Relevant bibliographies by topics / Perforations

Academic literature on the topic 'Perforations'

Author: Grafiati
Published: 4 June 2021
Last updated: 6 September 2023

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Journal articles on the topic "Perforations"

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Onken, Flurina, Moritz Senne, Alfred Königsrainer, and Dörte Wichmann. "Classification und Treatment Algorithm of Small Bowel Perforations Based on a Ten-Year Retrospective Analysis." Journal of Clinical Medicine 11, no. 19 (September 28, 2022): 5748. http://dx.doi.org/10.3390/jcm11195748.

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Background: Small bowel perforations are a rare diagnosis compared with esophageal, gastric, and colonic perforations. However, small bowel perforations can be fatal if left untreated. A classification of small bowel perforations or treatment recommendations do not exist to date. Methods: A retrospective, monocentric, code-related data analysis of patients with small bowel perforations was performed for the period of 2010 to 2019. Results: Over a 10-year period, 267 cases of small bowel perforation in 257 patients (50.2% male and 49.8% female; mean age of 60.28 years) were documented. Perforation’s localization was 5% duodenal, 38% jejunal, 39% ileal, and 18% undocumented. Eight etiologies were differentiated: iatrogenic (41.9%), ischemic (20.6%), malignant (18.9%), inflammatory (8.2%), diverticula-associated (4.5%), traumatic (4.5%), foreign-body-associated (1.9%), and cryptical (1.5%) perforations. Operative treatment combined with antibiotics was the most commonly used therapeutic approach (94.3%). The mortality rate was 14.23%, with highest rate for patients with ischemic perforations. Discussion: An algorithm for diagnostic and therapeutic steps was established. Furthermore, it was found that small bowel perforations are rare events with poor outcomes. Time to diagnosis and grade of underlying disease are the most essential parameters to predict perforation-associated complications.
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Matsuda, Y., T. Kurita, Y. Ueda, S. Ito, and T. Nakashima. "Effect of tympanic membrane perforation on middle-ear sound transmission." Journal of Laryngology & Otology 123, S31 (May 2009): 81–89. http://dx.doi.org/10.1017/s0022215109005155.

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AbstractTympanic membrane perforation causes a sound conduction disturbance, and the size of this conduction disturbance is proportional to the perforation area. However, precise evaluation of perforation size is difficult, and there are few detailed reports addressing this issue. Furthermore, such evaluation becomes more difficult for irregularly shaped perforations. This study conducted a quantitative evaluation of tympanic membrane perforations, using image analysis equipment.A significant correlation was found between the degree of sound conduction disturbance and the perforation area; this correlation was greater at low frequencies following a traumatic perforation. The conductive disturbance associated with chronic otitis media was significantly greater at low frequencies. Circular perforations caused only minor conduction disturbance. Perforations in the anteroinferior quadrant were associated with greater conduction disturbance. Traumatic spindle-shaped perforations and malleolar perforations were associated with greater conduction disturbance.
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Derbyshire, Edmund, Pali Hungin, Claire Nickerson, and Matthew Rutter. "Colonoscopic perforations in the English National Health Service Bowel Cancer Screening Programme." Endoscopy 50, no. 09 (March 28, 2018): 861–70. http://dx.doi.org/10.1055/a-0584-7138.

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Abstract Background Perforation is the most serious adverse event associated with colonoscopy. In this study of data from the English National Health Service Bowel Cancer Screening Programme, we aimed to describe the presentation and management of perforations, and to determine factors associated with poorer outcomes post-perforation. Methods The medical records of patients with a perforation following the national screening colonoscopy were retrospectively examined. All colonoscopies performed from 02/08/2006 to 13/03/2014 were studied. Bowel Cancer Screening Centres across England were contacted and asked to complete a detailed dataset relating to perforation presentation, management, and outcome. Results 263 129 colonoscopies were analyzed, and the rate of perforation was 0.06 %. Complete data were reviewed for 117 perforations: 70.1 % of perforations (82/117) occurred during therapeutic colonoscopies; 54.9 % (62/113) of patients with perforations who were admitted to hospital and in whom data were complete underwent surgery; 26.1 % (30/115) of hospitalized patients left the hospital with a stoma and 19.1 % (22/115) developed post-perforation morbidity. Perforations not detected during colonoscopy were significantly more likely to require surgery (P = 0.03). Diagnostic perforations were significantly more likely to require surgery (P = 0.002) and were associated with higher rates of post-perforation morbidity (P = 0.01). At presentation, the presence of abdominal pain (P = 0.01), a pulse rate > 100 beats per minute (P = 0.049), and a respiratory rate > 20 breaths per minute (P = 0.01) were significantly associated with the patient having surgery. Conclusions This is the largest retrospective observational case series in Europe to describe post-perforation presentation, management, and outcomes. We have confirmed that perforation leads to surgical intervention, stoma formation, and post-perforation morbidity. Perforations not recognized during the colonoscopy were significantly more likely to require surgery. Diagnostic perforations were at greater risk of requiring surgery and developing post-perforation morbidity.
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Grupp, Katharina, Rainer Grotelüschen, Faik Güntac Uzunoglu, Bianca Hofmann, Alexandra König, Daniel Perez, Maximillian Bockhorn, Jakob Robert Izbicki, and Kai Bachmann. "C-Reactive Protein in the Prediction of Localization of Gastrointestinal Perforation." European Surgical Research 60, no. 5-6 (2019): 179–85. http://dx.doi.org/10.1159/000501806.

