bluuebunny/crossref_metadata_2025 huggingface dataset:
Economic Factors in the Expanding LP-Gas Industry
Authors: Barnes Winthrop M.
Published: February 2020

Gas Technology Symposium, 17–18 April, Shreveport, Louisiana

Introduction

This study is directed toward examination of the techno-economic problems associated with the natural gas liquids industry. It aims at collection and analysis of the broad technical and economic data vital for a clear understanding of the opportunities available to/and the problems confronting the industry. Consideration is given to the LP-Gas and natural gasoline industries.

In considering the LP-Gas industry, attention is given to:the nature of demand for LP-Gas [for domestic and commercial applications, internal combustion engines, chemicals and synthetic rubber];the availability of supply and required incentives for increased supply;the importance of efficient transportation and storage to permit effective balance of supply and demand; andan over-all picture of industry action required to achieve the maximum potential. An analysis is made of the natural gasoline situation and of future engine and fuel developments which will influence it.

This study does not attempt to answer fully all of the industry problems. It does attempt to define the problems in their proper perspective, to supply some of the basic data required to study them, and to suggest possible avenues of approach. Its aim is to stimulate the individual and collective industry thinking and action required to achieve early maturity.

Domestic and Commercial Market for LP Gas

There are strong indications that the competitive position of LP-Gas as a domestic fuel is not as strong as it must be if this market is to continue to represent 50 per cent of the total for LP-Gas.

LP-Gas must compete with electricity and oil for the domestic and commercial markets. Frequently, appliance purchases are made on the basis of one fuel for cooking, another for water heating, and possibly a third for home heating; the public has not become particularly single utility conscious. The electric industry is invariably a fairly large, well-staffed organization, with funds available for well-planned advertising and sales promotion efforts, and has gone far to promote the domestic and commercial market for its product. On the other hand, the LP-Gas sales, particularly in rural areas, are frequently handled by small dealers who do not have the abilities and backing of the large utility.
Predicting Reservoir Performance by Applying an Unsteady State Solution
Authors: Layton D.D.
Published: February 2020

Gas Technology Symposium, 17–18 April, Shreveport, Louisiana

It is often desirable to predict gas well performance during a relatively short period after opening the well. The conventional methods will become unreliable in the cases of tight or altered formations. This paper explains the mechanics of one of several solutions of performance predictions under unsteady state conditions. The solution, devised by Katz and Cornell, centers around a graphical presentation of the pressure disturbances in a reservoir created by constant flow rates. The variables in the graphical presentation are dimensionless and can be applied to a variety of problems. The procedures in the solution of two problems determining reservoir limits and predicting maximum injection pressure are discussed here, including numericalexamples.

Introduction

The reservoir engineer is called upon to predict different aspects of performance of a gas well with time. Often new completions are involved with no production histories. The engineer then relies on core analyses, and backpressure or production tests using Darcy's law or the back pressure equation. This becomes unreliable when the formation has a low permeability or if it is sufficiently altered from its original state. In these cases performance prediction by applying solutions of the unsteady state equation are useful as well as in other situations where prediction of pressure change with time are needed.

Unsteady State

When a gas reservoir is in an unsteady state, it can be considered as unstable. The flowing pressure with a constant rate is continually changing with time. For practical purposes, the well becomes stabilized when gas in place at its ultimate drainage radius begins moving toward the well bore. After this time further pressure decline under constant rate is caused by depletion. In tight formations pressure change with distance from the well bore is rapid. Draw-down at the well bore is large, while a few feet away, the reservoir will be in an undisturbed condition. This results in steep pressure sinks, which move slowly toward the ultimate drainage radius. During this time, in which a pressure disturbance is being created outward from the wellbore to the ultimate drainage radius, the well is unstabilized and is regarded as being in a condition of unsteady state.
Applications of Recent Reservoir and Petrophysical Developments to a Field Study
Authors: Bethel F.T. , Welbourn M.E.
Published: February 2020

Fifth Annual Joint Meeting of the Rocky Mountain Petroleum Sections of AIME, 2–3 April, Casper, Wyoming

A reservoir and petrophysical study was made of the Red River (Ordovician)reservoir of the Gas City field. The heterogeneous carbonates which make up the reservoir were grouped by the physical properties which control fluid saturations and fluid flow. The fluid content of the reservoir was determined from the capillary characteristics of the groups of rocks and from porosities calculated from the radioactivity log. It was found that the reservoir void volume contains a large percentage of fine pores and a high average water saturation; however, distribution of the larger pores was such that all ranges of porosity will contribute some oil to production.

The utilization of an electronic computer to calculate porosity from the neutron log proved an effective, rapid means for evaluating a large number of logs. Saturation calculations from electrical logs were used as a check on capillary determinations, and the results of the two different methods were substantially in agreement.

The methods outlined should result in a more accurate estimate of reservoir fluid content and a better understanding of reservoir performance.

