bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of General Practitioners in Suicide Prevention-What you Said and Did then Actually Saved my Life
Authors: Styrvold Marte , Grimholt Tine K.
Published: May 2021

Background: General Practitioners (GP) have an important role in the prevention of suicidal behavior. The purpose of this study was to explore their views and experiences of identifying and assessing suicidal ideation. Methods: Ten GPs were recruited through convenience sampling, based on accessibility, interest and willingness to participate. In-depth interviews were carried out and results transcribed ver-batim. Aspects of experiences with suicidal patients emerged through the thematic analyses process. Results: The GPs described the varied clinical picture when patients presented in their office. How they identified depressive symptoms apart from originally somatic complaints, formed a trusting relationship and addressed suicide ideation. They described customized interventions as well as obstacles and factors that facilitated communication: time, own personal traits, pa-tient’s disclosure and organizational barriers. Conclusions: The levels of the suicidal process among patients in general practice vary greatly. GPs adjust their appraisals to profundity understand and intervene in order to prevent a crisis to escalate into subsequent suicidal behavior.
The Incidence of Community-Acquired Pneumonia in the Elderly Population of the United States of America: A Systematic Review and Meta-Analysis
Authors: Sadjadi Ryan
Published: May 2021

Current epidemiological data reports that adults aged 65 years and older comprise the most vulnerable age group with the highest proportion of CAP-attributable hospitalizations. Pneumococcal vaccine efficacy (VE) has been shown to decrease over time, contributing to increasing incidence rates of CAP. A holistic evaluation of age, sex, seasonality, and VE are is conducted in this systematic review and meta-analysis of 12 prospective and retrospective cohort studies. The findings suggest that incidence and age are positively associated and that incidence in females is more often reported to be higher in females than in males. In studies that observed seasonality of CAP, high seasons and low seasons were reported to be in winter and summer months, respectively. Lastly, studies that reviewed the effect of vaccination on incidence consistently found decreased observance of CAP in elderly adults following reception of PCV13 or PPSV23. However, one study suggested that such vaccinations may have decreased effectiveness in elderly populations and that research examining potential explanations for this require further investigation. Furthermore, distinct diagnostic and case ascertainment standards, descriptive measures, and methods of prevention and treatment of CAP used across the US are outlined in this review. Public health guidance such as encouraging the reception of pneumococcal vaccinations and mask-wearing during high seasons of CAP, and communicating the risks of not adhering to the aforementioned preventative measures can facilitate an effort to reduce the incidence of CAP and its associated adverse outcomes in the US elderly population.
New Results in Quantum Thermodynamics
Authors: Koutandos Spiros
Published: May 2021

Classical physics meets the obstacle of describing a point particle because from everyday experience we know that objects occupy a certain volume. We overcome this obstacle by using the equivalence principle for electric energy and describe a curved spacetime of fluid nature. From thereon by using the notion of a point volume the rest of the thermodynamic quantities appear.
Characteristics of susceptibility to antibiotics of Shigella sonnei caused three outbreaks in the North-Western region of Russia in 2018
Authors:   Pasteur Research Institute of Epidemiology and Microbiology, Saint Petersburg, Russian Federation, Makarova M.A. ,   I.I.Mechnikov North-Western State Medical University, Ministry of Health of the Russian Federation, St. Petersburg, Russian Federation, Matveeva Z.N. ,   Pasteur Research Institute of Epidemiology and Microbiology, Saint Petersburg, Russian Federation, Kaftyreva L.A. ,   Pasteur Research Institute of Epidemiology and Microbiology, Saint Petersburg, Russian Federation,   I.I.Mechnikov North-Western State Medical University, Ministry of Health of the Russian Federation, St. Petersburg, Russian Federation, Mikhailova E.A. ,   Center for Hygiene and Epidemiology in the Leningrad Region, Saint Petersburg, Russian Federation, Kuzakova M.A. ,   Center for Hygiene and Epidemiology in the Leningrad Region, Saint Petersburg, Russian Federation, Laushkina O.I. ,   Center for Hygiene and Epidemiology in the Leningrad Region, Saint Petersburg, Russian Federation, Kuzmina T.M. ,   Center for Hygiene and Epidemiology in the Leningrad Region, Saint Petersburg, Russian Federation, Samsonova O.E. ,   Center for Hygiene and Epidemiology in the Leningrad Region in the Luga District, Luga, Russian Federation, Alekseenko L.I. ,   Center for Hygiene and Epidemiology in the Leningrad Region in the Gatchinsky District, Gatchinа, Russian Federation, Postnova I.A. ,   Center for Hygiene and Epidemiology in the Leningrad Region in the Gatchinsky District, Gatchinа, Russian Federation, Fedorova L.M. ,   Center for Hygiene and Epidemiology in the Leningrad Region in the Gatchinsky District, Gatchinа, Russian Federation
Published: May 2021

