Numerical Simulation of Water and Sand Blowouts When Penetrating Through Shallow Water Flow Formations in Deep Water Drilling

In this study, we applied a two-phase flow model to simulate water and sand blowout processes when penetrating shallow water flow(SWF) formations during deepwater drilling. We define ‘sand' as a pseudo-component with high density and viscosity, which can begin to flow with water when a critical pressure difference is attained. We calculated the water and sand blowout rates and analyzed the influencing factors from them, including overpressure of the SWF formation, as well as its zone size, porosity and permeability, and drilling speed(penetration rate). The obtained data can be used for the quantitative assessment of the potential severity of SWF hazards. The results indicate that overpressure of the SWF formation and its zone size have significant effects on SWF blowout. A 10% increase in the SWF formation overpressure can result in a more than 90% increase in the cumulative water blowout and a 150% increase in the sand blowout when a typical SWF sediment is drilled. Along with the conventional methods of well flow and pressure control, chemical plugging, and the application of multi-layer casing, water and sand blowouts can be effectively reduced by increasing the penetration rate. As such, increasing the penetration rate can be a useful measure for controlling SWF hazards during deepwater drilling.

Effect of navigation endoscopy combined with threedimensional printing technology in the treatment of orbital blowout fractures

●AIM:To explore the combined application of surgical navigation nasal endoscopy(NNE)and three-dimensional printing technology(3DPT)for the adjunctive treatment of orbital blowout fractures(OBF).●METHODS:Retrospective analysis was conducted on the data of patients with OBF who underwent surgical treatment at the Affiliated Eye Hospital of Nanchang University between July 2012 and November 2022.The control group consisted of patients who received traditional surgical treatment(n=43),while the new surgical group(n=52)consisted of patients who received NNE with 3DPT.The difference in therapeutic effects between the two groups was evaluated by comparing the duration of the operation,best corrected visual acuity(BCVA),enophthalmos difference,recovery rate of eye movement disorder,recovery rate of diplopia,and incidence of postoperative complications.●RESULTS:The study included 95 cases(95 eyes),with 63 men and 32 women.The patients’age ranged from 5 to 67y(35.21±15.75y).The new surgical group and the control group exhibited no statistically significant differences in the duration of the operation,BCVA and enophthalmos difference.The recovery rates of diplopia in the new surgical group were significantly higher than those in the control group at 1mo[OR=0.03,95%CI(0.01–0.15),P<0.0000]and 3mo[OR=0.11,95%CI(0.03–0.36),P<0.0000]postoperation.Additionally,the recovery rates of eye movement disorders at 1 and 3mo after surgery were OR=0.08,95%CI(0.03–0.24),P<0.0000;and OR=0.01,95%CI(0.00–0.18),P<0.0000.The incidence of postoperative complications was lower in the new surgical group compared to the control group[OR=4.86,95%CI(0.95–24.78),P<0.05].●CONCLUSION:The combination of NNE and 3DPT can shorten the recovery time of diplopia and eye movement disorder in patients with OBF.

Biomechanical analysis of an absorbable material for treating fractures of the inferior orbital wall

AIM:To investigate the biomechanical properties and practical application of absorbable materials in orbital fracture repair.METHODS:The three-dimensional(3D)model of orbital blowout fractures was reconstructed using Mimics21.0 software.The repair guide plate model for inferior orbital wall fracture was designed using 3-matic13.0 and Geomagic wrap 21.0 software.The finite element model of orbital blowout fracture and absorbable repair plate was established using 3-matic13.0 and ANSYS Workbench 21.0 software.The mechanical response of absorbable plates,with thicknesses of 0.6 and 1.2 mm,was modeled after their placement in the orbit.Two patients with inferior orbital wall fractures volunteered to receive single-layer and double-layer absorbable plates combined with 3D printing technology to facilitate surgical treatment of orbital wall fractures.RESULTS:The finite element models of orbital blowout fracture and absorbable plate were successfully established.Finite element analysis(FEA)showed that when the Young’s modulus of the absorbable plate decreases to 3.15 MPa,the repair material with a thickness of 0.6 mm was influenced by the gravitational forces of the orbital contents,resulting in a maximum total deformation of approximately 3.3 mm.Conversely,when the absorbable plate was 1.2 mm thick,the overall maximum total deformation was around 0.4 mm.The half-year follow-up results of the clinical cases confirmed that the absorbable plate with a thickness of 1.2 mm had smaller maximum total deformation and better clinical efficacy.CONCLUSION:The biomechanical analysis observations in this study are largely consistent with the clinical situation.The use of double-layer absorbable plates in conjunction with 3D printing technology is recommended to support surgical treatment of infraorbital wall blowout fractures.

