Fracture propagation law of temporary plugging and diversion fracturing in shale reservoirs under completion experiments of horizontal well with multi-cluster sand jetting perforation

This study conducted temporary plugging and diversion fracturing(TPDF)experiments using a true triaxial fracturing simulation system within a laboratory setting that replicated a lab-based horizontal well completion with multi-cluster sand jetting perforation.The effects of temporary plugging agent(TPA)particle size,TPA concentration,single-cluster perforation number and cluster number on plugging pressure,multi-fracture diversion pattern and distribution of TPAs were investigated.A combination of TPAs with small particle sizes within the fracture and large particle sizes within the segment is conducive to increasing the plugging pressure and promoting the diversion of multi-fractures.The addition of fibers can quickly achieve ultra-high pressure,but it may lead to longitudinal fractures extending along the wellbore.The temporary plugging peak pressure increases with an increase in the concentration of the TPA,reaching a peak at a certain concentration,and further increases do not significantly improve the temporary plugging peak pressure.The breaking pressure and temporary plugging peak pressure show a decreasing trend with an increase in single-cluster perforation number.A lower number of single-cluster perforations is beneficial for increasing the breaking pressure and temporary plugging peak pressure,and it has a more significant control on the propagation of multi-cluster fractures.A lower number of clusters is not conducive to increasing the total number and complexity of artificial fractures,while a higher number of clusters makes it difficult to achieve effective plugging.The TPAs within the fracture is mainly concentrated in the complex fracture areas,especially at the intersections of fractures.Meanwhile,the TPAs within the segment are primarily distributed near the perforation cluster apertures which initiated complex fractures.

Numerical Analysis of Perforation during Hydraulic Fracture Initiation Based on Continuous-Discontinuous Element Method

Perforation is a pivotal technique employed to establish main flow channels within the reservoir formation at the outset of hydraulic fracturing operations.Optimizing perforation designs is critical for augmenting the efficacy of hydraulic fracturing and boosting oil or gas production.In this study,we employ a hybrid finite-discrete element method,known as the continuous–discontinuous element method(CDEM),to simulate the initiation of post-perforation hydraulic fractures and to derive enhanced design parameters.The model incorporates the four most prevalent perforation geometries,as delineated in an engineering technical report.Real-world perforations deviate from the ideal cylindrical shape,exhibiting variable cross-sectional profiles that typically manifest as an initial constriction followed by an expansion,a feature consistent across all four perforation types.Our simulations take into account variations in perforation hole geometries,cross-sectional diameters,and perforation lengths.The findings show that perforations generated by the 39g DP3 HMX perforating bullet yield the lowest breakdown pressure,which inversely correlates with increases in sectional diameter and perforation length.Moreover,this study reveals the relationship between breakdown pressure and fracture degree,providing valuable insights for engineers and designers to refine perforation strategies.

Conquer coronary artery perforation with magic hands

Coronary artery perforation(CAP) poses a significant challenge for interventional cardiologists. Management of CAP depends on the location and severity of the perforation. The conventional method for addressing the perforation of large vessels involves the placement of a covered stent, while the perforation of distal and collateral vessels is typically managed using coils, autologous skin, subcutaneous fat, microspheres, gelatin sponge, thrombin or other substances. However, the above techniques have certain limitations and are not applicable in all scenarios. Our team has developed a range of innovative strategies for effectively managing CAP. This article provides an insightful review of the various tips and tricks for the treatment of CAP.

Fractures interaction and propagation mechanism of multi-cluster fracturing on laminated shale oil reservoir