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Aim: Information regarding the localization of the anatomic site of gastrointestinal (GI) tract perforation is essential for the following surgical procedure. The purpose of this study was to evaluate the significance of C-reactive protein (CRP) and other circulating markers for the prediction of the localization of intra-abdominal hollow organ perforation. Methods: Measurements of serum markers were analyzed in 423 patients with GI tract perforations, who were divided according to the intraoperative diagnosis into colorectal and upper GI tract perforation groups. Results: Levels of CRP were higher in patients with colorectal perforations than in upper GI tract perforations (p < 0.001). Moreover, high levels of CRP were associated with increased mortality of patients with hollow organ perforations (p = 0.009), which was largely driven by the subset of patients with perforations of the upper GI tract (p = 0.001). Conclusion: Increased CRP levels predict worse clinical outcome in patients with intra-abdominal hollow organ perforations and are associated with perforations in the colorectal tract. Thus, CRP might be a useful marker for preoperative risk stratification and prediction of the localization of the perforation site.
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Al-Taha, Wadhah Hussein Abdulrazzaq. "Effect of the Circular Perforations on the Heat Transfer Enhancement by the Forced Convection from the Rectangular Fins." DJES 11, no. 3 (September 1, 2018): 62–70. http://dx.doi.org/10.24237/djes.2018.11310.

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This study aims to investigate the effect of the circular perforation of the rectangular fin on the enhancement of the heat transfer by forced convection. The solid rectangular fin considered as a reference for comparison purpose with the perforated fin. The parameters taken into consideration are thermal properties and geometrical dimensions of the fin and its perforations. The area and heat transfer gain of the perforations fins were considered being the main parameters in this study. The results of this study showed that the heat dissipation was improved when used the perforation fins compared with the equivalent solid fin. The enhancement quantity of the heat dissipation from the fin depends on the thermal conductivity, the perforation dimension, thickness, longitudinal and lateral spacing. Finally, the perforating of the fins enhances the rate of heat dissipation as well as decreases the weight of the fin
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Kouzmanova, Yaneta, and Ivanka V. Dimitrova. "PREVALENCE OF IATROGENIC PERFORATIONS ACCORDING TO THEIR LOCATION AND AFFECTED ROOT SURFACES." International Journal of Advanced Research 10, no. 7 (July 31, 2022): 794–800. http://dx.doi.org/10.21474/ijar01/15099.

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Background: The location of the endodontic perforation has shown a strong correlation with the healing process and successful outcome. The aim of this study was to determine the prevalence of iatrogenic perforations according to their location and affected root surfaces. Materials and methods: Over a period of 7 years, 100 cases of iatrogenic root perforations were recorded from the digital radiographs of each case. The perforations were classified according to the following criteria: (1) perforation location – cervical, furcation, stripping, lateral, and apical (2) affected root surface. The prevalence of different types of perforation was calculated and subjected to statistical analysis. Results: Among all types of perforations, the most common are those located in the furcation area of the molars (46%), followed by lateral root perforation (35.8%). The mesial root surfaces are most often affected by iatrogenic perforations (71.9%), followed by the distal ones (21%). Conclusion: Prior to root canal treatment, it is essential to assess the morphologic conditions in the key areas prone to iatrogenic perforations.
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Geun Eom, Young, and Youn Jib Chung. "Perforated Ray Cells in Korean Caprifoliaceae." IAWA Journal 17, no. 1 (1996): 37–43. http://dx.doi.org/10.1163/22941932-90000622.

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Perforated ray cells are recorded for the first time in species of Lonicera, Sambucus, Viburnum, and Weigela (Caprifoliaceae) that grow in Korea, These ray cells have simple perforations in Lonicera and Sambucus which have vessel elements with simple perforations, and have scalariform perforation s or variant types of scalariform perforations in Viburnum and Weigela which have vessel elements with scalariform perforations. In Korean Caprifoliaceae the perforations of ray cells are similar to the types of perforation plates in the vessel elements of the same wood.
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Najam, Muhammad Atif, Urwa Sarwar, Maqbool Raza, Khalid Azam Khan, Humaira Saleem, Najm u. Saqib Niazi, Muhammad Rashid, and Naeem Riaz. "ENDOSCOPIC CARTILAGE TYMPANOPLASTY. OUR TECHNIQUE AND EXPERIENCE OF 157 CASES." PAFMJ 71, Suppl-3 (December 28, 2021): S440–444. http://dx.doi.org/10.51253/pafmj.v1i1.7935.

