Research Paper
Petroleum Engineering – Reservoir
Mohammad Ashrafi; Seyyed Alireza Tabatabaei-Nezhad; Elnaz Khodapanah
Abstract
Challenges of rock absolute permeability prediction of tiny samples are remarkable when laboratory apparatus is not applicable and there is no pore network modeling. The prediction using the characterization of micro-computed tomography images has been studied in this paper. Twenty series of 2D micro-computed ...
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Challenges of rock absolute permeability prediction of tiny samples are remarkable when laboratory apparatus is not applicable and there is no pore network modeling. The prediction using the characterization of micro-computed tomography images has been studied in this paper. Twenty series of 2D micro-computed tomography rock binary images have been collected, and each was considered a 3D binary image. Their geometric measures in 2D and 3D for measuring image properties have been considered using Minkowski functionals and available functions, developing a regression model; absolute permeabilities have also been evaluated. Some 2D and 3D geometric properties are considered. The area, the perimeter, and the 2D Euler number are 2D binary image properties. The volume, surface area, mean breadth, integral of the mean curvature, and the 3D Euler number are 3D binary image properties. The porosity and number of objects have also been considered parameters of a regression model. Twenty-four parameters were evaluated, and some were chosen to perform linear regression. An equation was proposed based on the extensive study to predict rock permeability. This equation has two sets of parameter coefficients: one set predicts high-permeability rocks (above two Darcy), and the other used for low- and medium-permeability rocks (less than two Darcy) can be employed for carbonated rock. The average absolute relative error for conducted cases is 0.06.
Research Paper
Instrumentation & Automation in Oil Industries
Hamidreza Mousavi; Mehdi Shahbazian
Abstract
Auto-associative neural network (AANN) has been recently used in sensor fault diagnosis. This paper introduces a new AANN based algorithm named improved AANN (I-AANN) for sensor single-fault diagnosis. An algorithm is a two-aimed approach that estimates the correct value of the faulty sensor by isolating ...
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Auto-associative neural network (AANN) has been recently used in sensor fault diagnosis. This paper introduces a new AANN based algorithm named improved AANN (I-AANN) for sensor single-fault diagnosis. An algorithm is a two-aimed approach that estimates the correct value of the faulty sensor by isolating the source of the fault. The performance of the algorithm is compared with the so-called enhanced AANN (E-AANN) in terms of computational time and fault reconstruction accuracy. The I-AANN has high performance, and it can isolate the source of fault quickly and accurately. A dimerization process model is used as a case study to examine and compare the performance of the algorithms. The results demonstrate that the I-AANN has superior performance.
Research Paper
Geophysics
Mahammad Laribaghal; mehdi Torfi; Mehdi Khorasanian; Seyyed Reza Alavi Zaree
Abstract
Fin-pass rolls are the latest series of rolls in electric resistance welding (ERW) pipe production lines that form the sheets to tubular shape and adjust the edges of the sheet for welding. The rolls (made of AISI 8622 steel) lose their proper function after about 10 years of operation due to severe ...
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Fin-pass rolls are the latest series of rolls in electric resistance welding (ERW) pipe production lines that form the sheets to tubular shape and adjust the edges of the sheet for welding. The rolls (made of AISI 8622 steel) lose their proper function after about 10 years of operation due to severe wear and change of their original surface profile. The worn portions were removed by grinding and replaced by an AISI D2 high carbon steel ring to repair these rolls. After a short time of service (about one year), the edge of the repair ring was exposed to severe spalling and fracture. The present study investigated the causes of the rapid failure of the AISI D2 repair ring and proposed a solution to the problem. The surface morphology, hardness, and wear resistance were studied. Moreover, the stress analysis of fin-pass rolls was studied using ABAQUS 6.14 finite element software for the closer investigation of the failure mechanism. The leading cause of spalling was the inherent brittleness of the AISI D2 steel and the presence of a high-stress concentration at the edges of the repair ring. To overcome this problem, carburized AISI P20 steel, case hardened AISI 4140 steel, and hard chromium electroplated AISI 4140 steel were replaced, and the resulting properties were studied. The highest resistance to spalling and wear occurred with carburized AISI P20 steel because of the high surface hardness and the gradual increase of toughness from the surface to the depth in the carburizing process, increasing the wear resistance and retarding the growth of fatigue cracks.
Research Paper
Petroleum Engineering
Mehdi Amiri; Jafar Qajar; Azim Kalantariasl
Abstract
Sarvestan and Saadatabad oilfields produce more than 140 bbl/day of wastewater due to oil processing. Due to environmental issues, the produced water is injected into a disposal well through a pipeline with a diameter of 8 inch and a length of 5 km. Formation of inorganic scale may accelerate the need ...
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Sarvestan and Saadatabad oilfields produce more than 140 bbl/day of wastewater due to oil processing. Due to environmental issues, the produced water is injected into a disposal well through a pipeline with a diameter of 8 inch and a length of 5 km. Formation of inorganic scale may accelerate the need for frequent reservoir acid stimulation, restrict flow path, and generally add unpredicted costs for water injection operations. This study predicts scaling tendency and examines scale precipitation at different pressures, temperature, and mixing ratios of injection wastewater with formation water in Sarvestan and Saadatabad oilfields. The experimentally measured chemical analysis of the injection water and formation water was used to estimate the amount, type, and composition of scale due to mixing and changes in thermodynamic conditions. Scaling tendency values for eight types of scale, namely CaCO3 (calcite), CaSO4 (anhydrite), CaSO4.2H2O (gypsum), FeCO3 (siderite), Fe(OH)2 (amorphous), NaCl (halite), Mg(OH)2 (pyrochroite), and KCl (sylvite), were investigated by commercial software packages OLI ScaleChem and StimCADE. The results show that the significant scales are CaCO3 and FeCO3 formed in Sarvestan and Saadatabad oilfields. The formation of these scales can lead to severe problems, such as disrupting equipment and decreasing production; thus, it is necessary to predict all types of scales before forming. It allows design and planning for chemical inhibitor treatment and prediction of injectivity problems and acid stimulation.