Introduction

The engineering study of an oil reservoir has as its major objectives (1) the determination of the types and quantities of fluids in place at the original reservoir conditions, (2) the determination of the productive forces active in the reservoir, and (3) an estimate of the fluids which will be produced under various methods of operation. Particularly during the early life of an oil field, the original contents of the reservoir can be estimated most accurately by determining the volumetric and saturation parameters of the intervals being exploited. For this purpose core analysis and various types of well logs are in general use.
Gamma Ray-Density Logging
Authors: Zak Albin J. , Smith Joe Ed
Published: February 2020

Permian Basin Oil Recovery Conference, 7–8 May, Midland, Texas

This paper presents a review of current methods of interpreting and applying gamma ray-density logs in evaluating fundamental reservoir data. The basic theories and physical principles underlying the techniques of density logging with gamma rays are discussed along with some of the problems associated with the instrumentation of such a tool. An effort has been made to evaluate the instrument calibration techniques, and discussion and figures are presented which describe the effect of borehole conditions, pressure, temperature, etc. The relationship of natural density, grain density, and interstitial fluid density to porosity is presented. Field data illustrate how density logs can be correlated with porosity and grain density data. With the aid of adequate core analysis data, a reasonably accurate estimate of formation porosity can be obtained from density log interpretation. The paper also offers a discussion of the limitations of the density log as a porosity tool. The current applications of the density log to geologic work are cited, and the prospective uses and future developments are briefly explored.

The principle of gamma ray absorption as a function of density was adapted to the logging of petroleum formations through the utilization of a phenomenon known as "back-scattering". This technique uses a tool which contains both a gamma ray source and detector. The detector measures the intensity of the gamma rays emitted from the source that have been back-scattered to the detector by the formation. After proper instrument calibration, the log response can be used to compute the natural density of the formation. Since there is a definite relationship between natural density and porosity, it is possible to predict formation porosity from density logs. It is necessary to correlate carefully density log data with core analysis data before the direct correlation of density log response with porosity can be made.
Design and Operation of Jet-Bit Programs For Maximum Hydraulic Horsepower, Impact Force or Jet Velocity
Authors: Kendall H.A. , Goins W.C.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 219, 1960, pages 238–250.

Several investigations in recent years have shown that drilling rates are increased significantly with increased hydraulic horsepower. But, there has been no overall method of designing jet-bit programs that efficiently uses the surface power. A study of present practices indicates that frequently as little as 50 per cent of the possible effects at the bit are used.

Some observers have indicated that the best utilization of hydraulic horsepower (maximum effect on drilling rate) occurs when the bit hydraulic horsepower is maximum; others have stated that jet impact force is more important, and others have believed that maximum jet velocity is required. Limited efforts to date have shown some optimum conditions for bit hydraulic horsepower and impact, but these conditions cannot exist during drilling of a large part of the hole and do not provide a basis for designing a complete jet-bit program.

This paper shows the maximum obtainable bit horsepower, impact force and jet velocity at all depths, taking into account the limitations of the pump, piping, hole and minimum circulating rate for adequate cuttings removal. Ranges of operation are developed; and flow rates, surface pressure and bit pressures are specified for each range to provide a maximum of any one of the desired effects. It also is shown that, by proper selection of nozzle sizes and by following the rules presented, the maximum obtainable quantities can be effectively utilized from surface to total depth.

Finally, a simple graphical method of selecting nozzle sizes and flow rates is presented which can be used with familiar bit-company hydraulic tables and calculators to design jet-bit programs for maximum bit hydraulic horsepower, impact or jet velocity, as desired. These programs make most effective use of the pumps.

Heretofore, there was no method available for designing field tests which adequately separated the effects of bit horsepower, impact and jet velocity. The programs and procedures developed in the paper are dissimilar and, when used in future field testing, should demonstrate which program is the most important in obtaining the fastest drilling rate.
Chromatographic Transport of Reverse-Wetting Agents and Its Effect on Oil Displacement in Porous Media
Authors: Michaels Alan S. , Timmins Robert S.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 219, 1960, pages 150–157.

A study of the effect upon oil recovery from an unconsolidated porous medium of chromatographic transport of selected reverse-wetting additives during water displacement is described. Flow tests were performed on hydrocarbon oil-saturated sand columns (containing connate water) into which small volumes of short-chain aliphatic amine solutions were introduced during water flooding. Concurrently, measurements of oil-silica contact angles, oil-water interfacial tensions and oil-water distribution coefficients were measured as a function of additive concentration.

Certain treatments were found to cause a slight reduction in oil recovery, while others produced a significant increase (up to 50 per cent of the normal irreducible minimum oil saturation). Recovery efficiency was correlated most satisfactorily with the maximum degree of reverse wetting produced during additive transport; conditions which resulted in only mild oil wettability of the sand reduced recovery, while those favoring strong oil wetting increased recovery.

A mechanism of reverse-wetting additive action during chromatographic transport is developed which ascribes the results to transient changes in oil-solid contact angle during flow, with consequent release of oil trapped by capillary forces. implications of these observations with regard to improved waterflood efficiencies are discussed.

