79,255 research outputs found
Effect of fracture pressures on the selection of depths for casing setting in Slovakia
Purpose. The purpose of the article is to describe the method of casing wells for oil and gas in the Slovak Republic.
Methods. Apparently there is no general method or procedure that gives the optimal location. This article is an attempt to define this optimum casing seat location. The potential benefits will improve safety and economy of the operation. The methods of predicting fracture gradients for deeper wells already exist. In this article, a method of predicting fracture gradients for shallow well has been derived. This method is combined with kick tolerance criteria to obtain a casing depth selection method. Also, the variation in fracture pressures at any depth has been investigated.
Findings. The two major factors determine the depth of the casing shoe, that is, the fracture pressure and the pore pressure. A third factor is the lithology, because it is desirable to place the casing shoe in a competent shale section. Practical implications of this method is applicable in casing designing in deep hole drilling.
Originality. Originality of this method lies in the fact that in this process casing wells is achieved only essential as necessary length-casing with respect to all safety and strength parameters.
Practical implications. This interpretation provides the basis for vital decisions, such as selection of depths for casing setting, the maximum permissible values of mud density, method of drilling and the tightness verification of cement and cementation work. Incorrect estimates can result not only in a increase the cost of the wellbores, but also can cause potentially hazardous situations, such as lost circulation of drilling fluid, problems with managing the boreholes, borehole stability problems and also blowouts.Мета. Метою даної статті є опис методу обсадження нафтових і газових свердловин у Словацькій Республіці.
Методика. Мабуть немає загального методу або процедури, за допомогою яких можна визначати оптимальне місце розташування свердловин. Дана стаття є спробою визначити оптимальне розташування башмака обсадної колони. Потенційні вигоди дозволять підвищити безпеку та економічність експлуатації. Методи прогнозування градієнтів руйнування для більш глибоких свердловин вже існують. У статті описаний метод прогнозування градієнтів руйнування для неглибоких свердловин. Даний метод поєднується з критерієм опору породи руйнуванню, щоб отримати метод вибору глибини встановлення обсадної колони. Крім того, було досліджено зміну тисків руйнування на різних глибинах.
Результати. Два основні чинники визначають глибину встановлення башмака обсадної колони, тобто тиск руйнування і поровий тиск. Третім фактором є літологія, оскільки бажано розмістити башмак обсадної колони у відповідному інтервалі сланцю. Практичне значення полягає у застосуванні цього методу при проектуванні обсадної колони в глибоких свердловинах.
Наукова новизна. Унікальність даного методу полягає в тому, що в процесі обсадження свердловин важливе значення має визначення необхідної довжини обсадної труби з урахуванням всіх параметрів безпеки й міцності.
Практична значимість. Дана інтерпретація є основою для прийняття важливих рішень, таких як вибір глибини встановлення обсадної колони, гранично допустимих значень густини бурового розчину, способів буріння, контролю герметичності цементування та тампонажних робіт. Неправильна оцінка може призвести не тільки до збільшення вартості спорудження свердловини, але й до потенційно небезпечних ситуацій, таких як втрата циркуляції бурового розчину, проблеми з управлінням поглиблення свердловин, проблеми стійкості стовбура свердловини, а також викиди.Цель. Целью данной статьи является описание метода обсадки нефтяных и газовых скважин в Словацкой Республике.
Методика. Пожалуй, нет общего метода или процедуры, с помощью которых можно определять оптимальное месторасположение скважин. Эта статья является попыткой определить оптимальное расположение башмака обсадной колонны. Потенциальные выгоды позволят повысить безопасность и экономичность эксплуатации. Методы прогнозирования градиентов разрушения для более глубоких скважин уже существуют. В данной статье описан метод прогнозирования градиентов разрушения для неглубоких скважин. Этот метод сочетается с критерием сопротивления породы разрушению, чтобы получить метод выбора глубины установки обсадной колонны. Кроме того, было исследовано изменение давления разрушения на разных глубинах.
