فهرست مطالب مهدی اسکندرزاده

The aim of this study was to investigate the source of leaks in the natural gas pipeline network. According to the results obtained from the Failure Mode and Effects Analysis (FMEA), the three defects including lack of proper scraping, the presence of oil and existing of moisture at the welding zone in the installation and execution phase had the highest risk. These defect types studied further using experimental methods. The fracture mechanics analysis for the defects with the highest risk in Abaqus software was performed by XFEM method in three dimensions. According to the results, cracks with initial length of 4mm will grow at pressures higher than 1.4 MPa. To obtain results equivalent stress intensity factor has been used. The results imply the application of suitable nondestructive methods for determination of cracks with lengths higher than 4mm. The results of this research can be employed by inspection engineering of natural gas companies.

Annually, huge amount of money is lost due to corrosion problems in upstream and downstream oil and gas industries. In order to control the corrosion costs, recently, the corrosion control/corrosion management concept is developed. The aim of corrosion management philosophy is to reduce the corrosion costs and increase the safety by re-evaluation process in different stages of the project. Material selection process is one of key stages in integration assurance of the system, which plays important role in overall corrosion control process. Some important parameters in selecting suitable materials for using in a given working and environmental condition includes: design pressure and temperature, weldability, costs and corrosion concerns. Nowadays, the last one attracted attentions of the both researchers and owners. Codes like ISO 21457 necessitate providing Material Selection Procedure Report before proceeding executive steps of the project. Without any specific material selection procedure; the material selection process will be a complex and confusing task because of the diversity in codes and fluid service conditions. The aim of this study is to introduce researchers and engineering with corrosion concerns especially in CO2, H2S and salt contained services and the solutions which are normally employed in upstream oil industry to deal with associated problems. Towards, environmental deterioration problems in Iranian oil and gas fields are discussed and the related treatments are presented.

Recently, two development projects for the "Sepehr and Jufair" fields and "Aban and Paydar Gharb", have been handed over to their respective contractors under the new petroleum contract type so called the IPC (Iran Petroleum Contracts). Given that these two contracts are the first of their kind in the history of Iran, many aspects of the contract still need to be examined and explained. The legal aspects of the contract have been studied by various researchers, but the technical and managerial aspects of the contract have not been considered so far. Therefore, in this study, the capacities of this type of contract to monitor technical and engineering activities in the field of technical inspection and shortcomings in this regard have been considered. This article answers the question based on financial and environmental risk criteria, whether it is essentially necessary to conduct a technical inspection of the employer in this type of contract or not? Also, the level of required client surveillance on the contractor's activities in this type of contract has been discussed.

In Meshginshahr geothermal power plant, fluid with high temperature and pressure comes out of the NWS6D well and are divided into two phases of water and steam by the condenser of the wellhead and by two pipelines (loop1 carrying steam and loop2 carrying water) is transferred to the power plant and the electricity is generated. Risk-based technical inspection technique has never been used in the piping systems of geothermal power plants. In this paper, the implementation of risk-based inspection methodology in geothermal power plants is presented. To perform the risk-based inspection technique in the loops, first the corrosion mechanisms are identified and by specifying the corrosion mechanisms, the probability and consequence of failure of each mechanism and consequently the risk of corrosion in each loop are determined. Experiments using Potentiodynamic polarization test are employed to investigate the general corrosion rate of the pipe materials. According to the studies conducted in this article, in loop 1, the risk of corrosion of carbon dioxide and pitting corrosion is moderate and the risk of corrosion of sour water is low and the risk of loop 2 in case of pitting corrosion is high while in the case of sulfuric acid corrosion, it shows a low amount.