The continental shale reservoirs of Jurassic Lianggaoshan Formation in Sichuan Basin contain thin lamina,which is characterized by strong plasticity and developed longitudinal shell limestone interlayer.To improve the production efficiency of reservoirs by multi-cluster fracturing,it is necessary to consider the unbalanced propagation of hydraulic fractures and the penetration effect of fractures.This paper constructed a numerical model of multi-fracture propagation and penetration based on the finite element coupling cohesive zone method;considering the construction cluster spacing,pump rate,lamina strength and other parameters studied the influencing factors of multi-cluster fracture interaction propagation;combined with AE energy data and fracture mode reconstruction method,quantitatively characterized the comprehensive impact of the strength of thin interlayer rock interfaces on the initiation and propagation of fractures that penetrate layers,and accurately predicted the propagation pattern of hydraulic fractures through laminated shale oil reservoirs.Simulation results revealed that in the process of multi-cluster fracturing,the proportion of shear damage is low,and mainly occurs in bedding fractures activated by outer fractures.Reducing the cluster spacing enhances the fracture system's penetration ability,though it lowers the activation efficiency of lamina.The high plasticity of the limestone interlayer may impact the vertical propagation distance of the main fracture.Improving the interface strength is beneficial to the reconstruction of the fracture height,but the interface communication effect is limited.Reasonable selection of layers with moderate lamina strength for fracturing stimulation,increasing the pump rate during fracturing and setting the cluster spacing reasonably are beneficial to improve the effect of reservoir stimulation.

A Case of Esophageal Perforation Presenting as Cavitary Pneumonia: Diagnostic and Therapeutic Challenges

Esophageal perforation, a rare condition, can arise from iatrogenic, traumatic, or spontaneous origins. Even when therapy is initiated within the first 24 hours, it is associated with a mortality rate of up to 25%. Due to the varied initial presentation, treatment may be delayed, leading to poorer outcomes. Here, we present a unique case of a 27-year-old schizophrenic patient who initially presented with acute respiratory failure and septic shock and was ultimately diagnosed with cavitary pneumonia secondary to esophageal perforation.

Simple procedure for assessing diffuse subarachnoid hemorrhage successfully created using filament perforation method in mice

The murine model of subarachnoid hemorrhage(SAH)is a valuable experimental tool for investigating molecular and cellular mechanisms,and the endovascular filament perforation technique can be used to simulate prominent pathophysiological features observed after human SAH;however,current validation methods for assessing an appropriate SAH model are limited.Here,we introduce a simple procedure for se-lecting a mouse model of diffuse SAH.SAH was induced in 24 mice using a standard filament perforation method.After confirming survival at 24 h,SAH was scored 0-1 based on T2*-weighted images on whole-brain magnetic resonance imaging(MRI)and visual surveillance of the cisterna magna(CM)through the dura mater.The CM-based SAH grading correlated well with a reference parameter defined by extracted brain(r^(2)=0.53,p<0.0001).The receiver operating characteristic curve revealed a sensi-tivity of 85%and a specificity of 91%for detecting diffuse SAH,with a similar area under the curve(0.89±0.06[standard error of the mean])as the MRI-based grading(0.72±0.10,p=0.12).Our data suggest that confirming an SAH clot in the CM is a valuable way to select a clinically relevant diffuse SAH model that can be used in future experimental studies.

The Evolutionary Profile of Patients Operated for Peptic Ulcer Perforation in Bujumbura

Background: The evolutionary profile of patients operated for peptic ulcer perforation in Bujumbura. Perforated peptic ulcer is a serious complication of peptic ulcer with potential risk of grave complications. Aim: To study the early morbidity and mortality of surgery for peptic ulcer perforation in Bujumbura City Hall hospitals: Kamenge University Hospital Center (CHUK), Kamenge Military Hospital (HMK) and Prince Louis Rwagasore Clinic (CPLR). Patients and methods: This is a retrospective, descriptive and analytical study carried out in the three hospitals of Bujumbura over a period of three years from January 1, 2020 to December 31, 2022. It involved 57 cases (n = 57) of peptic ulcer perforation. Results: The frequency of surgery for peptic ulcer perforation was 2.7% with a mean age of 43.6 years +/- 15.3 years and a male predominance with a sex ratio of 3.7. Eight percent of patients presented with shock, 24.5% were smokers, and 67.9% had taken non steroidal anti-inflammatory drugs. The mean hospital stay was 15.2 days with a standard deviation of 12.1. The morbidity rate was 30.2%, 32% were classified in grade IIIb of the Clavien-Dindo Surgical Complications Scale. There were 9 deaths (17%). Seven patients who underwent surgery and received late consultations died. Conclusion: Surgery for peptic ulcer perforation remains an intervention associated with a high rate of morbidity and mortality in Bujumbura. Surgery for peptic ulcer perforation remains a procedure associated with a high morbidity and mortality rate in Bujumbura. The time before consultation was the only factor associated with early morbidity and mortality of Surgery for peptic ulcer’s perforations.

