Tubular Technology Research Articles

Failure Analysis and Ultimate Expansion Mechanical Behavior Analysis of Thin-Walled Solid Expandable Tubular

SummaryWith the vigorous exploitation of shale gas, the cost of drilling and production of shale gas wells, which can reduce the cost, has also received attention. Equal-diameter solid expandable tubular (SET) technology is one of the best choices at present. For this paper, we carried out a series of expansion experiments for 20G pipe, and the experimental results show that the pipe breaks and fails at 30% expansion ratio. The cracked pipe is analyzed by scanning electron microscopy (SEM), and the method to solve the failure of cracked pipe is proposed. In addition, a 3D dynamic model is established to study the relationship between the inner diameter, wall thickness, expansion ratio, and ultimate expansion ratio of the pipeline. The study results show that (1) SET made of 20G expanded successfully at 25% expansion ratio and failed at 30% expansion ratio, the fracture surface presents 45°, with typical shear failure characteristics; (2) SEM results showed that the pit characteristics were normal, the pipe was cracked under high stress, and the 20G pipe could not meet the expansion ratio of 30%; and (3) the maximum stress of 20G pipe during expansion is proportional to the expansion ratio. It is recommended that the SET expansion rate of 20G material should not exceed 26%. The research results will provide ideas and methods for the design of SET.

Low-Density Polyethylene – New insights into an old material under comparative studies using SEC-MALS, AF4-MALS, HT-HPLC and 2D-LC

LDPE can be produced by different types of autoclave or tubular reactors, which can also be cascaded. An important effort is to obtain materials with autoclave-process equivalent properties from tubular technology due to economic reasons. In this way, the molecular understanding of the materials attains a key role. Five LDPE materials were characterized, covering three applications (extrusion coating, blow molding, and film blowing) as well as three reactor technologies (type I autoclave, tubular type, and type II autoclave). SEC-MALS, SEC-IR, AF4-MALS, HPLC, and 2D-LC allowed a detailed characterization of the samples’ molar mass and branching structure while providing a unique opportunity for technique comparison. This allowed for an unprecedented understanding of the differences in molecular structure and the influence of application vs. reactor technology driven differences.Overall, SEC-IR-MALS was found to provide the most versatile information, making it an excellent choice for an initial characterization. Furthermore, the results indicate that the intended application (and thus property profile) influences LDPE structure much more than reactor technology. All five studied samples exhibit differences in molar mass distribution, short-chain as well as long-chain branching. Yet, the three extrusion coating samples (each derived from a different reactor type) appeared notably similar to each other with regard to each parameter.

Research on cohesive failure behavior and parameter sensitivity of rubber – SET under cohesive zone model

Solid expandable tubular (SET) technology is widely used in oil field. The cohesive failure of rubber reduces the suspension and sealing capacity of SET. Based on cohesive failure behavior between rubber and SET and morphological characteristics of rubber after expansion experiment. The cohesive zone model was introduced to describe cohesive behavior. The coupled three-dimensional finite element model of casing - rubber - SET was established. The effects of sensitive factors such as friction factors, rubber compression, rubber length, stiffness, damage initiation strength and fracture energy on cohesive failure behavior of SET rubber were researched. The results show that (1) In order to ensure that driving force in expansion process is small and meet the requirements of suspension force and sealing pressure after expansion. The friction coefficient of casing - rubber - SET system should be about 0.15. (2) On the premise of no cohesive failure occurs, the suspension force and sealing performance of rubber can be effectively improved by increasing theoretical compression and length of rubber. The optimum theoretical compression of rubber is about 50% of rubber thickness. The length of rubber should not exceed 60 mm. (3) Reducing stiffness and increasing damage initial strength of bonding material can reduce the risk of cohesive interface failure. The normal stiffness should not be greater than 5.4 N/m3 and the tangential stiffness should not be greater than 6.3 N/m3. The normal ultimate tensile stress should not be less than 9.6 MPa and the transverse shear stress strength should not be less than 9.7 MPa. It is not significant to increase bonding property of rubber by increasing fracture energy. The research results provide theoretical guidance for the structural design and bonding process parameters of SET rubber.