Fitness for Service (FFS) methodology assessment of defective pipes and pressure vessels in oil and gas industries is offered in API-579 standard. The defective pipes operation are allowed just if they have been evaluated based on FFS method and their operating pressure has been confirmed whether the defects caused by cracks or different corrosion types. Through the current study FFS evaluation procedure was benefited to find the safe operating pressure for a 16 inches defective pipe consisting a local metal loss defect (Max. depth of 8mm) with an internal pressure of 33 MPa. Furthermore, the time needed for the next FFS examination had been presented. The analyzed pipe was about 4 years in service and is located in an injection line of a natural gas reservoir. The required experimental data related to the thickness of this pipe were collected using phased array ultrasonic test on the operating site. The results indicated that the defective pipe could operate well in service for next two years without any demands for repair or replacement.

The aim of technical inspection activities is to ensure all components are working in a safe condition. Approaches in technical inspection turn to cost effective and much reliable strategies such as inspections based on the level of the risk of the components. Risk based inspection (RBI) is the process of developing a scheme of inspection based on knowledge of the risk of failure. RBI procedure is the combination of an assessment of the probability of failure due to flaws damage, deterioration or degradation in conjunction with an assessment of the consequences of such failures. RBI helps to increase the safety of the processing unit, reduce the costs, and improve environmental protection. Now the RBI procedure is the core of many inspection strategies in the oil and gas industry. However, the application of RBI in non-metallic components is rarely studied. In this paper, the risk assessment of the GRE/GRP components is investigated. Composite components are extensively using in water (includes deposit water, waste water, and wash water) systems. Through this study, different failure mechanisms in composite components are discussed. The results of RBI method indicated that composite components should be inspected within the second year after the start of the service. Because of the low and medium overall risk of the components, a visual inspection shall be performed in three/five years’ duration for non-metallic piping and tanks.

Nano composites of graphene oxide and modified nanoclay (Cloisite 15A) were produced based on 80 phr chlorobutyl and 20 phr natural rubber according to inner liner recipe. The results show modified nano fillers have remarkable change in dispersion in the matrix. Subsequently Improved cured products properties. Exfoliation of graphen oxide and Cloisite 15A was confirmed by XRD and TEM. In the case of graphite intercalation has happened. Also physical and mechanical properties of this composite was studied.

Incidence of breaks and leakages in fluid transportation pipes is a common issue in Iran. Depending on the type of pipes and environmental conditions, the breaks in the pipes may be caused by different factors, including mechanical damages, internal or external corrosions, failures, or applied stresses. In the repair of damaged pipes, there are several strategies for rebuilding and implementing the pipeline, most of which are replacing the entire exhausted pipe, using weld clamps and using composite patches. In recent years, the use of composite patches has been accepted as a low-cost, permanent, and standard method for different pipe sections with the least interruption in transportation. In the present study, the boding strength of glass fibers-reinforced epoxy composite patches on a structural steel substrate were investigated and optimal conditions of achieving enhanced adhesion strength of composite patches on the steel substrate were determined, using the Tagochi method at various curing temperatures and times. In this regard, the tensile and shear strength of epoxy, cyanoacrylate, and methacrylate-based glues as three kinds of appropriate polymers for bonding the epoxy composite on the steel substrates were tested. The mechanical strength measurements and fractured interfaces evaluations using a scanning electron microscopy (SEM) revealed that the methacrylate-based glue has the better adhesion strength to the steel substrate.

The main objective of this study was to evaluate the skills management required for the application of precision farming in the process of sustainable agricultural development in West Azerbaijan Province. This research in terms of purpose is an applied research and in terms of methodology is part of descriptive survey research. The statistical population of this research were the experts and officials of mechanization of West Azerbaijan Province that due to the limited number of population (n=86) a Census method used to collect the data. The survey instrument was a questionnaire which its validity confirmed by executive experts. Reliability of the questionnaire calculated with using Cronbach's alpha coefficient, which was equal to 0.77. Based on the results of the factor analysis showed that seven factors (accounting skills; agronomic skills; diagnostic skills of variability, information seeking skills, setting goals and decision-making skills, economic skills in applying of agricultural machinery and technical skills in applying of agricultural machinery) in total, 61.27 percent of variance have been explained the management skills necessary for precision farming in the process of sustainable agriculture developing. Among them, accounting skills with explanation 23.91 percent of total variance had a greater role