Introduction

The need for finding improved methods of oil production is amply illustrated by the large volume of oil considered economically unrecoverable by existing production practice. Water flooding has long been an excellent method of secondary recovery. However, even in those areas of a formation which are well swept by a water flood, 20 per cent or more of the oil remains trapped within the formation and is not recovered. This trapping of oil within the pores of the rock structure results primarily from interfacial forces. If these interfacial forces were altered, it is possible that the trapped oil could be released and recovered.
Performance Predictions for Low Productivity Reservoirs
Authors: Carter R.D. , Tracy G.W.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 219, 1960, pages 195–200.

Numerical calculations were made to determine the behavior of reservoirs with high-pressure drawdown and wide well spacing where the initial productivity is low and the wells are completed by hydraulic fracturing. The two-phase flow equations were solved for the flow into a single well. This well was assumed to be producing from a reservoir with hydraulically created horizontal fractures (four different systems with fractures were studied).

For comparison purposes, additional two-phase flow calculations were made assuming a reservoir with uniform rock properties. The two-phase flow results were also compared with the conventional calculation methods, which do not include the effect of saturation gradients resulting from a simultaneous flow of oil and gas which are normal to this type reservoir.

It was found that the conventional methods predicta high and too optimistic value of ultimate recovery,a high producing rate and a high reservoir pressure at a given oil recovery anda low trend of gas-oil ratio with oil recovery.

Included in the two-phase flow calculations were provisions to control the oil production rate by an allowable rate and, also, by a gas-oil ratio penalty rule. For the systems with hydraulic fractures, the producing rate was controlled by the gas-oil ratio penalty rule for most of the life. This is in contrast to the system with uniform rock properties which went "on decline" almost immediately. An unexpected characteristic of the systems which included fractures was the early rise in producing gas-oil ratio from 730 cu ft/bbl to approximately 1,200 cu ft/bbl, followed by a "leveling off" before the normally expected gas-oil ratio rise began. Additional features which are a result of hydraulic fracturing aregreater ultimate recovery,higher average producing rates anda lower average reservoir pressure at a given oil recovery.
Calculation of Crude-Oil Recoveries by Steam Injection
Authors: Landrum Bobby L. , Smith James E. , Crawford Paul B.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 219, 1960, pages 251–256.

A method is presented by which the displacement efficiency of a steam-injection process may be determined. The method consists of a determination of the position of the steam front at a particular time and the application of the Buckley-Leverett theory to the hot and cold regions of the reservoir with the appropriate hot or cold fluid properties. A uniform, linear flow system is assumed for this study.

The method is applied to a number of reservoir conditions. The primary properties which affect the results of a steam-injection process are the oil viscosities at steam and reservoir temperatures, injection rate, pay thickness and oil saturation.

The efficiency of steam injection is compared with that of water injection for a 10-acre, linearly flooded reservoir. In reservoirs where the oil viscosity is about 35 times the water viscosity, the steam process yields recoveries about 20 per cent higher than the waterflood. Where the oil viscosity is near 500 cp, the steam process may recover from three to four times as much oil as a water flood.

Introduction

In a previous paper, a method was suggested for evaluating a steam-injection process. Emphasis was placed upon the determination of the steam-front position in the reservoir at various times. In the present paper, the displacement process is studied in more detail. The approach is essentially that employed by Jordan, Rayne and Marshall in their study of hot-water injection.

The steam-injection process is quite complex, and an exact description of the process has not been found; however, a qualitative description can be made. When a quantity of steam is injected into a relatively cold reservoir, the leading edge of the steam front continually flows into cool sand, and some steam condenses. As more and more steam condenses, a bank of condensed water will form which is augmented by displaced connate water. The reservoir may be divided in three regions,a region containing displaced fluids at reservoir temperatures,a region containing water at reservoir temperature anda region occupied by steam. The reasons for the lack of a region of hot water or oil of any appreciable size have been discussed.
Design and Operation of Stage 1 of the KMA Waterflood, Southwest Unit
Authors: Calhoun G.H. , Sleeper W.J.
Published: February 2020

Secondary Recovery Conference, 2–3 May, Wichita Falls, Texas

The design and early operation of Stage 1 or this 4640-acre water flood unit, involving 45 working interest owners and 175 royalty owners, are described and illustrated. The KMA sandstone (Zones I and II), whose subsea depth is about 2800 feet, is the reservoir being flooded. Unitization was effected July 1, 1958, and Stage I, which covers 1800 acres, began operating on May 8, 1959.

The fundamental design principle, whose objective was to effect the maximum oil recovery from the minimum combined capital and operating costs, is no different than the aim of most well-planned projects; however, some of the flood facility features - such as centrifugal injection pumps, bare steel lines, simplicity of water conditioning, and the degree of automation - are somewhat pioneering for a secondary recovery project. For example, the automation, which includes complete electrification, affords routine operating control and emergency shutdown of any part or all the system.

As a result thereof, only four men - each working five 8-hour days per week- are required to operate Stage I, which includes 14 water source wells, 118flood wells (58 injection and 60 producing), and the central injection and treating plant having a nominal injection capacity of 40,000 barrels per day.

