Tubular Goods Research Articles

Evaluation of Sulfide Stress Cracking Susceptibility of Welded Joints of Supermartensitic Stainless Steel Used in Oil Country Tubular Goods (OCTG)

Evaluation of Sulfide Stress Cracking Susceptibility of Welded Joints of Supermartensitic Stainless Steel Used in Oil Country Tubular Goods (OCTG)

Experimental investigation and numerical simulation of swaging process of tubes for oil country tubular goods

AbstractPremium integrated seamless pipes made from high strength low alloy steels are used to produce oil country tubular goods. Operational requirements of these pipes in petroleum industry lead to an adequate tube end connection with better mechanical strength and sealing properties. Therefore a cold swaging process or calibration of pipe end is necessary for the mechanical threading process of the tube. Applications of typical calibration mandrels result in heavy wear due to higher swaging loads and the optimal necessary geometry of end tube could not be achieved. In this study, a new mandrel geometry with a finished surface was developed to modify the pipe end profile and reduce the wear tool. The investigated pipe made from P110- pipe steel was plastically preformed using a cold swaging process. Experimental measurements of the pipe end geometry after swaging process resulted an increase of the inner tube diameter of approximately 4.9% and an outer tube diameter of 3.7% respectively. Furthermore, a rather constant tube wall thickness was also observed. An Abaqus plug-in was developed to characterize the swaging process of pipe ends. The influence of friction between tool and pipe surfaces on the final geometry of pipe ends and residual stresses in pipe ends due to preforming were numerically predicted. The new designed swaging process resulted a better final pipe end geometry and low tool wear during the preforming of pipe end. The presented plug-in in this work could be used for tool optimization and characterization of swaging process of pipes in oil and gas industries.

Effect of shot peening on surface characteristics and high-temperature corrosion behaviour of super 13Cr martensitic stainless steel

Super 13Cr, as an economy stainless steel (SS) for oil country tubular goods, needs stable corrosion resistance in high-pressure and high-temperature (HPHT) downhole medium. Severe plastic deformation (SPD) are the surface modification technology to improve mechanical properties, fatigue behavior and corrosion resistance of metals, and shot peening (SP) has been the most widely used SPD process. However, there are quite limited studies about the microsutructure evolution, residual stress, and high-temperature corrosion behavior of SP-treated martensitic SS. In this study, super 13Cr martensitic SS was treated by SP with various air pressures and nozzle speeds. The surface characteristics and high-temperature corrosion behaviour in 3.17 mol/L K2HPO4 solution were investigated through finite element model analysis, characterization of residual stress and microstructure, as well as electrochemical and stress corrosion cracking (SCC) tests at 160 °C and 10 MPa. The results showed that SP-treated super 13Cr could generate high-level compressive residual stress and SPD microstucture, including nano-sized equiaxed grains, gradient lamellar structure and fragmented carbides. Increasing air pressure contributed to achieve uniform nanocrystalline, but tended to generate high dislocation density and surface defects. The improving effect of SP treatment at low air pressure of 0.15 MPa on passivation ability was limited, and high air pressure adversely impacted corrosion resistance. SP-treated specimens showed high SCC susceptibility, due to the introduction of more surface defects, high angle grain boundaries, and dislocations.

Continuous casting tundish quality study by mathematical & physical simulations, economics with plant result justifications

A combination of physical modeling, computational fluid dynamics modeling, and economics with plant trial studies was performed for quality improvement of Special Bar Quality (SBQ) and Oil Country Tubular Goods (OCTG) grade tundish steels. The present study consists of operating parameters like inert gas shrouding, non-isothermal conditions, and flow control devices (FCD) used on the billet product and slab quality. This work uses mathematical modeling using the fluid volume and discrete phase method (DPM) and the standard k-ε turbulence model validated with one-third scale physical water model experiments. A strong correlation between the physical model and computational simulation was found with rejection ratio and inclusion counts. Data about customer demands correlated with operating parameters for proper plant insights with an economic study to predict the cost-related issue. With the incorporation of FCD, the weight of the tundish skull was reduced by 6–10 M USD/year with a simulation studies expenditure of around 200 K. FCD also reduced the customer complaint index (CCI).