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Objective: To assess the graft take rate and hearing gain in trans-canal endoscopic tympanoplasty Study Design: Descriptive study. Place and Duration of Study: Pakistan Naval Ship Hafeez, Islamabad Pakistan, form Dec 2015 to Jun 2018 Methodology: All patients with dry central perforations of >3 months history were included in the study. All Patients with perforations of pars tensa were booked for endoscopic cartilage tympanoplasty. All perforations were divided into four types small, medium, large and subtotal or total based on size of the tympanic membrane perforations. Small perforations involving <25% area of Pars Tensa. Medium perforation are Perforations involving 25-50% of Tympanic membrane. Large perforations include Perforations involving 50-75% of pars tensa. Subtotal or total perforations are defined as perforations with >75% perforation of the tympanic membranes. Wet Ears and perforations involving the Pars Flacida were excluded from the study. Preoperative Audiogram was carried out for all patients and A-B Gap were noted for all groups separately so as the demographic data including age and gender. Success was defined as complete closure of Tympanic membrane perforation at 3 months. All patients were operated with 0 Degree 3mm, 14cm rigid endoscope under general anesthesia. Results: Mean age of patients was. 37 years and standard deviation was 12.34 (range 12-58 years). Out of total 157 cases 81 patients male were males (51%) and 76 patients were females (49). Out of 157 ears operated 146 Perforations healed completely an overall success rate of 92%. Patients with small perforations had 100 percent success.....
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Singh, Mahavir, Satish Dalal, and Mridul Gera. "Spectrum of gastrointestinal perforation peritonitis in 462 consecutive patients in tertiary care institute of North India." International Surgery Journal 8, no. 10 (September 28, 2021): 2993. http://dx.doi.org/10.18203/2349-2902.isj20213982.

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Background: Gastrointestinal perforation is one of the common surgical emergencies in developing countries. The diagnosis is mainly clinical and is aided by radiological investigations. This study was designed to highlight the spectrum of hollow viscus perforation peritonitis in terms of etiology, clinical presentations, site of perforation, surgical treatment, postoperative complications, and mortality.Methods: The study was a hospital‑based observational study and included 462 patients of perforation peritonitis (diffuse or localized) who were studied retrospectively in terms of cause, site of perforation, surgical treatment, complications, and mortality. Only those patients who underwent exploratory laparotomy for management of perforation peritonitis were included.Results: Overall stomach was the most common site of perforation (33%). Ileum (26%) was the second common site of perforation. Duodenal perforations were seen in 88 (19%) cases whereas appendicular perforations were seen in 46 (10%) cases. Colonic perforations were least common. Acid peptic disease was the most common etiology of stomach perforations. Enteric fever (63%) was the most common etiology of jejuno-ileal perforation. Other causes include tuberculosis (23%), trauma (8%), malignancy (3%) and idiopathic in rest. Males were six times more commonly affected than females. Peak incidence was noted in the 2nd and 3rd decades of life.Conclusions: Spectrum of perforation peritonitis cases in developing world is different from developed countries The Western literature suggests that foreign body, ischemia, radiotherapy, diverticula, and Crohn’s disease are the main causes of perforations. In contrast to this, infection is the most common cause for perforations in developing countries.
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Tamae, A., and S. Komune. "Clinical study of transcanal closure of tympanic membrane perforations using a collagen sponge." Journal of Laryngology & Otology 129, S2 (February 23, 2015): S21—S26. http://dx.doi.org/10.1017/s0022215114002333.

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AbstractMaterials and methods:We used an artificial dermis (Terdermis®), which is an atero-collagen sponge covered with a sheet of silicon.Patients:Nineteen ears of 17 patients with perforation of the tympanic membrane under various conditions, including large and wet perforations, underwent operation using this collagen sponge.Results:The success rate of closure after the initial surgery was 8/19. The overall success rate of closure after initial and re-operation was 14/19. The success rate of closure was 12/14 for small-sized perforations, 1/4 for middle-sized perforations and 1/1 for a large-sized perforation. Middle- and large-sized perforations required multiple surgeries. The success rate of closure was 11/11 for dry perforations, 3/4 for perforations with light otorrhoea and 0/4 for perforations with extensive otorrhoea.Conclusion:This surgery is a low-cost and minimally invasive surgery and has a high closure rate. This surgery is effective on small-sized, dry perforations although it can also close middle- and large-sized dry perforations.
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Dissertations / Theses on the topic "Perforations"

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Herzhaft, Laurent. "Ruptures et perforations de l'oesophage." Caen, 1990. http://www.theses.fr/1990CAEN3068.

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Abdel-Rahman, Nabil Mahmoud. "Cold-formed steel compression members with perforations." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ30065.pdf.

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Hubert, Philippe, and FREDERIC SARTORI. "Les perforations coliques chez l'insuffisant renal hemodialyse." Lille 2, 1988. http://www.theses.fr/1988LIL2M358.

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Rahman, Anisur. "Healing of tympanic membrane perforations : an experimental study /." Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-243-9/.