The system is entirely unattended 128 hours per week. Any operating upset or emergency, that might occur during an unattended period, automatically signals the local telephone exchange, which in turn calls the Operator's appropriate personnel who correct the defect.

Some 8,700,000 barrels of water had been injected at the end of January,1960, or an average of 32,400 barrels per calendar day. Limited yet encouraging flood response was realized by the end of 1959.

Introduction

The unitization for water flooding purposes of the southwestern portion of the KMA Field, which is now designated "KMA Water Flood, Southwest Unit", was first envisioned about 1949. The geographic location of the Unit is shown on Figure 1. Subsequent cooperative studies by several of the major leaseholders in the subject area indicated the engineering feasibility and economic justification of the project.
ESP Failures: Can We Talk the Same Language?
Authors: Alhanati F.J.S. , Solanki S.C. , Zahacy T.A.
Published: February 2020

Several operators have recently launched a new industry-wide initiative focused on sharing failure information, operational practices and other pertinent data, in an effort to gain a better understanding of the various factors that affect ESP run life in any one application. Early on, the companies involved acknowledged that there were many challenges in such an effort, one of the main ones being how to achieve consistency in the data collected by several operators.

This paper presents an approach to establish consistent practices for collecting, tracking and sharing ESP run life and failure information. The approach is based on two key elements:

- a general and common data set; and

- a standard nomenclature for coding ESP failure information.

The general data set contains basic information on operating conditions, ESP equipment, and the observed failures. While this data set is not overly detailed, in that the information is typically already collected by most operators and relatively easy to obtain, it is comprehensive enough so that meaningful analyses can be performed. The nomenclature standard builds on the International Standard ISO142241 and on the API Recommended Practice (RP) 11S12. Broad definitions and failure attributes follow the guidelines of ISO 14424, while nomenclature for components, parts and possible teardown observations follow the terminology suggested by API RP 11S1.

The paper also provides a review of the past practices in the industry, with regards to the types of data collected, and the main types of analysis performed with the data. Comments are included on difficult related issues, such as the tracking of used equipment and the treatment of running systems, when evaluating current operations or making future failure rate predictions.

It is hoped that the paper will encourage discussion on the topic, and help the industry share ESP run life data in a more consistent manner. The ultimate goals are to assist the industry improve ESP run life, expand the use of ESP's, and better realize the full potential of the ESP technology.

Introduction

Operators and vendors have long identified that having a failure tracking system in place is key to reducing failure rates of ESP systems3–33. Problems with system design, equipment specification, manufacturing, installation, and day-to-day operation can be identified and corrected, contributing to increased run lives, lower operating costs and increased profits. As a result, many operators and vendors have set up database systems to track ESP run life and failure information.
There's No Free Lunch, Pumping Two Phase Fluids with ESP
Authors: Wilson B.L.
Published: February 2020

This paper examines the conjecture that a properly designed centrifugal pump will have no problem with free gas. The centrifugal pump is a dynamic pumping device. One of the traditional limitations has been their inability to handle significant quantities of gas. This doesn't mean that it can't handle gas but there is a cost. The user must recognize the operation boundaries that depend on the situation and the equipment selected.

This presentation reviews the nature of gas in its relation to well production with Electrical Submersible Pumps and examines some gas handling methods and devices more recently introduced to the industry. It also attempts to quantify limitations to two phase production with ESPs.

What is Gas?

Crude oil is not by nature a homogeneous substance. It is a mixture of a large variety of elements and short, medium and long chain hydrocarbons. The API gravity of an oil can be interpreted as a bulk average of the substances present at standard conditions. Under sufficient pressure, the natural gas and the oil exist together in a liquid phase. When the pressure is decreased, the mixture expands. As pressure is continued to decreased, the elemental gases and lighter hydrocarbons molecules have sufficient energy to liberate themselves from the liquid to form a separate gas phase. The point at which the gas phase first appears is the bubble point. The composition of the gas at this point is a function of the solubility of the individual constituents in the remaining liquid. The lighter gasses tend to come off first. The gas phase is in a complex equilibrium state between the evolved substances and the substances still left behind in solution. As pressure continues to decrease, the gas phase expands and the liquid phase shrinks.

The Bubble Point is a property of the bulk solution. High bubble point crude oils may have larger volumes of gas in solution, and/or greater percentages of the light substances in the gas phase. Removing a portion of the dissolved gas changes the properties of the remaining crude. For a given sample of crude with a 5,000 psi bubble point, if the pressure is lowered to 3,000 psi and the gas cap is bled off, the remaining crude will have an increased API gravity, viscosity and a 3,000 psi bubble point.