Effect of Nano-sized Cu-Rich Phase on Microbiological Corrosion Behavior of Cu and Ni-Added Steel for Oil Country Tubular Goods

Effect of Nano-sized Cu-Rich Phase on Microbiological Corrosion Behavior of Cu and Ni-Added Steel for Oil Country Tubular Goods

Estimation of the repeatability and reproducibility of test results in determining the degree of cure of protective paint coatings using differential scanning calorimetry

The degree of curing of protective paint-and-varnish coatings for oil country tubular goods is a parameter characterizing the completeness of their polymerization, and allows drawing a conclusion about the final physicomechanical properties and the possibility of using the material under specific conditions. This parameter is considered decisive in conducting acceptance tests and incoming quality control of pipe products with plated protective epoxy coatings despite a low accuracy of the obtained results and the impact of various instrumental factors and methodological approaches. The authors have developed a methodology for determining the curing degree of coatings based on the procedures given in regulatory documents (CSA Z245.20 Series-18, GOST R ISO 21809-2), taking into account the analysis of factors affecting the results of determining the curing degree carried out in the previous work. According to the conducted studies, the rates of heating and cooling during the measurement process, the temperature test program (in particular, the presence and duration of isothermal exposures before heating cycles), and curve processing methods were corrected and selected in the proposed methodology. The aim of this work is the analysis of the precision of the developed method for determining the curing degree of protective coatings to confirm the high accuracy of the obtained values under observing the prescribed procedure. The analysis was carried out by statistical processing of the results obtained in comparative tests performed in four testing laboratories, and included calculation of the repeatability of the results by their standard deviation, reproducibility and assessment of the acceptability of these parameters. The developed procedure for determining the curing degree of protective coatings, from sampling to processing of DSC curves, showed good precision, which indicates the reproducibility and repeatability of the proposed method. The developed method can be used as a unified sequence for determining the curing degree of paints and varnishes used as protective coatings in different laboratories.

CO2 Joule-Thomson effect: Application on premium connections for CCS well

CCS (Carbon Capture and Storage) is a major technology aiming to reduce greenhouse gases and reduce carbon footprint. In these applications, Oil Country Tubular Goods (OCTG) and associated premium connections are used to inject industrial CO2 into stable geological formations such as depleted oil and gas fields or saline aquifers, in liquid or dense phase to permanently store it. While current standards (API RP 5C5, ISO 13,679) allow qualification of premium connections for Oil & Gas application, no standard exists for CCS applications. In that frame, a new test methodology was developed to evaluate the impact of Joule-Thomson effect on premium connection, in the scenario of a CO2 blow-out and intermittent operation of the injection wells, such as shut-in of the subsurface safety valve (SSSV) or injection phase. To confirm that premium connections remain tight and safe after being exposed to a rapid depressurization of CO2, they have been physically tested in a horizontal load frame. The test consisted in the filling of the sample with CO2 up to a minimum of 100 bar and a temperature below 30 °C to ensure liquid state, or above 32 °C to ensure supercritical state inside the sample, and then depressurizing the sample through an orifice of 2 or 4 mm until complete drop of pressure. Minimum measured temperature on outer pipe wall reached around -50 °C before dry ice CO2 formation. Maximum measured gradient of temperature observed was around 70 °C. No leakage nor connection damages were observed during the pressure release sequences. Sealability was then confirmed during the internal pressure and external pressure test performed afterwards.

The erosion-corrosion behaviors of the full-scale Ni-P and Ni-Cu-NiW internal coating tubing

In the present work, a self-built device called the “full scale tubular goods erosion-corrosion test system” was used to investigate the erosion-corrosion behavior of Ni-P and Ni-Cu-NiW internal coating tubing in a simulated operating condition of a water injection well in the Xinjiang oil field, China. The tubing, with a total length of 10 m, was tested under accelerated conditions. The erosion-corrosion performance was evaluated using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The results showed that the Ni-P coating experienced severe corrosion, including internal cracking and peeling. The corrosion failure of the Ni-P coating was mainly attributed to the presence of defects such as pores and the penetration and self-catalysis of chloride ions. On the other hand, the Ni-Cu-NiW coating exhibited excellent corrosion resistance due to its three-layer composite structure and the addition of tungsten (W), which enhanced its resistance to chloride ion penetration.

