bluuebunny/crossref_metadata_2025_split huggingface dataset:
Challenging Assumptions About Fracture Stimulation Placement Effectiveness Using Fiber Optic Distributed Sensing Diagnostics: Diversion, Stage Isolation and Overflushing
Authors: Ugueto C. Gustavo A. , Huckabee Paul T. , Molenaar Mathieu M. 
Published: February 2021

Abstract
The connection of the wellbore to the hydrocarbon resource volumes via effective fracture stimulation is a critical factor in unconventional reservoir completions. Various well construction and dynamic placement methods are used to distribute treatment volumes into targeted sections of the wellbore. This paper provides some insights into the effectiveness of hydraulic fracture stimulation process using Fiber Optics (FO): distributed acoustic sensing (DAS) and distributed temperature sensing (DTS). This paper reviews examples from multiple wells where FO has been used to gain a better understanding of three highly debated fracture stimulation distribution topics: Diversion, Stage Isolation and Overflushing. Diversion is increasingly being used as a way to improve the efficiency of hydraulic fracture stimulation distributions. The effectiveness of the diversion techniques has traditionally been judged on the basis of surface pressure response during treatment and ultimately, from production comparisons to reference wells. Unfortunately, getting clear answers from production performance takes significant time. FO allows for monitoring of the diversion process in real-time. Analysis of DAS and DTS responses is used to quantify diversion efficiency in re-directing hydraulic fracture stimulation from dominant perforation clusters to those not being stimulated. Lack of isolation between stages has frequently been observed in wells with diagnostics. There is consensus amongst the completion community that communication between stages is highly undesirable because the energy and materials of the stimulation are partially or totally misdirected from the target interval to other portions of the wellbore. The analysis of DAS and DTS not only can help determine the frequency of occurrence of communication between stages in cemented and uncemented horizontal wells but also can provide insights about the different communication paths. Fiber Optic distributed sensing in conjunction with complementary diagnostics is also being used to investigate if connections are being maintained at the end of the treatment between the newly created fracs and the wellbore. The use of integrated diagnostics allows evaluation of the frequency in which overflushing (over-displacement) occurs in both vertical and horizontal wells and its impact on well inflow performance where production profiling data is available.
Calculation and Implications of Breakdown Pressures in Directional Wellbore Stimulation
Authors: Barree Robert D. , Miskimins Jennifer L. 
Published: February 2021

Abstract
In 1898, Kirsch published equations describing the elastic stresses around a circular hole that are still used today in wellbore pressure breakdown calculations. These equations are standard instruments used in multiple areas of petroleum engineering, however, the original equations were developed strictly for vertical well settings. In today's common directional or horizontal well situations, the equations need adjusted for both deviation from the vertical plane and orientation to the maximum and minimum horizontal in-situ stress anisotropy. This paper provides the mathematical development of these modified breakdown equations, along with examples of the implications in varying strike-slip and pore pressure settings. These examples show conditions where it is not unusual for breakdown pressure gradients to exceed 1.0 psi/ft and describes why certain stages in "porpoising" horizontal wells experience extreme breakdown issues during hydraulic fracturing treatments. The paper also discusses how, in most directional situations, the wellbore will almost always fail initially in a longitudinal direction at the borehole wall, after which the far-field stresses will take over and transverse components can be developed. Tortuosity and near wellbore friction pressure can actually add to forcing the initiation of such longitudinal fractures, which can then have cascading effects on other growth parameters such as cluster-to-cluster and stage-to-stage stress shadowing. Special considerations for highly laminated anisotropic formations, where shear failure of the wellbore may precede or preclude tensile failure, are also introduced. Such failure behaviors have significant implications on near wellbore conductivity requirements and can also greatly impact well production and recovery efforts.
Evolution of Completion Techniques in the Lower Shaunavon Tight Oil Play in Southwestern Saskatchewan
Authors: Schlosser D. J. , Johe M. , Humphreys T. , Lundberg C. , McNichol J. L. 
Published: February 2021

