Reservoir Characterization and Flow Simulation for CO 2-EOR in the Tensleep Formation Using Discrete Fracture Networks, Teapot Dome, Wyoming

The Tensleep oil reservoir at Teapot Dome, Wyoming, USA, is a naturally fractured tight sandstone reservoir that has been considered for carbon-dioxide enhanced oil recovery (CO2-EOR) and sequestration. CO2-EOR analysis requires a thorough understanding of the Tensleep fracture network. Wireline image logs from the field suggest that the reservoir fracture network is dominated by early formed structural hinge oblique fractures with interconnectivity enhanced by hinge parallel and hinge perpendicular fracture sets. Available post stack 3D seismic data are used to generate a seismic fracture intensity attribute for the reservoir fracture network. The resulting seismic fracture intensity is qualitatively correlated to the field production history. Wells located on hinge-oblique discontinuities are more productive than other wells in the field. We use Oda\u27s method to upscale the fracture permeabilities in the discrete fracture network for use in a dual porosity fluid flow simulator. We analytically show that Oda\u27s method is sensitive to the grid orientation relative to fracture set strike. Results show that the calculated permeability tensors have maximum geometric mean for the non-zero permeability components (kxx,kyy,kzz,kxy) when the dominant fracture set cuts diagonally through the grid cell at 45° relative to the grid cell principal directions (i,j). The geometric mean of the permeability tensor components falls to a minimum when the dominant fracture set is parallel to either grid wall (i or j principal directions). The latter case has off-diagonal permeability terms close to zero. We oriented the Tensleep reservoir grid to N72°W to minimize the off-diagonal permeability terms. The seismic fracture intensity attribute is then used to generate a realization of the reservoir fracture network. Subsequently, fracture properties are upscaled to the reservoir grid scale for a fully compositional flow simulation. We implemented a PVT analysis using CO2 swelling test results to build an 8 component equation of the state. A fully compositional flow simulation is conducted to acquire a history match between model production and production history. The history matching process reveals that high fracture permeabilities enhance water conning around the producers and decreases the oil production. Moreover, increasing apertures in the model DFN will result in higher oil production from the field. Thus, aperture and vertical permeabilities are adjusted for the model DFN to approximate the production history. We analyzed two CO2-EOR cases with different injection patterns. One has the injectors parallel to the main fracture set and the second one has injectors perpendicular to the main fracture set. Results show that the former model has higher oil recovery with later CO2 breakthrough than the second model. The dominant fracture set (N76°W) affects the CO2-EOR sweep efficiency in the Tensleep reservoir. We show that CO2 breakthrough is inevitable in both cases. The fault transmissibility multipliers are also assumed; they are uncertain parameters that could influence CO2-EOR. The model with completely impermeable faults yields a lower CO2-EOR sweep efficiency compared to the case for which all faults are fully permeable

Fracturing Fluid Cleanup by Controlled Release of Enzymes from Polyelectrolyte Complex Nanoparticles