The work is devoted to the study of susceptibility to antibiotics of 42 strains of Shigella sonnei isolated from patients involved in three food-borne outbreaks that occurred in the North-Western region of Russia in 2018. All strains belonged to biovar IIg, showed resistance to tetracycline and trimethoprim/sulfamethoxazole. The strains were susceptibility to nitrofurantoin, ciprofloxacin, but were resistant to nalidixic acid, were susceptibility to aminoglycosides (gentamycin, tobramycin, and amikacin), and resistance to streptomycin. All strains were susceptibility to azithromycin (MIC 8 mg/L). One outbreak was caused by S. sonnei additionally resistant to chloramphenicol and cephalosporins, producing ESBLs. Key word: Shigella sonnei biovar IIg, antibiotic resistance, outbreaks, ESBL
Molecular-genetic methods for studying microbial biofilms
Authors:   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Russian Federation, Detusheva E.V. , Slukin P.V. ,   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Russian Federation, Fursova N.K. ,   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Russian Federation
Published: May 2021

The review article contains information on the clinical significance of microbial biofilms and the main modern molecular genetic methods used to study microbial biofilms: comparative study of genome, transcriptome and proteome of planktonic cells and biofilms; genetic control of biofilm extracellular matrix production; analysis of the contribution of individual genes and gene clusters to the formation of the biofilm phenotype; identification of microorganism species in polymicrobial biofilms. Key words: microbial biofilms, molecular genetic methods, genome, transcriptome, proteome, microbial species identification
Development of candidate vaccines against infection caused by shiga-toxin producing Escherichia coli. Part 1
Authors:   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Moscow Region, Russian Federation, Svetoch E.A. , Dyatlov I.A. ,   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Moscow Region, Russian Federation, Kartsev N.N. ,   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Moscow Region, Russian Federation, Eruslanov B.V. ,   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Moscow Region, Russian Federation, Kanashenko M.E. ,   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Moscow Region, Russian Federation, Fursova N.K. ,   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Moscow Region, Russian Federation
Published: May 2021

Shiga-toxin producing Escherichia coli (STEC) strains cause serious and life-threatening diseases, hemorrhagic colitis (HC) and associated hemolytic uremic syndrome (HUS). Antibacterial etiotropic therapy against these diseases are not recommended. There are no vaccines against human HA and HUS. The review provides materials on the design of various types of candidate vaccines against STEC strains and assessment of their immunogenic and protective properties in experiments on laboratory and farm animals. The prospects for the use of inactivated corpuscular and live (vector) vaccines, lipopolysaccharide vaccines, DNA vaccines and nanovaccines, vaccines based on bacterial cell membranes (ghost), as well as vaccines created by reverse vaccinology methods in practice are considered. Key words: STEC, hemorrhagic colitis, immunodominant antigens, shiga toxins, EspA, EspB, Tir, intimine, IgG, sIgA
Prototype of a multiplex PCR test system for differentiation of anthrax microbe from close-kinded bacilles
Authors:   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation, Bakhteeva I.V. , Kaptelova V.V. ,   Central Research Institute of Epidemiology, Moscow, Russian Federation, Titareva G.M. ,   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation, Kravchenko T.B. ,   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation, Goncharova Yu.O. ,   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation, Khlopova K.V. ,   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation, Timofeev V.S. ,   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation
Published: May 2021

Bacillus anthracis is a Gram-positive spore-forming bacterium capable of causing anthrax, a particularly dangerous disease of warm-blooded animals. The indication of B. anthracis is often complicated by the hight genetic similarity between B. anthracis and some closely related Bacillus species. In present work, we propose a set of oligonucleotide primers and Taq-man probes intended for simultaneous detection of three hight-specific for B. anthracis chromosomal loci in multiplex PCR. The proposed set of oligonucleotides makes it possible to identify B. anthracis with a high degree of certainty without regard to the plasmid profile of the strain and to differentiate B. anthracis from closely related microorganisms, even those with atypical genetic properties. Key words: Bacillus anthracis, PCR, species diagnostics
Expression of beta-lactamase genes in multidrug-resistant bacteria
Authors:   M.V.Lomonosov Moscow State University, Moscow, Russian Federation, Filippova A.A. ,   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Russian Federation, Rubtsova M.Yu. ,   M.V.Lomonosov Moscow State University, Moscow, Russian Federation, Ulyashova M.M. ,   M.V.Lomonosov Moscow State University, Moscow, Russian Federation, Fursova N.K. ,   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Russian Federation
Published: May 2021

