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Vertical linear lucencies through the atlas may be due to congenital clefts or fractures. We report a case of an isolated midline vertical fracture through the anterior atlas arch. The absence of corticated fracture margins on computed tomography distinguished this fracture from a congenital cleft. In similar cases, computed tomography is recommended to identify fractures that might other-wise be dismissed as congenital clefts.

Summary In the Adriatic offshore area, conventional cased-hole gravel-pack completions have generally produced low flow efficiences (10 to 50%) from the multilayered reservoirs of low-to-medium gas permeability (1 to 50 md). This has been attributed to the poor communication between the wellbore and the producing layers, caused by limited exposure of the interval and poor filling of the perforation tunnels with gravel. This is confirmed by openhole gravel-pack (OHGP) completions where much higher flow efficiencies are observed. The frac-pack technique, which combines gravel-pack and fracturing technologies, can improve communication between the layers in perforated completions by creating a vertical fracture with high conductivity and the injectivity necessary to fill the perforation tunnels. In addition, any existing near wellbore damage will be bypassed. This paper reviews the field experience gained from over 80 frac-pack operations that have been performed during the last 2 years in the thin, interbedded layers of poorly consolidated sand and shale commonly found in the Adriatic area. Owing to their relatively low permeability, these formations can be fractured with nonviscosified fluids at pump rates less than 1 bbl/min. Consequently, completion brine was selected as the treating fluid. To reduce operational time and costs, the frac-pack treatments were carried out with the gravel-pack assembly in place and injection rates of up to 7 bbl/min were used with gravel concentrations staged from 1 to 4 lbm/gal. Fluid losses were encountered after the frac-pack treatments and were controlled by spotting a small pill of drill-in fluid (containing calcium carbonate) that was sized to bridge inside the screens. This paper presents the production performance of the frac-pack completions and establishes guidelines for future applications of frac-pack operations in similar reservoirs.

Recently, steamflood and immiscible CO2 field pilots in a heavy oil reservoir in the Ikiztepe field, Turkey were successfully completed by Japan National Oil Corporation and Turkish Petroleum Corporation in collaboration with Japan EOR Research Association. The 1, 400m deep formation is a layered carbonate with 4.3-13.2°API heavy oil with a viscosity of 936mPa. s@Tres=50°C. The primary production by natural depletion was less than 1%. Though the viability of known EOR processes under such adverse reservoir conditions remained uncertain, field pilots were decided to be conducted, since the EOR technologies would give a large impact on recovery of heavy oils in southeastern Turkey.Both steam and CO2 processes employed inverted 5-spot pattern in areas of 100m×100m and 200m×200m, respectively. High pressure and temperature steam was injected through insulated tubing. After the initial cyclic steam stimulation, continuous injection and production followed. A total of 81, 400 CWEbbl steam was injected and 26, 200bbl of oil was recovered. Low injectivity of the steam and a vertical fracture created during the operation caused lower sweep efficiency. As the thermal conductivity of the insulated tubing was deteriorated with time and injection pressure, significant amount of heat was lost in the wellbore. Due to ultra high temperature, scaling of silica compound caused low operational time of the steam generator.The CO2 gas obtained from a neighbouring field was subjected to a membrane separation process to raise its purity to over 90%. The continuous injection of CO2 was preceded by three cycles of CO2 huff'n puff. A total of 340 MMSCF gas was injected which resulted in the recovery of 17, 000bbl of incremental oil. Production data indicated that the higher the CO2 gas purity and injection pressure, the higher was the oil recovery due to increased gas solubility into the reservoir oil.A good simulation history match has been obtained for each process. Additional post-pilot simulation studies included various approach, such as utilizing horizontal wells and injection strategy including a combined steam-CO2 process.

The icing flashover is increasingly becoming a serious problem with the development of the extra-high voltage engineering. Reducing the bonding strength between the substrate and the ice by super-hydrophobic coating is a choice for the anti-icing. The bare insulator, RTV coated insulator and the super-hydrophobic insulator are chosen for comparing. The experimental facility is set up. The vertical bonding strength, the vertical fracture energy, the shear bonding strength and the shear fracture energy are detected after first ice glaciations and second one. Results show that bonding strength between the super-hydrophobic substrate and the ice is less than that of the RTV coated insulator and the ice. The deiced surface still shows good super-hydrophobicity and the small ice bonding strength keeps almost the same which show good prospect for the anti-icing and de-icing.

Summary Pioneer Natural Resources in the Texas unconventional shale plays continues to utilize various microseismic technologies to better understand stress and pressure relationships that occur during hydraulic stimulation. Company-wide we have been primarily utilizing seismic monitoring equipment placed in the well bore, and to a lesser extent surface systems, to capture stimulation fracture geometries. These data are used to obtain a better understanding of the stress heterogeneity within the reservoir and completion as well as to optimize the well spacing. Over the past year we have monitored over 30 wellbores in Texas. In one study area, utilizing microseismic data as a proxy for pressure we have observed differences in fracture height, overlap of stages, magnitudes of events, number of events, as well as azimuthal changes within the microseismic data for various zones within our lower Permian age reservoirs. Pioneer has recently collected over twelve microseismic jobs (386 stages) using predominately one downhole acquisition system that allows for inter-comparisons of data in Reagan and Upton Co. Texas. We have minimized changes with the acquisition of the data, and the stimulation pumping parameters, so that we can track how changes to completion design are manifested in the rock. In some cases, our landing zones between wells have been modified so that we can assess the specific stress heterogeneity related to the geomechanical properties of different layers within the main pay zones. This broad foundation of data allows the individual to recognize differences within the stimulation as they relate to the geology or completion. Our datasets demonstrate the geometry of the pressure field as imaged with the microseismic data is variable and appears to be controlled by a number of factors including the local geology, completion practices, previous stimulations and adjacent production. Pioneer has mapped in detail the density of the microseismic event field, and noted variations in the height, length and widths of the hydraulic stimulation as well as the development of the pressure field away from the perforations. We have used the data to better understand well spacing and placement as well as define potential vertical fracture barriers for the Wolfcamp Formation. The knowledge gained from microseismic investigations, combined with reservoir models, have economic importance to the company as it plans future development of a shale oil play. Spacing decisions directly impact well count and capital deployed by the firm to maximize development of reserves.