Результаты. Два основных фактора определяют глубину установки башмака обсадной колонны, то есть давление разрушения и поровое давление. Третьим фактором является литология, поскольку желательно разместить башмак обсадной колонны в соответствующем интервале сланца. Практическое значение состоит в применении этого метода при проектировании обсадной колонны в глубоких скважинах.
Научная новизна. Уникальность данного метода заключается в том, что в процессе обсадки скважин важное значение имеет определение необходимой длины обсадной трубы с учетом всех параметров безопасности и прочности.
Практическая значимость. Данная интерпретация является основой для принятия важных решений, таких как выбор глубины установки обсадной колонны, предельно допустимых значений плотности бурового раствора, способов бурения, контроля герметичности цементирования и тампонажных работ. Неправильная оценка может привести не только к увеличению стоимости строительства скважины, но и к потенциально опасным ситуациям, таким как потеря циркуляции бурового раствора, проблемы с управлением углубления скважин, проблемы устойчивости ствола скважины, а также выбросы.This article and the research results so far have not been and are not subject to the grant of research solutions. Research in this area has not yet been supported financially. Technical paper is the result of the research cooperation between BERG Faculty of Technical University in Košice Slovakia and the Institute of Petroleum Engineering of Ivano-Frankivsk National Technical University of Oil and Gas
Measurement of intangibles in current society: challenges, perspectives and choice
Intangible cultural value has temporal, directional, geospatial, transactional, transference & multiplier effects. Social Earnings Ratio non-financial currency is used to unravel volition in dystopia
New normalized constant modulus algorithms with relaxation
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A new family of blind adaptive equalization algorithms
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Evidence for symmetric chromosomal inversions around the replication origin in bacteria.
BackgroundWhole-genome comparisons can provide great insight into many aspects of biology. Until recently, however, comparisons were mainly possible only between distantly related species. Complete genome sequences are now becoming available from multiple sets of closely related strains or species.ResultsBy comparing the recently completed genome sequences of Vibrio cholerae, Streptococcus pneumoniae and Mycobacterium tuberculosis to those of closely related species - Escherichia coli, Streptococcus pyogenes and Mycobacterium leprae, respectively - we have identified an unusual and previously unobserved feature of bacterial genome structure. Scatterplots of the conserved sequences (both DNA and protein) between each pair of species produce a distinct X-shaped pattern, which we call an X-alignment. The key feature of these alignments is that they have symmetry around the replication origin and terminus; that is, the distance of a particular conserved feature (DNA or protein) from the replication origin (or terminus) is conserved between closely related pairs of species. Statistically significant X-alignments are also found within some genomes, indicating that there is symmetry about the replication origin for paralogous features as well.ConclusionsThe most likely mechanism of generation of X-alignments involves large chromosomal inversions that reverse the genomic sequence symmetrically around the origin of replication. The finding of these X-alignments between many pairs of species suggests that chromosomal inversions around the origin are a common feature of bacterial genome evolution
Terahertz wave transmission in flexible polystyrene-lined hollow metallic waveguides for the 2.5-5 THz band.