Antimicrobial resistance is a global public health problem. In recent years, increasing of multi-drug resistant bacteria has been noted, which are resistant to different antimicrobial groups simultaneously, including beta-lactams. The main mechanism of anti-beta-lactam resistance in gram-negative bacteria is synthesis of various beta-lactamases that hydrolyze the antibiotics. The review is devoted to the analysis of data on the expression of beta-lactamase genes by multi-drug resistant bacteria and molecular genetic methods for their determination in RNA transcripts. Key words: antibiotic resistance, transcriptome, molecular genetic methods, beta-lactamases
The danger of anthrax soil foci during excavation
Authors:   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation, Dyatlov I.A. , Marinin L.I. ,   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation, Shishkova N.A. ,   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation, Mokrievich A.N. ,   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation, Tyurin E.A. ,   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation
Published: May 2021

The anthrax pathogen trapped in the soil forms spores that retain their viability and virulence for a long time. Analysis of the available data shows that the anthrax microbe can retain virulence in soil up to 1300 years. All this time, the soil remains dangerous for people during earthworks on the territory of anthrax soil foci. Soil foci of anthrax include anthrax burial grounds (burials), places of death, sites, spontaneous burials of animals killed by anthrax and other environmental objects containing the causative agent of anthrax. Under favorable conditions, the pathogen, being in the soil, can go through a full multiple biological cycle of its development. As a result, we observed a change in properties the pathogen isolated from soil samples taken from a 70 years age cattle burial ground. Key words: anthrax, burial ground, risk of infection, PCR
Obtaining and determination of the concentration in the culture fluid of phaecin – peptide bacteriocin Enterococcus faecium
Authors:   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow region, Russian Federation, Borzenkov V.M. , Levchuk V.P. ,   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow region, Russian Federation, Surovtsev V.I. ,   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow region, Russian Federation
Published: May 2021

Phaecin, a peptide bacteriocin with a molecular mass of ~5 kDa, was obtained and purified to an electrophoretically pure state with a yield of ~70% of the total activity in the culture fluid. The method of time-of-flight mass spectrometry (MALDI) showed that bacteriocin consists of two components A and B with similar molecular mass. In previously published works, the yield of purified bacteriocins, usually did not exceed 4–5% of the total activity in the culture fluid. The authors believe that the increase in yield is due to the fact that not only the similarity of bacteriocins with high molecular mass proteins was taken into account, but also differences associated with low molecular mass, the ability to hydrophobic interaction at slightly alkaline pH values and resistance to denaturation. Using the Scopes method, it was possible to determine the concentration of phaecin in the final stage of purification and in the culture fluid in absolute units (mg/l). The methods of the purification with high yield described in this work are probably applicable to other bacteriocins due to the proximity of their physicochemical properties. Key words: Enterococcus faecium, Listeria monocytogenes, bacteriocin, phaecin, culture liquid, adsorption chromatography, Scopes equation
Adhesins of pathogenic Yersiniae
Authors:   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Moscow Region, Russian Federation, Trunyakova A.S. , Vagaiskaya A.S. ,   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Moscow Region, Russian Federation, Dentovskaya S.V. ,   State Research Center for Applied Microbiology and Biotechnology, Rospotrebnadzor, Obolensk, Moscow Region, Russian Federation
Published: May 2021

The genus Yersinia includes 26 species, three of which are pathogenic to humans: Yersinia enterocolitica and Yersinia pseudotuberculosis, which cause yersiniosis and pseudotuberculosis, infections with mainly gastrointestinal symptoms, and Yersinia pestis, the causative agent of plague. Pathogenic Yersiniae express proteins that mediate attachment to host cells, facilitate invasion or evasion of the host’s immune system, allowing pathogens to proliferate and spread within the host. In addition, these species, and Y. pestis serve as models for studying the evolution of pathogenicity factors in bacteria. The virulence of pathogenic Yersinia strains depends on the presence of molecules with adhesive properties in their outer membrane. Some of them, such as the YadA and Inv proteins of enteropathogenic species, as well as the pH 6 antigen of Y. pestis, have been adequately studied. However, the whole-genome sequencing has revealed many other adhesins present in these microorganisms, which functions are just under investigation. This review briefly summarizes current knowledge about Yersinia adhesins, their functions and their putative role in the infectious process. Particular attention is paid to one of the families of β-cylindrical proteins of the outer membrane of Yersinia, associated with the pathogenicity of bacteria, namely, autotransporter adhesins. Key words: adhesion, pathogenesis, pathogenic factor, Yersinia
Rapid methods in the study of food
Authors:   St.-Petersburg Pasteur Institute, Saint Petersburg, Russian Federation, Kraeva L.A. , Smirnova E.V. ,   Eastern Branch of the Center for Hygiene and Epidemiology in Saint Petersburg, Saint Petersburg, Russian Federation, Derevyanchenko I.A. ,   Eastern Branch of the Center for Hygiene and Epidemiology in Saint Petersburg, Saint Petersburg, Russian Federation
Published: May 2021