Unconventional resource plays involve the development of some unusual reservoirs such as shale with effective permeability in the nano-Darcy range. Reservoir development of these resource plays requires drilling horizontal well with multi-stage hydraulic fracturing. Completion design that incorporates geological constraints is often the critical step as it dictates the drainage volume and well spacing to decide how the play will be developed in the future. There are numerous variables that dictate the choice of potential completion design and its impact on well performance. Understanding these key variables that control the outcome of massive hydraulic fracturing in a horizontal well is the need of the hour. This paper explores how readily available fracture pump data, pressure and rate data can be utilized to estimate and understand the unknowns involved in the completion and the reservoir parameters. In this paper, we compared wide range of datasets from multiple shale plays in North America to analyze the effect of well spacing, wellbore geometry, fracture spacing, fracture proppant to liquid ratio, and completion inefficiency on well performance. The results show how the changes in these parameters can be correlated to understand the overall potential of the well. These results can be used to build a knowledge base which can guide us towards best field development planning by reducing the amount of experimentation and thus help in cost saving. Introduction Completion parameters can have a significant impact on horizontal well performance in unconventional plays. Understanding completion effectiveness of these wells is always a challenge. Effective drilling and completing well requires understanding of the reservoir and rock quality. Reservoir quality parameters define hydrocarbon accumulation and flow properties. Rock quality defines the mechanical properties that dictate how rocks fracture. Reservoir quality is estimated from permeability (k), original gas in place (OGIP), porosity (φ) and water saturation (Sw). Rock mechanical properties can be estimated from rock mineralogy, Young’s moduli (Y) and Poisson’s ratio (PR). Jayakumar et al. (2013) studied the effect of completion parameters such as amount of proppant pumped during stimulation, pumping rate, lateral landing and wellbore placement on well performance. We studied other completion parameters such as well spacing, wellbore geometry, fracture spacing, fracture proppant to fluid ratio and other completion inefficiencies. Researchers have tried to understand the impact reservoir and rock quality on the overall well performance. Agarwal et al. (2012) has addressed some of the widely used completion techniques in five different shale plays from North America. Shebl et al. (2012) showed the effect of various rock and completion properties on vertical fracture growth and well performance. Shebl et al. (2013) talked about the importance of lateral placement in a shale reservoir based on the reservoir and rock properties of a nearby vertical well. Hashmy et al. (2012) identified sweet spots for stimulation based on the reservoir and rock properties of the horizontal well. Bartuska et al. (2012) showed how proppant and fluid tracers can be useful to answer several completion design questions. Xie et al. (2012), Bai (2012) URTeC 2013 Page 1329

Purpose: Marginal bone loss around implants is of great concern, and its cause may be multifactorial. Recently, clinical cases presenting marginal bone loss, in most cases accompanied by vertical fracture of internal connection implants in the bucco-lingual direction, have been reported, in which unfavorable stress distribution is one possible factor for marginal bone resorption. The purpose of the current study was to characterize this type of marginal bone loss and implant fracture by applying finite element analysis. Materials and Methods: From clinical and radiographic evaluation, the prostheses of all reported cases had implant-level setups and were directly screwed to the internal implants. Intriguingly, the vertical fractures reported were all in the bucco-lingual direction. Therefore, to characteristic the specific implant fracture, finite element analysis (FEA) was conducted with misfit models created for 2 different setups; abutment-level and implant-level, both with screw-retained prostheses. The 2 models were subjected to initial misfits of 0 µm (representing perfect fit), 50 µm, 100 µm, 150 µm or 200 µm, and vertical load was then applied to the models. Results: FEA revealed that for the implant-level setup, excessive stress at the neck of the implant gradually increased in the bucco-lingual direction as the misfit increased, which was not seen for the abutment-level setup. A broad maximum stress distribution was evident for the implant-level setup but not observed with the abutment-level setup. Conclusion: Broad distribution of excessive stress observed in the FEA correlated to the clinical cases, and marginal bone loss in these cases may be associated with the mechanical alterations. To avoid unnecessary complications, selection of an abutment-level setup is strongly suggested.

Summary This paper gives an accurate method for modeling the deliverability of gas-condensate wells. Well deliverability is calculated with a modified form of the Evinger-Muskat1 pseudopressure (originally proposed for solution-gas-drive oil wells). The producing gas/oil ratio (GOR) is needed to calculate pseudopressure, together with pressure/volume/temperature (PVT) properties (black-oil or compositional), and gas/oil relative permeabilities. The proposed method is successfully tested for radial, vertically fractured, and horizontal wells. Using the proposed deliverability model, we show that fine-grid single-well simulations can be reproduced almost exactly with a simple rate equation that uses pseudopressure. The key is knowing the producing GOR accurately. The effect of near-wellbore damage, vertical fracture, or flow improvement caused by horizontal well trajectory is readily incorporated into the rate equation as a constant skin term. The effect of gas/oil relative permeability is studied. We show that well deliverability impairment resulting from near-wellbore condensate "blockage" is dependent only on relative permeabilities within the range defined by 1 0.3) affect deliverability only for richer gas condensates. A key observation and conclusion from this study is that critical oil saturation has no direct effect on well deliverability. We also show that interfacial tension (IFT) dependence of relative permeability has little or no effect on gas-condensate well performance (e.g., length of plateau production). The most important application of this study is to provide a simple method for calculating bottom-hole flowing pressure (BHFP) in coarse-grid models. We show that the proposed pseudopressure method is readily calculated for each well grid cell on the basis of only grid-cell pressure and saturation (i.e., producing GOR). Local grid refinement near wells is not necessary, and relatively large well grid cells can be used and still provide an accurate description of well deliverability.