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LE, BONNIEC LOIC. "Perforations stercorales du rectum : a propos d'une observation." Toulouse 3, 1989. http://www.theses.fr/1989TOU31233.

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CHMAIT, AKRAM. "Perforations de diverticulose colique lors de traitements corticoides." Amiens, 1993. http://www.theses.fr/1993AMIEM108.

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García, Padilla Marta. "Optimization of thin sheet structures with patterns perforations." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13712.

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Mestrado em Engenharia Mecânica
Nowadays, metal storage systems are generally used in industrial companies. The several stages of the metallic structures design are based in the standard EN 15512:2009. However, this standard do not the most efficient design solution, only design constraints. In this work, it is intended to improve the structural elements that are on the base of the metal storage systems, particularly shelves, in order to reduce costs and increase the structure stiffness, enforcing the international standard that define the characteristics of these products. The main purpose is the optimization of a representative section of profiled steel component taking into account the variable thickness, geometry and number of perforations. In order to do this a computational finite element model is developed and pre-­‐validated, replacing a numerous set of experimental tests in a design of Experiments (DoE) methodology. The optimized solutions were obtained through a response surface optimization methodology (RSM). The final results were analysed and discussed.
Hoje em dia, os sistemas metálicos de armazenamento são vulgarmente utilizados pela indústria. As várias etapas de projeto destas estruturas metálicas são baseadas na norma EN 15512:2009. No entanto, esta norma não propõe a solução de projeto mais eficiente, apenas as suas restrições. Neste trabalho, pretende-­‐se aperfeiçoar os elementos estruturais que estão na base dos sistemas de armazenamento de metal, particularmente prateleiras, a fim de reduzir custos e aumentar a rigidez da estrutura, satisfazendo a norma internacional que define as características necessárias desses produtos. O objetivo principal é a otimização de uma secção representativa do componente de aço perfilado tendo em conta as variáveis espessura, geometria e número de perfurações. Para isso, é desenvolvido e validado um modelo computacional de elementos finitos, substituindo um numeroso conjunto de testes experimentais numa metodologia de Design of Experiments (DoE). As soluções otimizadas são obtidas através de uma metodologia de otimização baseada numa superfície de resposta (RSM). Os resultados finais são analisados e discutidos.
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Kennedy, Brian Wayne. "Punching shear of high-strength concrete slabs with perforations." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq21178.pdf.

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PANISSET, FRANCOISE. "Perforations coliques sous corticoides : a propos de 21 cas." Lyon 1, 1994. http://www.theses.fr/1994LYO1M101.

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Chiarini, Jean-Michel. "Les perforations iatrogènes de l'oesophage : à partir de deux cas." Montpellier 1, 1990. http://www.theses.fr/1990MON11245.

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Books on the topic "Perforations"

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Belasco, Steven R. Guide to United States vending and affixing machine perforations, 1907-1927. Katy, TX: United States Stamp Society, 2009.

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Randall, John M. Catalog of United States perfins: A catalog and album of security punches on United States postage stamps, 1908-1998. Long Beach, NY: Perfins Club, 1998.

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Davey, Paul N. The perfins of China. Bettendorf, IA: China Stamp Society Inc., 1992.

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Needham, John. Catalog of Bavarian perfins. [United States]: Perfins Club, 1990.

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J, Nussbickel John, and Perfins Club, eds. Austria perfins. [United States]: Perfins Club, 1991.

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Almanakh bŭlgarski perfini. 2nd ed. Sofii︠a︡: [s.n.], 2011.

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Chan, Calvin Chi Lun. Testing of reinforced concrete membrane elements with perforations. Ottawa: National Library of Canada, 1990.

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Santisteban, Tomas Silva. Through-holes, cavities and perforations in polydimethylsiloxane (PDMS) chips. Freiburg: Universität, 2014.

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1959-, Brendel Micha, and Hochschule für Bildende Künste Dresden., eds. Ordnung durch Störung: Auto-Perforations-Artistik : Oktogon, Hochschule für Bildende Künste Dresden. Nürnberg: Verlag für moderne Kunst, 2006.

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A, Madreperla Steven, and McCuen Brooks W, eds. Macular hole: Pathogenesis, diagnosis, and treatment. Boston: Butterworth-Heinemann, 1999.

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Book chapters on the topic "Perforations"

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Pimenta, Amadeu, Valdemar Cardoso, Joaquim Rodrigues, and Diogo Ayres-De-Campos. "Esophageal Perforations." In Recent Advances in Diseases of the Esophagus, 281–85. Tokyo: Springer Japan, 1993. http://dx.doi.org/10.1007/978-4-431-68246-2_44.

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Furay, Elisa, and W. Drew Fielder. "Gastroduodenal Perforations." In Emergency General Surgery, 103–9. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-96286-3_8.

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Søreide, Kjetil. "Gastroduodenal Perforations." In Hot Topics in Acute Care Surgery and Trauma, 95–103. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-59704-1_9.

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Meyer, Rodolphe, Jean-Claude Berset, Jean-François Emeri, and Daniel Simmen. "Septal Perforations." In Secondary Rhinoplasty, 211–43. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56267-9_24.