Guar-based polymer gels are used in the oil and gas industry to viscosify fluids used in hydraulic fracturing of production wells, in order to reduce leak-off of fluids and pressure, and improve the transport of proppants. After fracturing, the gel and associated filter cake must be degraded to very low viscosities using breakers to recover the hydraulic conductivity of the well. Enzymes are widely used to achieve this but injecting high concentrations of enzyme may result in premature degradation, or failure to gel; denaturation of enzymes at alkaline pH and high temperature conditions can also limit their applicability. In this study, application of polyelectrolyte nanoparticles for entrapping, carrying, releasing and protecting enzymes for fracturing fluids was examined. The objective of this research is to develop nano-sized carriers capable of carrying the enzymes to the filter cake, delaying the release of enzyme and protecting the enzyme against pH and temperature conditions inhospitable to native enzyme. Polyethylenimine-dextran sulfate (PEI-DS) polyelectrolyte complexes (PECs) were used to entrap two enzymes commonly used in the oil industry in order to obtain delayed release and to protect the enzyme from conditions inhospitable to native enzyme. Stability and reproducibility of PEC nanoparticles was assured over time. An activity measurement method was used to measure the entrapment efficiency of enzyme using PEC nanoparticles. This method was confirmed using a concentration measurement method (SDS-PAGE). Entrapment efficiencies of pectinase and a commercial high-temperature enzyme mixture in polyelectrolyte complex nanoparticles were maximized. Degradation, as revealed by reduction in viscoelastic moduli of borate-crosslinked hydroxypropyl guar (HPG) gel by commercial enzyme loaded in polyelectrolyte nanoparticles, was delayed, compared to equivalent systems where the enzyme mixture was not entrapped. This indicates that PEC nanoparticles delay the activity of enzymes by entrapping them. It was also observed that control PEC nanoparticles decreased both viscoelastic moduli, but with a slower rate compared to the PEC nanoparticles loaded with enzyme. Preparation shear and applied shear showed no significant effect on activity of enzyme-loaded PEC nanoparticles mixed with HPG solutions. However, fast addition of chemicals during the preparations showed smaller particle size compared to the drop-wise method. PEC nanoparticles (PECNPs) also protected both enzymes from denaturation at elevated temperature and pH. Following preparation, enzyme-loaded PEC nanoparticles were mixed with borate crosslinked HPG and the mixture was injected through a shear loop. Pectinase-loaded nanoparticles mixed with gelled HPG showed no sensitivity to shear applied along the shear loop at 25 °C. However, EL2X-loaded PEC nanoparticles showed sensitivity to shear applied along the shear loop at 40 °C. Filter cake was formed and degraded in a fluid loss cell for borate crosslinked HPG solutions mixed with either enzymes or enzyme-loaded PEC nanoparticles. Cleanup slopes of filter cake degraded using enzyme-loaded PEC nanoparticles and systems with enzymes mixed with HPG gel were significantly higher than for the filter cake formed with HPG gel mixed with no enzyme. In a different application, enzyme-loaded PEC nanoparticles showed significantly slower reduction in viscosity of HPG solution over time compared to the HPG systems mixed with enzyme. Increasing the viscosity of low concentration HPG, used as slick-water, decreases the proppant settling velocity. This is of specific interest in fracturing fluids used for unconventional reservoirs

Sensitivity analysis of Monte Carlo model of a gantry-mounted passively scattered proton system

PURPOSE: This study aimed to present guidance on the correlation between treatment nozzle and proton source parameters, and dose distribution of a passive double scattering compact proton therapy unit, known as Mevion S250. METHODS: All 24 beam options were modeled using the MCNPX MC code. The calculated physical dose for pristine peak, profiles, and spread out Bragg peak (SOBP) were benchmarked with the measured data. Track-averaged LET (LET RESULTS: For the physical dose distribution, the MCNPX MC model matched measurements data for all the options to within 2 mm and 2% criterion. The Mevion S250 was found to have a LET CONCLUSIONS: This study revealed the importance of considering detailed beam parameters, and identifying those that resulted in large effects on the physical dose distribution and LETs for a compact proton therapy machine

The relationship between quality of life and demographic variables in hemodialysis patients

Introduction: Quality of life is an important criterion in evaluation of medical treatment and status of health and well-being, contributing to the prediction of mortality rate in hospitals. QOL may be affected by diseases and their related complications. This study aims to investigate the relationship between the quality of life (QOL) of hemodialysis patients and demographic variables. Materials and Methods: In this descriptive analytic study, SF36 questionnaire was used to examine the QOL of 60 hemodialysis patients in Kerman. Results: The mean score of the QOL in hemodialysis patients was 49.83 ± 17.56. The maximum of score was related to the physical activity domain (57.09) and minimum score was given to the vitality domain (43.85). The relationship between quality of life and age, job, literacy and marriage was significant. Conclusion: Our results revealed that the QOF in hemodialysis patients was less that in than normal people. It was shown that these patients need to live a happy life. Therefore, appropriate mental support and instruction on compatibility methods can increase their QOF