A two-dimensional numerical model of coupled fluid flow, heat transfer and rock mechanics in naturally fractured rock is developed. The model is applicable to assessments of hot dry rock (HDR) geothermal reservoir characterisation experiments, and to the study of hydraulic stimulations and the heat extraction potential of HDR reservoirs. Modelling assumptions are based on the characteristics of the experimental HDR reservoir in the Carnmenellis granite in Cornwall, S. W. England. In particular, the model assumes that fluid flow is horizontal and is confined to the most hydraulically conductive fractures in two orthogonal and vertical fracture sets. The mathematical model representing the hydro-mechanical interactions that are induced during reservoir creation is described. Furthermore, the solution method for calculating thermally induced stresses and strains in the reservoir due to heat extraction is discussed. The resultant numerical model, HOTGRID, is used to investigate the effects of stress perturbations on the fluid flow distribution in an HDR geothermal reservoir.

Aim To investigate the effect of MTA root canal fillings on the resistance to vertical root fracture (VRF) over different time intervals. Material and methods Freshly extracted anterior human teeth with single canals and minimal curvatures were decoronated, instrumented to size 50/.05 ProTaper file, irrigated with 1%NaOCl and randomly allocated to one of three groups (n = 36): (i) filled with MTA, (ii) filled with gutta-percha and sealer and (iii) unfilled roots used as a negative control. Each group was subdivided into three subgroups (n = 12) according to the storage time of 48 h, 1 and 6 months at 37°C in synthetic tissue fluid (STF). Following the storage periods, filled roots were mounted in acrylic supports, and the periodontal ligament was simulated using elastomeric impression material. Vertical loading was carried out with a ball-ended steel cylinder fitted on a universal testing machine at 1 mm/min crosshead speed. The maximum force at fracture (F-max) and the fracture mode were recorded for each root. Results Data were statistically analysed using two-way anova and Bonferroni post hoc tests. The mean F-max was significantly higher in the MTA subgroups after 1 and 6 months compared with all other subgroups. Two modes of fracture were identified: split and comminuted. The mean F-max values recorded with the latter were significantly higher compared with the former (P

We present the case of fishtail deformity of distal humerus in a 13-year-old boy presenting with a refracture 8 years after the original surgically treated lateral condyle fracture. This unusual incomplete vertical fracture of distal humerus starting at the apex of fishtail was treated non-surgically and went on to union but refractured yet again 12 months later. This also went on to full healing with conservative treatment, however the fishtail deformity persists. We discuss the possibility that fishtail deformity reflects an inherent weakness in the distal humerus. We suggest that children and parents should be warned about the potential risk for refracture, particularly if they participate in contact sports.

An analytical model for the constant-head pumping test is developed for a partially penetrating well that has a finite thickness skin, and intersects a single vertical fracture. In the model, the fracture is fully confined and flow occurs only in the fracture. The model is developed using Laplace transform and finite Fourier transform methods. The model is to be used for analysing well test data from vertically fractured media and for verifying numerical models. Dimensionless curves are used to study the effects of a finite thickness skin and a partially penetrating wellbore. In the presence of a finite thickness skin, or a partially penetrating wellbore, a typical flow response for the constant-head pumping test has three distinct periods of flow corresponding to small-, intermediate- and large-time. Small- and large-time approximations are presented for the model. For tests where the wellbore is fully penetrating, or the partial penetration ratio is known, these approximations can be used to analyse field data.

Hydraulic fractures as long as 13 m were created at depths of 2 m in overconsolidated silty clay glacial drift during a field test using equipment designed to create hydraulic fractures in oil wells. The vicinity of each fracture was excavated, typically revealing a continuous fracture whose geometry was defined by four zones: a vertical fracture adjacent to the parent borehole; a flat-lying fracture in the vicinity of the borehole; a gently dipping fracture that assumes a preferred direction of propagation away from the borehole; a vertical fracture that intersects the ground surface. The hydraulic fractures were gently dipping with a preferred direction of propagation that apparently was controlled by loading of the ground surface; the fractures propagated away from a back hoe parked next to the parent borehole. Sand pumped into some of the fractures formed permeable layers that could increase flow into or out of low-permeability soils or rock, suggesting that sand-filled hydraulic fractures could have a variety of geotechnical or environmental applications.

Numerical simulation of fluid explusion from geopressured sediments using a one-dimensional finite difference model shows that large volumes of fluid can be transported through a fractured seal during short-lived (

Fractures of the occipital condyle are rare. No previous report was found of concomitant fractures of the occipital condyle and the atlas, with the exception of a single case described under an unrelated title. The present case is that of a 26-year-old woman involved in a motor vehicle accident. The traumatic event resulted in significant axial loading. The pertinent clinical and radiographic findings are described, together with a review of the literature and a discussion. This case is felt to represent the first specific reporting of the simultaneous occurrence of fracture of the occipital condyle and cervical 1. An associated vertical fracture of the body of cervical 5 and subsequent advancement of the odontoid into the foramen magnum make this case even more unusual.