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Taourel, Patrice, Joseph Pujol, and Emma Pages-Bouic. "Bowel Perforations." In CT of the Acute Abdomen, 309–27. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/174_2010_86.

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Bhat, Amar, and Vishal Jhanji. "Corneal Perforations." In Corneal Emergencies, 171–90. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-5876-1_8.

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Patel, Bobby. "Iatrogenic Perforations." In Endodontic Treatment, Retreatment, and Surgery, 279–96. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-19476-9_12.

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Soundappan, S., R. Pradeep, G. V. Rao, and D. N. Reddy. "ERCP-Induced Perforations." In GI Surgery Annual, 177–89. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-3227-2_7.

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Augustin, Goran. "Nontraumatic Gastroduodenal Perforations." In Acute Abdomen During Pregnancy, 145–77. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-05422-3_4.

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Fernández-Jalvo, Yolanda, and Peter Andrews. "Pits and Perforations." In Vertebrate Paleobiology and Paleoanthropology, 101–53. Dordrecht: Springer Netherlands, 2016. http://dx.doi.org/10.1007/978-94-017-7432-1_4.

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Conference papers on the topic "Perforations"

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Eckdahl, Rick, Adam Vigrass, Amit Singh, Xinghui Liu, and Larry Chrusch. "Assessment of Limited Entry Cluster Distribution Effectiveness and Impactful Variables using Perforation Erosion Measurements." In SPE Hydraulic Fracturing Technology Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/209122-ms.

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Abstract Limited entry perforating is the most common method of diversion used in unconventional hydraulic fracturing. Still it is not immediately apparent how even the stimulation treatments are distributed between the clusters, and the impact of different perforating variables. This paper presents the finding of two well perforation erosion measurement in the Duvernay formation of Western Canada using two logging techniques, optical imaging and ultrasonic measurements. In two wells multiple perforating variables were tested including shot diameter, shot orientation, perforation pressure drop, variable vs constant cluster shot count, and cluster count per stage. Unstimulated perforations were measured for each perforating charge type and orientation to validate baseline perforation dimensions prior to erosion and use to calibration data for incremental erosion calculation. Each of the two wells were logged with an ultrasonic measurement device while one of the two was also logged with an optical imaging tool separately. Perforation area increase for each perforation and the total area increase for each perforation cluster were analyzed to assess the impact of perforating variables on erosion of individual perforation and effectiveness of different perforating designs with respect to equal distribution. The erosion measurement using both logging techniques provided unique opportunity to compare their measurement capability (optical imaging measured 90% of fracture stages as compared to ultrasonic, but both techniques missed ~10% of total measured perforations to quantify perforation size) and range of uncertainties of measurement erosion (general variability in eroded perf diameter measurement of individual perforation by each technique, but statistically R2 of 0.95 correlation excluding 3 outliers of total 873 perforations measured). Of the variables tested a few stood out as providing more even perforation distribution than others. Not surprisingly, reducing total shot count and subsequent flow area, creating a larger pressure drop at the perforations, resulted in a more even distribution of erosion. Smaller initial hole size with an increased shot count, to provide a similar expected pressure differential, also resulted in improved cluster distribution. Variable shot count perforating achieved a more even distribution and counteracted a nature tendency for heel bias. In general perforations on the lower side of the casing showed increase erosion compared to perforations in the upper part of the casing, providing credence to the notion that sand densities are higher in the bottom of the casing even with very high sand transport velocities. This paper shares a case history with results comparison of two major erosion measurement techniques, erosion variability of each perforation as per its azimuth, and highlights some of the variables that have a large impact on cluster distribution and is of benefit to anyone optimizing a perforating design or developing a similar trial to test cluster distribution in other basins.
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Horton, Blake. "A Shot in the Dark: How Your Post-Fracture Perforation Imaging can be Misleading and How to Better Understand Cluster Efficiency and Optimize Limited Entry Perforating." In SPE Hydraulic Fracturing Technology Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/204177-ms.

