Fatigue Life Analysis of Coiled Tubing in Deep Well Jet Plugging Removal

The coiled tubing plugging has become the main means of plugging in gas Wells in Xinjiang. These Wells are deep and have high pressure, which can easily affect the fatigue life of the operating coiled tubing. In order to improve the life of coiled tubing in high-pressure gas Wells, this paper studies the plugging conditions of coiled tubing in high-pressure ultra-deep Wells. Firstly, the cross section deformation of coiled tubing under high internal pressure is analyzed. Secondly, the factors influencing the fatigue life of coiled tubing and the influence of surface damage on the fatigue life of coiled tubing were studied. Finally, the mechanism of furrow damage caused by coiled tubing and the main measures to reduce furrow damage are analyzed. The following suggestions are made to improve the life of coiled tubing: select the right material and the right size coiled tubing;Use appropriate measures to prevent premature coiled tubing failure and reduce operating costs.

Investigations into the coiled tubing partial underbalanced drilling (CT-PUBD)technique for drilling hard formations

To improve the rate of penetration(ROP) in drilling deep and hard formations, this paper proposes a new drilling method called coiled tubing partial underbalanced drilling(CT-PUBD). As a preliminary investigation into the new drilling method, this paper presents predictions of hole cleaning efficiency, drilling speed, cuttings migration and pressure loss in the drilling process with CT-PUBD. Based on numerical simulation and full-scale experimental studies, we conclude that using CT-PUBD, an underbalanced drilling condition can be achieved near the bit while maintaining wellbore safety at the same time. This condition can be achieved using a cuttings discharge device, a rotary packer and a backflow controller.According to the numerical simulations performed in this study, CT-PUBD can achieve high efficiency of hole cleaning.Along the cuttings migration process, the fluid velocities can reach the maximum values in the backflow holes. A full-scale laboratory experimental system was used to test the hydraulic characteristics and obtain the drilling performance of the new technology. The result shows that CT-PUBD significantly improves the ROP compared to the conventional drilling method.

ANALYSIS OF SPATIAL COMPLIANCE BEHAVIOR OF COILED SPRINGS VIA SCREW THEORY

A new method is presented to describe and analyze the spatial compliance ofcoiled springs using screw theory. After an abbreviated description for the deformation of a beamelement using screw theory, the spatial compliance density for a beam element is derived based onthe fundamental material theory and reasonable assumptions, and the spatial compliance of the beamwith finite length is obtained by integral. The spatial compliance of coiled springs is furtheranalyzed using the spatial compliance density of the beam element. By calculating theeigencompliance and Ball's principle screws for the whole compliance of system, the complianceproperties varying with the basic physical parameters of the system are illustrated in detail. Thebasic ideas can be used for the design and application of the coiled springs and the other compliantmechanisms with spatial compliant beam element.

Effects on the mixing process of a coiled tube after a T-junction:Simulation and correlation

Simulations were performed to examine the effects of a coiled tube after a T-junction on the mixing and flow characteristics. A coiled tube was found to have two effects: inducing a radial flow and flattening the axial velocity distribution, which enhances and weakens the mixing, respectively. In the straight tube section connecting the Tjunction and coiled tube, the latter may dominate and cause the mixing to deteriorate. An experiment was performed with the Villermaux/Dushman method to verify the simulation results. Based on a mixing performance simulation with various fluid and geometric structure parameters, a dimensionless correlation was obtained that can be used to determine the mixing intensity along the coiled tube with a deviation of less than 1.5%.These results provide guidance for designing a coiled tube or optimizing the operating conditions to meet the mixing requirements of specific chemical processes.

Preliminary build and application of a data analysis platform for coiled tubing steel strips

To solve the problems in the quality control and improvement of coiled tubing steel strips production, such as scattered and inefficient production data, difficult performance fluctuation factor analysis, complex multivariate statistical analysis, and low accuracy and difficulty in mechanical property prediction, an industrial data analysis platform for coiled tubing steel strips production has been preliminarily developed.As the premise and foundation of analysis, industrial data collection, storage, and utilization are realized by using multiple big data technologies.With Django as the agile development framework, data visualization and comprehensive analyses are achieved.The platform has functions including overview survey, stability analysis, comprehensive analysis(such as exploratory data analysis, correlation analysis, and multivariate statistics),precise steel strength prediction, and skin-passing process recommendation.The platform is helpful for production overviewing and prompt responding, laying a foundation for an in-depth understanding of product characteristics and improving product performance stability.