Testicular Dose and Associated Risk from Common Pelvis Radiation Therapy in Iran

This study aimed to investigate testicular dose (TD) and the associated risk of heritable disease from common pelvis radiotherapy of male patients in Iran. In this work, the relation between TD and changes in beam energy, pelvis size, source to skin distance (SSD) and beam directions (anterior or posterior) were also evaluated. The values of TDs were measured on 67 randomly selected male patients during common pelvis radiotherapy using 1.17 and 1.33 MeV, Theratron Cobalt-60 unit at SSD of 80 cm and 9 MV, Neptun 10 PC and 18 MV, GE Saturne 20 at SSD of 100 cm at Seyed-Al Shohada Hospital, Isfahan, Iran. Results showed that the maximum TD was up to 12% of the tumor dose. Considering the risk factor for radiation-induced heritable disorders of 0.1% per Sv, an excess risk of hereditary disorders of 72 per 10000 births was conservatively calculated. There was a significant difference in the measured TD using different treatment machines and energies (P < 0.001). The TD at 100 cm SSD were much less than that for 80 cm SSD (P <0.001). The Pearson Correlation test showed that, as expected, there was a strong correlation between TD and patient's pelvis size (r = 0.275, P <0.001). Using the student's t-tests, it was found that, there was not a significant difference between TD and beam direction (P = 0.231). Iranian male patients undergoing pelvic radiotherapy have the potential of receiving a TD of more than 1 Gy which might result in temporary azoospermia. The risk for induction of hereditary disorders in future generations should be considered as low but not negligible in comparison with the correspondent nominal risk

Testicular Dose and Associated Risk from Common Pelvis Radiation Therapy in Iran

This study aimed to investigate testicular dose (TD) and the associated risk of heritable disease from common pelvis radiotherapy of male patients in Iran. In this work, the relation between TD and changes in beam energy, pelvis size, source to skin distance (SSD) and beam directions (anterior or posterior) were also evaluated. The values of TDs were measured on 67 randomly selected male patients during common pelvis radiotherapy using 1.17 and 1.33 MeV, Theratron Cobalt-60 unit at SSD of 80 cm and 9 MV, Neptun 10 PC and 18 MV, GE Saturne 20 at SSD of 100 cm at Seyed-Al Shohada Hospital, Isfahan, Iran. Results showed that the maximum TD was up to 12% of the tumor dose. Considering the risk factor for radiation-induced heritable disorders of 0.1% per Sv, an excess risk of hereditary disorders of 72 per 10000 births was conservatively calculated. There was a significant difference in the measured TD using different treatment machines and energies (P < 0.001). The TD at 100 cm SSD were much less than that for 80 cm SSD (P <0.001). The Pearson Correlation test showed that, as expected, there was a strong correlation between TD and patient's pelvis size (r = 0.275, P <0.001). Using the student's t-tests, it was found that, there was not a significant difference between TD and beam direction (P = 0.231). Iranian male patients undergoing pelvic radiotherapy have the potential of receiving a TD of more than 1 Gy which might result in temporary azoospermia. The risk for induction of hereditary disorders in future generations should be considered as low but not negligible in comparison with the correspondent nominal risk

Recognizing and ranking the impediments of private sector investment in sport of Chahar Mahal Bakhtiari province from the view point of managers, experts and accountable sporting party

This study is aimed at ranking the impediments of private sector investment in the sport activities of Chahar – Mahal Bakhtiari province from the view point of managers, experts and accountable sporting party in Chahar Mahal and Bakhtiari. The research population includes all managers related to subject in the sport and youth headquarters of Chahar Mahal and Bakhtiari province. To collect information, self- reported questionnaire was used and its validity coefficient (Alpha Cronbach) was estimated as much as 82%. The research findings were analyzed by Fried man tests, independent t-test, and variance analysis. The research results indicated the relative majority of this research population (about 65 %) believed impediments in sport privation procedure was effective, also between managers view with different positions and different age groups, there isn’t significant difference, but there is significant difference with different education in the field of privation in province sport , and this difference is seen in diploma or bachelor level

The effect of group discussion and telephone counselling on perceived stress of women as caregivers of patient with Alzheimer disease