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Abstract With recent advances in downhole imaging technology, it has become evident that surface perforation testing does not directly translate to downhole conditions. A total of 279 pre- and 595 post- fracture treatment perforations were imaged in this analysis. Pre-treatment perforation hole size was highly variable, even with oriented equal-entry charges. Because of high pre-fracture treatment variability, it is not recommended to use an average diameter of unstimulated perforations to evaluate cluster efficiency of perforations post-fracture treatment. Ideally, perforations should be individually imaged before and after treatment for direct comparison. However, since pre-treatment imaging is costly, an alternate methodology is presented. The findings in this paper will challenge current understanding of actual pre-treatment hole sizes, their variability, and their implications on cluster efficiency. Cluster efficiency cutoff limits have historically been subjective and promoted a false confidence in the ability of Completions Engineers to extend stage lengths and adjust perforation designs. A more stringent and calculated method of determining cluster efficiency is presented. Utilizing both wireline pumpdown for pre-treatment measurements, and coil tubing for post-treatment measurements, downhole imaging technology was deployed to measure perforations from four separate perforation charge manufacturers for pre- and post- treatment erosional analysis. Additionally, while understanding the strike/slip stress state of the Anadarko basin, perforations were oriented at 90° and 270° (degrees from top of wellbore), parallel to the maximum rock stress, promoting a shorter and less tortuous path to the fracture initiation point. Perforating at 90° and 270° reduced tortuosity and surface treating pressure, promoted a less variable pre-treatment perforation hole size due to its symmetry, and resulted in a significant increase in cluster efficiency verses pervious designs. This project effectively optimized a perforation design utilizing pre- and post- fracture treatment perforation imaging and a thorough understanding of pre-treatment perforation hole size to evaluate the effectiveness of stress-targeted, oriented perforating and its effect on cluster efficiency, tortuosity, and pre-treatment hole size variability. The optimized design resulted in 84%-97% cluster efficiency and reduced surface treating pressure by 770 psi. This workflow can be applied by Completions Engineers to any unconventional basin where plug and perf design is utilized.
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Simpson, Greer, Ashley Mercer, Matt Mantell, Charles Bourgeois, Anthony Battistel, Trent Pehlke, and Tom Littleford. "Virtually Unplugging Perforations: High-Resolution Acoustic Imaging Enabling Statistical Analysis of Calibration and Post-Frac Perforation Entry and Exit-Hole Datasets." In SPE/ICoTA Well Intervention Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/212908-ms.

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Abstract High-resolution acoustic imaging technology provides operators the ability to extract submillimetric measurements of perforations at any depth into the casing wall. Due to its three-dimensional nature, submillimetric acoustic data permits the extraction of highly accurate area-based measurements at any radial distance into the perforation, with key distances at the inner and outer casing boundary. This novel technology is fluid agnostic and is unaffected by fluid opacity or clarity. The platforms robust 3D measurement capabilities have made it into an ideal means to evaluate casing and perforations in challenging environments such as hydraulically fractured wells. The integration of high-resolution acoustic imaging into numerous operators’ hydraulic fracture and completions evaluation workflows has resulted in a highly insightful aggregate submillimetric perforation dataset. This large dataset has led to the development of a method to virtually unplug perforations by using a well-specific "perforation entry and exit-hole area correlation". The correlation established can only be extracted using acoustic based imaging as it requires submillimetric resolution of both the ID and OD profile of each perforation Using this correlation, the resulting set of post-frac perforation exit-hole measurements improves an operators’ ability to complete a holistic well completion evaluation, even when well conditions cause perforations to be plugged. The outcome is improved operational insight through the ability to directly compare stages with plugged perforations to those without. This approach can be applied at any point in the well's life cycle, which allows operators to revisit assessments and virtually unplug obscured and proppant-filled perforations. The methodology requires a sound baseline knowledge of the performance of the downhole perforating charges. The baseline is commonly obtained through a calibration stage, which is a stage of charges that are shot but left unstimulated to provide the control measurements for the specific charge in the given well conditions. Current industry performance of downhole perforating charges is investigating through the aggregated dataset of calibration charges. To validate this solid-state acoustic technology and demonstrates its high degree of accuracy for entry and exit-hole perforation measurements, machined samples were scanned with this technology, and with a metrology-grade laser scanner for comparison. This paper presents a novel virtual unplugging methodology, enabled by highly accurate and validated entry-hole measurements, as well as other insights garnered from the aggregate analysis of the world's largest calibration perforation datasets.
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Churchwell, Phil, B. Adam McQueen, and Paul M. Weddle. "Optimization of Perforation Efficiency in the Delaware Basin Through XLE Perforating and Innovative Perforating Charge; A Case Study." In SPE Hydraulic Fracturing Technology Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/212345-ms.

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Abstract This case study looked to identify a perforation design and a perforation charge that measurably increases Perforation Efficiency (PE) and reduces PE variability from stage to stage. Achieving these goals allows for more economic fracture surface area generation as well as more informed decisions toward frac design and full field development. Primarily relying on industry-standard pre-fracture Step-Down Tests (SDT) to estimate number of perforation holes open, a variety of strategies and technologies were tested by altering perforation friction, orientation, entry hole diameter (EHD), perforations per cluster (PPC), and charge type. The trial was performed across multiple horizons in the Delaware Basin, consisting of over 4,500 stages from 193 wells across 13 horizons from the 1st Bone Spring Sand to the Wolfcamp C in Lea and Eddy Counties, New Mexico. With the legacy perforation strategy and technology, the operator historically achieved a probability 50 (P50) using the cumulative distribution function (CDF) of 47% of perforations open pre-fracture. Utilizing eXtreme Limited Entry (XLE), 0 degree-oriented perforating, larger EHD, single perforation clusters, and a shaped charge which increases the reservoir contact area, the operator was able to increase the CDF P50 to 93% of perforations open pre-fracture. This straightforward trial allowed the operator to meaningfully reduce the cost of operations while type curves were met or exceeded. Contributing to the success of this field trial was a clear and restricted design of the experiment in combination with a special shale-optimized perforating charge designed for greater near wellbore reservoir contact area.
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Almulhim, Abdulraof, and Jennifer Miskimins. "Numerical Investigation of the Perforation Friction Loss and Discharge Coefficient." In SPE Hydraulic Fracturing Technology Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/212329-ms.