Introduction Fracture of rotary nickel-titanium files is a real concern among endodontists; it affects the long-term prognosis of treatment. Ultrasound is a favorable technique for removing broken files, although it may result in some complications. The aim of this study was to determine the success rate of ultrasonic technique in removing file fragments and to evaluate its influence on the force required to fracture a tooth root. Methods An in vitro study was carried out on 70 extracted maxillary premolars. In the experimental group a #30/.04 taper Hero file was guided into the canal to break and lodge therein. The lodged file was removed by ultrasonic vibration and use of a dental operating microscope. The canals were instrumented with Hero files by using crown-down technique and then obturated. All the teeth were prepared for mechanical testing in Testometric machine to measure the required force for root fracture. The Fisher exact test and independent two-sample t test were used to analyze data. Results Ultrasonic technique exhibited a success rate of 80% in removing broken files. Success rate in the roots with file fracture before the curve was 11.5 times more than that of file fracture cases beyond the curve. Other factors such as bypass possibility did not affect success rate. The average time required for removing file fragments was 36.3 ± 7.15 minutes, which did not significantly differ in different file locations within the canal. According to mechanical test results, ultrasonic application did not significantly affect the required force for root fracture. The force required to fracture a root did not significantly differ in various file locations. Vertical fracture in the buccolingual direction (split tooth) was the most incident fracture pattern. Procedural errors observed in this study predominantly included transportation, perforation, and craze line. Conclusions Ultrasonic technique was successful in removing 80% of fractured rotary files and did not significantly affect the required force for root fracture.

Rate decline analysis is a significant method for predicting well performance. Previous studies on rate decline analysis of fractured wells are all based on homogeneous reservoirs rather than homogeneous ones considering fracture face damage. In this article, a well model intercepted by a finite conductivity vertical fracture with fracture face damage is established to investigate how face damage factor affects the productivity of fractured well. Calculative results show that in transient flow, dimensionless rate decreases with the increase of fracture face damage and in pseudo steady-state flow, all curves under different face damage factors coincide with each other. Then, a new pseudo steady-state analytic formula and its validation are presented. Finally, new Blasingame type curves are established. It is shown that the existence of fracture damage would decrease the rate when time is relatively small, so fracture damage is an essential factor that we should consider for type curves analysis. Compared with traditional type curves, new type curves could solve the problem of both variable rate and variable pressure drop for fractured wells with fracture face damage factor. A gas reservoir example is performed to demonstrate the methodology of new type curves analysis and its validation for calculating important formation parameters. [DOI: 10.1115/1.4006865]

A unique case of a vertical fracture of the mandibular posterior ramus border secondary to the stress of the rigid internal fixation material is described in this study. We think that the surgeon's experience and awareness play a key role in avoidance of such a complication.

Svrha endodontskog liječenja je ukloniti inficirano tkivo iz korijenskih kanala, dezinficirati njihove stijenke, oblikovati i hermetički zatvoriti kanale te restaurirati zubnu krunu trajnim materijalom kako bi se osigurala funkcija, dugovječnost i estetika zuba. To se postiže trepanacijom i uklanjanjem koronarnog dijela pulpnog tkiva, određivanjem duljine korijenskog kanala te njegovim čišćenjem, oblikovanjem i punjenjem. Endodontska terapija može se pokazati neuspješnom zbog čitavog niza čimbenika. Terapeut može pogriješiti u dijagnostičkim postupcima kao što su uzimanje anamneze ili provođenje kliničkih testiranja, no i sama morfologija zuba i pulpnog prostora mogu bitno utjecati na ishod terapije. Pri čišćenju i oblikovanju korijenskih kanala do pogreške može doći zbog oblikovanja stube, stvaranja umjetnog kanala, perforacije stijenke korijena ili loma instrumenta u kanalu. Nadalje, pri punjenju kanala može se javiti nedovoljno apikalno, koronarno ili lateralno brtvljenje, može se krivo odrediti duljina punjenja, previdjeti postojanje lateralnih kanala, a pri kondenzaciji punila može doći i do vertikalne frakture korijena. Čimbenici koji ugrožavaju uspješnost endodontskog liječenja su intra ili ekstraradikularne infekcije te prisutstvo stranih materijala, kristala kolesterola, ožiljaka ili cista u periapeksu. Endodontsko liječenje mora se procijeniti na redovnim kontrolnim pregledima koji obuhvaćaju klinički pregled i radiološki nalaz. The main goal of the endodontic treatment is to remove the infected tissue from the root canals, to disinfect their walls, to shape and hermetically seal them and to restore the tooth crown with a permanent material in order to maintain the functionality, the longevity and the aesthetics of the tooth. This is achieved by trepanating the tooth, removing the coronal part of the pulp, determining the length of the canal and by cleaning, shaping and filling the root canal. The endodontic therapy can be unsuccessful for various reasons. The therapist can make errors during diagnostic procedures such as the gathering of the anamnestic information or the conducting of clinical tests. However, the morphology of the tooth and its pulp space can also greatly affect the outcome of the therapy. During the cleaning and shaping of the root canal the following errors can occour: zipping of the root canal, canal transportation, stripping or lateral wall perforation and instrument separation. Furthermore, the errors that can happen during the filling of the root canals include: apical, coronal or lateral leakage, the determination of a wrong filling length, the existance of lateral accessory canals or the vertical root fracture during lateral condensation. Factors that can compromise the outcome of the endodontic treatment include intra and extraradicular infections and the presence of alien materials, cholesterol crystals, cysts and scar tissue in the periapical area. The endodontic treatment must be evaluated during regular recalls that must include a clinical check-up and a radiological overview.

