scholarly journals Determination of NMR T2 Cutoff and CT Scanning for Pore Structure Evaluation in Mixed Siliciclastic–Carbonate Rocks before and after Acidification

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1338 ◽  
Author(s):  
Mengqi Wang ◽  
Jun Xie ◽  
Fajun Guo ◽  
Yawei Zhou ◽  
Xudong Yang ◽  
...  
Keyword(s):  
Pore Structure ◽  
Carbonate Rocks ◽  
Carbonate Rock ◽  
Experimental Results ◽  
Normal Distribution Function ◽  
Core Samples ◽  
Irreducible Water Saturation ◽  
Significant Difference ◽  
Before And After ◽  
Structure Evaluation

Nuclear magnetic resonance (NMR) is used widely to characterize petrophysical properties of siliciclastic and carbonate rocks but rarely to study those of mixed siliciclastic–carbonate rocks. In this study, 13 different core samples and eight acidified core samples selected amongst those 13 from the Paleogene Shahejie Formation in Southern Laizhouwan Sag, Bohai Bay Basin, were tested by scanning electron microscopy (SEM), micro-nano-computed tomography (CT), and NMR. SEM and CT results revealed a complex pore structure diversity, pore distribution, and pore-throat connectivity in mixed reservoirs. Sixteen groups of NMR experiments addressed changes in these properties and permeabilities of mixed siliciclastic–carbonate rocks before and after acidification to determine its effects on such reservoirs. NMR experimental results showed no “diffusion coupling” effect in mixed siliciclastic–carbonate rocks. Distributions of NMR T2 cutoff values (T2C) are closely related to the pore structure and lithologic characteristics before and after acidification. The T2C index separates irreducible and movable fluids in porous rocks and is a key factor in permeability prediction. Centrifugation experiments showed that, before acidification, the T2C of mixed siliciclastic–carbonate rocks with 60–90% siliciclastic content (MSR) ranged widely from 1.5 to 9.8 ms; the T2C of mixed siliciclastic–carbonate rocks with 60–90% carbonate content (MCR) ranged from 1.8 to 5.6 ms. After acidification, the T2C of MSR ranged widely from 2.6 to 11.6 ms, the T2C of MCR ranged from 1.5 to 5.6 ms, and no significant difference was observed between MCR reservoirs. Based on an analysis of the morphology of NMR T2 spectra, we propose a new T2 cutoff value prediction method for mixed siliciclastic–carbonate rocks based on a normal distribution function to predict various T2C values from morphological differences in NMR T2 spectra and to calculate the irreducible water saturation (Swir), i.e., the ratio of irreducible total fluid volume to effective porosity. The reliability of the proposed method is verified by comparing predicted T2C and Swir values with those from NMR experimental results. New experiments and modeling demonstrate the applicability of NMR for the petrophysical characterization of mixed siliciclastic–carbonate rock reservoirs. Our results have potential applications for identification and evaluation of mixed siliciclastic–carbonate rock reservoirs using NMR logging.

Predicting the Performance of the Acid-Stimulation Treatments in Carbonate Reservoirs With Nondestructive Tracer Tests

SPE Journal ◽  
2015 ◽  
Vol 20 (06) ◽  
pp. 1238-1253 ◽  
Author(s):  
A.S.. S. Zakaria ◽  
H.A.. A. Nasr-El-Din ◽  
M.. Ziauddin
Keyword(s):  
Porous Media ◽  
Pore Structure ◽  
Carbonate Rocks ◽  
Tracer Tests ◽  
Structure Characterization ◽  
Hydrochloric Acid Concentration ◽  
Thin Sections ◽  
Characterization Methods ◽  
Core Samples ◽  
Flow Through

Summary Carbonate formations are very complex in their pore structure and exhibit a wide variety of pore classes, such as interparticle porosity, moldic porosity, vuggy porosity, and microporosity. Geologists have defined carbonate pore classes on the basis of sedimentology, thin sections, and porosity/permeability relationships, but the question remains concerning how these pore classes govern the acid flow through porous media. Core samples from six different carbonates, mainly limestone, were selected for the study. The samples were first investigated with thin-section analysis, high-pressure mercury-injection tests, and nuclear-magnetic-resonance measurements for pore-structure characterization, and X-ray diffraction for mineralogy examination. Next, tracer experiments were conducted, and the tracer-concentration profiles were analyzed to quantify the carbonate pore-scale heterogeneity. The heterogeneity is expressed with a parameter f—the available fraction of pore structure contributing to the flow. The data were used to study the flow of acid through carbonate rocks and correlate the pore classes to the acid response. More than 30 acid-coreflood experiments were conducted at 150°F and a hydrochloric acid concentration of 15 wt% on 1.5 × 6-in. core samples at different injection rates on each carbonate rock type. The objective of these sets of experiments is to determine the acid pore volume to breakthrough for each carbonate pore class. The findings of this study help us to connect the results from different characterization methods to the acid flow through the porous media of carbonate rocks. It was also found that the response of the acid depends on the carbonate pore classes. Application to the design of matrix acid treatments in carbonate rocks is discussed.