The relation between the liquid phase and the gas phase is represented by the gas oil ratio (GOR). It represents the volume of liberated gas in contrast to the volume of liquid at standard conditions of temperature and pressure. This can be expressed as a direct ratio, (barrels per barrel, or cubic meter per cubic meter) or in Oil Field Units as standard cubic feet of gas per barrel of oil (SCF/BBL). GOR values of several hundred are common and values exceeding1000 are not unknown. The goal of artificial lift is to maximize the production of oil from a well and it is accomplished by drawing the well pressure down as far as practical.
Determination of Fracture Orientation from Pressure Interference
Authors: Elkins Lincoln F. , Skov Arlie M.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 219, 1960, pages 301–304

Inclusion of anisotropic permeability in mathematical analysis of pressure transients observed during development of the huge Spraberry field indicates a major fracture trend which is in good agreement with that observed by fluid-injection tests spread over a 12- by 17-mile area. Delineation of this trend is important in selecting a pattern of injection for the pending large-scale water flooding in this field. Determination of reservoir parameters yielding best agreement between calculated pressures and observed reservoir pressures in newly completed wells was made using an IBM 650 computer.

Introduction

The Spraberry field covering 400,000 acres is a tight sand of less than 1-md permeability cut by an extensive system of vertical fractures. Primary recovery dominated by capillary retention of oil in the fractured sand matrix blocks is less than 10 per cent of oil in place. Strong forces of capillary imbibition of water into the sand, coupled with water flow under dynamic pressure gradient, indicate considerable increase in oil recovery can be achieved through water flooding. Best results will occur if the pattern of water injection is selected to force the water flow across the grain of the major fracture system.

Existence of an oriented vertical fracture system in the Spraberry, observed first in cores, was highlighted more recently by the 144-fold contrast in permeability along and at right angles to the major fracture trend required to match relative water breakthrough times in Humble Oil and Refining Co.'s waterflood test there. Spraberry Operators since have conducted two gas-injection tracer tests for further areal confirmation of the fracture trend. Re-analysis of early reservoir pressure transients for evidence of anisotropic permeability has permitted many more local determinations of major fracture trend without resort to further field tests.

This paper is limited to updating analysis of reservoir pressure transients to include anisotropic permeability as a test for orientation of the major fracture trend in the Spraberry. The reader is referred to Ref. 1 and 2 for information about general Spraberry reservoir performance and to Refs. 3 and 4 for information about significance of fracture orientation in selection of the injection well pattern for water flooding the Spraberry.
Successful Application of Volatile Acid System to Treat Water Blockage in a Gas Well: A Case Study
Authors: Hussnain Muhammad Sana-ul , Anjum Zulfiqar Ali , Arif Muhammad , Ansari Mansoor Ahmed , Dar Afnan Ahmed , Temuri Saqib Jah , Yousaf Arif , Ali Yasir , Khokhar Saad Yousaf
Published: February 2020

Formation damage associated with water blockage is a common problem in oil/gas producing wells. Water blockage is a damage mechanism which occurs when water saturation increases near wellbore, resulting in reduced hydrocarbon saturation and relative permeability to gas. When pore spaces around the well get nearly saturated with water, it reduces gas saturation to near irreducible level that block the gas flow. It decreases the gas production and may recover naturally by extended flow back or excessive drawdown. However, in depleted reservoirs, gas production may completely be lost and shall require chemical treatment. In this paper, a case study has been presented illustrating the complete loss of production of a gas well owing to the water blockage and the treatment mechanism to restore the production (SPE 102383).

Well ‘A’ was drilled in Sindh, Pakistan in 2010 in Lower Goru Formation. Later, the well was put on compression and was found on natural decline. By Feb 2019, well was producing 1.14 MMSCFD gas, 6 BPD condensate, and 43 BPD water with 123 psi FWHP. In March 2019, well was shut-in for the pressure build-up (PBU) survey. However, when the well was opened to flow, there was complete loss of production.

Identification of the causes of production loss was a major challenge in designing the job. After analysis of well behavior, gradient survey data and formation properties, it was found that the loss of production was attributed to water blockage caused by prolonged exposure of water.

Based on above analysis, a stimulation treatment using Volatile Acid System was designed to address the water blockage. The improved cleanup with volatile acid can be expected for two reasons; (1) increased volatility and (2) lower surface & interfacial tensions (SPE-191292-MS). The increased volatility results in lower water saturation and improving relative permeability to gas. Volatile acid system lowers the surface tension and increases the vapor pressure (gas saturation/relative permeability of gas near the damaged zone) and improves the clean-up of spent acid and retained water. In addition, presence of alcohol in acid system helps in achieving deeper penetration into the rock matrix. The proposed solution of Volatile acid system proved successful not only in reviving well's production but also with a gain in production of about 300%.
The use of the ratio of C-reactive protein to albumin for the diagnosis of complicated appendicitis in children
Authors: Feng Wei , Yang Qian-Yu , Zhao Xu-Feng , Li Miao-Miao , Cui Hua-Lei
Published: February 2020