Conventional pressure-transient models have been developed under the assumption that reservoirs are areally homogeneous. Yet, core, log, and outcrop data indicate this assumption is not justified in many cases. Still, homogeneous models are applied to obtain an effective permeability corresponding to a fictitious homogeneous reservoir. This approach seems reasonable if the correlation length of the permeability variation is small compared with the interwell scale and the permeability variation is sufficiently small. Mishra et al. formed a heterogeneity index that contained the spatial correlation and the variation. One would suspect the homogeneous model might eventually fail as the permeability variation and correlation-length scale increase. The field data given below confirm that homogeneous models do not always apply. Instead, a model developed for a heterogeneous reservoir with a fractal structure matches the field tests. The model considers a reservoir that contains permeable and impermeable rock. The resulting permeable network is assumed to have a fractal structure, which imposes heterogeneities at all length scales. The permeability distribution is bimodal because, at any location, the permeability is either zero or a fixed finite value. The model treats a well with a vertical fracture in an infinite reservoir and is an extension of a previousmore » fractal model that handles a finite circular wellbore. Chang and Yortsos have previously applied a fractal model to naturally fractured reservoirs.« less

This paper is the second of two papers that address the influence of geologic structures on ground water flow at various scales in fractured rocks. The ultimate purpose of this research is to investigate the feasibility of grouting preferentially permeable zones as a strategy to minimize the production of acid mine drainage in underground hard rock mines in which the major permeability is structure and fracture controlled. The aim of grouting is to reduce permeability around mined-out openings, to minimize the rate of inflow of ground water into such openings via the structurally controlled preferentially permeable pathways. A series of hydraulic stress tests were conducted to help characterize the role of geologic structures in controlling the ground water flow system in the vicinity of the Bunker Hill Mine in north Idaho. The results of these tests indicate that most of the ground water that flows from the underground drillholes used for hydraulic stress testing is derived from a few discrete, structurally produced fracture zones that are more or less connected through smaller-scale fractures. Four types of analytical models are considered as a means of analyzing the results of multiple drillhole hydraulic stress tests, as follows: cross-hole equivalent porous media; double-porosity equivalent porous media; a solution to flow in and around a single vertical fracture; leaky equivalent porous media, partial penetration. The estimation of hydraulic coefficients in complex fractured rock environments involves the combined application of a number of deterministic analytical models. The models to be used are selected dependent on the location of the drawdown observations relative to the water-producing zone and the length of the test. The result of the tests can be related to the permeability hierarchy discussed in our first paper.

Most of the drilled wells are conducted on acidizing in order to eliminate the permeability reduction due to mud filtration. This type of formation damage is more sever in naturally fractured wells due to the high conductivity of fracture. If the radius of the damage due to lost circulation of drilling fluid is determined, the volume of acid needed to conduct any acid job could be calculated. Also, prediction of the near-wellbore conditions, such as mud filtrate radius, is important for accurate interpretation of the well-logs used for measuring and monitoring the properties of the near-wellbore formations. In this paper a mathematical model is developed to investigate the amount of mud filtration during drilling operation in a well with a finite conductivity vertical fracture in an infinite slab reservoir. Convection-dispersion filtrate transport model is developed in which the drilling mud can be mixed with the formation fluid. A systematic step-by-step procedure illustrating the methodology of the proposed model for the analysis of mud filtration in a finite conductivity fractured well is presented. This model is formulated for linear flow in both fracture and matrix. The effect of the filter cake is simulated by means of an empirically decaying filter rate equation. The developed model is solved by numerical analysis. The consistency of the numerical solution is checked and the best situation is considered. The sensitive analysis has been done on all the parameters of the model and the effect of each parameter such as wellbore pressure, fracture permeability, fracture diffusion coefficient, matrix permeability, matrix diffusion coefficient, matrix porosity, viscosity, constants related to the filter cake formation and fracture width on the amount of filtration are investigated. By means of the proposed model, the mud filtration can be plotted against position in both fracture and matrix for different wellbore and reservoir properties. The position in the fracture and matrix at which the curve of concentration reaches zero could be considered to represent skin radius. This radius could be used for the determination of the acid volume which is needed for the acidizing operation. Also, this model is a useful tool for accurate interpretation of the resistivity profiles which are essential for the development of efficient well-log interpretation.

An uncertainty and probabilistic sensitivity study of a hypothetical underground high-level waste (HLW) repository intersected by a vertical fracture or fault and under saturated conditions is presented. Several recently developed probabilistic methods, including the advanced mean value method and the adaptive importance sampling method, are applied to a previously developed one-dimensional analytical model. These probabilistic methods are based on a limit-state formulation and provide an effective means of computing performance probability distribution and probability-based random parameter sensitivities. A numerical example related to the transport of 237 Np in a system of Iayered fractured rock is used to illustrate the application of these probabilistic methods for efficient uncertainty and probabilistic sensitivity and analyses

Madarati AA, Qualtrough AJE, Watts DC. Vertical fractureresistance of roots after ultrasonic removal of fractured instru-ments. International Endodontic Journal, 43, 424–429, 2010 . Aims To investigate ex vivo root resistance tovertical fracture after fractured instruments wereultrasonically removed from different locations inthe root canal.Materials and methods Fifty-three canine rootswere weighed and divided into four groups. Eight rootsserved as a control group in which canals wereinstrumented to a size F5-ProTaper instrument. In theexperimental groups, F5-ProTaper fragments werefractured in the coronal, middle and apical one-thirds,and then removed ultrasonically. The time required forremoval was recorded. Roots were reweighed, andcanals were shaped to a size F5-ProTaper and filledwith GuttaFlow. After incubation, roots underwent avertical fracture test in which the force at fracture wasrecorded. The difference in root mass before and aftertreatment (fractured file removal or canal preparation)was calculated. Data were analysed using the Kruskal–Wallis, Mann–Whitney post-hoc and regression tests atP < 0.05.Results The highest root-mass loss was recordedwhen fragments were removed from the apical one-third (46.04 mg) followed by the middle and coronal(27.7 and 13.5 mg, respectively); these differenceswere significant (P < 0.05). There were significantdifferences in the force required for vertical fractureamongst the experimental groups (P < 0.05) with thelowest mean force recorded in the apical-third group(107.1 N) followed by the middle and coronal (152.6and 283.3 N, respectively). The highest mean forcewas recorded in the control group (301.5 N) whichwas not significantly different from that in the coronalgroup (P=1.00). A negative exponential correlation(r = 0.669) existed between the root-mass loss and theforce required to fracture the roots.Conclusion Whilst removal of fractured instrumentsfrom the coronal one-third of the root canal can beconsidered as a safe procedure, removal from deeperlocations renders the root less resistant to verticalfracture.Keywords: complications, fractured instruments,removal, root resistance, separated, ultrasonics, verticalfracture.