A solids-free brine drilling fluid system for coiled tubing drilling

There are many problems associated with coiled tubing drilling operations, such as great circulation pressure loss inside pipe, difficulties in weight on bit(WOB) transferring, and high probability of differential sticking. Aiming at these problems, solids-free brine drilling fluid system was developed on the basis of formulation optimization with brine base fluid experiment, which was evaluated and applied to field drilling. Based on the optimization of flow pattern regulator, salt-resisting filtrate reducer, high performance lubricant and bit cleaner, the basic formula of the solids-free brine drilling fluid system was formed: brine +(0.1%-0.2%) Na OH +(0.2%-0.4%) HT-XC +(2.0%-3.0%) YLJ-1 +(0.5%-2.0%) SDNR +(1.0%-2.5%) FT-1 A +(1.0%-5.0%) SD-505 + compound salt density regulator. Lab evaluation showed that the fluid had satisfactory temperature resistance(up to 150 ℃), excellent cuttings tolerance(up to 25%), and strong inhibition(92.7% cuttings recovery); Moreover, its lubrication performance was similar to that of all oil-based drilling fluid. The wellbore could be fairly cleaned at annular up-flow velocity of more than 0.8 m/s if the ratio of yield point to plastic viscosity was kept above 0.5. This fluid system has been applied in the drilling of three coiled tubing sidetracking wells in the Liaohe Oilfield, during which the system was stable and easy to adjust, resulting in excellent cuttings transportation, high ROP, regular hole size, and no down hole accidents. In summary, the solids-free brine drilling fluid system can meet the technical requirements of coiled tubing drilling.

The Effect of Injected Air Bubble Size on the Thermal Performance of a Vertical Shell and Helical Coiled Tube Heat Exchanger

In the present study,the effect of injecting air bubble size on the thermal performance of a vertical counter-current shell and coiled tube heat exchanger is experimentally investigated.The experiments were accomplished in a cylindrical shape heat exchanger with a 50 cm height and 15 cm outer diameter.Copper coil with 3.939 m equivalent length and 0.6 cm outer diameter was used to carry the hot fluid(water).Four different cold fluid(shell side)flow rates(Q_(s)=2;4;6 and 8 LPM)Þunder laminar flow conditions(316≤Re≤1223),constant hot(coil side)flow rate fluid rates(Q_(h)=1 LPM),four different injected air flow rates(Q_(a)=0:5;1;1:5 and 2 LPM),invariant temperature difference(ΔT=20°C),and constant bubble’s number(1400)were tested.To demonstrate the effect of bubble size,a sparger with orifice diameters of 0.1,0.8,and 1.5 mm was manufactured and used in the study.The overall heat transfer coefficient(U),NTU,effectiveness,and pressure loss were invested.The experimental results clearly showed that the heat exchanger’s thermal efficiency significantly improved with increasing the shell side flow rate and the injected air flow rate.The maximum improvement in U,NTU,and effectiveness was 153%,153%,and 68%,respectively.The thermal performance of the heat exchanger was shown to be improved with increasing the bubble size.Although the latter finding agrees with recent CFD published results,more studies need to be confirmed.

Periarterial stem villous edema is associated with hypercoiled umbilical cord and stem obliterative endarteritis

To assess clinicopathologic correlations of a novel placental lesion featuring a distinct ring-like periarterial edema of stem villi (PASE). A retrospective case-control statistical comparison (Yates χ2 or analysis of variance) of 30 clinical and 41 placental features of 100 consecutive placentas with PASE and 100 gestational age-matched cases without PASE, extracted from 2403 placentas from high-risk pregnancies signed out by the author since year 2006. The PASE was seen in 4.2% of placentas, average gestational age 35.9 weeks (range, 24 - 42 weeks). Frequencies of stem obliterative endarteritis and hypercoiled umbilical cord (coiling index > 0.3) were 23% vs 5% (p = 0.005), and 20% vs 9% (p = 0.04) in the study group and comparative group, respectively. There were no statistically significant differences (p > 0.05) between the groups in clinical or other placental variables. The PASE may be linked to chronically abnormal blood flow in umbilical cord arteries and their stem branches and may be a histological placental sign of non-obliterative umbilical cord compromise.