The incidence of acute intestinal infections among the population of the Russian Federation continues to cause significant social and multibillion- ruble economic damage. At the same time, the etiological factor of diseases can be established only in one third of cases. Since the main route of transmission of acute intestinal infections is the food pathway, and the factors of transmission are food, it is quite justified that there is an increasing need to develop and use fast and effective methods of microbiological diagnostics for food control. Currently, they are presented in several versions: fully automated systems and devices for microbiological diagnostics of food products; manual tests for microbiological diagnostics of food products; devices and manual tests to speed up some stages of microbiological diagnostics. All the presented developments are based on various methods. Fully automated systems and devices for microbiological diagnostics of food products have a very high productivity (up to several hundred analyses at a time), which is very convenient and in demand in large laboratories. With the high price of devices, the economic efficiency of their use in such laboratories is also high. For laboratories with a small flow of samples for research, manual tests or kits are more preferable, as well as nutrient media for microbiological diagnostics of food products or to speed up its some stages. High quality and speed of food analysis are essential for reducing morbidity due to consumption of poor quality in microbiological terms of food and economic loss from diseases. Key words: food products, еxpress methods, laboratory diagnostics
Ensuring biological safety requirements when carrying out biotechnological processes with microorganisms of I–IV pathogenicity groups
Authors:   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation, Tyurin E.A. , Chekan L.V. ,   State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation
Published: May 2021

The article deals with the issue of ensuring and monitoring biological safety requirements in units performing work with microorganisms of I–IV pathogenicity/hazard groups using biotechnological equipment. It is shown that the specificity of the production of biotechnological products requires strict observance of the requirements and provisions of sanitary and epidemiological regulatory and methodological documents establishing requirements, including safety, at all stages of the technological process. Key words: biosafety, microorganisms, biotechnology, technogenic situations
Endoscopic Treatment of Calcific Tendinitis of the Gluteus Maximus
Authors: Su Charles A. , Ina Jason G. , Raji Yazdan , Strony John , Philippon Marc J. , Salata Michael J.
Published: May 2021

Case:

Calcific tendinitis of the gluteus maximus is a rare condition with poorly described operative treatment options. We present a 51-year-old man with chronic left posterolateral hip pain because of gluteus maximus calcific tendinitis that was refractory to conservative treatment. Endoscopy was pursued given the severity and chronicity of his symptoms. The patient remains asymptomatic without recurrence.

Conclusion:

This is the first description of endoscopic management of calcific tendinitis of the gluteus maximus. This is a minimally invasive, efficacious option for management of this pathology.
Successful Hydraulic Isolation Assessment Saves Rig Utilization Time and Unnecessary Cement Remedial Squeeze Operation - Case Study, Kuwait
Authors: Elyas Mohamed , Freile Daniel Agustin , Pawlowski Maciej , Tagarieva Larisa , Elaila Shamseldin Zakrya , Sergeev Evgeny
Published: May 2021

While drilling an 8 1/2-incli section of a north Kuwait producer well, severe mud losses were encountered. Hence, it was decided to design a light weight cement for the 7-inch liner section to avoid further losses while pumping the slurry. The main objective was to achieve a hydraulic isolation to avoid any heavy remedial intervention and potential dump flood behind the liner from the high-pressure Lower Burgan (LB) to Shuaiba.

Full suite of well integrity logs were ran to properly assess whether enough hydraulic isolation was in place. To evaluate the bonding quality of the cement, two independent measurements were carried out across the 7-inch liner with the ultrasonic and sonic bond logs. A subsequent temperature survey was recorded to determine any geothermal anomaly, which could be indicative of fluid movement behind the casing. Finally, oxygen activation stations were conducted based on the cement log and temperature surveys to assure no water movement behind the casing.

The ultrasonic and sonic bond log measurements showed an acceptable bond quality generally. However, the top part of Shuaiba formation up to LB exhibited relatively lower bond quality. The subsequent temperature and oxygen activation logs indicated that the zonal hydraulic isolation was achieved by showing no water movement behind the 7-inch liner. The two complementary surveys helped to take the proper forward decision for this well to go ahead with the planned perforation without cement remedial squeeze, since enough hydraulic isolation was proved to be in place behind the 7-inch liner. Additionally, this saved the rig utilization time and cost by avoiding unnecessary remedial operation. This is usually a heavy-duty operation, which takes time and induces holes in the casing that should be avoided, knowing this type of operation only provides a very marginal gain in terms of isolation. Furthermore, the well is currently producing at 0% water cut after completion.

The proper cement design using light weight cement and optimized casing-landing plan were crucial to achieve good cement placement against formation. The use of the right well integrity approach helped to confirm that effective hydraulic isolation was achieved. Hence all these efforts resulted in the saved rig utilization time and cost by avoiding unnecessary squeeze intervention.
Assessing the Impact of Drilling Tools on Wellbore Quality Using Ultrasonic Borehole Imaging
Authors: Penman Andrew , Wong Siong Ming , Cooper Paul , Fares Wael , Parker Tim , Goraya Yassar , Alfelasi Ali Saeed , Khemissa Hocine , Al Dhafari Bader Mohamed , Khaled Islam , Ashraf Muhammad , Al-Mutwali Omar , Okuzawa Takeru
Published: May 2021

A detailed visualization of borehole size and shape, both while drilling and prior to running casing, completions, or wireline logging equipment, is an essential requirement to minimize non-productive time (NPT) associated with poor borehole quality or wellbore stability issues. The required visualization is made possible using logging-while-drilling (LWD) high-resolution ultrasonic imaging technology, suitable for both water-based mud (WBM) and oil-based mud (OBM) systems.