P>The aim of this in vitro study was to test the effect of different post systems on fracture strength of roots with re-attached fragments. Root canals of eighty extracted single-rooted human teeth were instrumented (ProFile) and randomly divided into two groups. The roots in the first group were vertically cracked, and the fragments were re-attached using Super Bond C&B (Sun Medical, Tokya, Japan). The roots in the second group were kept sound. Obturation of the roots was performed with MetaSEAL (Sun Medical) and gutta-percha. Post spaces were prepared, and the roots were restored with one of the followings: UniCore (Ultradent), Everstick (Stick Tech), Ribbond (Ribbond), ParaPost (Coltene/Whaledent) (n = 10). Four mm high build-ups were created (Clearfil DC Bond Core; Kuraray, Tokyo, Japan). Compressive loading of the samples was performed after 24 h (1 mm min-1). Mean load necessary to fracture each sample was recorded (Newton) and statistically analysed (One-way anova, t-tests). ParaPost showed the highest fracture strength among the roots with re-attached fragments (P < 0.05). UniCore and ParaPost systems showed similar fracture strength in the sound roots (P > 0.05). Re-attached fragments significantly reduced the fracture strength of roots in UniCore group (P = 0.000). Ribbond post showed mostly repairable fractures. Metal post (ParaPost) showed the highest fracture strength in the roots with re-attached fragments; however, fracture pattern was 41% non-repairable. Re-attached fragments significantly reduced the fracture strength of the roots in UniCore group. Prefabricated posts showed similar fracture strength in the sound roots. Customized post systems EverStick and Ribbond showed mostly repairable failure after loading in sound roots or roots with re-attached fragments.

An 18-year-old rugby player suffered pain at the left lumbosacral junction after intensifying his level of practice. Plain radiographs were negative, but single-photon-emission computed tomography and three-dimensional bone scan images showed a lesion on the left neural arch of L-5. After conservative treatment and 10 pain-free weeks, he resumed training. One week later, symptoms recurred, and standard computed tomography showed a vertical fracture through the S-1 facet. This rare fracture illustrates the need to consider the unusual injury, especially in younger athletes who participate in high-level sports.

Standardized plastic analogues simulating an endodontically treated maxillary central incisor root were used to investigate the resistance to root fracture in endodontically treated teeth. Three different post and core systems were used: (1) cast post and core, (2) Para-Post Plus post, and (3) Flexi-Post post. The core build-up material selected in this study was Ketac Silver material, after which a crown preparation was made on each analogue. Two types of preparations were used: a wide chamfer margin (butt-joint) and a wide chamfer margin with a 1.0 mm circumferential bevel. An overcasting was fabricated and was permanently cemented on each preparation. Assemblies were subjected to an increasing lingual oblique force until fracture occurred. Results were tabulated using the analysis of variance (F test) and Student's t test. Beveled preparations with a concomitant final restoration provided a significant increased resistance to root fracture. Furthermore, vertical fracture occurred twice as often with nonbeveled preparations.

The various structures and yarn-bundle spacing of 3D-5 (three directions, 5 mm), 5D-5 (five directions, 5 mm), and 3D-7.5 (three directions, 7.5 mm) preforms are fabricated into three-dimensional carbon-carbon (C/C) composites. The fracture behaviour is different due to the increased number of arrangement directions and fracture toughness. The flexural strength, short-beam shear strength, and microstructure of fractured specimens were investigated to study the mechanical behaviour of these composites. The results revealed that the strengths of the three-dimensional composites were larger than the five-dimensional ones in all reinforcement structures, but five dimensions were better than three dimensions in fracture toughness. The five-dimensional composites showed stepwise fracture, and the three-dimensional vertical fracture. In the aspect of yarn-bundle spacing, the flexural strength of the 7.5 mm type (spacing between twoZ axial yarn bundles is 7.5 mm) was higher than the 5 mm type, while the short-beam shear strength was contrary, Furthermore, according to SEM observations, the fractural surface was ruptured along theZ-axis, indicating that a stress concentration would exist in the fringe of theZ-axis, and that theZ-directional fibres arrested delamination propagation.

We reviewed 28 cases of tension band wiring for the fracture of the patella, in which subcutaneous wiring was used in 21 cases. There were 11 males and 17 females with an average age of 58 years old (20-80). They were classified into 17 transverse, 6 three-parts, 4 comminuted, and 1 vertical fracture. The evaluation of the treatment, before the removal of the wire, was performed based on Watanabe's score. All patients showed satisfactory results, with 22 evaluated as excellent, 5 as good, and 1 as fair.

We report a patient with vertical fracture of the mandibular condyle visualized by computed tomography (CT). A 43-year-old woman visited our department the day after the injury occurred. At the initial examination, she experienced pain in the left temporomandibular joint (TMJ) when opening her mouth. Maximum mouth opening distance was 15 mm. Routine radiography showed normal findings, but CT revealed vertical fracture of the left mandibular condyle. Based on clinical findings, conservative therapy consisting of intra-articular pumping therapy and training for mouth opening was initiated. After 10 days, mouth opening distance increased to 36 mm, and pain in the left TMJ disappeared.

Isolated sacral fractures which occur by shear forces on the pelvic ring are seen less commonly and they are commonly transversely oriented. A 29-year-old Turkish female patient, who sat in front seat in the car, was unrestrained, and another car hit them from right front side of their vehicle. Physical examination revealed considerable tenderness over the right superior gluteal region and excruciating pain during sacral and iliac compression. There was no clear fracture line in her plain radiographs. CT revealed incomplete, zone I fracture located on the superior and anterior part of the first sacral vertebra. Type 1 lateral compression pelvic fractures are relatively common and they include impacted sacral and ipsilateral rami fractures. Only a few cases, related with the isolated sacral fracture, have been reported in the literature. To our knowledge, no isolated vertical zone I fracture of the first sacral vertebra which occurred with the lateral compression injury has been described previously. Fracture of the sacrum should be suspected in the presence of sacral pain and tenderness.