Coiled Polymer Artificial Muscles Having Dual-Mode Actuation with Large Stress Generation

Coiled polymer artificial muscles with both large tensile stroke and giant force generation are needed for practical applications in robotics,soft exosuits,and prosthesis.However,most polymer yarn artificial muscles cannot generate a large force or stress.Here,we report an inexpensive Twisted and Coiled Polymer artificial muscle(TCP)that performs both large isobaric and isometric contractions.This TCP can generate a tensile stroke of 20.1%and a specific work capacity of up to 1.3 kJ kg^(−1) during temperature changes from 20 to 180℃.Moreover,the nylon yarn artificial muscle produced a reversible output stress of 28.4 MPa,which is 100 times larger than human skeletal muscle.A robot arm and a simple gripper were made to demonstrate the isobaric actuation and isometric actuation of our TCP muscle,repectivley.Thus,the polymer artificial muscles with dual-mode actuation show potential applications in the field of robotics,grippers,and exoskeletons and so on.

Relationship between the Intensity of Secondary Flow and Convection Heat Transfer in a Helically Coiled Circular Tube with Uniform Wall Temperature

Numerical method is used to investigate fully developed laminar flow in helically coiled circular tube in this paper.The non-dimensional parameter(secondary flow Reynolds number Se)based on absolute vorticity flux along the mainstream is used to indicate the intensity of secondary flow caused by the centrifugal effect in helically coiled circular tube.The relationship between the intensity of secondary flow and the intensity of laminar convective heat transfer is studied.The effects of curvature and torsion on the enhancement of heat transfer are also considered.The results reveal that the absolute vorticity flux along the mainstream can be used to indicate the local or averaged intensity of secondary flow;the non-dimensional parameter of the absolute vortex along the main flow determines the convective heat transfer and friction factor.The relationships of Nusselt number and friction factor with the Se are obtained.The effect of curvature on Nusselt number is obvious,but the effect of torsion on Nusselt number is less obvious.

鞣花酸对大肠杆菌感染肉鸡生长性能和抗氧化功能的影响

本试验旨在研究鞣花酸(EA)对大肠杆菌感染肉鸡生长性能和抗氧化功能的影响。实验选用216只1日龄遗传背景相同、体重均一、健康的罗斯308肉雏鸡,按照单因素试验设计,随机分为对照组、E.coil K88组和E.coil K88+EA组3个处理组,每组6个重复,每个重复有12羽(公母各半)。对照组和E.coil K88组肉鸡饲喂基础饲粮,E.coil K88+EA组肉鸡饲喂含200 mg/kg EA的基础饲粮。E.coil K88组和E.coil K88+EA组肉鸡在第10日龄口腔灌服1mL E.coil K88菌悬液,对照组灌服1 mL无菌LB培养基。试验期42 d。结果显示:①与对照组相比,E.coil K88感染有降低1~42日龄肉鸡平均日采食量(ADFI,P=0.05)和平均日增重(ADG,P=0.054)的趋势,同时提高了42日龄肉鸡胸腺器官指数、21日龄肉鸡血清谷草转氨酶(ALT)、碱性磷酸酶(ALP)活性、尿酸(UA)和过氧化氢(H_(2)O_(2))含量(P<0.05),提高42日龄肉鸡空肠髓过氧化物酶(MPO)活性以及十二指肠IL-17、空肠和回肠IL-8的mRNA水平(P<0.05);E.coil K88感染降低了21日龄肉鸡十二指肠和空肠过氧化氢酶(CAT)、总超氧化物歧化酶(T-SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性(P<0.05),也降低了42日龄肉鸡十二指肠CAT活性及空肠CAT、GSH-Px活性(P<0.05)。②与感染组相比,饲粮中添加EA提高了21日龄肉鸡血浆GSH-Px活性、十二指肠的CAT、GSH-Px活性、回肠GSH-Px活性,42日龄肉鸡十二指肠CAT、T-SOD、GSH-Px活性及空肠CAT、GSH-Px活性(P<0.05),还降低了21日龄肉鸡血清ALP活性以及十二指肠丙二醛(MDA)含量和一氧化氮合成酶(i-NOS)活性(P<0.05)。与感染组相比,日粮中添加EA下调了42日龄血清UA含量和MPO活性、十二指肠MPO活性、空肠MPO含量与i-NOS活性、十二指肠IL-17、空肠IL-8以及回肠IL-17、IL-8的转录水平(P<0.05)。由以上可知,日粮中添加200 mg/kg鞣花酸可改善大肠杆菌感染肉鸡生长性能和血液生化指标,增强其抗氧化和免疫功能。

