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... 

In this work, a reliable dimensionless correlation is proposed for prediction of permeability reduction rate in porous media, which is verified by experimental data obtained in this work in glass bead and sand pack as well as the core data from the literature. Although this correlation is based on the data which were obtained in our work in glass bead and sand-packed media at low pressure, it shows considerable flexibility to match with the extracted data for sandstone cores at high pressure, various flow rates, different temperatures and concentrations of calcium, and sulfate ions in brine solutions. In addition, a novel relationship for predicting the rate of precipitation of CaSO4 in... 

Liquefaction phenomenon is usually accompanied by large amounts of settlement owing to disruption of soil structure. In addition to that, large settlement also occurs by a significant increase in soil permeability during seismic excitation. To properly simulate the post-liquefaction settlement, it is important to take the compressibility properties of the liquefied sand as well as the permeability increase into account. Using initial permeability coefficient in the course of simulation of liquefaction leads to underestimation of settlement. In addition to that, using unrealistic values for permeability may cause erroneous predictions of other aspects of soil behavior. Therefore, an accurate... 

Pr doped spinel nanoferrites having following composition Cu Pr x Fe 2-x O 4 (x = 0, 0.25, 0.50, 0.75, 1.00) were synthesized using sol-gel route. Prosademium (Pr) which is a rare earth metal was doped to tailor the properties of the Cu spinel nanoferrites. Characterization tools such as FTIR, XRD, FESEM and VSM were employed to investigate the phase, absorption bands, structure, microstructure and magnetic properties. FTIR was used to see the absorption bands and force constants of the Pr doped Cu spinel nanoferrites. Crystallite size, lattice parameters, cell volume and micro strains were determined from XRD data. Bulk density, X-ray density and porosity of the Pr doped Cu spinel... 

This fact is well known that during any scenario of production, asphaltene deposition in porous media has a substantial effect on oil flow. But a clear understanding of asphaltene deposition mechanisms can help to minimize asphaltenic problem in oil-bearing formations. In this study, the experimental results of three dynamic CO 2 miscible injection tests were investigated. Regarding the effects of adsorption, mechanical entrapment, and sweeping mechanisms on permeability behavior, a mathematical mass and permeability variation model were developed. According to the experimental results asphaltene deposition causes a 70% loss of sand stone initial permeability while the loss is significantly...