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.

The influence of osteopathic correction on the rate of various rhythms of the body

2019 ◽  
pp. 64-71 ◽  
Author(s):  
A. E. Chernikova ◽  
Yu. P. Potekhina
Keyword(s):  
Heart Rate ◽  
Respiratory Rate ◽  
Age Groups ◽  
Biomechanical Properties ◽  
Dispersion Analysis ◽  
The Body ◽  
Body Tissues ◽  
Age Related ◽  
Significant Difference ◽  
Before And After

Introduction. An osteopathic examination determines the rate, the amplitude and the strength of the main rhythms (cardiac, respiratory and cranial). However, there are relatively few studies in the available literature dedicated to the influence of osteopathic correction (OC) on the characteristics of these rhythms.Goal of research — to study the influence of OC on the rate characteristics of various rhythms of the human body.Materials and methods. 88 adult osteopathic patients aged from 18 to 81 years were examined, among them 30 men and 58 women. All patients received general osteopathic examination. The rate of the cranial rhythm (RCR), respiratory rate (RR) heart rate (HR), the mobility of the nervous processes (MNP) and the connective tissue mobility (CTM) were assessed before and after the OC session.Results. Since age varied greatly in the examined group, a correlation analysis of age-related changes of the assessed rhythms was carried out. Only the CTM correlated with age (r=–0,28; p<0,05) in a statistically significant way. The rank dispersion analysis of Kruskal–Wallis also showed statistically significant difference in this indicator in different age groups (p=0,043). With the increase of years, the CTM decreases gradually. After the OC, the CTM, increased in a statistically significant way (p<0,0001). The RCR varied from 5 to 12 cycles/min in the examined group, which corresponded to the norm. After the OC, the RCR has increased in a statistically significant way (p<0,0001), the MNP has also increased (p<0,0001). The initial heart rate in the subjects varied from 56 to 94 beats/min, and in 15 % it exceeded the norm. After the OC the heart rate corresponded to the norm in all patients. The heart rate and the respiratory rate significantly decreased after the OC (р<0,0001).Conclusion. The described biorhythm changes after the OC session may be indicative of the improvement of the nervous regulation, of the normalization of the autonomic balance, of the improvement of the biomechanical properties of body tissues and of the increase of their mobility. The assessed parameters can be measured quickly without any additional equipment and can be used in order to study the results of the OC.

Melatih Kepemimpinan Perangkat Desa Kebonharjo Kulonprogo: Membangun Sikap Anti Korupsi

2018 ◽  
Vol 1 ◽  
pp. 107
Author(s):  
Adi Heryadi ◽  
Evianawati Evianawati
Keyword(s):  
Transformational Leadership ◽  
Data Collection ◽  
Paired Samples ◽  
Significant Difference ◽  
Before And After ◽  
Post Test ◽  
Sample Test ◽  
Corruption Perception ◽  
Measuring Tool

This study aims to prove whether transformational leadership training is effective for building anti-corruption attitudes of villages in Kebonharjo village, subdistrict Samigaluh Kulonprogo. This research is an experimental research with one group pre and posttest design.Subject design is 17 people from village of 21 candidates registered. Measuring tool used in this research is the scale of anti-corruption perception made by the researcher referring to the 9 anti-corruption values with the value of reliability coefficient of 0.871. The module used as an intervention made by the researcher refers to the transformational leadership dimension (Bass, 1990). The data collected is analyzed by statistical analysis of different test Paired Sample Test. Initial data collection results obtained sign value of 0.770 which means> 0.05 or no significant difference between anti-corruption perception score between before and after training. After a period of less than 1 (one) month then conducted again the measurement of follow-up of the study subjects in the measurement again using the scale of anti-corruption perception. The results of the second data collection were analysed with Paired Samples Test and obtained the value of 0.623 sign meaning p> 0.05 or no significant difference between post test data with follow-up data so that the hypothesis of this study was rejected.

