This paper presents the mechanism of scale formation by water in oil fields and suggests an accurate model capable of predicting scaling phenomena in Iranian Oilfield operations due to mixing of incompatible waters or change in thermodynamics, kinetics and hydrodynamic condition of systems. A new and reliable scale prediction model which can predict scaling tendency of common oilfield water deposits in water disposal wells, water-flooding systems and in surface equipment and facilities is developed and present. The development of the model is based on experimental data and empirical correlation, which perfectly match Iranian oil fields conditions. Furthermore the simultaneous deposition of oilfield scales and competition of various ions to form scale which is common phenomena in oil fields are reflected in the development of the model allowing the effect of each scale on the others to be taken into account. The new model has been applied to investigate the potential scale precipitation in Iranian oilfields, either in onshore or offshore fields where water injection is being performed for desalting units' water disposal purpose or as a method of secondary recovery or reservoir pressure maintenance. Introduction Scale formation in surface and subsurface oil and gas production equipment has been recognised to be a major operational problem. It has been also recognised as a major causes of formation damage either in injection or producing wells. Scale contributes to equipment wear and corrosion and flow restriction, thus resulting in a decrease in oil and gas production. Experience in the oil industry has indicated that many oil wells have suffered flow restriction because of scale deposition within the oil -producing formation matrix and the downhole equipment, generally in primary, secondary and tertiary oil recovery operation as well as scale deposits in the surface production equipment. Oil field scales costs are high because of drastic oil and gas production decline, frequently pulling of downhole equipment for replacement, reperforation of the producing intervals, reaming redrilling of the plugged oil wells, stimulation of the plugged oil-bearing formation, and other remedial workovers. As scale deposits around the wellbore, the porous media of formation becomes plugged and may be rendered impermeable to any fluids. Many case histories [14,15,21,23–26,28,29,32,34–41,44–47] of oil well scaling by calcium carbonate, calcium sulphate, strontium sulphate and barium sulphate have been reported. Problems pertaining to oil well scaling in North Sea fields have been reported [24] and are similar to cases in the Russia where scale has severely plugged wells. Oilfields scale problems have occurred as a result of water flooding in Algeria, Indonesia in south Sumatra oilfields, Saudi oil fields and Egypt in El-Morgan oilfield [12] where calcium and strontium sulphate scales have been found in surface and subsurface production equipment. This study investigated scale formation and deposition in Iranian oilfields.
TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe fine migration and the scale formation into the porous media and the resulting production decline have long been the problem to the petroleum industry. It is also generally accepted that formation due to the particle movement and the scale formation are not thoroughly understood. In contributing to the solution of this problem, an experimentally study of calcium sulphate scale formation and the particle movement in the porous media using of packing bed with 12 different size of the glass and sand bead and the 8 core plug that gathered from the Siri oilfields. The purpose was to study the different physical and mechanical aspects of the processes leading to the formation damage caused by the movement and the entrapment of the suspended particles and the scale formation.The permeability is the key parameter among several others that control the reservoir performance. The experiments are based on the results of the permeability reduction. The interception of the permeability reduction by the interaction between the operational parameter is very complex. Therefore, several of these factors such as the temperature, the concentration, the fluid dynamic and the type of porous media are considered.The experimental results are analyzed and a new model which can predicts particle movement and the scaling tendency of the common oilfield water deposits in the water disposal wells, the water flooding systems, and in surface equipment's and the facilities is developed. The developed of the model is based on the experimental data and the empirical correlation, which perfectly mach the Iranian oilfields condition. This model has been applied to the investigate of the potential of the scale precipitation in the Iranian oilfields, either in the onshore or the offshore fields, where the water injection is being performed for the desalting units water disposal purpose or as the method of secondary recovery or the reservoir pressure maintenance.
The grateÀbed resistance coefficient appears to be an important operating parameter with a strong influence on overall performance during downdraft fixed-bed gasification. It directly affects the velocity profile, temperature distribution, and height of the bed. To date, no information on the pressure drop as a result of the grateÀbed resistance has been found. The objective of the present investigation is to propose a correlation that can predict the total effect of pressure drop through a grate of a certain surface porosity covered by the porous bed. The term related to the grateÀbed resistance is based on the effective grate porosity, which combines surface bed porosity with geometrical criteria of the grate. On the basis of these criteria, a new term has been integrated into the Ergun equation. The prediction has been validated against the experimental results and conducted on a 0.7 MW th downdraft, fixed-bed gasifier that was fueled with wood pellets of a feeding rate 50À100 kg/h. Three types of grates of different porosities (0.6, 0.2, and 0.04) and thicknesses (2 mm and 10 mm) of an orifice diameter of 6 mm each have been tested under various operating conditions. The oxidizer (air or mixture of air and steam) was preheated over 1000°C and supplied with a rate of 60À110 kg/h. The predicted values are in agreement with the experimental results. Although lower grate porosity, higher conversion of fuel, and heating value of the gas is produced, the stability of the process is disturbed. Therefore, a grate porosity reduction below 20% is not recommended.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.