Application of Solid Expandable Tubulars in the Petroleum Industry

The development of solid expandable tubular (SET) technology and products (open hole liner, open hole clad, cased hole liner, liner hanger, internal casing patch, etc.) has enabled operators to plan well design in a new way and solve various problems that arise during drilling and exploitation on land and offshore. By including an expandable open hole liner, monobore open hole liner or monobore openhole clad in well design, it is possible to achieve a slim hole design and/or resolve unwanted situations that occur during the drilling of problem zones with minimal hole size reduction and reach hydrocarbon reserves which cannot be achieved economically by conventional technology. By installing an expandable cased hole liner or internal casing patch in production wells to cover the intervals of a corroded casing or to close old perforations, it is possible to extend the life cycle of a production well and increase the final hydrocarbon recovery and speed up the return on investment. The aim of this paper is to systematically review the relevant literature and give an overview of solid expandable tubular technology and its applications in the petroleum industry, as well as the cementing technology of open hole expandable liners. The available data for 21 case studies of SET application in onshore and offshore wells were analyzed in detail. Based on an extensive review of the literature and analyzed data, it can be concluded that SET technology is being successfully applied worldwide and that expandable liners with a diameter of 114.3 mm to 339.72 mm are being run in wells to ever greater depths (up to 5166 m) and in ever more extreme downhole conditions.

Numerical investigation of tubular expansion and swelling elastomers in oil wells

Abstract Solid expandable tubular technology and swelling elastomer seals find extensive use in the repair of aging reservoirs. To improve productivity and cost-effectiveness, they have also become an integral part of new developments such as slim wells and completions with reduced or no cementing. This work reports the use of numerical simulation to investigate the joint use of expandable tubulars and swell packers in various petroleum drilling applications. Material properties of steel tubular and five different swelling elastomers are obtained through mechanical testing. Simulations are performed to study the sealing pressure at the elastomer-formation boundary. Different parameters are studied, such as elastomer material, expansion or compression ratio, seal length, seal thickness, tubular end condition, and formation type. Higher values of rubber elasticity, tubular expansion (expansion ratio), and elastomer compression result in higher seal contact pressure. Contact pressure is higher when the elastomer is pressing against wellbore formation as compared to steel outer casing (zero friction vs. friction), and when the formation is assumed to be rigid as compared to elastic or elastic-plastic. Results of this investigation can be used both for performance evaluation and design enhancement of coupled solid-expandable-tubular and swellable-packer applications.

Finite Element Analysis of a Novel Anterior Locking Plate for Thoracolumbar Burst Fracture.

Purpose The finite element analysis method was used to explore the biomechanical stability of a novel locking plate for thoracolumbar burst fracture fusion fixation. Methods The thoracolumbar CT imaging data from a normal volunteer was imported into finite software to build a normal model and three different simulated surgical models (the traditional double-segment fixation model A, the novel double-segment fixation model B, and the novel single-segment fixation model C). An axial pressure (500 N) and a torque (10 Nm) were exerted on the end plate of T12 to simulate activity of the spine. We recorded the range of motion (ROM) and the maximum stress value of the simulated cages and internal fixations. Results Model A has a larger ROM in all directions than model B (flexion 5.63%, extension 38.21%, left rotation 46.51%, right rotation 39.76%, left bending 9.45%, and right bending 11.45%). Model C also has a larger ROM in all directions than model B (flexion 555.63%, extension 51.42%, left rotation 56.98%, right rotation 55.42%, left bending 65.67%, and right bending 59.47%). The maximum stress of the cage in model A is smaller than that in model B except for the extension direction (flexion 96.81%, left rotation 175.96%, right rotation 265.73%, left bending 73.73%, and right bending 171.28%). The maximum stress value of the internal fixation in model A is greater than that in model B when models move in flexion (20.23%), extension (117.43%), and left rotation (21.34%). Conclusion The novel locking plate has a smaller structure and better performance in biomechanical stability, which may be more compatible with minimally invasive spinal tubular technology.