SUBLINGUAL VITAMIN D3 DRUG THERAPY IN VITAMIN D DEFICIENCY PATIENTS AT PRAVARA RURAL HOSPITAL

2019 ◽  
pp. 18-20
Author(s):  
Sanjeeva Kumar Goud T ◽  
Rahul Kunkulol
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Vitamin D3 ◽  
Serum Vitamin ◽  
Cross Sectional ◽  
Serum Vitamin D ◽  
Significant Difference ◽  
Before And After

The present study was aimed to study the effect of Sublingual Vitamin D3 on Serum Vitamin D level in Vitamin D deficiency patients. This was a cross-sectional and interventional study. All the Vitamin D deficiency patients of age 18-60years and either gender, willing to participate in the study were included. Patients who had greater than 20 ng/ml were excluded from the study. The total number of participants in our study was 200, out of these 111 males and 89 females, the mean age in our study was 51.07 ± 7.39Yrs. All volunteers were given sublingual vitamin D3 (60,000IU) in six doses every fifteen days of follow up for 3 months. The subject’s serum 25(OH)D levels were estimated before and after the treatment of sublingual vitamin D3. There was a statistically significant difference in serum vitamin D3 level before 16.61±6.71 ng/ml and after 35.80±7.80 ng/ml after treatment with Sublingual Vitamin D3. Six doses of 60,000IU of Vitamin D3 sublingual route having improved the role of serum 25(OH)D levels in the treatment of Vitamin D3 deficiency patients.Keywords: Vitamin D3; Sublingual route

STUDY CLINICAL FEATURE AND RESULT OF TREATMENT PHACOMORPHIC GLAUCOMA

2015 ◽  
pp. 71-75
Author(s):  
Van Nam Phan ◽  
Ba Ken Tran
Keyword(s):  
Visual Acuity ◽  
Intraocular Pressure ◽  
Statistical Significance ◽  
Corneal Edema ◽  
Clinical Feature ◽  
Anterior Chamber Angle ◽  
Male Population ◽  
Significant Difference ◽  
Operative Complications ◽  
Before And After

Purpose: Study clinical feature of phacomorphic glaucoma. To evaluate the result of treatment phacomorphic glaucoma. Method: The retrospective, interventional study on 36 cases with phacomorphic glaucoma who underwent treated at Hue Central Hospital from 6/2010 to 6/2011. Standard of research: visual, IOP, before and after surgery, accompanying lesions and post-operative complications. The surgery is considered successful when postoperative IOP less than 21 mmHg. Results: Age 50-59 presented 30.5 percent, ≥ 60 presented 91.7 percent. There was a slight female preponderance (66.7%) compared to the male population (33.3%) which implies a statistically marginally significant difference. However there was no statistical significance difference when compared by the two subgroups. Patient in country presented 61,1% and city presented 38,9%. The duration between the onset of pain and surgery from 0 to < 5 days (77.8%), from 6 to 10 (16.7%) and >10 days presented 5.5%. The preoperative intraocular pressure 35 to 45mmHg (47.2%), 46-55 (30.6%), 56-65 (13.9%) and more than 65 presented 8.3%. The visual acuity preoperation less than 1metre count finger (94.5%), less than 3 metre count finger presented 5.5%. Close anterior chamber angle presented 80.6% and shallow was presented 19.4%. Corneal edema presented 100%, iritis presented 94.4%, dilated pupil larger 5mm presented 83.3%, Synchynea iris and cataract presented 72.2%. ECCE, implantation IOL combined trabeculectomy presented 11.1%, Phaco, implantation IOL combined trabeculectomy presented 69,5%, ECCE implantation IOL presented 5.6%, Phaco, implantation IOL presented 13.8%. Postoperative visual acuity from 1/10 to 5/10 presented 72.2%, no case have VA larger than 5/10. Postoperative 3 months VA 1/10 to 5/10 presented 72.2%, larger VA 5/10 presented 8.3%. Postoperative 3 months intraocular pressure ≤ 21mmHg presented 91.7%, 22 to 24mmHg presented 8.3%, no case have IOP ≥25mmHg. Postoperative edema presented 58.3%, iritis presented 58.3%. Key words: phacomorphic Glaucoma

PERBEDAAN FINANCIAL PERFORMANCE PASCA SECONDARY OFFERINGS

Wahana ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 41-49
Author(s):  
Djaja Perdana ◽  
Herbowo Herbowo
Keyword(s):  
Financial Performance ◽  
Stock Exchange ◽  
Hypothesis Test ◽  
Poor Performance ◽  
Rank Test ◽  
Growth Ratio ◽  
Significant Difference ◽  
Before And After ◽  
Signed Rank Test ◽  
Asset Turnover