Microstructure Control of Non-quenched and Tempered CT80Grade Coiled Tubing Steel

Complex working condition of coiled tube （CT） steel demands high strength and low ratio of yield strength （YS） to tensile strength （TS）. Reasonable microstructure control is a key problem of CT steel. Controlled rolling and controlled cooling experiments were carded out by two kinds of tested steels with different chemical compositions to develop the non-quenched and tempered CT80 steel. Mechanical properties of the tested steels at different processes are all in good agreement with the properties requirement of CT80. Increasing of Mo and Nb contents improves transformation of acicular ferrite and martensite-austenite （M-A） islands. 4 vol% of fine M/A islands increase TS and decreases ratio of YS/ TS, Cooling rate increasing also improves acicular ferrite transformation and enhances TS, but has little effect on ratio of YS/TS. To meet the requirement of high strength and low ratio of YS/TS, optimized complex microstructure of the CT80 steel is composed of acicular ferrite, about 30 vol% of bainite and 4 vol% of M-A islands.

Rho-associated coiled kinase inhibitor Y-27632 promotes neuronal-like differentiation of adult human adipose tissue-derived stem cells

Background Y-27632 is a specific inhibitor of Rho-associated coiled kinase （ROCK） and has been shown to promote the survival and induce the differentiation of a variety of cells types. However, the effects of Y-27632 on adult human adipose tissue-derived stem cells （ADSCs） are unclear. This study aimed to investigate the effects of Y-27632 on the neuronal-like differentiation of ADSCs. Methods ADSCs were isolated from women undergoing plastic surgery and cultured. ADSCs were treated with different doses of Y-27632 and observed morphological changes under microscope. The expression of nestin, neuron specific enolase （NSE） and microtubule-associated protein-2 （MAP-2） in ADSCs treated with Y-27632 was detected by immunocytochemistry and Western blotting analysis. Results Y-27632 had the potency to induce neuronal-like differentiation in ADSCs in a dose-dependent manner. Moreover, the differentiation induced by Y-27632 was recovered upon drug withdraw. ADSCs treated with Y-27632 expressed neuronal markers such as NSE, MAP-2 and nestin while untreated ADSCs did not express these markers. Conclusion Selective ROCK inhibitor Y-27632 could potentiate the neuronal-like differentiation of ADSCs, suggesting that Y-27632 could be utilized to induce the differentiation of ADSCs to neurons and facilitate the clinical application of ADSCs in tissue engineering.

HEAT TRANSFER OF TiO_2/WATER NANOFLUID IN A COILED AGITA-TED VESSEL WITH PROPELLER

An attempt is made to investigate heat transfer enhancement using nanofluid in a coiled agitated vessel fitted with propeller agitator. The heat transfer coefficient in coiled agitated vessel for water and TiO2/water nanofluid of 3 different volume concentrations （0.10%, 0.20% and 0.30%） are estimated and compared. The heat transfer coefficient for nanofluid is found to be higher than that for water and also found to increase with increasing volume concentrations. The enhancement in the convective heat transfer using nanofluid is found to be a maximum of 17.59%. Empirical correlations are separately formed for water and TiO2/water nanofluid as well as found to fit the experimental data within ±5% for water and within ±10% for nanofluid.

CONDENSATION HEAT TRANSFER OF R-134A IN HORIZONTAL STRAIGHT AND HELICALLY COILED TUBE-IN-TUBE HEAT EXCHANGERS

This article presents an experimental investigation on condensation heat transfer of R-134a in horizontal straight and helically coiled tube-in-tube heat exchangers. The experiments were carried out at three saturation temperatures（35 ℃ , 40 ℃ and 45 ℃ ） with the refrigerant mass flux varying from 100 kg/m2 s to 400 kg/m2 s and the vapor quality ranging from 0.1 to 0.8. The effects of vapor quality and mass flux of R-134a on the condensation heat transfer coefficient were investigated. The results indicate that the condensation heat transfer coefficients of the helical section are 4%-13.8% higher than that of the straight section. The experimental results were compared with the data available in literature for helical and straight pipes.