For vertical fracture sets at arbitrary orientation angles to each other – but not perfectly randomly oriented – a detailed model is presented in which the resulting anisotropic fractured medium generally has orthorhombic symmetry overall. Analysis methods of Schoenberg are emphasized, together with their connections to other similarly motivated and conceptually related methods by Sayers and Kachanov, among others. Examples show how parallel vertical fracture sets having HTI symmetry turn into orthotropic fractured media if some subsets of the vertical fractures are misaligned with the others, and then the fractured system can have VTI symmetry if all the fractures are aligned either randomly, or half parallel and half perpendicular to a given vertical plane. Another orthotropic case of vertical fractures in an otherwise VTI earth system treated previously by Schoenberg and Helbig is compared to and contrasted with other examples discussed here.

The propagation of Stoneley waves in a fluid‐filled borehole with a vertical fracture is investigated both theoretically and experimentally. The borehole propagation excites fluid motion in the fracture and the resulting fluid flow at the fracture opening perturbs the fluid‐solid interface boundary condition at the borehole wall. By developing a boundary condition perturbation technique for the borehole situation, we studied the effect of this change in the boundary condition on the Stoneley propagation. Cases of both hard and soft formations have been investigated. The fracture has minimal effects on the Stoneley velocity, except in the very low frequency range in which the Stoneley velocity drastically decreases with decreasing frequency. Significant Stoneley‐wave attenuation is produced because of the energy dissipation into the fracture. The quantitative behavior of these effects depends not only on fracture aperture and borehole radius, but also on the acoustic properties of the formation and fluid. Ultrasonic experiments were performed to measure Stoneley propagation in laboratory fracture borehole models. Aluminum and lucite were used to simulate a hard and a soft formation, respectively. Array data for wave propagation were obtained and were processed using Prony’s method to give velocity and attenuation of Stoneley waves as a function of frequency. In both hard and soft formation cases, the experimental results agreed with the theoretical predictions. The important result of this study is that it presents a quantitative relationship between the Stoneley propagation and the fracture character in conjunction with formation and fluid properties. This relationship provides a method for estimating the characteristics of a vertical fracture by means of Stoneley wave measurements.

In a departure from previous studies [1, 4] no restrictions are imposed on the shape of the fracture and the effect of the latter on the change in well productivity as a result of hydraulic fracturing and on the lengthwise distribution of the flow through the fracture surface is investigated.

Metopism is partially or totally persisting suture extending from the nasion to the anterior angle of the bregma. The time of physiological closure of the meto- pic suture varies from birth to 8 years of age. Widely accepted closuring time is approximated at 2 years of age. Although formerly reported skull studies mentioned the persistent metopic suture, it is extremely rare in clinical practice. We presented a trauma case of 43 years of age who was demonstrated radiologically to have a persisting suture. Persistent metopic suture may be misdiagnosed as a vertical traumatic skull fracture extending in the mid-line in head trauma patients. Therefore the surgeon should be aware of this anatomical condition in the primary and secondary surveillance of the traumatized patient and during surgical intervention including especially frontal craniotomy. Reconstructed tomography scan demonstrating sutural closuring status may provide additional informative value in the diagnostic sequence superior to plain X-ray in the emergency setting. El cuadro denominado metopismo consiste en la persistencia parcial o total de la sutura que se extiende desde el nasion hasta el ángulo anterior del bregma. El tiempo de cierre de la sutura metópica oscila desde el momento del nacimiento hasta los ocho años. El criterio más aceptado es que el cierre suele terminar a los dos años. Algunos estudios mencionaban la posibilidad de la persistencia de dicha sutura a lo largo de toda la vida, pero es excepcional en la práctica clínica. Se presenta un caso de traumatismo de 43 años de edad, que mostraba en la radiología la falta de cierre de dicha sutura metópica. Aunque puede considerarse como una anomalía rara, también puede con una fractura vertical frontal, cercana a la línea media, en pacientes con traumatismos. Por lo tanto, el cirujano debe percatarse de este hecho anatómico en la atención inicial del paciente y en la planificación de una craneotomía bifrontal. En este trabajo se señala que la reconstrucción tridimensional de la TAC añade una información valiosa al estudio radiológico convencional en la unidad de urgencias.

WOS: 000248997400009 PubMed: 17622463 Metopism is partially or totally persisting suture extending from the nasion to the anterior angle of the bregma. The time of physiological closure of the metopic suture varies from birth to 8 years of age. Widely accepted closuring time is approximated at 2 years of age. Although formerly reported skull studies mentioned the persistent metopic suture, it is extremely rare in clinical practice. We presented a trauma case of 43 years of age who was demonstrated radiologically to have a persisting suture. Persistent metopic suture may be misdiagnosed as a vertical traumatic skull fracture extending in the mid-line in head trauma patients. Therefore the surgeon should be aware of this anatomical condition in the primary and secondary surveillance of the traumatized patient and during surgical intervention including especially frontal craniotomy. Reconstructed tomography scan demonstrating sutural closuring status may provide additional informative value in the diagnostic sequence superior to plain X-ray in the emergency setting.

Microseismic imaging of a hydraulic fracture stimulation showed significant fracture reorientation across a thrust fault. Fracture orientations were identified through a combination of alignment of event locations, polarization of the seismic waves and injection details. Stimulation below the fault indicated a near horizontal fracture geometry. Above the fault, a near vertical fracture geometry was observed. This difference in fracture geometry was attributed to rotations in the direction of minimum principle stress, which is consistent with observed differences in the injection pressures. The fracture reorientation suggests a significant difference in the stimulated permeable pathways.