BOP shear force evaluation under complex scenarios

As the“throat”of the drilling well control system,ram blowout preventers(BOPs)can effectively prevent blowout accidents.However,the ram shear mechanism under complex working conditions is unclear,and it is difficult to evaluate the ram BOP shear force,leading to frequent shear failure accidents in oilfields.Aiming at the above problems,this paper takes the double-V ram BOP as the research object,and integrates the methods of theoretical analysis,simulation modeling,and test verification to analyze the shear force in the pipe shear process under both static and moving conditions.A ram BOP shear force evaluation method is proposed based on equivalent stress.Finally,by comparing with calculation data and experimental data,the error between them is less than 5%,demonstrating the applicability and effectiveness of the proposed method.The research results can provide a theoretical basis for oilfield operations of ram BOPs.

A mechanism for the origin and development of the large-scale dunefield on the right flank of the lower reach of Laoha River,Northeast China

By viewing satellite imagery, a striking large-scale dunefield can be clearly perceived, with a size of nearly 63 km long and 11 km wide, and trending NE-SW, on the right flank of the lower Laoha River, Northeast China. By means of remote sensing imagery analysis and field observation as well as a comparison with a small-scale dunefield on the right flank of the lower Xiangshui River, analogous to the case of the lower Laoha River, this paper presents a new mechanism for its origin and development. The results show that： （1） the large-scale dunefield bears a tile-style framework overwhelmingly composed of transverse barchanoid ridges perpendicular to the predominant winds, and inlaid diverse blowouts. （2） The small-scale dunefield, referred to as a primary structural unit of the large one, is typical of an incipient dunefield, following the same rules of evolution as the larger. （3） A succession of barchanoid ridge chains can steadily migrate downwind in much the same manner as surface wave propagation in air or water stimulated by an incised valley, and ultimately tend to bear roughly the same wavelength and amplitude under stable climate and hydrologic regimes. （4） The first ridge chain acquires its sand source substantially from the downwind escarpments exposing the loose Quaternary sandy sediments to the air, while the ensuing ridges derive their sands dominantly from in situ deflation of the underlain Quaternary loose sandy sediments in blowouts, partly from the upwind ridges through northern elongated horns. Theoretically, the sands from riparian escarpments can be transported by wind to the downwind distal end of a dunefield after sufficient long du- ration. （5） The lower Laohahe region experienced probably three significant climatic changes in the past, corresponding to the three active dune belts, suggesting that once a large-scale dunefield occurs, it is nearly impossible to be completely stabilized, at least in its central portions. At present, seasonal shrinkage and stagnation of the lower Laoha River, wide-spread farming and afforestation in the valley, and establishing windbreaks downwind of the valley as well as surrounding the dunefield, appear to have significantly modified local flow fields and sand sources, engendering significant degradation of the dunefield.

Evaluation of the Customer Satisfaction Index for Wellhead Blowout Preventers of China’s Petroleum Industry——A new method based on PLS

This paper establishes an evaluation model of the customer satisfaction index for the wellhead blowout preventers of China＇s petroleum industry based on evaluation models of the customer satisfaction index at home and aboard, and by considering the consuming situation in China and the features of the China＇s petroleum industry. For the existence of： （1） multiple correlations among the factors in the model; （2） the variables need to be explained, but that are hard to observe; （3） the customer satisfaction degree of observation variables appears the shape of skewness or two or three peaks, the correlations between the satisfaction index and its factors cannot be described by common multiple regression. This paper uses a partial least squares （PLS） method based on principal components and typical correlative analysis to solve the problem. When PLS is used in the model of the customer satisfaction index of the wellhead blowout preventers, the latent variables and the explanation degree coefficient of the manifest variable to the corresponding latent variables are estimated by PLS path analysis, and the influencing coefficient among the latent variables in the model is estimated by PLS regression analysis. PLS is also be used to calculate and analyze the model and disclose the correlations among the structural variables as well as the correlation between structural variables and its corresponding observation variables, evaluating results of which provide useful information for petroleum industry to improve the product quality and to the enhancement of the customer satisfaction to the product.