Previously undiagnosed Morgagni hernia with bowel perforation detected during repeat screening colonoscopy: A case report

BACKGROUND Morgagni hernia(MH)is a form of congenital diaphragmatic hernia(CDH)characterized by an incomplete formation of diaphragm,resulting in the protru-sion of abdominal organs into the thoracic cavity.The estimated incidence of CDH is between 1 in 2000 and 1 in 5000 live births,although the true incidence is unknown.MH typically presents in childhood and can be diagnosed either pre-natally or postnatally.However,it can also be asymptomatic and carry the risk of developing into a life-threatening condition in adulthood.CASE SUMMARY A 76-year-old female with no history of prior abdominal surgeries presented for an elective colonoscopy for polyp surveillance.During the procedure,when approaching the hepatic flexure,the scope could not be advanced further despite multiple attempts.The patient experienced mild abdominal discomfort,leading to the abortion of the procedure.While in the recovery area,she developed increa-sing abdominal pains and hypotension.Urgent abdominal imaging revealed her-niation of the proximal transverse colon through a MH into the chest with evi-dence of perforation.The patient underwent laparoscopic urgent colonic resection and primary hernia repair and was discharged uneventfully 2 d later.CONCLUSION A MH is a rare condition in adults that can present as a life-threatening compli-cation of colonoscopy,even in patients with a history of uneventful colonoscopies.This case highlights the importance of considering congenital and internal hernias when faced with sudden and unexplained difficulties during colonoscopy.If there is a suspicion of MH,the endoscopist should halt the procedure and immediately obtain abdominal imaging to confirm the diagnosis.

Vomiting-induced pharyngeal perforation during bowel preparation for colonoscopy:A case report

BACKGROUND Effective bowel cleansing is essential for a successful colonoscopy.Laxatives,such as polyethylene glycol,are commonly used for bowel preparation.Vomiting is a frequent complication during bowel preparation,and forceful vomiting can potentially lead to esophageal perforation,as reported in several previous cases.However,pharyngeal perforation during bowel preparation has not been previously documented.Here,we present a case of pharyngeal perforation induced by forceful vomiting during bowel preparation.CASE SUMMARY A 38-year-old man with a history of hypertension,dyslipidemia,diabetes mellitus,and end-stage renal disease on hemodialysis was admitted for evaluation of recurrent abdominal pain.The patient complained of sudden pain in the neck,throat,and anterior chest following forceful vomiting during bowel preparation.Physical examination revealed crepitus under the skin of the neck and anterior chest on palpation,and upper gastrointestinal endoscopy revealed pharyngeal perforation.The perforation site was located above the upper esophageal sphincter,which distinguished it from Boerhaave’s syndrome.Conservative medical management was chosen after consultation with a thoracic surgeon and an otolaryngologist,considering the patient's mild symptoms,stable vital signs,and the small size of the lesion;the perforation resolved without endoscopic or surgical intervention.The patient was discharged from hospital two weeks after the perforation.CONCLUSION Despite its rarity,pharyngeal perforation should be considered a potential complication of bowel preparation for colonoscopy.

Small intestine angioleiomyoma as a rare cause of perforation:A case report

BACKGROUND Angioleiomyoma is a rare and benign stromal tumor typically found in subcutaneous tissue.It rarely occurs in the gastrointestinal tract.Among the reported cases,the most common complication was gastrointestinal bleeding.Perforation has only been reported as a complication in the last few decades.CASE SUMMARY This case report detailed the discovery of intestinal angioleiomyoma in a 47-yearold male presenting with abdominal pain that had persisted for 3 d.After suspecting hollow organ perforation,surgical intervention involving intestinal resection and anastomosis was performed.CONCLUSION The report underscores the significance of early surgical intervention in effectively treating angioleiomyoma while emphasizing the pivotal role of timely and appropriate measures for favorable outcomes.