Forecasting Modelling For Oil Country Tubular Goods (OCTG)

Dalam teori, parameter dan distribusi permintaan diketahui, tetapi dalam praktiknya, berbagai ketidakpastian membuatnya sulit untuk menentukan faktor-faktor ini, terutama karena permintaan yang sporadis dan tidak terduga. Permintaan untuk produk oil country tubular goods (OCTG) bersifat fluktuatif dan tidak teratur, dan persediaan keselamatan adalah strategi umum untuk mengelola ketidakpastian pasokan dan permintaan. Ada beberapa metode yang tersedia untuk meramalkan permintaan yang tidak teratur, seperti model statistik, deret waktu, Croston, dan metode deep learning. Penelitian ini menggunakan metode long short-term memory (LSTM) untuk meramalkan permintaan OCTG dan membandingkannya dengan metode autoregressive integrated moving average (ARIMA), dengan menggunakan data penjualan dari periode tertentu. Untuk menilai akurasi ramalan, tingkat kesalahan dihitung, termasuk mean square error (MSE), root mean square error (RMSE), dan mean absolute error (MAE). Meskipun baik metode LSTM maupun ARIMA tidak memberikan hasil yang memuaskan dengan menggunakan data penjualan harian, data penjualan bulanan menghasilkan hasil yang lebih baik. Dengan menggunakan data 6 bulan, baik LSTM maupun ARIMA menghasilkan hasil yang relatif baik, dengan LSTM menunjukkan kesalahan yang lebih kecil daripada ARIMA. Mengingat waktu pembelian pipa hijau dari pemasok sekitar 5 bulan, data kumulatif terbatas pada 6 bulan. Berdasarkan hasil penelitian, metode LSTM dapat digunakan untuk meramalkan permintaan produk OCTG dan menentukan tingkat persediaan keselamatan yang diperlukan.

ANALISIS RISIKO KESELAMATAN DAN KESEHATAN KERJA (K3) PADA PENGOPERASIAN MESIN PIERCING MILL DI PT RAINBOW TUBULARS MANUFACTURE

The piercing mill machine is one of the machines used by the company PT Rainbow Tubulars Manufacturing in producing Oil country Tubular Goods (OCTG) seamless pipes. The work process in operating the piercing mill machine includes sprinkling salt and pushing the pipe directly exposed to high heat, noise, smoke and extreme dust. The company has established controls such as Personal Protective Equipment (PPE) and Occupational Safety and Health (OSH) training, but these control efforts have not been maximized, due to a lack of awareness and compliance in using Personal Protective Equipment (PPE). The purpose of this study is to identify the risks of operating a piercing mill machine using the Job Safety Analysis (JSA) method, calculate and analyze the value of the risk, and provide recommendations to the company. Research data was obtained by documentation, observation, interviews, and discussions with production supervisors and OSH experts. The results of this study obtained four job structures and 27 work stages and 31 sources of risk. There are three very high risks, including splashing of billet material with high temperatures, exposure to heat, dust and high noise. providing tools such as replacing tools that are no longer suitable for use.

An optimization framework for enterprise quality infrastructure system under coupling constraints

Improving quality infrastructure (QI) is the cornerstone of improving enterprise quality management activities. Currently, the lack of a QI system optimization approach makes it difficult to exploit the role of QI for enterprise quality improvement. In this study, a generic QI system optimization framework is proposed to guide the development of enterprise QI optimization strategies, and three ideas of coupling constraints are presented in QI optimization for the first time: (1) How does optimization reflect the logical connotation of QI? (2) How to incorporate the cost of optimization? (3) How to determine and guide the direction of QI optimization? Firstly, the QI optimization index system is constructed to reflect the current QI level and future development goals of the enterprise. Secondly, the coupling constraint mechanism of QI system optimization is modeled based on the idea of the heterogeneous information network: the QI indicator sensitivity algorithm is designed to integrate it with cost and urgency. Finally, the optimization index characterizing the priority of QI index optimization is proposed to realize the formulation of enterprise optimization strategies. The framework is applied to eight QI system optimization cases of typical Oil Country Tubular Goods (OCTG) companies. The results show that the proposed framework can solve the three major factors in QI optimization, which is more in line with the enterprise optimization construction and fills the gap in the field of QI optimization. This work can provide ideas for the optimization of systems with such coupling constraint characteristics in other fields.

Adsorption Characteristics between Ti Atoms of TiO2(100) and Corrosive Species of CO2-H2S-Cl- System in Oil and Gas Fields.