Analysis of the effect of repair materials for orbital blowout fracture on complications

AIM: To investigate the effect of repair materials for orbital blowout fractures on the occurrence of postoperative complications. METHODS: The clinical data and follow-up data of 54 subjects with orbital blowout fractures were retrospectively analyzed. The study was divided into three groups according to the used repair materials: titanium mesh(16 cases), Medpor(12 cases), and Medpor titanium mesh(26 cases). All test data were analyzed using the SPSS version 23.0 statistical software. The mean age and duration of disease between the groups were compared through oneway analysis of variance. The Chi-square(χ~2) test was used to compare the number of males and females, different fracture types, and different surgical approaches among groups. The χ~2 test was used to compare the frequencies for complications in each group.RESULTS: The baseline characteristics of age and gender in each group were matched(F=1.763, P=0.172;χ~2=0.026, P=0.987). In addition, there was no difference in the type of fracture and surgical approach(χ~2=0.460, P=0.977;χ~2=0.691, P=0.952), or the incidence of complications(χ~2=0.081, P=0.960) between the three groups. CONCLUSION: Although there is no difference in effect of various repair materials on the incidence of complications, the effect of repair materials on postoperative complications of orbital blowout fractures should not be ignored.

Research on arc root stagnation when small current is interrupted in self-excited circuit breaker

The self-excited DC air circuit breaker(SE-DCCB)has been widely used in urban rail transit due to its excellent stability.It can realize forward and reverse interruption,but has difficulty interrupting small currents due to the phenomenon of arc root sticking at the entrance of the arc chamber in the splitting process,which is known as arc root stagnation.A coupling model of the self-excited magnetic field and magnetohydrodynamics is established for the SE-DCCB with the traditional structure.The magnetic field,temperature and airflow distribution in the arc chamber are investigated with an interrupting current of 150 A.The simulation results show that the direction and magnitude of the magnetic blowout force are the dominant factors in the arc root stagnation.The local high temperature of the arc chamber due to arc root stagnation increases the obstruction effect of the airflow vortex on the arc root movement,which significantly increases the arc duration time of small current interruption.Based on the research,the structure of the magnetic conductance plate of the actual product is improved,which can improve the direction and magnitude of the magnetic blowout force at the arc root so as to restrain the development of the airflow vortex effectively and solve the problem of arc root stagnation when the small current is interrupted.The simulation results show that the circuit breaker with improved structure has a better performance for a small current interruption range from 100 A to 350 A.

Landscape pattern change and driving force of blowout distribution in the Hulun Buir Sandy Grassland

The land coverage pattern changes for the past 50 years in a typical region of the Hulun Buir Sandy Grassland were interpreted and analyzed based on a series of remote sensing images in 1959, 2002, 2004 and 2009. The temporal and spatial changes of landscape patterns were revealed and the driving forces were analyzed. The results show that all land coverage types had large variable amplitudes. The grassland area decreased, whereas other areas incleased. Owing to implementation of artificial sand fixation from 2004 to 2009, the areas of flowing blowouts and depositional area decreased by 71,369 and 128,835 m2, respectively. The average patch area reduced, but the number of blowouts increased, fractal dimension increased, and blowout structure became complex. The fragmentation index increased, whereas contagion index decreased. Driving force analysis shows that human factors such as overglazing are slightly larger than natural factors of increased temperature and decreased precipitation

Effects of wall thickness and material on flame stability in a planar micro-combustor

Flame is prone to lose its stability in micro-combustors due to the large amount of heat loss from the external walls. On the other hand, heat recirculation through the upstream combustor walls can enhance flame stability. These two aspects depend on the structural heat transfer, which is associated with the thickness and thermal conductivity of the combustor walls. In the present study, the effects of wall thickness and material on flame stability were numerically investigated by selecting two thicknesses (δ=0.2 and 0.4 mm) and two materials (quartz and SiC). The results show that when δ=0.2 mm, flame inclination occurs at a certain inlet velocity in both combustors, but it happens later in SiC combustor. For δ=0.4 mm, flame inclination still occurs in quartz combustor from a larger inlet velocity compared to the case of δ=0.2 mm. However, flame inclination in SiC combustor with δ=0.4 mm does not happen and it has a much larger blowout limit. Analysis reveals that a thicker wall can enhance heat recirculation and reduce heat loss simultaneously. Moreover, SiC combustor has larger heat recirculation ratio and smaller heat loss ratio. In summary, the micro-combustor with thicker and more conductive walls can harvest large flame stability limit.