Neochloris oleoabundans oil production in an outdoor tubular photobioreactor at pilot scale

Oil production was tested with Neochloris oleoabundans in a 6 m3, horizontal soft sleeve tubular reactor from 22 October to 7 November in Matalascañas, southern Spain. Biomass productivity during the nitrogen replete phase was 7.4 g dw m−2 day−1. Maximum lipid content in the biomass was 39% and average lipid productivity during the nitrogen depletion phase was 2.0 g m−2 day−1. Nitrogen depletion of the cultures was carried out in order to enhance fatty acid formation, using the inverse nitrogen quota in the biomass to predict the fatty acid content. TFA concentration at harvest was 14% DW, compared to a value of 17%, predicted by the inverse nitrogen quota. The overall feasibility of the horizontal tubular technology for microalgal oil production, including mixing energy expenditure, was evaluated.

Research on Large-diameter Solid Expandable Tubular Subsidy Technology and Suspension Seal Device

In view of the issue that the diameter is small and the suspension force is uncertain after solid expandable tubular (SET) subsidy. The uniaxial tensile test of SA106B metal is carried out, and the parameters of metal elastoplastic constitutive model are fitted accordingly. Then, a solid expandable tubular laboratory test is designed, and a finite element model of SET is established based on this test. Finally, the effects of the expansion cone radius and the thickness of the rubber ring on the expansion stress and contact pressure are researched. The results show that the established finite element model has small errors and reliable results. The optimal expansion cone radius is selected through the maximum stress and the residual stress of expanded tubular to improve the expansion quality of the tube. The thickness of the rubber ring has a great influence on the contact pressure and the suspension force, so it must be reasonably optimized under the premise of ensuring the sealing ability. The optimal solution of the expansion cone radius and the thickness of the rubber ring is given by comparison. This study provides a theoretical basis for the optimization of solid expandable tubular technology.

GAS BURNER DEVICES OF JET DIFFUSION TYPE AND JET BURNERS, CREATED BY TUBULAR TECHNOLOGY

The article discusses the design and operation features of two-wire gas burners developed at the Gas Institute of the National Academy of Sciences of Ukraine. These are jet-diffusion type burners and jet burners, the creation of which is based on the concept of burning gaseous fuels using a highly efficient unified tubular technology developed in conjunction with specialists from the National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute». A description of burners and burner devices of the jet diffusion type of the SG and SGL series is provided. The design of the SGL series burners provides for the possibility of interconnecting individual modules, which ensures the creation of heat generators of almost unlimited power. It is shown that such heat generators can operate in a wide range of excess air, this allows to get a coolant of any required temperature. Heat generators of this type operate in many industries. In jet burners created by tubular technology, as a result of the interaction of gas jets and air jets, diffuse gas flames are formed, which provide high reliability of the burners with possible fluctuations in the gas-air ratio. Also shown are the designs of burners created as a combination of these combustion technologies. The design of turbulent vortex burners, which provides a high degree of stabilization of the flame through the use of a central jet diffusion burner, is described. These burners are equipped with steam and hot water boilers, as well as melting furnaces. When operating these burners, it is possible to achieve 10 % of the natural gas consumption of the nominal load, which allows the operation of heating furnaces in the hot reserve with short-term shutdowns of technological equipment. Библ. 15, рис. 12.

Solid expandable tubular forming behavior based on twin shear stress yield criterion: Analytical, numerical simulation and experiment

Abstract Solid Expandable Tubular (SET) technology is a recent important breakthrough in petroleum exploration and drilling. The expansion forming theory and the constitutive model of the tubular materials are the theoretical basis for the development of this technology. This work focuses on establishing analytical and finite element models on the basis of the Twin Shear Stress (TSS) yield criterion to investigate the forming behavior of solid expandable tubular. The expansion force expression of the power exponential hardening material model was derived. A constitutive model using the TSS yield criterion and related flow rules was proposed and implemented into the ABAQUS software. Further to this, variations of the expansion forces, residual stresses and plastic deformation under different expansion ratios and friction coefficients were investigated. In addition, a tubular expansion experiment was conducted to validate the analytical and finite element solutions. Results show that the expansion force expression is reliable, but there are discrepancies within a reasonable range. The finite element model is capable of predicting the expansion forces, residual stress distributions, thickness reduction and length shortening accurately. Moreover, it is found that the expansion ratio should be controlled below 35% to avoid burst and collapse of the expandable tubular in practical application. For expansion operations, suitable lubrication conditions should be determined to ensure an acceptable expansion force and maintain a certain friction coefficient.