Background: No reliably specific marker for complicated appendicitis has been identified. The ratio of serum C-reactive protein (CRP) to albumin (ALB) (CRP/ALB ratio) is a new inflammation-based prognostic score that is associated with the severity of inflammation. However, its value in the diagnosis of complicated appendicitis has not been studied. The aim of this study was to evaluate the predictive value of the CRP/ALB ratio for the diagnosis of complicated appendicitis in children.
Methods: A retrospective study of 232 children with acute appendicitis was conducted with assessments of age, sex, symptom duration, albumin and routine blood indexes on admission. According to intraoperative findings and postoperative pathological results, patients were divided into a simple appendicitis group (127 patients) and a complicated appendicitis group (105 patients). SPSS version 17 was used to analyse the data.
Results: Of the 232 patients, 118 (50.9%) were male and 114 (49.1%) were female. The CRP/ALB ratio was higher in complicated appendicitis than in simple appendicitis (p<0.05). Logistic regression analysis showed that higher levels of mononuclear cell count (MC), CRP, procalcitonin (PCT) and CRP/ALB ratio were independent risk factors for complicated appendicitis in children. Receiver operating characteristic curve analysis showed that the area under the curve of the CRP/ALB ratio (0.946) was larger than that of MC (0.619), CRP (0.906) and PCT (0.843). A CRP/ALB ratio >1.43 was found to be a significant marker in the prediction of complicated appendicitis, with 91.4% sensitivity and 90.6% specificity. Patients with a CRP/ALB ratio >1.43 had a 102.22 times higher chance of having complicated appendicitis (95% CI: 41.322 - 252.874) than those with a CRP/ALB ratio ≤1.43.
Conclusion: The admission CRP/ALB ratio was significantly higher in children with acute complicated appendicitis. The CRP/ALB ratio is a novel but promising haematological marker that aids in the differentiation of acute complicated and simple appendicitis.
Water, sanitation and hygiene (WASH) Promotion: A qualitative analysis of experiences of stakeholders in rural KwaZulu-Natal
Authors: Mulopo Chanelle , Chimbari Moses J
Published: February 2020

The authors have requested that this preprint be removed from Research Square.
Neoneurogenesis in squamous cell carcinoma of tongue: a promoter to its progression and metastasis
Authors: Xu Zhenq , Shang Jianw , Xiang Xu , Long Li , Yan Yingb , Zhang Jun
Published: February 2020

Background : To explore whether neoneurogenesis is a predisposing factor to the development and metastasis of squamous cell carcinoma of tongue (TSCC) . Methods: Twenty patients diagnosed with TSCC were included. The objectives were divided into 4 groups according to WHO T-stage standard (five cases in each group) and 2 groups based on lymph node metastasis or not. Detection of neoneurogenesis in paraffin sections from primary tongue cancer tissues was stained by Neurofilament-Light chain antibody (NF-L) using immunohistochemistry method (IHC). The number of new growth nerve fiber bundles was calculated in each randomized view from 3 non-overlapping microscope fields of each tumor section under a light microscope at X 200. Differences in the density of nerve fiber bundles among the T-stage groups and lymph node metastasis groups were calculated using Chi-square test. An ɑ level of 0.05 was considered statistically significant. Results: The age of patients varied from 33 to 74 years with a mean age of 56.10±11.18 years. Males were affected predominantly with a ratio of 1.5:1 to females. IHC staining of NF-L was positive in all 20 paraffin sections of TSCC which suggested that newly growth nerves (namely neoneurogenesis) were observed in tumor mciroenvironment. The intensity of newly formed nerve bundles increased with T stage, and the difference was statistically significant between early stage (T1、T2) and late stage (T3、T4) (p=0.000). Increased prevalence of newly growth nerve bundles correlated significantly to the cervical lymph node metastasis (p=0.000). Conclusions: Neoneurogenesis in tumor microenviroment of TSCC is a predisposing factor to its aggressive development and cervical lymph node metastasis. From a therapeutic perspective, further studies on the topic may provide a new clinical opportunity through anti-neurogenesis.
A meta-analysis of tunica vaginalis fascia versus dartos fascia to prevent postoperative urethrocutaneous fistula in hypospadias and fistula repair
Authors: Yang Hao , Hu Dong-lai , Xuan Xiao-xiao , Zhang Hang , Shu Qiang , Guo Xiaodong
Published: February 2020

Background: Urethrocutaneous fistula (UCF) is the commonest postoperative complication in hypospadias and fistula repair. Several flap procedures have been recommended to decrease this complication rate, but no single flap procedure is ideal. The aim of this study was to compare the outcome of tunica vaginalis fascia (TVF) and dartos fascia (DF) as intermediate layers in prevention of the formation of UCF.
Methods: We searched PubMed, EMBASE, the Cochrane Library and Web of Science for comparative studies up to July 1st, 2019. Studies were selected by the predesigned inclusion criterias. The primary outcomes was UCF incidence.
Results: The pooled RR with 95% CI were calculated. We extracted the relevant informations from the included studie. 9 comparative studies were included The RR of UCF rate for TVF was 0.21 (95% CI: 0.09-0.51, P=0.0005) compared with DF in hypospadias and fistula repair. For other postoperative complications, the RR was 0.87 (0.28-2.70, P=0.80), 1.33 (0.41-4.35, P=0.64) and 0.17 (0.03-0.88, P=0.04) for meatal stenosis/ urethral stricture, glans dehiscence/ wound dehiscence and skin necrosis, respectively.
Conclusions: This meta-analysis reveals that TVF is a better option in TIP repair as compared to DF in terms of decreasing the incidence of the UCF and skin necrosis. But there is limited for other hypospadias operative techniques and fistula repair.
registration number: PROSPERO CRD42019148554
The experience of high flow nasal cannula in hospitalized patients with 2019 novel coronavirus–infected pneumonia in Chongqing, China
Authors: Wang Ke , Zhao Wei , Li Ji , Shu Weiwei , Duan Jun
Published: February 2020

