The analyses here presented allowed to characterize the dissolution potential of this product. An optimized workflow was designed, including different kind of experimental disciplines.

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