Study on the Expansion Force of TWIP Steel Expandable Tubular in Solid Expandable Tubular Technology

Abstract This paper focuses on the expansion process of twinning-induced plasticity (TWIP) steel tubular undergoing the large circumferential plastic deformation in expandable tubular technology. The expansion process was performed by propagating a mandrel through the tubular mechanically. This paper aimed at developing the mathematical models to predict the expansion force required for the radial expansion of the TWIP steel tubular using the rigid-perfectly plastic model and the linear hardening rigid plastic model, respectively. The volume incompressible condition together with the Tresca yield criterion was used to describe the plastic behavior of the tubular material in the expansion process. Besides, the finite element analysis of the expansion process was developed using the commercial software abaqus to validate the theoretical results and determine the scope of application of the derived expansion force formula. Further to this, the effect of the process parameters, such as the expansion ratio, friction coefficient and the cone angle, on the expansion force was investigated. It was found that the expansion force difference of two models have similar variation trend. The accuracy and applicability of the expansion force formula using the linear hardening rigid plastic model improve as the expansion ratio increases and the expansion cone angle decreases.

Failure analysis and solution study of 203 mm solid expandable tubular

The solid expandable tubular technology (SETT) is a permanent radial plastic deformation of the casing, which serves to block the leaking section and subsidize the casing. The difficulty of the SETT lies mainly in the material selection of the solid expandable tubular (SET) and the design of the expansion cone structure. The 20G steel casing pipe with 203 mm × 10 mm specification in dagang oilfield is subject to an expansion test with a variable-diameter expansion cone (an expansion rate of 20.2%), during which the casing pipe ruptured and failed. In this paper, the microstructure is analyzed by scanning electron microscope (SEM) and the failure analysis of SET is studied macroscopically by finite element analysis method, and the corresponding solution is proposed. The research shows that when the expansion ratio is 20.2% and the 20G steel casing is used as the material of SET, the maximum stress of SET during the expansion process exceeds the ultimate tensile strength of the material, the SET fracture fails, and 20G steel pipe is not suitable for use as materials of SET in the case of a large expansion ratio (20.2%). In this paper, the expansion cone is continuously optimized. It is found that the single-stage expansion cone is more conducive to the expansion operation than the variable-diameter expansion cone. The expansion cone chamfer and friction coefficient have a significant influence on the driving force, and should be fully lubricated during the expansion operation. In addition, this paper also prefers 316L steel material with better plasticity and toughness. It is found that 316L can expand successfully without failure at large expansion ratio. The research results provide a theoretical basis for the material selection of SET and the structural design of the expansion cone, and have important significance for ensuring the success of the expansion work.

Characterization of Pre- and Post-expansion Material Properties of Down-Hole Tubular

Down-hole tubular technology plays an important role in enhanced oil recovery over last decades. Many unresolved issues in drilling and oil/gas well completion are properly addressed and solved through down-hole tubular technology. However, post-expansion properties of tubulars are always a concern in implementing them in an economic and viable framework. A thorough understanding of post-expansion material properties is required in successful implementation of tubulars in adverse and high formation pressure environment. This work investigates the consequences of expansion on microstructure, grain size, and crystallographic texture of tubular material. Firstly, multiple samples are taken from unexpanded and expanded sections of tubulars that are hydraulically expanded to a desired expansion ratio. Secondly, microstructure and fractographic analyses are performed through optical and scanning electron microscopy, respectively. Finally, electron back-scattered diffraction analysis is used to investigate grain morphology, grain size distribution, and crystallographic texture of samples. It is observed that the grain size is affected by excessive plasticity of tubular. It is also noted that the presence of elongated grains is due to the crystallographic reorientation of grains, existence or formation of secondary phases, and dislocation pileup at grain boundaries. Moreover, expansion process results in the variation of grain orientation. However, due to complex loading conditions, strong texture has not been observed.