A vertical root fracture (VRF) in an endodontically treated tooth is one of the most frustrating complications of dental therapy. VRFs are a particularly significant clinical problem because they are associated with a poor prognosis for the affected tooth and often lead to tooth extraction. This report presents a case of a VRF in a nonendodontically treated mandibular second premolar, for which the displaced fractured fragment appeared to be that of a mandibular molar in the radiograph.

The aim of this study was to compare vertical forces at fracture of teeth obturated with different materials. Single-rooted teeth were divided into five groups. The first group served as a negative control. The remaining four groups were shaped using ProTaper rotary files (Dentsply Maillefer, Ballaigues, Switzerland). The second group was obturated with gutta percha and a zinc oxide sealer. The third group was obturated with EndoRez points and EndoRez sealer (both from Ultradent, South Jordan, UT). The fourth group was obturated with Resilon (Pentron Clinical Technologies, Wallingford, CT) and RealSeal sealer (Pentron Clinical Technologies). The fifth group was obturated with Guttaflow (Coltene/Whaledent, Altstatten, Switzerland). Roots were then fixed into a universal testing machine and loaded with a spreader until fracture. It was found that forces at fracture were statistically significantly higher in the Resilon and EndoRez groups. It was concluded that obturation of roots with resin-based obturation materials (Resilon and EndoRez) increased the resistance of root canal filled teeth to vertical root fracture.

This is the published version. Copyright 2006 American Geophysical Union. All Rights Reserved.

A mathematical model was developed to study the behavior of a well with variable finite-conductivity and skin fracture, for a vertical fracture in an infinite slab reservoir. The solution is valid for slightly compressible fluid and gas fluid applying the pseudo-pressure concept. The constant rate with wellbore storage and constant pressure are the production modes considered. Curves type are used to showsthe effect of the changes of conductivity and skin near the well and in the extreme of the fracture. A field test was analyzed to detect the changes of the properties. This model is a tool to analyze real cases when the fracture properties are affected during the productive life of the well.

We have developed a modeling code using the finite element method (FEM) to simulate laterolog responses in three-dimensional inhomogeneous formation models. The code has been benchmarked against analytical solutions and the numerical mode-match method (NMM) for subsets of the 3D geometry. The differences between our results and two others are within 5%. We have further employed the code to simulate the laterolog responses in horizontal and highly deviated wells. The results show that the apparent resistivity decreases with the degree of well deviation from vertical, given the formation model is unchanged. The decreasing ratio also increases with the increase of deviation angle. This becomes significant when the deviation angles are between 40 and 90 degrees. When the angle is close to 90 degrees, the response closes to the average resistivity of shoulder and mud. Finally, we have studied the response of laterolog in formations containing a vertical fracture. The results demonstrate that it is not possible to detect a single vertical fracture with such a laterolog when the fracture width is less than 0.001 m. However, the vertical fracture has significant effects on the apparent resistivity when its width is above 0.01 m. The resistivity of the fluids in the fracture is another important parameter to control the changes of the apparent resistivity. The relative influence of fractures on the apparent resistivity increases with the increase of the contrast between the fluid resistivity and the background formation resistivity.

AIM: To describe a rare case of gemination involving a mandibular first premolar. SUMMARY: The complex morphology of geminated teeth renders their endodontic and periodontal management difficult. Root canal and periodontal treatments were performed on a geminated mandibular first premolar with three canals. Clinical examination showed two separated crowns with united roots. Radiographically, two distinct pulp chambers with two joined and a third independent canal were seen. Conventional root canal treatment resulted in complete healing of the apical lesion. However, the occurrence of a vertical fracture led to the extraction of the mesial segment. At the follow-up visit, the distal segment was clinically healthy and continued to satisfy functional demands.

The patient was a 35-year-old man who was evaluated by a physical therapist in a direct-access capacity for a chief complaint of right ankle pain and an inability to bear weight. Because the patient was unable to bear weight on his right lower extremity, the physical therapist ordered radiographs of the right ankle, which demonstrated a vertical fracture through the body of the talus. J Orthop Sports Phys Ther 2014;44(9):722. doi:10.2519/jospt.2014.0410

International audience; A steady-state analytical solution is given describing the temperature distribution in a homogeneous massif perturbed by cold water flow through a discrete vertical fracture. A relation is derived to express the flow rate in the fracture as a function of the temperature measured in the surrounding rock. These mathematical results can be useful for tunnel drilling as it approaches a vertical cold water bearing structure that induces a thermal anomaly in the surrounding massif. During the tunnel drilling, by monitoring this anomaly along the tunnel axis one can quantify the flow rate in the discontinuity ahead before intersecting the fracture. The cases of the Simplon, Mont Blanc and Gotthard tunnels (Alps) are handled with this approach which shows very good agreement between observed temperatures and the theoretical trend. The flow rates before drilling of the tunnel predicted with the theoretical solution are similar in the Mont Blanc and Simplon cases, as well as the flow rates observed during the drilling. However, the absence of information on hydraulic gradients (before and during drilling) and on fracture specific storage prevents direct predictions of discharge rates in the tunnel.

This operation was designed out of a need for hydraulic stimulation - whithno height increase - in a highly homogeneous medium with a water table (SierrasBlancas Formation, YPF.Nq.Bco x-3 ST well). From this, an artificial lowerbarrier was placed to control growth in the direction of the water and acrosslinked gel pad was pumped (followed by sand concentrations carried by alinear gel for sand settling) to give rise -upon fracture closure - to adehydrated gel zone of poor permeability. Furthermore, a water inhibitor wasused as an additive for improved water control. Furthermore, a water inhibitorwas used as an additive for improved water control. As an additional advantage, Bottom Screen Out (BSO) pumping might result inan increased fracture length which in turn would lead to a better productionresponse from stimulation, a "sine qua non" condition in lowpermeability reservoirs.