Role of orthoptics and scoring system for orbital floor blowout fracture:surgical or conservative treatment

AIM:To assess the role of orthoptics in referring patients with orbital floor blowout fracture(OFBF)for conservative or surgical treatment and based on the results,to propose a scoring system for such decision making.METHODS:A retrospective analysis of 69 patients with OFBF was performed(35 treated conservatively,34 surgically).The role of orthoptics in referring to surgery or conservative treatment was retrospectively evaluated,the factors with the highest significance for decision making were identified,and a scoring system proposed using Logistic regression.RESULTS:According to defined criteria,the treatment was unsuccessful in 2(6%)surgically treated and only in one(3%)conservatively treated patient.The proposed scoring system includes the defect size and several values resulting from the orthoptic examination,the elevation of the eyebulb measured on Lancaster screen being the most significant.CONCLUSION:The study demonstrates the benefits of orthoptic examination when making decisions on conservative or surgical treatment and for diagnosing ocular motility disorder(with or without binocular diplopia)in OFBF patients.The proposed scoring system could,following verification in a prospective study,become a valuable adjunctive tool.

Capping stack:An industry in the making

This paper gives an overview of recent development of the marine well containment system (MWCS) after BP Macondo subsea well blowout occurred on April 20,2010 in the Gulf of Mexico. Capping stack,a hard-ware utilized to contain blowout well at or near the wellhead is the center piece of MWCS. Accessibility to the dedicated capping stacks is gradually becoming a pre-requirement to obtain the permit for offshore drilling/workover, and the industry for manufacturing,maintenance,transportation and operation of the capping stack is in the making.

A Real-time Monitoring System for Tire Blowout or Severe Leakage

The tire blowout or severe leakage real-time monitoring is one of key technologies for developing a tire blowout automatic braking system.An indirect real-time monitoring method to fuse analyses of tire vibration and effective radius is provided in this paper,and a monitoring system is developed.The calibration and related test results showthat the system can detect the tire blowout in low and middle vehicle speeds and the severe leakage in all speeds timely and accurately.

Generation of on-off intermittency based on RSssler chaotic system

In this paper, one-state on-off intermittency and two-state on-off intermittency are generated in two five- dimensional continuum systems respectively. In each system, a two-dimensional subsystem is driven by the Rossler chaotic system. The parameter conditions under which the on-off intermittency occurs are discussed in detail. The statistical property of the intermittency is investigated. It is shown that the distribution of the laminar phase duration time follows a power law with an exponent of -3/2, which is a signature of on-off intermittency. Moreover, the phenomenon of intermingled basins is observed when attractors in the two symmetric invariant subspaces are stable. We provide an effective way to generate on-off intermittency based on a chaotic system, which is important for application and theoretical study.

Carotid blowout syndrome caused by chronic infection:A case report

BACKGROUND Carotid blowout syndrome(CBS)refers to rupture of the extracranial carotid artery and its branches;as a severe complication,it usually occurs after surgery or radiotherapy for malignant tumours of the head and neck.We present a case of CBS caused by chronic infection of the external carotid artery(ECA).In this case,we did not find any evidence of head and neck tumours.CASE SUMMARY A 42-year-old man was referred to the Emergency Department with a complaint of a lump found on the left side of his neck with pain and fever for 4 d.We diagnosed the condition as neck infection with abscess formation based on physical examination,routine blood examination,ultrasound examination and plain computed tomography(CT)and decided to perform emergency surgery.During the operation,30 mL of grey and smelly pus was drained from the deep surface of the sternocleidomastoid muscle.The second day after the operation,the patient suddenly exhibited a large amount of haemoptysis and incision bleeding.The enhanced CT showed distal occlusion of the left ECA and irregular thickening of the broken ends of the artery encased in an uneven enhancement of soft tissue density.Infected ECA occlusion and rupture were considered.The patient was transferred to a vascular unit for transcatheter ECA embolization and recovered well.CONCLUSION Surgeons need to pay attention to vascular lesions caused by chronic infection that may develop into acute CBS.