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Abstract Among the efforts to optimize hydraulic fracturing treatments in multi-stage horizontal wells, extreme limited entry (XLE) perforating has evolved as a technique to increase the stage length and reduce the total stage count with no compromise to the well productivity. The frictional losses in such a choked fluid diversion practice is tremendous, and it is known to change dynamically due to the perforation erosion process. The orifice-based pressure drop equation, commonly used to estimate the perforation friction loss, contains a dimensionless kinetic energy correction factor, the coefficient of discharge (Cd). Cd is used to correct the ideal rate of discharge (Qi) obtained by solving Bernoulli's equation, to the actual rate (Q) due to the non-ideal effects of flow contraction and friction. Utilizing Computational Fluid Dynamics (CFD), this work modeled the flow through perforations and developed a quantitative understanding of the Cd for sharp-edge drilled and semi-round jet perforations. The study also investigated the Cd sensitivity to several design parameters such as the perforation diameter, tunnel length, and fluid viscosity. In addition to the steady state simulations, a transient erosion model with dynamic mesh capability was developed to predict the time-dependent Cd behavior due to the erosional process. The results identified a Cd value of 0.72 for a 0.35" sharp-edge drilled perforation. The discharge efficiency of actual jet and eroded perforations is higher. The model estimated a Cd ranging from 0.75 to 0.83 for a 0.35" jet perforation due to the semi-round entry and inlet burr effect. The erosion process, which dynamically changes the perforation size and shape, also improves the perforation's discharge efficiency. The transient erosion model predicted a 23% increase in the perforation size and a post-erosion Cd of 0.94. The sensitivity analysis indicated that the smaller the perforation size, the longer the tunnel, the higher the viscosity and proppant concentration, and the smaller the proppant size, the lower theCd. This numerical work provides an insight on the Cd value and its dependency on the perforation parameters, which helps to understand the wide range of values reported in the literature and reduce the uncertainty in estimating the perforation friction.
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Guoynes, J. C., W. M. Palmer, J. Grantham, J. B. Peters, and B. L. Friend. "Extreme-Overbalance Perforating Extends Perforations without Vertical Growth." In SPE Eastern Regional Meeting. Society of Petroleum Engineers, 1996. http://dx.doi.org/10.2118/37325-ms.

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Mohamed Elkordy, Mohamed, Bader Taqi Akbar, Milan Kumar Patra, AbdulSamad Ahmad, Abdullah Abu Eida, Nasser Al Azmi, AbdulAziz Dashti, et al. "Perforations Redefined: Measurements while Perforating using Digital Slickline." In International Petroleum Technology Conference. International Petroleum Technology Conference, 2020. http://dx.doi.org/10.2523/iptc-20049-abstract.

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Mohamed Elkordy, Mohamed, Bader Taqi Akbar, Milan Kumar Patra, AbdulSamad Ahmad, AbdulAziz Dashti, Alberto Abouganem Stephens, Hazim Ayyad, Khaled Abdulrahim, and Guillermo Luna Hernandez. "Perforations Redefined: Measurements while Perforating using Digital Slickline." In International Petroleum Technology Conference. International Petroleum Technology Conference, 2020. http://dx.doi.org/10.2523/iptc-20049-ms.

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Thiessen, Scott, Oliver Han, Ramadan Ahmed, and Rida Elgaddafi. "An Experimental Study of Coefficient of Discharge for Consistent Hole Perforating and the Effect on Limited Entry Designs." In SPE Hydraulic Fracturing Technology Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/204178-ms.

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ABSTRACT In hydraulic fracturing, determining the perforation pressure loss is a critical step in the design strategy, on-site troubleshooting diagnostics and post-fracture analysis. Historically, the most widely assumed and thus unknown components in the perforation friction equationare the coefficient of discharge and the holistic perforation diameter. The perforation coefficient of discharge has long been assumed as a dynamic variable dependent on the amount of fluid and proppant pumped through the perforations. This variable becomes increasingly important when clusters are spaced closer together and fewer perforations are shot such as in a limited entry design. Limited entry is a perforating technique used to generate uniform fractures along the wellbore by creating appropriate pressure differentials from cluster to cluster. With the adoption of consistent hole perforating shaped charges, the perforating diameters are more consistent and predictable. While not all consistent hole shaped charges have low diameter variability, the perforating diameters downhole are no longer an unknown, particularly after the introduction of downhole cameras. Therefore, the coefficient of discharge is the only unknown variable remaining. This paper presents an experimental methodology to accurately define the true coefficient of discharge in common completions perforated by a known consistent hole shaped charge. The test setup is illustrated, detailed test steps are discussed, and experimental data with correlations of rate per perforation and discharge coefficient is presented. Completions tested included 4-1/2", 5", and 5-1/2" casings in common weights and grades. Various perforating strategies were examined such as single shot and angled shot. Critical parameters such as entry hole diameters were made by the actual shaped charges and measured before and after the test. Freshwater and slickwater were used as hydraulic fluid and circulated at real-world pump rates through each perforation to simulate the actual field flow conditions. Based on the study, several correlations for the coefficient of discharge of flow through a perforation are created considering casing thickness, entry hole diameter and rate per perforation for the given consistent hole shaped charges. These correlations can improve perforation and fracturing designs where perforation friction are important variables.
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Varughese, Anisha, P. Lakshmi, Srilekha Rajarshi Pasula Valmiki, Abdur Rasheed, and Vinayak Malhotra. "Jet Perforations for Gas Turbine Applications." In ASME 2017 Gas Turbine India Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gtindia2017-4623.

