Sharif Digital Repository

Production of sand is a common issue in oil and gas fields causing various production problems. However, as a result of sand production, rock permeability can also be increased at near-wellbore areas, which is considered to be an advantage of solid particles production. Therefore, this study aims to investigate sand production behavior and permeability changes during sand production experimentally. To do so, a specific core flooding system capable of applying different radial and axial stresses has been designed which is equipped with a special fluid distributer at the outlet to prevent any sand particle blockage during fluid production. As part of this study, eleven unconsolidated synthetic... 

Simplicity of manufacturing and high reliability of airlift pumps have promoted these pumps to be used in different industries, such as petrochemical and oil industries, especially in oil recovery from dead wells. One of the main parameters affecting the performance of these pumps is two-phase flow regime in the main pipe of the pump. In this research, experimental data are utilized to investigate the influence of the flow regimes on the performance of an airlift pump. The data are obtained for air-water two-phase flow in a vertical pipe with a diameter of d = 50. mm and an aspect ratio of L/d = 120. In this study, the gas liquid upward two-phase flow regime in the upriser pipe is... 

Asphaltene deposition causes serious problems in the oil industry. Variation of oil composition and reservoir pressure is reported to be the most important factors that influence asphaltene deposition from reservoir oil. In this study, a mathematical model was developed to simulate asphaltene deposition during primary depletion and CO2 injection. The main purpose of this study is to investigate and to compare asphaltene deposition mechanisms due to primary depletion and CO2 injection. The solid model as thermodynamic model was applied to investigate asphaltene precipitation. A numerical model was established to the governing equations both in space and time and model parameters were... 

Rock formations are always under in situ stresses due to overburden or tectonic stresses. Drilling a well will lead to stress redistribution around the well. Understanding such a stress redistribution, and adopting a proper failure criterion, play a vital role in predicting any potential wellbore failure. However, most of the published analytical models are based on assumptions that do not satisfy the boundary conditions during production, that is, when the well pressure is less than the pore pressure. This paper is aimed at the modeling of the stress regime around the wellbore through combining the poroelastic model with proper boundary conditions under different flow regimes. As a result,... 

Produced water (PW), water extracted along with oil, can cause important environmental challenges due to its high volume and salinity and is considered a key factor in the economic exploitation of oil fields. Therefore, making use of a cost-effective integrated system of wastewater treatment is a fundamental requirement in oil and gas industries. In this paper, the integrated PW treatment system is presented using superstructure-based mathematical optimisation methodology which is aimed at minimising the total annual cost. Two distinct scenarios of injection and reuse in industrial scale are considered to propose an efficient and optimal integrated system. The results show that, despite the... 

Asphaltene deposition is one of the unresolved problems in oil industries. Little information is available on the critical question of "how fast" the flocculated asphaltene particles deposit across the production wells from the flowing oil. In this study, the mechanisms of deposition of flocculated asphaltene particles from oil have been studied experimentally and theoretically under forced convective conditions using an accurate thermal approach. The effects of oil velocity, flocculated asphaltene concentration and temperature on the rate of asphaltene deposition are investigated. It is observed that during the first few weeks the deposition mechanism is dominant and the erosion of the... 

To meet stringent emission standards stipulated by regulatory agencies, the oil industry is required to bring down the sulfur content in fuels. Oil supplies 38% of the worldwide energy, and as the light oil is limited and meanwhile the energy demand is increasing, it is a must to use heavy crude oil and therefore desulfurize it to meet environmental standards. As it is not feasible to desulfurize all the sulfur containing compounds of heavy crude oil by the existing methods (such as hydro-desulfurization) we have focused on biodesulfurization of heavy crude oil. We have isolated the first native fungus which has been identified as Stachybotrys sp. and is able to remove sulfur and nitrogen... 

Dynamic hydrosalinity models are available, but are not used extensively on a large scale soil which receives wastewater from industrial areas, partly because adequate database are expensive to be obtained. Thus, for this reason, there is an urgent need to assess the salt and other pollutant loads collected in wastewater flows into the soil and/ or ground water systems. A conceptual hydrosalinity model was used on two major underlying principals of mass balance and steady state. This model was initially tested on the 4,117 km2 plains west of the Yazd-Ardakan district in the central part of Iran. This model was used at a time when the soil and ground water salinity problem was serious due to... 

In recent decades, utilizing of water-based muds (WBMs) in drilling oil and gas wells is ever increasing comparing to oil-based muds and synthetic-based muds due to the lower environmental issues. However, the main drawbacks with WBMs are rheological properties inefficiency and shale swelling which have caused attentions turn to improvement of WBMs’ rheological properties. In this study, the effects of various nanoparticles (NPs) namely titanium dioxide (TiO2), silicon dioxide (SiO2), and zinc oxide (ZnO) on improving rheological properties and shale recovery rate of a WBM sample at two temperatures (25 and 50 °C) were investigated. The concentrations of NPs in the base mud were set at 0.01,... 

Strategic health, safety, and environmental management system (HSE-MS) involves systematic and cooperative planning in each phase of the lifecycle of a project to ensure that interaction among the industry group, client, contractor, stakeholder, and host community exists with the highest level of health, safety, and environmental standard performances. Therefore, it seems necessary to assess the HSE-MS performance of contractor(s) by a comparative strategic management model with the aim of continuous improvement. The present Strategic Management Model (SMM) has been illustrated by a case study and the results show that the model is a suitable management tool for decision making in a contract... 

One of the main challenges in elimination of oil contamination from polluted environments is improvement of biodegradation by highly efficient microorganisms. Bacillus subtilis MJ01 has been evaluated as a new resource for producing biosurfactant compounds. This bacterium, which produces surfactin, is able to enhance bio-accessibility to oil hydrocarbons in contaminated soils. The genome of B. subtilis MJ01 was sequenced and assembled by PacBio RS sequencing technology. One big contig with a length of 4,108,293 bp without any gap was assembled. Genome annotation and prediction of gene showed that MJ01 genome is very similar to B. subtilis spizizenii TU-B-10 (95% similarity). The comparison...