Background The outbreak of a novel coronavirus (2019-nCoV)–infected pneumonia (NCIP) is currently ongoing in China. Most of the critically ill patients received high flow nasal cannula (HFNC). However, the experience of HFNC in this population is lacking. Methods We retrospectively collected the NCIP patients who received HFNC in two hospital of Chongqing, China from January 1st to February 18th, 2020. The clinical characteristics were collected. Patients who required upgrading to noninvasive ventilation (NIV) were defined as HFNC failure. Results We enrolled 17 patients in this study. Of them, 7 patients (41%) experienced HFNC failure (6 required upgrading to NIV, and one to NIV and further to intubation). The HFNC failure rate was 0% (0/6), 57% (4/7) and 75% (3/4) (p =0.03 between 3 groups) in patients with PaO2/FiO2 >200, 150-200, and <150 mmHg, respectively. In the successful patients, the respiratory rate, heart rate and PaO2/FiO2 significantly improved from initiation to termination of HFNC (27±3 vs. 21±2 breaths/min, p <0.01; 86±15 vs. 76±12 beats/min, p =0.03; and 213±49 vs. 299±125 mmHg, p =0.04, respectively). However, in the unsuccessful patients, the respiratory rate and PaO2/FiO2 significantly deteriorated (22±3 vs. 25±3 breaths/min, p =0.04; and 160±27 vs. 105±24 mmHg, p =0.01, respectively). When they upgraded to NIV, the PaO2/FiO2 improved after 1-2 h of NIV (105±24 vs. 202±111 mmHg, p =0.04). In the total cohort, only PaO2/FiO2 at baseline was lower in unsuccessful patients than that in successful ones (213±49 vs. 160±27 mmHg, p =0.02). Conclusions This study firstly provides the experience of how to use HFNC in patients with NCIP. Patients with lower PaO2/FiO2 were more likely to experience HFNC failure. Among the failure patients, most of them can avoid intubation when they were ungraded to NIV.
A tracheostomy shared decision making program in respiratory care center patients in Taiwan
Authors: Huang Chienhsiu , Chen Ihung
Published: February 2020

Background: Tracheostomy is recommended for respiratory care center prolonged mechanical ventilation patients who cannot be liberated from the ventilator in the short term. However, most patients or their families oppose having this procedure. We applied [If my family is difficulty liberated from the ventilator, do he/she need to undergo tracheostomy?] tracheostomy shared decision making program for respiratory care center prolonged mechanical ventilation patients. The program is expected to enable patients to undergo tracheostomy, improving patients’ medical care and outcomes. Methods: We apply tracheostomy shared decision making program to patients who were admitted to a respiratory care center. Data of patients in the respiratory care center who participated in tracheostomy shared decision making program were collected and analyzed. The survival of patients and the optimal decision marking of tracheostomy shared decision making program were tracked. Results: A total of 57 patients participated in tracheostomy shared decision making program. Of these, 39 patients (68.4%) were men, and 18 (31.6%) were women. The mean age was 69.6 years. At the end of the study, 37 patients underwent tracheostomy (64.9%), and 20 patients maintained endotracheal tube intubation (35.1%). There was no significant difference in the factors of concern and the degree of concern about the methods of treatment in the two group patients. Patients or their families of the two groups have a good understanding of the two methods of treatment. The survival rate of patients undergoing tracheostomy was 86.5%, but only 86.5% of participants believed that they made an optimal decision based on the result of the tracheostomy shared decision making program. Conversely, the survival rate of patients who maintained endotracheal tube intubation was 40%, but the all of participants believed that they made an optimal decision based on the result of the tracheostomy shared decision making program. The overall 91.2% of participants made an optimal decision marking of the tracheostomy shared decision making program. Conclusions: The clinical application of tracheostomy shared decision making program has achieved excellent results. Patients who underwent tracheostomy will have a longer survival time.
A facile extramedullary method to perform primary total knee arthroplasty in patients without hardware removal: a case series
Authors: Tseng Yu-Kai , Chen Yen-Nien , Chang Chih-Han , Lai Kuo-An , Yang Chyun-Yu , Chang Chih-Wei
Published: February 2020