Analytical computation of magnetic field in coil-dominated superconducting quadrupole magnets based on racetrack coils

Currently,three types of superconducting quadrupole magnets are used in particle accelerators:cos 2θ,CCT,and serpentine.However,all three coil configurations have complex spatial geometries,which make magnet manufacturing and strain-sensitive superconductor applications difficult.Compared with the three existing quadrupole coils,the racetrack quadrupole coil has a simple shape and manufacturing process,but there have been few theoretical studies.In this paper,the two-dimensional and three-dimensional analytical expressions for the magnetic field in coil-dominated racetrack superconducting quadrupole magnets are presented.The analytical expressions of the field harmonics and gradient are fully resolved and depend only on the geometric parameters of the coil and current density.Then,a genetic algorithm is applied to obtain a solution for the coil geometry parameters with field harmonics on the order of 10^(-4).Finally,considering the practical engineering needs of the accelerator interaction region,electromagnetic design examples of racetrack quadrupole magnets with high gradients,large apertures,and small apertures are described,and the application prospects of racetrack quadrupole coils are analyzed.

Gradient coil design with enhanced shielding constraint for a cryogen-free superconducting MRI system

The relatively fragile low-temperature stability of cryogen-free superconducting magnetic resonance imaging(MRI)magnets requires the careful management of exogenous heat sources.A strongly shielded gradient magnetic field is important for the optimal operation of cryogen-free MRI systems.In this study,we present an enhanced shielding method incorporating a regionalized stray field constraining strategy.By optimizing the constraint parameters,we could develop engineering-feasible gradient coil schemes without increasing system complexity but with the stray field intensity reduced by half.In real measurement in an integrated MRI system,the developed gradient assembly demonstrated good performance and supported to output images of excellent quality.Our findings suggested that the proposed method could potentially form a useful design paradigm for cryogen-free MRI magnets.

Designing Stable Antiparallel Coiled Coil Dimers

The history of antiparallel coiled coil dimer design is briefly reviewed and the main principles governing the successful designs are explained. They include analysis of the inter subunit electrostatic repulsion for determining partners for dimerization and of the buried polar interaction for determining the relative orientation of the partners. A theory is proposed to explain the lack of antiparallel coiled coil homodimers in nature.

THE FRICTIONAL RESISTANCE CHARACTERISTICS OF GAS LIQUID TWO PHASE FLOW IN HELICAL COILED TUBES

This paper deal with the frictional resistance characteristics of gas liquid two phase flow in vertical upward helical coiled tubes under the system pressure 0.1 0.6MPa. By means of dimension analysis and π theorem, the correlation formulas were obtained for calculating the frictional resistance coefficients of gas liquid two phase flow in helical coiled tubes. The calculated results agree well with the experimental results.

Microsurgical ligation for incompletely coiled or recurrent intracranial aneurysms:a 17-year single-center experience

Background:In this retrospective single-center study,we presented our experience in the microsurgical management of incompletely coiled or recurrent aneurysms after initial endovascular coiling.Methods:During a 17-year period,48 patients underwent microsurgical clipping of incompletely coiled or recurrent aneurysms after coiling (Gurian group B).The clinical data,surgical technique,and postoperative outcome were recorded and analyzed.Results:Before coiling,42 patients (87.5%) experienced aneurysm rupture.Most of the aneurysms (46/48,96%) were located in the anterior circulation.After coiling,6 patients had incompletely coiled aneurysms and 42 patients had recurrent aneurysms,with a mean time of 20.2 months from coiling to recurrence.Coil extrusion occurred in none of the incompletely coiled aneurysms and 71% (30/42) of the recurrent aneurysms.Clipping techniques are direct microsurgical clipping without coil removal in 16 patients,partial coil removal in 14 patients,and total coil removal in 18 patients.Postoperative and follow-up angiography revealed complete occlusion of the aneurysms in all patients.No patient died during postoperative follow-up period (mean,78.9 months;range,10-190 months).Good outcomes (GOS of 4 or 5) were achieved in 87.5% (42/48) of the patients at the final follow-up.Conclusions:Microsurgical clipping is effective for incompletely coiled or recurrent aneurysms after initial coiling.For recurrent aneurysms that have coils in the neck,have no adequate neck for clipping,or cause mass effects on surrounding structures,partial or total removal of coiled mass can facilitate surgical clipping and lead to successful obliteration of the aneurysms.