زمینه و هدف: مراقبت از بیماران مبتلا به دمانس و بالاخص آلزایمر از آسیب پذیرترین و چالش برانگیزترین نوع مراقبت‌هاست که مراقبین ممکن است با آن مواجه شده و باعث تجربه استرس زیاد در آنها می گردد. در این میان فقدان آموزشهای لازم نیز مشکلات آنها را دو چندان نموده است. هدف این مطالعه تعیین تاثیر بحث گروهی و مشاوره تلفنی بر استرس درک شده زنان مراقبت کننده از سالمند مبتلا به آلزایمر بوده است. روش بررسی: در این پژوهش تجربی، 150 زن 18 تا 60 سال که از وابستگان درجه یک سالمند مبتلا به آلزایمر بوده و مراقبت مستقیم از سالمند مبتلا به آلزایمر را به مدت حداقل 6 ماه به عهده داشتند با روش نمونه گیری مستمر مبتنی بر هدف انتخاب شده و آزمودنی ها با روش تصادفی بلوکه شده به تصادف در دو گروه آزمون و کنترل قرار گرفتند. گروه آزمون در یک برنامه مداخله‌ای شامل یک جلسه بحث گروهی، دریافت یک پمفلت آموزشی و دو مشاوره تلفنی شرکت نمودند. 6 هفته پس از مداخله، پس‌آزمون برای هر دو گروه انجام گرفت. ابزار گردآوری اطلاعات، پرسشنامه اطلاعات دموگرافیک و استرس درک شده بود. برای مقایسه متغیرها از آزمون‌های آماری تی زوجی، تی مستقل، کای اسکوئر و آنالیز واریانس یک طرفه استفاده شد. یافته‌ها: نتایج نشان داد که قبل از بحث گروهی و مشاوره تلفنی 7/50 نمونه‌ها در گروه آزمون و 3/57 از نمونه‌ها در گروه کنترل استرس درک شده بالایی داشتند. پس از انجام بحث گروهی و مشاوره تلفنی میانگین استرس درک شده در گروه آزمون از 62/8± 38/28 به 55/5±45/22 تقلیل یافت (001/0 > P). بین استرس درک شده و متغیرهای وضعیت تحصیلات (03/0P=) و وضعیت اقتصادی (01/0 P=) از نظر آماری ارتباط معنی‌دار وجود داشت. نتیجه‌گیری: زنان مراقبت‌کننده از سالمند مبتلا به آلزایمر به عنوان مهم‌ترین مراقبین غیر‌رسمی، سطوح استرس بالایی را تجربه می‌کنند که همین امر سلامت آنها و سالمندان تحت مراقبت ایشان را تحت الشعاع قرار می‌دهد، لذا لزوم مداخله برای این مراقبین به منظور بهبود وضعیت آنها پیشنهاد می‌شود

Identification of Candida Species Associated with Blood Infection by Multiplex PCR and Phenotypic Characteristics

Background and Aim: The correct identification of Candida species is one of the most critical procedures in prognostic and therapeutic significance, allowing an early and appropriate antifungal therapy. This study aimed to evaluate multiplex PCR as a rapid diagnostic method and traditional phenotypic tests in identifying Candida species isolated from candidemia cases. Methods: In this study, 38 Candida spp were isolated from culturing of human blood obtained from patients suspected to candidemia. The isolated species were evaluated by phenotypic and molecular methods including carbohydrate assimilation test, colony colour on CHROMagar Candida, chlamydoconidia production, germ tube formation and Multiplex PCR. Multiplex PCR was performed using specific primers of 4 common species. The results of multiplex PCR were compared with those obtained from phenotypic tests. Results: According to multiplex PCR findings, the isolated Candida species were identified as C. albicans, C. parapsilosis, C. glabrata, and C. tropicalis. Phenotypic tests identified that 23 (60.52%), 8 (21.05%), 5 (13.15%), and 2 (5.26%) isolates belonged to C. albicans, C. parapsilosis, C. glabrata, and C. tropicalis, respectively, that were confirmed by multiplex PCR results. C. albicans and C. parapsilosis had the same carbohydrate assimilation pattern but were differentiated based on their colonies color on CHROMagar and the ability of C. albicans to produce chlamydoconidia and germ tube. C. glabrata (100%) and C. tropicalis (100%) assimilated trehalose and cellobiose, respectively. Conclusion: Our study showed that the both phenotypic and molecular techniques provide appropriate information for identification of Candida spp from blood samples. *Corresponding Author: Masoomeh Shams-Ghahfarokhi; Email: [email protected]; ORCID ID: 0000-0003-2562-965X Please cite this article as:  Fallah B, Shams-Ghahfarokhi M, Salehi M. Identification of Candida Species Associated with Blood Infection by Multiplex PCR and Phenotypic Characteristics.  Arch Med Lab Sci. 2023;9:1-9 (e1). https://doi.org/10.22037/amls.v9.3840