Abstract
The Oil and Gas industry has explored and developed the Lower Shaunavon formation through vertical drilling and completion technology. In 2006, previously uneconomic oil reserves in the Lower Shaunavon were unlocked through horizontal drilling and completions technologies. This success is similar to the developments seen in many other formations within the Williston Basin and Western Canadian Sedimentary Basin including Crescent Point Energy's Viewfield Bakken play in southeast Saskatchewan.
In the Lower Shaunavon play, the horizontal multistage completion era began in 2006, with horizontal divisions of four to six completion stages per well that utilized ball-drop sleeves and open-hole packers. By 2010, the stage count capabilities of ball-drop systems had increased and liners with nine to 16 stages per well were being run.
With an acquisition in 2009, Crescent Point Energy began operating in the Lower Shaunavon area. The acquisition was part of the company's strategy to acquire large oil-in-place resource plays. Recognizing the importance that technology brings to these plays, Crescent Point Energy has continuously developed and implemented new technology. In 2009, realizing the success of coiled tubing fractured cemented liners in the southeast Saskatchewan Viewfield Bakken play, Crescent Point Energy trialed their first cemented liners in the Lower Shaunavon formation.
At the same time, technology progressed with advancements in completion strategies that were focused on fracture fluids, fracture stages, tool development, pump rates, hydraulic horsepower, environmental impact, water management, and production.
In 2013, another step change in technology saw the implementation of coiled tubing activated fracture sleeves in cemented liner completions. Based on field trials and well results in Q4 2013, Crescent Point Energy committed to a full cemented liner program in the Lower Shaunavon.
This paper presents the evolution of Crescent Point Energy's Lower Shaunavon resource play of southwest Saskatchewan. The benefits of current completion techniques are: reductions in water use, increased production, competitive well costs, and retained wellbore functionality for potential re-fracture and waterflooding programs.
Unconventional Technology: The Difference Between Successful Application and Unsuccessful Application (North America and Overseas)
Authors: Casero A. , Rylance M. 
Published: February 2021

Abstract
The past two decades have seen the development and expansion of an approach to wellbore completions that has resulted in unlocking significant reserves from previously disregarded resource, and has been responsible for the North American shale gas ‘revolution’ or ‘evolution’ (depending upon how you see it). However, this approach has faced significant complications to appropriate, successful and economic deployment, when attempts have been made to export this process overseas.
This ground-breaking completion approach was achieved as a direct result of the combination of two well-known and widely applied industry technologies, from distinct disciplines: namely horizontal lateral drilling and propped hydraulic fracture stimulation. This simple combination is referred to by a number of different designations which are used to describe the process, but it is most commonly referred to simply as multi-stage horizontal well hydraulic fracturing.
The North American success story has been primarily accomplished through the application of two distinct variants of this technique, split by fundamental approach to the stage sequencing: namely the Plug & Perf approach and the Open Hole Multi-Stage completion system (typically ball-activated fracture ports). The Open Hole Multi-Stage completion system has typically been applied selectively, with a bias towards clastic formations, whereas Plug & Perf has been more widely applied and almost exclusively dominates the shale completion environment.
This paper will describe the engineering aspects of the multi-stage horizontal well hydraulic fracturing process, as well as those particular North America conditions and deliberate compromises that have been made, in order to encourage this approach to become established and develop further. Such analysis will include a holistic approach to the global market conditions, in order to better understand the local and regional factors that have played such a fundamental role in North American success, many of which have been erroneously overlooked elsewhere. This paper will investigate a number of these key issues and factors, particularly related to completion and reservoir interaction that should be considered carefully when choosing to export such techniques to new areas of application outside of North America. This will include an understanding of the key data that should be acquired, from the early exploration and subsequent appraisal wells, so that appropriate decisions can be made efficiently.
Quantitative and Visual Analysis of Proppant Transport in Rough Fractures and Aperture Stability
Authors: Raimbay A. , Babadagli T. , Kuru E. , Develi K. 
Published: February 2021

Abstract
The consensus reached in the literature is that the roughness of fractures plays a crucial role on proppant transport affecting the aperture sustainability of hydraulic fractures. In this paper, an experimental scheme to visually and quantitatively investigate the hydraulic characteristics of rough fractures in the presence of proppants was presented. Rock samples of different kinds (i.e., granite, marble, and limestone) were fractured under the Brazilian test and molded to manufacture 20x20 cm transparent replicas. Propping agents were injected in a similar fashion and were introduced into the well with fracking fluid at a constant rate. Two types of fracture models were used: (1) perfectly mating (joint) and (2) sheared fractures in polymeric solutions. During the experiments, the inlet pressure was continuously monitored to quantify the permeability changes due to proppant distribution caused by the roughness of fracture surfaces. Meanwhile, corresponding images were collected to trace the transport of proppants and their behavior was correlated to the measured permeability change. For a better visualization of proppants, the injected fluid was dyed with a fluorescent material.
In both joint and shear type fractures, existing closure areas controlled the proppant movement and permeability change significantly. The fracture roughness controlled by the lithological properties of the rocks was a critical factor affecting the permeability and proppant transport. After quantifying the roughness characteristics through the variogram fractal dimension, relationship between fracture permeability in the presence of proppant and rock types were presented. Also provided was a semi-quantitative analysis of the stability (or settlement) of proppants during injection with respect to the roughness type (and lithology). The quantitative and visual data collected for a wide range of rock types with original roughness characteristics are expected to be useful in fracking design and selection of proper proppants for different reservoirs.
A New Technical Standard Procedure to Measure Stimulation and Gravel-pack Fluid Leak-off under Dynamic Conditions
Authors: Asadi Mahmoud , Ainley Brain , Archacki David , Aubry Eric , Brannon Harold , Ghalambor Ali , Parker Mark , Watson Russell 
Published: February 2021