Clinical Epidemiology and Surgical Treatment of Spontaneous Perforations of the Terminal Ileum: A Multicentre Study in Cameroon

Background: Perforations of the terminal ileum are a frequent clinical situation and a therapeutic challenge. Surgical treatment is controversial. Several surgical modalities have been proposed and postoperative morbidity and mortality remain high. The aim of this study was to review our experience in the surgical management of perforations of the terminal ileum. Patients and methods: This is a descriptive cross-sectional study with retrospective data collection from January 1, 2017 to December 31, 2021, in five hospitals in Cameroon. Patients’ demographic, clinical presentation, surgical findings and 30-days postoperative outcomes data were collected. Results: We collected 34 files. The sex ratio was 1.4 and the average age was 20.28 years. The average consultation time was 9.1 days. Abdominal pain was present in all our patients. Peritoneal irritation was present in 46 cases (88.5%). The mean time to treatment after admission was 17.5 hours. The perforation was unique in 40 cases (76.9%) and located between 6 and 10 cm from the ileocecal valve in 29 cases (55.8%). Typhoid was the most suspected etiology intraoperatively in 38 cases (73.1%). A simple suture was performed in 18 patients (34.6%), resection with anastomosis in 11 patients (21.2%) and an ileostomy in 5 patients (9.6%). The average length of hospitalization was 21.74 days. Postoperative morbidity and mortality were 32.7% and 17.3% respectively. Conclusion: Perforations of the terminal ileum are common and affect young people. Surgical procedures are varied. Reducing consultation and care times and respecting treatment principles could improve postoperative morbidity and mortality, which remain high.

Efficacy of Cyanoacrylate Tissue Adhesive Application in the Management of Corneal Perforations at Preah Ang Duong Hospital in Cambodia

Purpose: The study was to evaluate the efficacy of cyanoacrylate tissue adhesive (CTA) application in corneal perforations. Method: This was a prospective study on 20 patients of corneal perforations who received cyanoacrylate tissue adhesive application as treatment between March 2021 and March 2022 at Preah Ang Duong Hospital. The primary outcome measure was success rate of CTA application, while the secondary outcome was to measure postoperative best-corrected visual acuity (BCVA) and ocular complications. Results: The mean age of patients was 44.15 ± 16.05 years old and 7 (35%) were female. Causes of perforation were microbial infection in 12 patients (60%), trauma in 5 patients (25%), and sterile melting in 3 patients (15%). The perforation of size smaller than 1.5 mm was in 8 patients (40%) while 12 patients (60%) had perforated size between 1.5 mm to 3 mm. The perforation was 60% (12 patients) central, 25% (5 patients) paracentral, and 15% (3 patients) peripherally. Out of 20 patients, 5 patients (25%) received CTA application more than 1 time. The mean glue retention was 57.60 ± 31.84 days. Success rate of glue application (defined as intact globe without surgical intervention regardless of number of CTA applications) was 85%. At the last visit, 7 patients (35%) had BCVA of 6/120 or better. Common complications were uveitis (45%), ocular hypertension (30%), cataract (25%) and neovascularization (20%). No serious complications were found. Conclusion: Cyanoacrylate tissue adhesive is an effective treatment option in sealing corneal perforations with no serious complications. .

Simulation Method and Feature Analysis of Shutdown Pressure Evolution During Multi-Cluster Fracturing Stimulation

Multistage multi-cluster hydraulic fracturing has enabled the economic exploitation of shale reservoirs,but the interpretation of hydraulic fracture parameters is challenging.The pressure signals after pump shutdown are influenced by hydraulic fractures,which can reflect the geometric features of hydraulic fracture.The shutdown pressure can be used to interpret the hydraulic fracture parameters in a real-time and cost-effective manner.In this paper,a mathematical model for shutdown pressure evolution is developed considering the effects of wellbore friction,perforation friction and fluid loss in fractures.An efficient numerical simulation method is established by using the method of characteristics.Based on this method,the impacts of fracture half-length,fracture height,opened cluster and perforation number,and filtration coefficient on the evolution of shutdown pressure are analyzed.The results indicate that a larger fracture half-length may hasten the decay of shutdown pressure,while a larger fracture height can slow down the decay of shutdown pressure.A smaller number of opened clusters and perforations can significantly increase the perforation friction and decrease the overall level of shutdown pressure.A larger filtration coefficient may accelerate the fluid filtration in the fracture and hasten the drop of the shutdown pressure.The simulation method of shutdown pressure,as well as the analysis results,has important implications for the interpretation of hydraulic fracture parameters.