Background It is technical demanding to execute primary total knee arthroplasty (TKA) for post-traumatic knee arthritis with periarticular implants. Our purpose is to present a simple extramedullary guide technique and report the clinical results of our series of primary TKAs in patients with post-traumatic arthritis without hardware removal. Methods Between April 2014 and March 2019, a series of seven patients with post-traumatic knee arthritis and retained hardware were included. All the surgeries were performed by the same surgeon. The mean age of the patients was 67 years. All the index procedures were performed with primary TKAs by the same surgeon according to simple extramedullary technique. The parallelism between the distal femoral and proximal tibial cuts as well as the required limb alignments were verified intra-operatively. Radiographic measurements and clinical outcomes were reviewed retrospectively. Results Overall, there was a good restoration of postoperative mechanical alignment in all cases. The mean post-operative Hip-Knee-Ankle (HKA) angle was 179.4°. No patient required allogenic blood transfusion or prolonged hospital stays. No surgical site-specific complications were noted by chart review. In the last follow-up, no implant failure was found. Clinical assessments according to knee society score showed good knee scores (89.1), functional scores (87.9) and motion arc (112.9). Conclusions Our results show that post-traumatic knee arthritis can be safely managed with this extramedullary method without hardware removal.
Biceps tendon instability with or without pulley tears: an arthroscopic diagnostic study
Authors: Kao Jo-Ting , Chiu Chih-Hao , Hsu Kuo-Yau , Chang Shih-Sheng , Chan Yi-Sheng , Chen Alvin Chao-Yu
Published: February 2020

Background To investigate long head of the biceps tendon (LHBT) instability and biceps reflection pulley (BRP) lesions with dynamic arthroscopy in patients with refractory anterior shoulder pain and determine associated intraarticular pathologies. Methods Patients with refractory anterior shoulder pain and arthroscopically-diagnosed LHBT instability were enrolled. LHBT instability was confirmed by either static dislodge from the groove or subluxation induced by the hook probe (ramp test), and the integrity of BRP and concomitant intra-articular lesions were investigated. Demographics and arthroscopic findings were compared between patients with and without BRP tear. Results A total of 40 patients with refractory anterior shoulder pain and arthroscopically-diagnosed LHBT instability identified through review of medical records at a single surgeon’s practice from 2014 to 2017 were enrolled. BRP tear was noted in 25 patients (group A) and superior glenohumeral ligament (SGHL) insufficiency through ramp test, in 15 patients (group B). No significant difference of patient characteristics was observed between the two groups. Concomitant intraarticular pathologies were noted in 27 patients, including 19 in group A (76%) and eight in group B (53%), without significant group-wise difference (P = 0.083). The incidence of articular-side subscapularis tear was significantly higher in group A (P = 0.021), and those of the other intraarticular pathologies were similar between groups A and B. Fraying at the articular side of the subscapularis and supraspinatus tendons was frequent in group B, without difference of incidence as compared to group A (P = 0.5 and P = 0.084, respectively). Conclusions LHBT instability was a common disorder in patients with refractory shoulder pain. In patients with refractory anterior shoulder pain, dynamic assessment of BRP lesions and SGHL insufficiency and meticulous survey of associated intra-articular pathologies, including subscapularis tear are necessary for making accurate diagnosis.
Vitrectomy for branch retinal vein occlusion with vitreous hemorrhage: proposal for a new grading system
Authors: Tong Gengmin , Hu Xuting , Zhu Chenlei , Gao Zhiqiang , Chen Xuhao , Guo Linning , Pan Qintuo
Published: February 2020

Purpose To investigate the long-term surgical outcomes after treatment with pars plana vitrectomy (PPV) combined with photocoagulation in different severities of branch retinal vein occlusion (BRVO) with vitreous hemorrhage (VH) in order to propose a new grading system. Methods We retrospectively reviewed the medical records of 117 eyes of 117 patients who underwent PPV for VH associated with BRVO and who were followed up for at least 12 months. Preoperative best-corrected visual acuity (BCVA), surgical intervention, final BCVA, and central foveal thickness (CFT) were evaluated using optical coherence tomography. We proposed a system to grade BRVO with VH from Grade I to Grade III with increasing severity: Grade I,pure persistent VH; Grade II,VH with epiretinal membrane (EM) (Grade IIa,VH with EM without macular involvement; Grade IIb,VH with EM with macular involvement); and Grade III,VH with tractive retinal detachment. Different surgical methods were appliedaccording to the different retinal conditions. Results BCVA significantly improved at final follow-up in all groups. There was no significant difference among the four groups in terms of preoperative BCVA, final BCVA,CFT,or the number of patients whose macular edema recurred after surgery (p>0.05), but there was a significant difference in vision improvement(p<0.05). Vision improvement in the Grade IIb group was significantly worse than in the Grade I group(p=0.006) and in the Grade IIa group(p=0.046). The percentage of patients in the Grade I, Grade IIa, Grade IIb, and Grade III groups needing further laser treatment after surgery was 0%, 8.3%, 16.3%, and 23.5%, respectively (p<0.05). Conclusion We proposed a new grading system for BRVO treated with PPV. Vitrectomy is a safe and effective treatment for BRVO with VH. Visual acuity improvement was significantly worse when the EM had macular involvement (Grade IIb).