A low-loss and low-dispersive optical-fiber-like hybrid HE11 mode is developed within a wide band in metallic hollow waveguides if their inner walls are coated with a thin dielectric layer. We investigate terahertz (THz) transmission losses from 0.5 to 5.5 THz and bending losses at 2.85 THz in a polystyrene-lined silver waveguides with core diameters small enough (1 mm) to minimize the number of undesired modes and to make the waveguide flexible, while keeping the transmission loss of the HE11 mode low. The experimentally measured loss is below 10 dB/m for 2 < ? < 2.85 THz (∼4-4.5 dB/m at 2.85 THz) and it is estimated to be below 3 dB/m for 3 < ? < 5 THz according to the numerical calculations. At ∼1.25 THz, the waveguide shows an absorption peak of ∼75 dB/m related to the transition between the TM11-like mode and the HE11 mode. Numerical modeling reproduces the measured absorption spectrum but underestimates the losses at the absorption peak, suggesting imperfections in the waveguide walls and that the losses can be reduced further. © 2013 Optical Society of America
Accuracy assessment of global and local atrophy measurement techniques with realistic simulated longitudinal data
The main goal of this work was to assess the accuracy of several well-known methods which provide global (BSI and SIENA) or local (Jacobian integration) estimates of longitudinal atrophy in brain structures using Magnetic Resonance images. For that purpose, we have generated realistic simulated images which mimic the patterns of change obtained from a cohort of 19 real controls and 27 probable Alzheimer's disease patients. SIENA and BSI results correlate very well with gold standard data (BSI mean absolute error < 0.29%; SIENA < 0.44%). Jacobian integration was guided by both fluid and FFD-based registration techniques and resulting deformation fields and associated Jacobians were compared, region by region, with gold standard ones. The FFD registration technique provided more satisfactory results than the fluid one. Mean absolute error differences between volume changes given by the FFD-based technique and the gold standard were: sulcal CSF < 2.49%; lateral ventricles < 2.25%; brain < 0.36%; hippocampi < 1.42%
Medication adherence in type 2 diabetes patients: study of patients in Alimosho General Hospital, Igando, Lagos, Nigeria.
Background: Poor adherence is an obstacle in therapeutic control of diabetes. Despite the advances in the treatment of diabetes mellitus over the years, diabetes places an immense burden on the individuals living with the condition, their families and the overall health care system.Objective: Evaluation of the impact of medication adherence on the clinical outcomes of type 2 diabetes patients at Alimosho general hospital, Igando Lagos state.Method: The medication adherence study was both descriptive (retrospective) and prospective. The retrospective study assessed the prevalence of medication non-adherence leading to poor glycemic control. This involved the review of case notes of one-hundred and fifty two randomly selected patients. Prospective study was done by counselling and educating the patients on medication adherence and assessing their medication adherence and the impact of medication adherence on glycemic control.Results: The proportions of females/males with type 2 DM was found to be 69% and 31% respectively. 51.32% of these patients viewed their medications to be unaffordable. 56.6% of the patient population were 61 years and above in age. There was a significant relationship between patient age, gender and adherence to medication. There was however no significant P ≥ 0.05 association between educational level and adherence. Health education and counselling resulted in adherence rate and clinical parameters improvements.Conclusion: Non-adherence is a major factor that could lead to morbidity and mortality in diabetic patients. The overall improvement in adherence rate of 86.8% was observed with a decline in non- adherence rate after interventions.Key words: Diabetes type 2, adherence, glycemic level, health education and counselling
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Analysis of gas chromatography/mass spectrometry data for catalytic lignin depolymerization using positive matrix factorization
Various catalytic technologies are being developed to efficiently convert lignin into renewable chemicals. However, due to its complexity, catalytic lignin depolymerization often generates a wide and complex distribution of product compounds. Gas chromatography/mass spectrometry (GC-MS) is a common analytical technique to profile the compounds that comprise lignin depolymerization products. GC-MS is applied not only to determine the product composition, but also to develop an understanding of the catalytic reaction pathways and of the relationships among catalyst structure, reaction conditions, and the resulting compounds generated. Although a very useful tool, the analysis of lignin depolymerization products with GC-MS is limited by the quality and scope of the available mass spectral libraries and the ability to correlate changes in GC-MS chromatograms to changes in lignin structure, catalyst structure, and other reaction conditions. In this study, the GC-MS data of the depolymerization products generated from organosolv hybrid poplar lignin using a copper-doped porous metal oxide catalyst and a methanol/dimethyl carbonate co-solvent was analyzed by applying a factor analysis technique, positive matrix factorization (PMF). Several different solutions for the PMF model were explored. A 13-factor solution sufficiently explains the chemical changes occurring to lignin depolymerization products as a function of lignin, reaction time, catalyst, and solvent. Overall, seven factors were found to represent aromatic compounds, while one factor was defined by aliphatic compounds
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