Abstract
Historically, leak-off analyses of stimulation fluids have been performed using in-house laboratory procedures. The lack of industry standard procedures to perform leak-off and wall building coefficient analyses of stimulation fluids has introduced inconsistency in both results and reporting for many years. A technical standard adopted in 2006 by both API and ISO for static conditions has provided the oil and gas industry with the first standardized procedure to measure and report leak-off1. However, the more complex testing under dynamic conditions was not addressed. As a result, a group of industry experts have compiled their years of experiences in developing a new technical standard to measure the leak-off characteristics of stimulation and gravel-pack fluids under dynamic flow conditions.
Stimulation and gravel-pack fluids are defined, for the purpose of this technical standard, as fluids used to enhance production from oil and gas wells by fracturing and fluids used to place filtration media to control formation sand production from oil and gas wells. Leak-off is the amount of fluid lost to porous media during these operations. The leak-off procedure was developed through the colaberation of several industry companies by evaluating numerous in-house laboratory techniques and conducting round robin testing to ensure that any modifications to these procedures were reliable and repeatable. The new standard provides a step-by-step procedure that includes fluid preparation, experimental equipment design, testing procedure and data analyses for fluids exhibiting viscosity controlled leak-off or wall building characteristics. Example calculations are reviewed within this paper.
Behavioural Evidence and Chemical Identification of a Female Sex Pheromone in Anagrus Atomus (Hymenoptera: Mymaridae)
Authors: Zanolli Penelope , Annoscia Desiderato , Zanni Virginia , Nazzi Francesco , Pavan Francesco 
Published: February 2021

Abstract
Anagrus atomus (L.) is an egg parasitoid used for the biological control of Empoasca vitis (Goethe) in vineyards. Sex pheromones play a crucial role in mate finding process of several parasitoid species and could be used for monitoring under field conditions. We carried out lab and field studies aiming at assessing the existence and identity of a possible A. atomus sex pheromone. We found that males were significantly attracted by virgin female independently from female age. Males were not attracted from individuals of the same sex but they were attracted by crude extract of an unmated female and its polar fraction. Eugenol (4-allyl-2-methoxyphenol) was identified as the attractive substance and proved to be attractive not only in the olfactometer but also in another laboratory bioassay and under field conditions. Attraction of males, but not females, confirms that this is not an aggregation pheromone. This is the first sex-pheromone component identified in Mymaridae but more compounds could be involved in the mating behaviour of A. atomus. The utility of a sex pheromone in A. atomus is discussed in the context of fitness returns.
Biometric and Genetic Stability Assessment of In Vitro Rooted Populus alba L. Micro-Shoots
Authors: Ahmed Mohamed Fathy , Ahmed Eman Zakaria , Hussien Eman Tawfik 
Published: February 2021

Abstract
Populus alba is a deciduous large woody tree. The plant was introduced to shooting, then rooting multiplication on MS media. This work's design depends on two factors (media power and sucrose concentrations) with different concentrations resulted in 12 treatments. There were nine responses measured in the new individuals. Some morphological parameters had a significant difference, such as shoot length, leaf and root numbers. Where in the physiological measurements, all the parameters measured had significant differences. RAPD-PCR molecular marker was applied to assess the variation in the new individuals' genetic stability from treatments with the two factors. Four RAPD primers gave reproducible bands and resulted in a total polymorphism percentage of 38.33%. The new individuals resulted from the tissue culture technique were identical to the mother plant and each other. However, in this work, the use of different media power and sucrose concentrations resulted in different values in morphological, physiological responses, and P. alba's molecular variation.
Application of electrochemical plasma on iron electrodes for treating 2,4-Dichlorophenoxyacetic acid (2,4-D) and 2,4,5-Trichlorophenoxyacetic acid (2,4,5-T) in water environment
Authors: Tran Cong Van , Nguyen Hung Duc , Tran Dung Thi Ngoc , Nguyen Hoang Van 
Published: February 2021

