Sharif Digital Repository

Wax deposition crude oils, with high pour point causes, many problems arise in production, transfer and storage. In this project, wax appearance temperature of three samples of crude oil caculated, using techniques viscometer. Maximum absolute error on oil.no2 was with a value of 0.559% and the results had in good agreement with experimental data. By using the rheometer MCR301, for three crude oil samples, steady shear tests and sweep time tests was done. Flow diagrams were obtained. According to wax appearance temperature (WAT) of each samples, diagrams shear stress versus shear rate are nonlinear at low temperatures than WAT. Crude oil shows non-newtonian behavior. Arrhenious model,... 

Economic loss due to wax precipitation in oil exploitation and transportation has reached several billion dollars a year recently. Development of amodel for better understanding of the process of wax precipitation is therefore veryimportant to reduce the loss.Currently, there are two types of soild models. One is the solid-solution model, and the other is the multisolid-phase model.In this work, a new thermodynamic model that combines the two methods mentioned above, has been presented. The PC-SAFT EOS is used to describe the vapor, liquid and wax phase.SAFT equations describe the phase behavior of large molecules accurately. Intermolecular forces in wax phase are caused by London and Van-... 

Wax deposition is one of the main problems in the oil industry. The formation of wax deposition causes problems such as reducing the effective tube radius, increasing pressure, reducing the flow capacity and etc. Even crude oil waxes can block the pipeline due to deposition of wax during crude oil production and transportation operations. If wax deposition is well predicted and effective parameters are well known and studied, they can be useful in reducing the deposition of wax, and consequently its problems and wax deposition costs will be significantly reduced. In this research, wax deposition has been investigated in Underbalanced drilling by OLGA software. In the first part, by... 

Wax precipitation is one of the major problems in the transfer of crude oil from field production to refineries. This wax with asphaltene compounds and some water and solids, closes the oil pipeline. One of the ways to reduce the amount of wax in pipes is to use additives (flow improvers) to crude oil and improve its rheological behavior. In this research, Five Iranian crude oils were characterized with SARA test and then the effects of various additives including ethylene vinyl acetate (EVA) in concentrations of 500 and 1500 ppm, alkyl phenol ormaldehyde resins (NPFR) with 1500 ppm and styrene-(ethylene-cobutylene)- styrene (SEBS) with 1500 ppm on viscosity, wax appearance temperature... 

Wax precipitation may occur in production or transportation of crude oil form field which is a serious problem in petroleum industry. Flow assurance issues concerning wax precipitation make it necessary to develop a precise thermodynamic model to predict the wax appearance temperature and amount of precipitation at different conditions. In this work a new procedure has been proposed to characterize crude oil based on the SARA test considering the wax and asphaltene as single pseudo components. Two scenarios have been investigated for the survey of the crude oil characterization, with and without asphaltene pseudo component. Also, in this work, the Perturbed ...