Effect of perforation density distribution on production of perforated horizontal wellbore

To address the issue of horizontal well production affected by the distribution of perforation density in the wellbore,a numerical model for simulating two-phase flow in a horizontal well is established under two perforation density distribution conditions(i.e.increasing the perforation density at inlet and outlet sections respectively).The simulation results are compared with experimental results to verify the reliability of the numerical simulation method.The behaviors of the total pressure drop,superficial velocity of air-water two-phase flow,void fraction,liquid film thickness,air production and liquid production that occur with various flow patterns are investigated under two perforation density distribution conditions based on the numerical model.The total pressure drop,superficial velocity of the mixture and void fraction increase with the air flow rate when the water flow rate is constant.The liquid film thickness decreases when the air flow rate increases.The liquid and air productions increase when the perforation density increases at the inlet section compared with increasing the perforation density at the outlet section of the perforated horizontal wellbore.It is noted that the air production increases with the air flow rate.Liquid production increases with the bubble flow and begins to decrease at the transition point of the slug-stratified flow,then increases through the stratified wave flow.The normalized liquid flux is higher when the perforation density increases at the inlet section,and increases with the radial air flow rate.

Formation and rupture of liver hematomas caused by intrahepatic gallbladder perforation:A case report and review of literature

BACKGROUND Gallbladder perforation is a serious complication of acute cholecystitis.Such perforation is a rare but life-threatening situation that can lead to the formation and rupture of liver hematomas.Here,we report a case of a ruptured intrahepatic hematoma caused by intrahepatic gallbladder perforation,and we present a literature review.CASE SUMMARY A 70-year-old male was admitted to the hospital with a complaint of right upper quadrant abdominal pain,flustering and dizziness.The preoperative diagnosis was a ruptured malignant liver tumor,and the patient’s medical images and increased level of carbohydrate antigen-199 suggested that the gallbladder had been invaded.However,the tumor was proven to be a liver hematoma secondary to gallbladder perforation after surgery.The patient was discharged uneventfully on the fifteenth postoperative day.CONCLUSION Intrahepatic gallbladder perforation is difficult to diagnose preoperatively.Radiological examinations play a crucial role in the diagnosis but only for partial cases.Early diagnosis and appropriate surgery are key to managing this rare condition.

Colon perforation with severe peritonitis caused by erotic toy insertion and treated using vacuum-assisted closure:A case report

BACKGROUND Colorectal foreign bodies are commonly encountered during surgery.They are frequently observed in men 20 to 90 years of age and have bimodal age distribution.Surgical management is necessary for cases of rectal perforation.However,surgical site infections are the most common complications after colorectal surgery.CASE SUMMARY We discuss a case of rectal perforation in a patient who presented to our hospital 2 d after its occurrence.The perforation occurred as a result of the patient inserting a sex toy in his rectum.Severe peritonitis was attributable to delayed presentation.CONCLUSION Vacuum-assisted closure was performed to treat the wound,which healed well after therapy.No complications were noted.

Sigmoid Micro-Perforation and Pelvic Abscess Masquerading as Hyperactive Delirium

Diagnoses Background: Delirium is a common finding in elderly patients with sepsis. Early identification of the cause of delirium and treatment is important to avoid any worsening of mental or physical status. Sepsis secondary to colonic micro-perforation (CMP) in a patient with a history of diverticulosis should be high on the list of differential diagnosis. Case Report: We present a case of a patient who presented with hyperactive sepsis-associated delirium (SAD). Six days after the presentation, the patient started complaining of abdominal pain. An abdominal and pelvic computed tomography (CT) scan showed free air in the abdomen. The patient underwent surgical intervention and treatment with intravenous antibiotics. Pathological examination showed CMP connected to the patient’s history of diverticulosis. Delirium superimposed on dementia (DSD) resulted in the worsening of both the mental and physical status of our patient with the need for placement in a nursing home.