This paper provides borehole size and shape assessment from field deployments of a 4¾-in. ultrasonic calliper and imaging tool, illustrating the impact on borehole quality of various bottom-hole assembly (BHA) designs, including positive displacement mud motors (PDMs) and rotary steerable systems (RSS). The visualization of borehole quality enables features such as borehole spiralling and enlargement to be assessed and used as input into optimizing completions planning and formation-evaluation programs. In addition, the combination of high-resolution travel-time and reflection-amplitude images enables artefacts induced by drilling equipment, including RSS, to be identified and understood.

High-resolution travel-time and reflection-amplitude images and 3D borehole profile plots are presented from multiple wells, showing how different drilling systems and logging parameters, including drillstring rotation and logging speeds, impact borehole quality. The relationship between the angular bend in the PDM and the impact it has on borehole spiralling is discussed.

The LWD logs presented illustrate the factors that influence borehole quality and the methodology used to ensure that high-resolution images are available in both vertical and high-inclination wellbores, leading to the ability to reduce the NPT associated with wellbore stability issues. The observation and assessment of drilling artefacts and irregular borehole size and shape act as inputs into optimizing completion and logging programs, evaluating the optimal placement of packers and other completion equipment, and the design of the drill bit and BHA.

The ability to collect high-resolution travel-time and reflection-amplitude ultrasonic images in both WBM and OBM, in wellbores ranging from 5¾ to 7¼-in., leads to significant improvements in the understanding of wellbore quality. Borehole size and shape can now be visualized in real time in either water or oil-based drilling fluids at a resolution capable of identifying all significant drilling-induced geometric artifacts. This allows the adjustment of drilling parameters to minimize NPT associated with common drilling hazards, the optimization of completion programs and wireline logging programs.
Effect of Drilling Fluid Temperature on Formation Fracture Pressure Gradient
Authors: Samak Ahmed Mostafa , Elsayed Abdelalim Hashem
Published: May 2021

During drilling oil, gas, or geothermal wells, the temperature difference between the formation and the drilling fluid will cause a temperature change around the borehole, which will influence the wellbore stresses. This effect on the stresses tends to cause wellbore instability in high temperature formations, which may lead to some problems such as formation break down, loss of circulation, and untrue kick.

In this research, a numerical model is presented to simulate downhole temperature changes during circulation then simulate its effect on fracture pressure gradient based on thermo-poro-elasticity theory. This paper also describes an incident occurred during drilling a well in Gulf of Suez and the observations made during this incident. It also gives an analysis of these observations which led to a reasonable explanation of the cause of this incident.

This paper shows that the fracture pressure decreases as the temperature of wellbore decreases, and vice versa. The research results could help in determining the suitable drilling fluid density in high-temperature wells. It also could help in understanding loss and gain phenomena in HT wells which may happen due to thermal effect.

The thermal effect should be taken into consideration while preparing wellbore stability studies and choosing mud weight of deep wells, HPHT wells, deep water wells, or wells with depleted zones at high depths because cooling effect reduces the wellbore stresses and effective FG. Understanding and controlling cooling effect could help in controlling the reduction in effective FG and so avoid lost circulation and additional unnecessary casing points.
Pore Pressure Prediction in Sandstone Using a Lateral Transfer Approach
Authors: Consuegra Jose Francisco
Published: May 2021

Accurate pore pressure prediction is required to determine reliable static mud weights and circulating pressures, necessary to mitigate the risk of influx, blowouts and borehole instability. To accurately estimate the pore pressure, the over-pressure mechanism has to be identified with respect to the geological environment. One of the most widely used methods for pore pressure prediction is based on Normal Compaction Trend Analysis, where the difference between a ‘normal trend' and log value of a porosity indicator log such as sonic or resistivity is used to estimate the pore pressure. This method is biased towards shales, which typically exhibit a strong relationship between porosity and depth. Overpressure in non-shale formations has to be estimated using a different method to avoid errors while predicting the pore pressure.

In this study, a different method for pore pressure prediction has been performed by using the lateral transfer approach. Many offset wells were used to predict the pore pressure. Lateral transfer in the sand body was identified as the mechanism for overpressure. This form of overpressure cannot be identified by well logs, which makes the pore pressure prediction more complex. Building a 2D geomechanical model, using seismic data as an input and following an analysis methodology that considered three type of formation fluids - gas, oil and water in the sand body, all pore pressure gradients related to lateral transfer for the respective fluids were evaluated. This methodology was applied to a conventional reservoir in a field in Colombia and was helpful to select the appropriate mud weight and circulating pressure to mitigate drilling risks associated to this mechanism of overpressure. Seismic data was critical to identifying this type of overpressure mechanism and was one of the main inputs for building the geomechanical earth model.