Gas Blowout Impacts on Ground Water Environs around the Tengratila Gas Field, Chattak, Bangladesh

Gas blowout is one of the major hazard in petroleum field which normally damages the gas bearing geologic formation, structure, local tectonic setting, environment and so on. In Bangladesh, there have been three well known gas blowouts. Among them, the most dangerous gas well blowout took place on 8 January 2005 in Sunamganj district when chattak-2 (also known as Tengratila) gas field was drilled. As a result, the surrounding area is facing various problems among them water is the top of the list. From this point of view, the present study has been considered to find the impact of blowout on water around the gas blowout area. In this regard, the water samples (some are very near and some are away from the well) are collected and analyzed in the laboratory following the standard method. Some physical and chemical parameters of water such as pH, turbidity, EC, total solids, dissolved solids, suspended solids, manganese ion, calcium ion, magnesium, iron, chloride and total hardness have measured where without turbidity, manganese and iron, all are still in tolerable state for all purposes and ranging within standard limit based on WHO, EU and EQS for Bangladesh. The quality of the near well tube wells water is much decreased than far away tube wells water which might be the direct or indirect influence of the blowout incident around the area.

Case Report: Autoimmune Disease Triggered by Exposure to Hair Straightening Treatment Containing Formaldehyde

Formaldehyde (FHO) is a multipurpose chemical that is an eye, nose, throat and skin irritant, sensitizer and allergen, as well as a class 1 human carcinogen. Brazilian hair treatments, containing high levels of FHO (up to 11%), have become regularly used that have the potential to expose clients to toxic levels in excess of current regulatory standards. We report on a patient who underwent a single hair treatment and subsequently developed an autoimmune disease. We review the relevant literature on autoimmune disease and formaldehyde exposure. Our case adds to existing knowledge and suggests that physicians ask their patients about commercial products that contain formaldehyde when diagnosing autoimmune conditions.

Management of post-operative fistula in head and neck surgery: Sweeping it under the carpet?

The most dreaded complication in head and neck surgery is the development of fistula. Fistulas are common and devastating. The prevalence and the risk factors that contribute to fistula formation after head and neck procedures were discussed briefly. The main goal of this manuscript is to discuss current management of head and neck fistula. We believed that the best management strategy for head and neck fistulas is prevention. We recommend a holistic preventive approach during the perioperative period. The roles of different types of wound products and hyperbaric oxygen therapy were also discussed and highlighted. We also discussed the operative repair of fistulas, which relies on the tenet of providing well-vascularized tissue to an area of poor wound healing. Most often, the surgeon’s preference and range of operative skills dictate the timing and the type of repair. We highlighted the use of the pectoralis major, a well-known fap, as well as a novel technique in the surgical repair of complex, diffcult-to-heal head and neck fstula.

Off-Pump Multilayered Sutureless Repair for a Left Ventricular Blowout Rupture after Aortic Dissection Repair

A left ventricular (LV) free wall rupture is a highly lethal condition. A 75-year-old female who experienced chest pain was diagnosed as having an acute aortic dissection Stanford type A and underwent emergent surgery. Under cardiopulmonary bypass with LV venting through the right superior pulmonary vein, a proximal aortic stamp was formed. The patient was cooled, selective antegrade brain perfusion was performed, and a hemiarch repair was performed. After the patient was transferred to the intensive care unit, her blood pressure suddenly fell to 50 mmHg. She had a blowout rupture in the left ventricular anterolateral free wall. Since the bleeding hall was not large and the damage to the surrounding left ventricular tissue was not very wide, an off-pump multilayered sutureless repair was performed by using three layers of collagen fleece squares with fibrinogen-based impregnation (TachoComb;CSL Behring, Tokyo, Japan) and three layers of gelatin-resorcin-formalin glue reinforced by an equine pericardial patch (Xenomedica;Edwards Lifesciences, LLC, Irvine, CA). The blow-out rupture seemed to be caused by perioperative myocardial infarction generated by the compression of the left ventricular vent to the LV lateral wall. The patient was free from re-rupture or aneurysm enlargement. The thickness of the hemostatic material seemed to help control the bulging of the aneurysm and to prevent further LV aneurysm enlargement and re-rupture.

“美发”节目Blow Out将携新的经营模式重返荧屏

美国通用电气集团与法国Vivendi公司创建的大媒体集团NBC Universal的下属Bravo有线电视网．将要隆重推出“美发”节目——Blow Out的第二季．并会使用新的运营模式来进行筹措。