Research Paper
Petroleum Engineering
Borzu Asgari pirbalouti
Abstract
This study investigated the application of iron oxide nanoparticles in the presence of an external magnetic field to control the rheology of drilling fluids. Drilling fluid rheology is one of the most critical factors in determining the optimal fluid. Drilling fluid must have good rheological properties ...
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This study investigated the application of iron oxide nanoparticles in the presence of an external magnetic field to control the rheology of drilling fluids. Drilling fluid rheology is one of the most critical factors in determining the optimal fluid. Drilling fluid must have good rheological properties to carry the drilled cuttings. On the other hand, polymers in the water-based drilling fluid control fluid loss. In low-density oil-based fluids, where the water content is low, rheological control is generally difficult since there is a limitation in selecting additives. In this study, the ferromagnetic fluid has been generated by adding nanoparticles of Fe3O4 to silicon oil. By adding ferromagnetic fluid to the oil-based mud under the influence of the external magnetic field, we examined the rheological behavior of the oil-based drilling mud. The external magnetic field can be applied in actual conditions in the middle of a magnetic drilling string. The results showed that the magnetic nanoparticles improved the drilling mud rheological properties. Moreover, the viscosity of the oil-based fluid without nanoparticles was measured 2 cP and increased to 33 cP by adding 4 wt % of iron oxide nanoparticles under an external magnetic field of 0.321 T. The magnetic field was also used for water-based mud (WBM), and the results showed that in water-based fluids containing polyanionic cellulose (PAC) polymer, the magnetic field did not have much effect on the rheological properties of the drilling mud compared to oil-based mud (OBM). Since water is the main component of the water-based fluid, increasing the magnetic field reduces the viscosity of the water-based fluid. The magnetic field increased fluid’s rheology by adding iron oxide nanoparticles to the polymer-based fluid. The viscosity of the water-based fluid containing nanoparticles increased to 850 cP under the magnetic field.
Research Paper
Petroleum Engineering – Exploration
Bahram Habibnia; Omid Vallipour; Majid Alipour
Abstract
The Qale-Nar oilfield is an asymmetric two-humped anticline located in the northernmost part of the Dezful embayment, in which the fractured Asmari carbonates are the primary reservoir rock. In this study, for the first time, the organic geochemistry of oils produced from the Asmari reservoir is used ...
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The Qale-Nar oilfield is an asymmetric two-humped anticline located in the northernmost part of the Dezful embayment, in which the fractured Asmari carbonates are the primary reservoir rock. In this study, for the first time, the organic geochemistry of oils produced from the Asmari reservoir is used to investigate the reservoir continuity and possible compartmentalization. To this end, geological information from the studied oilfield was combined with bulk geochemistry (e.g., °API gravity) and molecular characteristics (e.g., gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS) data) of the produced oils. Two oil samples obtained from wells 6 and 10 of the studied oilfields indicate significant differences in their bulk and molecular geochemical properties. Accordingly, a scenario was presented to better explain the reservoir charging and compartmentalization in the Qale-Nar oilfield. In this scenario, low-maturity hydrocarbon pulses first charge the eastern culmination of the Qale-Nar oilfield. The activity of a fault plane located between wells 6 and 10 could induce a barrier between the two wells. Consequently, the late hydrocarbon charges with higher maturity could only charge the compartment belonging to well 6. Therefore, well 10 could not receive these high-maturity hydrocarbon pulses due to the lack of lateral connectivity. The information obtained from this study can be of great help in future reservoir studies with important implications for field development projects and enhanced-recovery plans.
Research Paper
Petroleum Engineering – Production
Abdorrahman Mehri Ghahfarrokhi; Hassan Shokrollahzadeh Behbahani; Ezzatollah Kazemzadeh; Gholam Abbas Safian
Abstract
Nowadays, use of visco-elastic surfactants as the main component of gel diverters is becoming more and more common among well completion engineers, as well as stimulation service companies. Gel diverter, as other kinds of diverters, is used in multi-layered carbonated reservoirs to diver acid into less ...
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Nowadays, use of visco-elastic surfactants as the main component of gel diverters is becoming more and more common among well completion engineers, as well as stimulation service companies. Gel diverter, as other kinds of diverters, is used in multi-layered carbonated reservoirs to diver acid into less permeable sublayer. As use of these materials becomes more common, modeling and simulating the gel-acid injection process becomes more required. In this study, a mathematical model is generated to simulate gel-acid injection process, and experimental data is compared with data predicted by the model. The purpose of this study is to investigate the field possibility of injection gel-acid and to generate a model for simulating this process, in order to smart permeability enhancement in Ahwaz oilfield, one of Iranian Southwest oilfields. The solutions predicted by model are in an acceptable correlation with experimental data. The generated model can be used for other multi-layered carbonated oilfields.