This methodology enables drilling engineers and geoscientists to confidently predict, assess and mitigate the risks posed by overpressure in non-shale formations where lateral transfer is the driving mechanism of overpressure. This will ensure a robust well plan and minimize drilling/well control hazards associated with this mode of overpressure.
Chemically-Induced Pressure Pulse: Fracturing Competent Reservoirs
Authors: Al-Nakhli Ayman R. , Tariq Zeeshan , Mahmoud Mohamed , Abdulraheem Abdulazeez
Published: May 2021

Commercial volumes of hydrocarbon production from tight unconventional reservoirs need massive hydraulic fracturing operations. Tight unconventional formations are typically located inside deep and over-pressured formations where the rock fracture pressure with slickwater becomes so high because of huge in situ stresses. Therefore, several lost potentials and failures were recorded because of high pumping pressure requirements and reservoir tightness. In this study, thermochemical fluids are introduced as a replacement for slickwater. These thermochemical fluids are capable of reducing the rock fracture pressure by generating micro-cracks and tiny fractures along with the main hydraulic fractures. Thermochemical upon reaction can generate heat and pressure simultaneously. In this study, several hydraulic fracturing experiments in the laboratory on different synthetic cement samples blocks were carried out. Cement blocks were made up of several combinations of cement and sand ratios to simulate real rock scenarios. Results showed that fracturing with thermochemical fluids can reduce the breakdown pressure of the cement blocks by 30%, while applied pressure was reduced up to 88%, when using thermochemical fluid, compared to slickwater.

In basins with excessive tectonic stresses, the current invention can become an enabler to fracture and stimulate well stages which otherwise left untreated. A new methodology is developed to lower the breakdown pressure of such reservoirs, and enable fracturing.

Keywords: Unconventional formation; breakdown pressure; thermochemicals; micro fractures.
Anti-Collision Study for the Wells from New Artificial Islands Across Gigantic Mature Oil Field in Middle East Area
Authors: Fujinaga Ryota , Alzaabi Mohamed Abdulrahman , Toki Takahiro , Toma Motohiro , Andrews Kerron Kerman
Published: May 2021

107 new wells are planned to be drilled primarily from two new Artificial Islands during the period of one project from 2023 to 2029. The number of existing wells in the oil field has reached 1,068 Mother bores, 2,178 wellbores @16,453,666ft total well length as of December 2019. Trajectories, especially from existing Artificial Islands, are getting more complex so as to avoid collision issues, and it is becoming increasingly difficult to drill accordingly. It is of great importance to assure that it is possible to drill the planned wells without serious collision issues before the execution of the project.

Trajectories for planned wells were drafted one-by-one utilizing "DecisionSpace Well Planning" based on the predetermined slot allocation with the planned drilling pad design. Geological models are incorporated into DecisionSpace Well Planning. Therefore, formation tops were taken into account in order to make the trajectories more realistic. After that, trajectories were exported to "COMPASS" and anti-collision scan was performed on well-by-well basis. Anti-collision scan was performed among planned wells as well as actual wells. In case that one well has such serious collision issues that the well cannot/should not be planned based on company policy as a result of Anti-collision scan, trajectory or Landing Point (LP)/Total Depth (TD) location were adjusted. Then, Anti-collision scan was carried out again. If it was confirmed that there is no serious Anti-collision issues, trajectory was considered as final.

It has been found that all the wells during the period from 2023 to 2029 can be drilled without serious collision issues by slightly adjusting LP/TD while satisfying several practical drilling requirements.

Through the Anti-collision study, following recommendations for the avoidance of collision were obtained:Multi Station Analysis (MSA)+In-Field Referencing (IFR)+SAG correction should be applied in all the Jack up operations as well as Island operationsApplication of real-time MSA should be considered on a case-by-case basisMWD survey for the past wells should be corrected with IFR+MSA to reduce EOU sizeRe-Gyro jobs for low-quality survey wells should be enhanced around the project's development areaKick off point (KOP) should be deeper in the center of the drilling pad and shallower in the edge of the drilling pad
Successful Implementation Of Geomechanics In Deep Water Setting: A Case Study From KG Offshore, India
Authors: Bhimpalli Sarah , Shinde Ashok , Rao Bayye L , Perumalla Satya , Panchakarla Anjana , Chakrabarti Prajit , Saha Sankhajit
Published: May 2021

Geomechanics has an important role in assessing formation integrity during well construction and completion. It also has its effect when the wellbore is in production mode. Geomechanical study evaluate the impact of the present day in-situ stress and related mechanical processes on reservoir management. The study field ‘K' belongs to Plio-Pleistocene sequence of deep-water environment with hydrocarbon prospects. This belongs to Post-Rift tectonic stage of evolution with hydrocarbon occurring in structurally controlled traps. As a part of exploration activity, four offset oil wells were drilled earlier which were considered for the geomechanical model construction. Field (K) development plan comprising of six hydrocarbon producers and four water injectors was prepared.