Abstract
The herbicide compounds contain aromatic ring and chlorine atom such as 2,4-dichlorophenoxylacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic (2,4,5-T) cause serious environmental pollution. However, it is very difficult to decompose by chemical, physical and biological methods. The high voltage direct current electrochemical method can be control to form plasma on metallic electrodes. Thus, it creates active species like as H 2 , O 2 , H 2 O 2 and free radicals such as: H•, O•, OH•. Especially, OH• free radicals that has a high oxidation potential, so it is possible to oxidize benzene oring compounds more effective. The iron electrode is used in the studing to combine the dissolve process of the iron anode electrode with aims is to create Fe 2+ ions and electrochemical fenton reaction. Besides, the flocculation process by Fe(OH) 2 also happen. The plasma will appear with a voltage of 5 kV on the iron electrode in a solution of 30 mg/L 2,4-D or 2,4,5 T. After a period time of the reaction, the aromatic oring compounds contaning the chlorine was treated, the electric conductivity of the solution increases due to the amount of Cl - ions releasing in the solution. The degradable products of the 2,4-D and 2,4,5-T were analyzed qualitatively by the gas chromatograph mass spectrometer GC-MS 6890-5975 Agilent system. The results described that the straight chain carboxylic acids were formed in the solution. These compounds are easy to oxidize thoroughly under appropriate conditions in solution by OH• free radicals . Moreover, the 2,4-D and 2,4,5-T were also analyzed quantitatively by a calibration curve from GC-MS 6890-5975 Agilent system or high performance liquid chromatograph HPLC 1100 Agilent system. The treatmental process can be controlled to achieve optimum performance by technological factors such as input voltage, distance between anode and cathode electrodes, initial concentration of 2,4-D and 2,4,5-T as well as flowing air through solution. The analysis results showed that the degradation efficiency of 2.4-D and 2,4,5-T reached at 99.98%; 99.83%, respectively.
One-pot, multi-component synthesis of novel 2-amino-[1,2,4]triazolo[1,5-a] pyrimidine-6-carboxamide derivatives as antiproliferative agents&nbsp;
Authors: Huo Xian-Sen , Ma Yu-Feng , Chen Zhi-Ru , Yuan Li-Li , Zheng Xiao-Lan , Li Xiong-Li , Liang Feng-Ting , You Wen-Wei , Zhao Peiliang 
Published: February 2021

Abstract
A novel series of 2-amino-[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxamide derivatives has been achieved successfully via an efficient one-pot three-component Biginelli-like heterocyclization reaction between different benzaldehydes, 1H-1,2,4-triazole-3,5-diamine, and N-substituted acetoacetamides in the presence of p-toluenesulfonic acid as a catalyst. Moreover, the effects of different conditions on the reaction were well investigated. In addition, cancer cell growth inhibition activity for these target compounds was also explored, and analogue 5l demonstrated the most potent cytotoxic activity against different cancer cells. These finds indicat that 2-amino-[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxamide core could be well worth further optimization as a potential scaffold for development of anticancer agents.
Human Papillomavirus and Chlamydia trachomatis in oral and genital mucosa of women with normal and abnormal cervical cytology
Authors: Mosmann Jessica Paola , Zayas Sofia , Kiguen Ana Ximena , Venezuela Raul Fernando , Rosato Otilio , Cuffini Cecilia Gabriela 
Published: February 2021

Abstract
Background. STI such as HPV and C.trachomatis are important to public health, because of the high risk of asymptomatic genital or oral infections could lead to complications and coinfections may be an important cofactor for the oncogenic transformation.Objective. Evaluate the prevalence of oral and genital HPV and C.trachomatis infection in women with normal and abnormal cervical cytology.Study design. The cross-sectional study included 200 oral and cervical swabs from 50 women with normal and 50 with abnormal cervical cytology. HPV and C.trachomatis infections were detected using PCR with specific primers. Results. HPV DNA was detected in 27% of women with normal and abnormal cytology. Out of 27 we detected HPV DNA in 18% of genital samples and 14% of oral samples. HPV genotypes detected were genotype 6 of low-risk and 16, 31, 52, 58 and 16-31 coinfection of high-risk. C.trachomatis DNA was detected in 49% of patients, out of 49 we detected C.trachomatis in 35% of genital samples and 31% of oral samples. There is statistically significant (p<0.05) between cytology and HPV and C.trachomatis infection but there is no statistically significant between cytology and the other characteristics.Conclusions. The morphological similarity between oropharyngeal and genital epithelia would allowed us to infer that the infection in one of this mucosa could occur in the other. Therefore, is important C.trachomatis detection and specific treatment in asymptomatic women because it is known that may increase the risk of HPV persistence and coinfection induces a pro-inflammatory environment that may promote the carcinogenesis. This study highlight the importance of identified possible cofactors for oncogenesis.