Study of the effect of the expansion cone on the expansion process in solid expandable tubulars with thread joints

As the core technology of petroleum extraction engineering in the 21st century, Solid Expandable Tubular (SET) technology is applied to drilling, well completion, and cementing. However, the expansion process for tubulars in site operation may well lead to stress concentration, leakage, or even fracture failure in thread joints of the tubular assembly due to the irregular deformation of thread teeth. With the aim of studying the issue with regard to the thread joint of J55 steel expandable tubulars, this study extended a series of finite element models using the commercial software ABAQUS to investigate the structural response of tubulars during the expansion process. The simulation results include the stress evolution, deformation of the thread joint of the tubular assembly, and the effect of expansion cone geometry on the expansion consequences. A laboratory experiment was performed to validate the validity of the simulated solution. It was found from results that both the axial and hoop compressive stress concentrations were generated in the thread teeth edges near the contact surfaces of threads during the expansion process due to the mutual squeezing of box and pin thread teeth. An increase of the tubular diameter led to a reduction of wall thickness and axial length due to the law of volume-constancy. The expansion process resulted in a deterioration of the contact condition between the thread teeth. A cone angle of 9° and sizing section length of 65–75 mm were the optimal choice of the geometric size of the expansion cone according to their superior analytical results.

Experimental study of mechanical properties and residual stresses of expandable tubulars with a thread joint

As the core of drilling technology in the 21st century, expandable tubular technology could solve practical engineering problems including inadequate casing displacement and high-pressure formations in drilling, and it could be applied in many fields such as well workover, cementation, and well completion. However, the difficulties of breakage and leakage at the thread joint in the expansion process limited the development of this technology. This study investigated the effect of the expansion process on various aspects of the J55 steel expandable tube involved in deformation, residual stress, mechanical properties, and microstructure variation by experimentation. The results showed that in the top and root of the box thread zone the residual stresses were relatively high. That is because much wall thickness was lost due to thread cutting in the top zone and the bending moment was generated from the cone mandrel pressing outwards in the root zone of box thread. It was noticeable that the yield and ultimate strength of the expanded tube were increased after the expansion process, which is work hardening. Furthermore, the microstructure of the unexpanded and expanded tubes was similar, and consisted of pearlite surrounded by ferrite. But in the expanded tube, the pearlite and ferrite were more uniformly and compactly distributed.

Effects of expansion rate on plasticity and structural integrity of downhole tubular

The current work presents an investigation of the effects of expansion rate on plasticity and structural integrity of down-hole solid tubular. Down-hole tubular has proven itself to be a promising technology in oil well applications by providing optimum solutions for many issues. One of the challenges still facing researchers and field engineers in implementing and making down-hole tubular technology cost effective is to conserve structural integrity of tubular. Cold expansion affects mechanical properties and induces residual stresses in tubular, hence reduces its collapse, burst, and fatigue ratings. The knowledge of properties variation is required in correctly predicting life span of tubular under given operational conditions. In present work, cold expansion of tubular under down-hole conditions is experimentally and numerically investigated at different strain rates. Strain rates are varied by changing the velocity of mandrel that is used to expand the tubular. Firstly, different tubular expansion experiments are performed to achieve 16%, 20%, and 24% expansion ratio. Secondly, finite element model of tubular expansion is developed in commercial finite element software ABAQUS. Simulation results are found to be in good agreement with experimental observations. Finally, further simulations are performed to thoroughly analyze the effects of expansion rate on the deformation behavior of tubular. It is found that there is variation in contact pressure at tubular-mandrel interface, effective stress, equivalent plastic strain, and thickness reduction during expansion process. These variations ultimately influence post-expansion properties of tubular particularly collapse and burst strengths, and hence its structural integrity. However, length shortening has marginally affected by expansion rates.