The service environment of OCTG (Oil Country Tubular Goods) in oil and gas fields is becoming more and more severe due to the strong affinity between ions or atoms of corrosive species coming from solutions and metal ions or atoms on metals. While it is difficult for traditional technologies to accurately analyze the corrosion characteristics of OCTG in CO2-H2S-Cl- systems, it is necessary to study the corrosion-resistant behavior of TC4 (Ti-6Al-4V) alloys based on an atomic or molecular scale. In this paper, the thermodynamic characteristics of the TiO2(100) surface of TC4 alloys in the CO2-H2S-Cl- system were simulated and analyzed by first principles, and the corrosion electrochemical technologies were used to verify the simulation results. The results indicated that all of the best adsorption positions of corrosive ions (Cl-, HS-, S2-, HCO3-, and CO32-) on TiO2(100) surfaces were bridge sites. A forceful charge interaction existed between Cl, S, and O atoms in Cl-, HS-, S2-, HCO3-, CO32-, and Ti atoms in TiO2(100) surfaces after adsorption in a stable state. The charge was transferred from near Ti atoms in TiO2 to near Cl, S, and O atoms in Cl-, HS-, S2-, HCO3-, and CO32-. Electronic orbital hybridization occurred between 3p5 of Cl, 3p4 of S, 2p4 of O, and 3d2 of Ti, which was chemical adsorption. The effect strength of five corrosive ions on the stability of TiO2 passivation film was S2- > CO32- > Cl- > HS- > HCO3-. In addition, the corrosion current density of TC4 alloy in different solutions containing saturated CO2 was as follows: NaCl + Na2S + Na2CO3 > NaCl + Na2S > NaCl + Na2CO3 > NaCl. At the same time, the trends of Rs (solution transfer resistance), Rct (charge transfer resistance), and Rc (ion adsorption double layer resistance) were opposite to the corrosion current density. The corrosion resistance of TiO2 passivation film to corrosive species was weakened owing to the synergistic effect of corrosive species. Severe corrosion resulted, especially pitting corrosion, which further proved the simulation results mentioned above. Thus, this outcome provides the theoretical support to reveal the corrosion resistance mechanism of OCTG and to develop novel corrosion inhibitors in CO2-H2S-Cl- environments.

Experimental investigation of galling occurrence in sliding contact under high pressure of a manganese phosphate versus steel interface: Comparison of two greases

In OCTG (Oil Country Tubular Goods) field, surface treatments and greases are used to make connections reliable by avoiding galling in metal-metal contacts. This study compares the anti-galling performances and wear behavior of two tribo-systems: steel versus manganese phosphate coated steel contact tested with two different greases. The damage scenario and the kinetics of the involved tribological phenomena will be investigated thanks to a test based on the ASTM G196 standard and appropriate surface analyses. A rotational oscillatory movement is applied on two cylindrical samples under static normal loads. Friction coefficient is computed using torque-sensor records. Counterparts are made of carbon steel of yield strength 550 MPa. One has been subjected to a manganese phosphate treatment to generate a protective layer of few microns thick. The other counterpart is used as machined. Two different industrial greases with anti-wear and extreme pressure additives are tested. Results showed a significant difference of tribological behavior between both greases. XPS analyses are done to understand the composition of the interfacial materials. The protective mechanisms of both greases are compared. Pb-containing grease allows the instantaneous formation of a protective layer whereas Pb-free grease forms a thin and durable protective layer after quite long running-in phase. Manganese phosphate layer participate in the protective layer formation.

Selection of the Technical Framework Contract to Avoid Supply Failures of Oil Country Tubular Goods

To meet the demands of Oil Country Tubular Goods (OCTG) in PTEP, the company made a Long-Term Contract – Call Off Order (LTC-COO) with several OCTG manufacturers/suppliers in Indonesia. Since 2021, there have been two significant problems related to the supply of OCTG. First, two contractors in WA 6 could not fulfil the tubing demand totaling 10,581 joints with a value of USD 2,850,839. The second is four contracts LTC-COO at PTEP could not supply for 2022 needs, worth USD 28,579,436. The problems above are closely related to the price increase of global OCTG price. The proposed price increase could not be approved. As a result, contractors are unwilling to meet supply demand at the original contract price. Long Term Contracts are not fully effective if dealing with fluctuating material prices. The contract failed to supply the needs of OCTG as expected initially. In the end, six LTC-COO contracts had to be terminated early, with an unrealizable value of USD 33,982,587. The company is in critical because it does not have a contract to meet the OCTG demands. This study aims to find the best alternative to solve the OCTG supply failure problem. Several methods and analysis tools are used to simplify the study. BPMN, price, and risk analysis are used for business situation analysis. To determine the root cause using the Current Realty Tree method. Furthermore, for selecting the best alternative solutions using the Analytic Hierarchy Process (AHP). Based on the research that has been done, the best alternative solution to overcome OCTG supply failure in PTEP is using a Technical Framework Contract (TFC) as a contract model for providing OCTG. TFC has main advantages: it binds a minimum of two contractors in a technical aspect and has flexible prices following market prices. The price is formed when there is an OCTG request. With these advantages, the TFC OCTG contract will resist to supplier failure, price increases, and open other optimization opportunities in inventory management. The TFC contract is expected to be effective in overcoming OCTG supply failures.