Considering the thick water column (300m-650m) in this deep water area of offshore and young unconsolidated sedimentary sequence in the sub-surface, expected pore-pressures can be high whereas the fracture gradient can be low. As a result, the safe drilling mud window can be narrow. Upon successful drilling of a well in such challenging environment without NPT (Non-Productive time), completing the well with best possible technologies suitable to the reservoir's mechanical behavior is utmost important for maximizing the production and minimizing the risk. To mitigate these problems in developing this field, an integrated reservoir geomechanics approach is adopted to optimize the drilling plan and reservoir completion parameters for the planned well. This paper covers the geomechanical study of four wells namely W, X, Y & Z drilled in the field ‘K'. The principal constituents of the geomechanical model are in-situ stresses, pore pressure and the rock mechanical properties.

Geomechanical model for the field ‘K' was built utilizing the available data by integrating drilling, geology, petrophysics and reservoir data. Methodology adopted in this paper also highlights how a reliable geomechanical model can be built for a field, which is having data constraints. Constraining of stress magnitudes, orientation and anisotropy added value for efficient well planning in deep waters reservoirs. Calculating well specific reservoir rock mechanical properties, it made possible to identify the most optimal completion strategy. Approach contributed knowledge of geomechanical parameters based on the data of four offset wells has been used for successfully drilling and completion of all the subsequent wells without major challenges. Overall, geomechanical modeling has played a major role in drillability and deliverability of the reservoir. Integrated approach adopted in this paper can be used for well planning and drilling of future wells in East Coast of India with similar geological set up.
No Tag to Hard Tag - Case History About Effective Cement Plug Placement Techniques
Authors: Prabhu Pratik , Abad Juan Miguel
Published: May 2021

The success or failure of cement plugs are known to alter the timeline of an oil well; not to mention the additional costs and NPT associated with the rig activities. Unsuccessful cement plug costs oil companies considerable amount of capital both in extra rig time and service company expenses. Suggested procedures for placing cement plugs have been presented in number of papers - comprising of slurry design, spacer recommendations, laboratory testing and placement techniques. However, it is very easy to deviate from these standard practices due to over confidence, negligence or both.

In Mexico, it was observed that the success rate of placing cement plugs dropped due to operational and engineering design shortcomings. Towards the end of 2018 there were several unsuccessful cement plug jobs that questioned the regular plug procedures. Careful analysis of the past mistakes led to the conclusion that an effective approach to alter the local plug placement practices was necessary.

An updated cement plug placement software was used in conjunction with strict standard practices that turned around the trend and enabled consistent successful placement of cement plugs in the first attempt itself. A detailed yet simple approach towards cement plugs was adopted in both engineering design and operational execution. Additionally the updated plug placement software ensured accurate prediction of the cement plug top; that was confirmed by the actual tag of the plug.

This paper will enlist the major analysis carried out on the unsuccessful plug jobs and highlight the different techniques that were adopted in the subsequent jobs to ensure successful placement and tagging of the cement plug. The paper will also focus on how the plug placement software's new additional features have made a significant contribution to this success story.
Machine Learning as New Approach for Dogleg Severity Prediction
Authors: Fakhrylgayanov Ayrat , Soh Azrin Aik Jun , Osman Ahmed
Published: May 2021

Conventionally offset well studies are performed by individuals where the results depend very much on visual perception, interpretation, and experience. In the specific cases for predicting the dogleg severity (DLS) output, the offset well study will take time proportionate to the volume of input, with the results being averaged out and contain high tolerances. In specific projects, these tolerances are larger than accepted, encouraging the service provider to utilize conservative solutions such as rotary steerable system (RSS) with high DLS capability in order to reduce the residual risks. These solutions can often be more costly in terms of maintenance and may add unnecessary tortuosity to the hole leading to issues during execution. This paper explores the concept of using machine learning (ML) to perform offset well study and defining key parameters affecting the DLS output. This concept consolidates the vast volumes of data that have been acquired while drilling and defines the relationship of each parameter to the final output of DLS.

The first analysis reviewed five offset wells and found a multivariable correlation between applied drilling parameters to the DLS output. This correlation was then applied in 6 boreholes (3 multilateral wells), observing consistent DLS output increase by 50% using the same technology and optimal drilling parameters. The second analysis uses the same process to determine a planning DLS limit in a curve section over different formations.