The use of contact heat generators of the new generation for heat production

We substantiated the need for searching for, and realization of, fundamentally new approaches, using more efficient physical, heat-mass-exchanging and aerodynamic processes, which will make it possible to improve energy effectiveness and ecological cleanliness of heat generation in the systems for individual and decentralized heat supply. For the heat supply to large cities and industrial regions, we examined the advantages of using highly efficient contact heat-generators of different types, which include compactness due to low metal consumption and, as a result, attractive price. It is proposed to use a heat-generator of contact type of the new generation, with the aid of which it was possible to solve a set of problems on the qualitative combustion of fuel and effective heat exchange of gases with the heated water. The use of tubular technology for the combustion of gas is its special feature. Due to it, quality heat exchanging characteristics are provided. In view of further studies, we presented the relevance of creating heat-generators with the use of highly effective hydrogen technologies, which will make it possible to devise the new energy paradigm of heat supply for residential areas and industrial zones through the possibility of accumulation of electrical energy and accumulation of hydrogen.

Numerical study of solid expandable tubular technology

Numerical study of solid expandable tubular technology

Dynamic Analysis of Solid Expandable Tubular and Its Applications in Tahe Oilfield

For ultra-deep horizontal wells in Tahe Oilfield in China, the solid expandable tubular (SET) technology was applied in the buildup section to isolate unstable mud stone with clays above the pay zone. This technology satisfies the requirements of geological water avoidance, and a larger hole size is adopted in the pay zone. This paper proposed a finite element dynamic model to analyze the expansion of the SET, and the impacts of the following factors on the expansion force required for the expandable tubular were analyzed: yield strength of the tubular material, solid tubular expansion ratio, the coefficient of friction between the expansion cone and the tubular, the angle of the expansion cone, movements velocity of the expansion cone, and DLS (dogleg severity). The calculation results indicate that a higher expansion ratio, a higher yield strength, and a higher friction coefficient of the SET result in a larger expansion force to different degrees, whereas the other factors have little effect on the expansion force. The dynamic expansion force calculation model established in this paper is consistent with the actual conditions, and the simulation calculation results can be applied to provide theoretical guidance for SET expansion operations.

Microsurgical resection for lateral ventricular meningiomas with neuronavigation and tubular retractor system

Objective To study the microsurgical modality for lateral ventricular meningiomas with neuronavigation and tubular retractor system and evaluate its long term outcome. Methods The clinical and follow-up data of 23 lateral ventricular meningioma patients during the past 3 years were collected for a retrospective analysis in our center. 12 patients used neuronavigation and tubular brain retractor system, 11 patients received traditional manual measurement anatomic landmarks with traditional brain retractor. The tumor resection extent, overall survival, recurrence, operation exposure, operation trauma, peri-operative complications and? post-operative quality of life were compared between two groups. Results The total tumor resection was achieved at 100% in both groups and the perioperative death or tumor recurrence within the follow-up period was not observed in both groups. The overall survival rate achieved 100%. Neuronavigation combined with tubular brain retractor technology did not increase the overall complications(P=0.414), nor decrease the operative field exposure(P=0.667). Its utility did not extend the operation time(P=0.695), but reduced the occurrence of aphasia and hemianopia after operation and significantly shortened the length of incision(P=0.034), the size of craniotomy(P=0.021) , the cortical incision length(P=0.001)and the days of hospitalization(P=0.037). Importantly, neuronavigation with tubular brain retractor system could significantly improve the postoperative quality of life for lateral ventricular meningioma patients(KPS, P=0.029). Conclusions Neuronavigation and tubular brain retractor system used in microsurgical resection of lateral ventricular meningioma doesn't decrease the total tumor resection and the operation exposure, but reduced intra-operative brain trauma and peri-operation complications. For the improvement of post-operative quality of life, it was suitable for lateral ventricular meningiomas. Key words: Neuronavigation; Lateral ventricl; Meningioma; Microsurgery