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Gas turbine engines operate under varying conditions. Subsequently, thrust varies under diverse conditions. Owing to combustion the exhaust runs full. The flow jets have been in utilization for engineering systems, present work investigates the merits of jet perforations for gas turbine engine applications. Controlling thrust when device is running is not an option in the present world. This led us to do the study on the flow of jet through various perforated shapes. At present, thorough experiments are carried out for flow analysis of diverse jet perforations and related flow optimization for better performance. Experiments are carried out on a scaled cascade tunnel. The perforations are of circle, square, triangle and ellipse in shape. The physical insight from this work would be very informative and useful for gas turbine engine operations. Systematic experiments are carried out to fundamentally understand flow behavior with different perforations at the exit. Gas turbine engines have revolutionized the propulsion systems. The very idea of generating large amount of thrust from a small volume has always intrigued scientific community about the effectiveness of operations. Though, the engine works, however, effectiveness have always been questioned and worked upon. Results significantly state that jet perforations do modify the flow jet characteristics. The results show the increase in velocity by 6.2% on using the circular perforation. For the circular perforation wall jet, velocity increases by 14.7% with respect to reference jet i.e. jet without perforation.
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Reports on the topic "Perforations"

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Welling, Bradley. Fibroblast Growth Factor Regeneration of Tympanic Membrane Perforations. Fort Belvoir, VA: Defense Technical Information Center, October 2013. http://dx.doi.org/10.21236/ada591173.

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Cruse, John. Roman grinding stones from Northern Britain with two opposed perforations. Edicions de la Universitat de Lleida, 2019. http://dx.doi.org/10.21001/rap.2019.extra-4.3.

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Pescatore, C., and T. M. Sullivan. Modeling of gaseous sup 14 CO sub 2 release from perforations in spent fuel disposal containers. Office of Scientific and Technical Information (OSTI), November 1991. http://dx.doi.org/10.2172/5789466.

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Pescatore, C., and T. M. Sullivan. Modeling of gaseous {sup 14}CO{sub 2} release from perforations in spent fuel disposal containers. Office of Scientific and Technical Information (OSTI), November 1991. http://dx.doi.org/10.2172/10132933.

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Levy, Brittany E., Aaron P. Garrison, Daniel von Allmen, Anthony Kraft, and Todd A. Ponsky. Esophageal Foreign Bodies. StayCurrentMD, March 2022. http://dx.doi.org/10.47465/sc00002.

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Children less than 5 years old are at high risk for foreign body ingestion or aspiration. Therefore, identifying workup and management principles of foreign body ingestion, in the pediatric population, is necessary for pediatric practitioners. Differentiation of caustic ingestion versus benign ingestion is necessary to determine urgency of management. Plain film X ray imaging can be used to differentiate a button battery versus a coin ingestion, based on the halo sign. The urgency of battery ingestion requires immediate medical attention and endoscopic removal, however treatment with honey during transport may improve outcomes. Perforation can occur via caustic ingestion, sometimes with a delayed presentation. However, the most common cause of esophageal perforation is iatrogenic. In many cases perforation can be managed non operatively if contained and adequately drained.
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Morris, J. P., I. N. Lomov, and L. A. Glenn. Simulating perforation permeability damage and cleanup. Office of Scientific and Technical Information (OSTI), December 2000. http://dx.doi.org/10.2172/15006161.

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Morris, J. P., I. N. Lomov, and L. A. Glenn. Simulating Perforation Permeability Damage and Cleanup. Office of Scientific and Technical Information (OSTI), September 2000. http://dx.doi.org/10.2172/793699.

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Silling, Stewart A., and Muge Fermen-Coker. Computational Model for Microballistic Perforation of Multilayer Graphene. Office of Scientific and Technical Information (OSTI), June 2020. http://dx.doi.org/10.2172/1638573.

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Smart, Moises E. High Temperature Perforating System for Geothermal Applications. Office of Scientific and Technical Information (OSTI), February 2017. http://dx.doi.org/10.2172/1345110.

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Chen, E. P. Simulation of concrete perforation based on a continuum damage model. Office of Scientific and Technical Information (OSTI), October 1994. http://dx.doi.org/10.2172/10185320.

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