This paper demonstrates the potential of ML in offset well studies and beyond to predict behavior and define the relationship in a big data environment.
Successful Off Bottom Cementation of a Highly Deviated 4 ½ in Production Liner in UAE
Authors: Hamidzada Ahmedagha , Alaleeli Ahmed Rashed , Hassan Azza El , Tarsh Fatima Bin , Abdelkarim Islam
Published: May 2021

Cementing a highly deviated production liner is associated with cement placement challenge that can compromise zonal isolation. A major operator in UAE, was facing a challenge to cement 4 ½ in slim production liner set at + 5000 ft off-bottom. The corresponding 6 in. section was drilled with a relatively high mud weight in the range of 12 to 13 PPG. One of the main challenge was the risk of solids settling on the low side of the wellbore, making mud displacement difficult to achieve while cementing. Additionally, cementing off-bottom without an ECP in a highly deviated wellbore with multiple exposed production zones, further increased cement placement complexity. A holistic engineering approach was integrated to ensure successful zonal isolation. Wellbore parameters and fluid properties were critically evaluated.

To overcome off-bottom cementing and prevent slurry fallback risks, a weighted high viscosity pill with high yield point was placed as a temporary basement to support the cement column and isolate the reservoir during 4 ½ in liner job. After placement of the pill, the wellbore was observed for flow checks to ensure stable downhole conditions prior to displacing the drilling fluid across the liner interval to brine within the same density.

A centralization program was implemented to achieve more than 70% stand-off which required a minimum centralization pattern of two rigid centralizers per joint which helped minimize the presence of mud channels on the narrow side.

Effective mud removal was ensured through implementation of a spacer train in front of the cement. The first spacer was pumped with same mud density to reduce ECD followed by another advanced low invasion loss circulation spacer to mitigate losses as well as provide a sustained downhole rheology. A resilient, expandable and gas tight cement slurry, was selected to target long-term zonal isolation. Multiple hydraulic simulations were performed to optimize ECDs and ensure safe margins during placement

A CFD (computational fluid dynamics) model was utilized to simulate hydraulics, expected mud removal and fluids inter-mixing especially during liner rotation. In addition, the model simulated high-calculated torques based on flow restrictions through liner hanger assembly. Lack of mechanical liner movement was compensated by additional pre-job circulation to fully condition the wellbore.

The job was executed with no losses during cementing, and spacer and cement returns were received on the surface during reverse out. Utilizing the best engineering approach, practices, and techniques from this job is implemented in the future wells as the production of the well is directly affected by the cement quality. Post job cement integrity evaluation via a cement bond log confirmed excellent bonding of cement to the liner and reservoirs across the entire open-hole interval.
Solving Dual Casing Zonal Isolation with the Deployment of a New Well Abandonment System. Rock-to-Rock Barriers Sets for Major Operators
Authors: Khan Muhammad Zafar , Swadi Shantanu , Caminari Richard T , Burdett Timothy A , Stronach Graham
Published: May 2021

The Plug and Abandonment (P&A) requirement stipulates a permanent barrier to be placed for restoring the cap rock during well abandonment. For a single casing, section milling has been successfully implemented and widely used for a number of years. For a dual casing string, this becomes particularly challenging when both casing strings are cemented. Conventional techniques require milling the entire inner casing from the top of cement followed by section milling the outer casing. This could require milling up thousands of feet on of the inner string and is not a cost-efficient solution. The service company has been heavily involved in a number of P&A campaigns, where the requirement was to come up with a solution for dual casing section milling. This paper discusses the design, technology, field runs and best practices developed to overcome this operational and economic challenge and save rig time in P&A operations. The challenge was to design a robust section mill that can drift through the inner casing restriction and expand to a high ratio to mill the outer casing. It was equally critical to manage shock and vibrations during the milling operation, ensure stability and, competitive ROP without incurring tool damage.

To solve the operational and economic challenges, a unique system was developed to reduce the rig time. The system is a combination of the newly engineered high-ratio hydraulic section mill, with a 180% expansion ratio and a precisely oriented hydraulic stabilizer below it. This creates a unique 6-point stabilization system that helps to maintain the dynamic loads and vibrations to a manageable level. The system allows for a dual casing section window in few trips as compared to conventional techniques. In the first run, a window in the inner casing is milled by a section mill. During the second run, the High-Expansion Ratio Section Mill (HRSM) is run through the restriction, and mill the entire casing. A high ratio under reamer can be included in the bottom hole assembly to clean the section and expose the formation prior to the cementing operation. This completes achieving a rock-to-rock barrier in a dual cemented casing application.

The new HRSM system has so far been 100% successful on the five challenging jobs completed in Europe, Asia and the Middle East, resulted in significant rig-time savings along with the added benefits of fewer trips and less swarf at the surface.

Two sizes have been developed and tested for 7"x9-5/8" and 9-5/8"x13-3/8" applications. The success during the early jobs is largely due to the robustness of the mill design, proper pre-job planning, meticulous execution, and implementation of key learnings from in-house and prior field tests.