This study aims to examine the differences in corporate financial performance before and after secondary offerings. The financial performance is proxied by WCR, DER, Solvency, ROA, ROE, Asset Turnover (ATO) and Growth ratio which representing the value of liquidity, financing, activity, performance and growth of the firm. The study involved 67 samples of the companies listed on the Indonesia Stock Exchange conducting secondary offerings during 2008-2013 period and selected through purposive random sampling method and using Financial Statement data from 2005-2016 period. Hypothesis test is performed using Wilcoxon Signed Rank test. The results of this study indicate that there is no significant difference in the ratio of Solvency, ROA and ROE between before and after secondary offerings, but there are significant differences in the ratio of WCR, DER, Asset Turnover and Growth. WCR ratio after secondary offerings increased, while DER ratio after secondary offerings decreased, the condition of both ratios showed better performance. While the indication of poor performance seen in decreasing asset turnover ratio and growth ratio.Keywords : agency theory, financial performance, secondary offerings

ANALISIS KINERJA KEUANGAN PERUSAHAAN PROPERTI YANG TERDAFTAR DI BEI SEBELUM DAN SESUDAH KEBIJAKAN LOAN TO VALUE

2019 ◽  
Vol 4 (1) ◽  
pp. 79-90
Author(s):  
Ghaniy Ridha Prima ◽  
Hermanto Siregar ◽  
Ferry Syarifuddin
Keyword(s):  
Real Estate ◽  
Financial Performance ◽  
Stock Exchange ◽  
Sample Selection ◽  
Test Analysis ◽  
Asset Return ◽  
Return On Equity ◽  
Analysis Technique ◽  
Significant Difference ◽  
Before And After

The purpose of this study is to provide empirical evidence of the effects of the Loan to Value (LTV) policy on the financial performance of property and real estate companies listed on the Indonesia Stock Exchange (IDX). The sample selection uses a purposive sampling method of 42 property and real estate companies that meet the criteria. The research period is divided into 2 namely before the Loan to Value policy (2013-2014) and after the Loan to Value policy (2016-2017) with the Paired Sample t Test analysis technique. The test results show if the current ratio, Return on Asset, Return on Equity and Debt to Asset have significant differences between before and after the LTV policy is applied. While the fast ratio, cash ratio, net profit margin and Debt to Equity did not show a significant difference. Keywords: Financial Performance, Loan to Value, Property and Real Estate, Profitability Ratio, Liquidity Ratio, Solvability Ratio.

scholarly journals Bioelectric Effect of a Microcurrent Toothbrush on Plaque Removal

2021 ◽  
Vol 18 (16) ◽  
pp. 8255
Author(s):  
Ji-Hyun Lee ◽  
Jin-Hee Ha
Keyword(s):  
Bacterial Flora ◽  
Gingival Index ◽  
Direct Electric Current ◽  
Plaque Removal ◽  
Bioelectric Effect ◽  
Biofilm Removal ◽  
Significant Difference ◽  
The Us ◽  
Before And After ◽  
Previous State

This study evaluated the effectiveness of a microcurrent toothbrush (approved by the US Food and Drug Administration [FDA]), which employs a superimposed alternating and direct electric current, named as a Proxywave® technology, similar to the intensity of the biocurrent, in plaque removal and reducing gingivitis by biofilm removal through the bioelectric effect. This study enrolled 40 volunteers with gingivitis. Dental observations were made every two weeks, before and after the use of each toothbrush. We randomly assigned participants into two groups: one group used the Proxywave® toothbrush (PB) for two weeks followed by the control toothbrush (CB) for two weeks, while the other group used the CB for two weeks followed by the PB. The participants had a two-week washout period. If the toothbrush used earlier has had an effect on the bacterial flora in the oral cavity, this is to remove this effect and return it to its previous state. During each dental visit, we recorded plaque index (PI) and gingival index (GI) scores. The PI and GI scores were significantly lower in both the PB and the CB (p < 0.05). Considering the PI, there was no significant difference between the toothbrushes on all the surfaces. Considering the GI, the PB showed a significant decrease in the interproximal surface, compared to the CB (p < 0.05). The PB showed a significant decrease in the interproximal GI and had a beneficial effect in the interproximal area where the bristles could not reach. No adverse events were observed in the participants during the clinical trial. The microcurrent toothbrush is a device that can be safely used for plaque removal.

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