Structure formation of hyper-compacted and modified concrete

Production of axisymmetric products -pressure and non-pressure pipes, rings, wells, bridges and drainage elements represents one of the main branches of construction industry in water and wastewater industry of Uzbekistan and Central Asian republics. However, positive tendencies of its development are only emerging and still do not meet the potential of progressive, competitive and economical modern technology, capable of providing significant shifts in reduction of resource intensity of new products, expansion of raw material base of construction industry and involvement of technogenic products into its balance, as well as solution of important economic and environmental problems. Prospects for further development of high-efficiency tubular goods production and scientific and technological progress of their production are largely determined by the importance of regularities and methods of controlling technological processes of structure formation with regard to given high level of product quality and criteria of resource intensity of production. In this regard, the analysis of general regularities of material structure formation in the complex process of hypercompaction and cementations modification in axisymmetric concrete is of primary importance.

Grading evaluation of non-API OCTG quality level based on working conditions

The non-API standard series of oil country tubular goods (OCTG) have been developed rapidly to meet the increasing demand of the oil and gas fields, while the frequent accidents of non-API OCTG still occur due to the lack of a perfect quality management system. In this paper, the main types, service conditions, and the current status of quality evaluation technology of non-API OCTG at home and abroad were introduced. For the quality problems of non-API OCTG during the domestic application, the needs of the industry development needs and continuous improvement of quality management system were taken into consideration. Based on the working conditions, the quantitative evaluation method of quality grading was built by the grading idea represented by capability maturity model integration (CMMI) based on the field working conditions. And an evaluation method, including process maturity level, items, indexes and procedures, was proposed and verified. The results showed that the average value and level of quantitative evaluation results of quality grading were 81.5 and C, respectively, which was in good accordance with the current status of non-API product management. The evaluation method is more quantitative and targeted, which would provide for the completeness of the non-API product quality management system with methodological support and theoretical reference.

Complex analysis of collapse strength for tubulars used in the oil and gas industry

Oilfield Country Tubular goods are an important component in the oil and gas industry. Tubing is generally used for the production phase of a well, especially for gas wells. The integrity of tubing is critical for a safe and correct functioning of different installations in the oil and gas industry, and possible malfunctions can incur substantial financial or environmental problems. In these circumstances an exact appreciation of the tubing resistance is of paramount importance. The method that produces the most exact results is the collapse pressure test, but it is expensive and time consuming. Therefore, the authors propose a different approach in the sense that a Finite Element Analysis (FEA) could, if carefully performed, produce a reliable result for the assessment of the collapse pressure for tubing. In this paper, a quadruple analysis is proposed: a collapse pressure test, a geometric measuring (3D scanning) of the deformed (collapsed) pipe segment, an analytical calculation of the collapse pressure and a finite element analysis for a pipe segment. The results obtained will be compared and will allow the authors to evaluate and value the FEA, as a cheaper and rapid approach in assessment of the collapse pressure resistance for tubing.

Effect of Zr Microalloying on Sulfide Stress Cracking Resistance in 125ksi Grade Oil Country Tubular Goods Steel

Effect of Zr Microalloying on Sulfide Stress Cracking Resistance in 125ksi Grade Oil Country Tubular Goods Steel

On the sulfide stress cracking resistance of a 125 ksi grade high-strength low-alloyed steel for oil country tubular goods

Excellent sulfide stress cracking (SSC) resistance was achieved in a 125 ksi grade high-strength low-alloyed steel with increased C content and Cu alloying. Results showed that increased C content allowed tempering at higher temperature, obtaining low dislocation density without decreasing strength. Moreover, Cu alloying refined martensite blocks and inhibited dislocation annihilation, but hardly influenced the precipitation of Cr-rich carbides. The decrease in dislocation density was the main reason for improving SSC resistance, and sufficient precipitation of Cr-rich carbides came in second. Despite Cu alloying failing to improve the SSC resistance, it increased the yield strength without sacrificing SSC resistance.

Влияние режимов термической обработки на механические свойства и стойкость сталей нефтепромысловых труб в модельной СО2-содержащей среде

The influence of heat processing conditions on the experimental steel resistance to carbon dioxide corrosion for Fe-V-Si alloying system in a model CO2-containing operating environment, is viewed. Findings of the alloy structural, mechanical and corrosion characteristics, giving that it had new constitution, can be of great importance in the development of new steel grades for the production of oilfield casing and tubular goods, resistant to CO2-containing operating environment