Post Blast Tympanic Perforations, Clinical and Paraclinical Study at Six Yaounde Hospitals

Introduction: Post-blast tympanic perforations represent an entity of traumatic perforations;various mechanisms are at the origin of the latter, and the increase in conflicts and acts of violence are increasing the studies on this subject, but few data are available in our context. Objective: This paper aims to study post-blast tympanic perforations in Yaounde, specifically the epidemiological, clinical, and paraclinical aspects. Methodology: We conducted a descriptive cross-sectional study with retrospective and prospective data collection in six Yaounde hospitals over 63 months from January 1, 2018, to March 31, 2023. All patients with at least one post-blast tympanic perforation were included. Socio-demographic, clinical and paraclinical data were collected on a questionnaire and analysed using SPSS 28 software. Results: We included 124 patients. The prevalence of post-blast tympanic perforations was 0.1% of the consultations in the departments. 71 The average age was 28.6 ± 9.1 years, with extremes ranging from 7 to 49 years. The median consultation time was five days. The most frequent injury circumstances were physical aggression (81.45%) and armed conflict (10.5%). The injury mechanisms were slaps (75%), punches (21.74%) and grenades (4.8%). The main symptoms on admission were hearing loss (63.7%), tinnitus (58.1%) and otalgia (57.3%). The tympanic perforations were unilateral in all cases, the anterior-inferior location was more characteristic, and the deafness was conductive in 58.3% of cases, followed by mixed deafness in 23.3% of cases. Conclusion: Post-blast tympanic perforations are rare in consultation. The population is primarily male and from the second decade of life. The main circumstance is aggression.

Appendicitis combined with Meckel’s diverticulum obstruction, perforation, and inflammation in children: Three case reports

BACKGROUND Meckel’s diverticulum is a common congenital malformation of the small intestine,with the three most common complications being obstruction,per-foration,and inflammation.To date,only a few cases have been reported world-wide.In children,the clinical symptoms are similar to appendicitis.As most of the imaging features are nonspecific,the preoperative diagnosis is not precise.In addition,the clinical characteristics are highly similar to pediatric acute appendicitis,thus special attention is necessary to distinguish Meckel’s diver-ticulum from pediatric appendicitis.Patients with poor disease control should undergo laparoscopic exploration to avoid serious complications,including intestinal necrosis,intestinal perforation and gastrointestinal bleeding.CASE SUMMARY This report presents three cases of appendicitis in children combined with intestinal obstruction,which was caused by fibrous bands(ligaments)arising from the top part of Meckel's diverticulum,diverticular perforation,and diver-ticular inflammation.All three patients,aged 11-12 years,had acute appendicitis as their initial clinical presentation.All were treated by laparoscopic surgery with a favorable outcome.A complete dataset including clinical presentation,dia-gnostic imaging,surgical information,and histopathologic findings was also provided.CONCLUSION Preoperative diagnosis of Meckel’s diverticulum and its complications is challenging because its clinical signs and complications are similar to those of appendicitis in children.Laparoscopy combined with laparotomy is useful for diagnosis and treatment.

How to preserve the native or reconstructed esophagus after perforations or postoperative leaks: A multidisciplinary 15-year experience

BACKGROUND Esophageal perforation or postoperative leak after esophageal surgery remain a life-threatening condition.The optimal management strategy is still unclear.AIM To determine clinical outcomes and complications of our 15-year experience in the multidisciplinary management of esophageal perforations and anastomotic leaks.METHODS A retrospective single-center observational study was performed on 60 patients admitted at our department for esophageal perforations or treated for an anastomotic leak developed after esophageal surgery from January 2008 to December 2023.Clinical outcomes were analyzed,and complications were evaluated to investigate the efficacy and safety of our multidisciplinary management based on the preservation of the native or reconstructed esophagus,when feasible.RESULTS Among the whole series of 60 patients,an urgent surgery was required in 8 cases due to a septic state.Fifty-six patients were managed by endoscopic or hybrid treatments,obtaining the resolution of the esophageal leak/perforation without removal of the native or reconstructed esophagus.The mean time to resolution was 54.95±52.64 days,with a median of 35.5 days.No severe complications were recorded.Ten patients out of 56(17.9%)developed pneumonia that was treated by specific antibiotic therapy,and in 6 cases(10.7%)an atrial fibrillation was recorded.Seven patients(12.5%)developed a stricture within 12 months,requiring one or two endoscopic pneumatic dilations to solve the problem.Mortality was 1.7%.CONCLUSION A proper multidisciplinary approach with the choice of the most appropriate treatment can be the key for success in managing esophageal leaks or perforations and preserving the esophagus.