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Collaborating Authors
Moghadasi, J.
Abstract Due to the extensive use of water injection for oil displacement and pressure maintenance in oilfields, many reservoirs experience the problem of scale deposition when injection water starts to break through. In most cases the scaled-up wells are caused by the formation of sulfate and carbonate scales of calcium and strontium. Due to their relative hardness and low solubility, there are limited processes available for their removal and preventive measures such as the ‘squeeze’ inhibitor treatment have to be taken. It is therefore important to gain a proper understanding of the kinetics of scale formation and its detrimental effects on formation damage under both inhibited and uninhibited conditions. This paper presents the results of an experimental and theoretical study of permeability reduction of porous media caused by scaling. Two incompatible solutions of calcium and /carbonate ions were injected into the porous medium, where calcium or calcium carbonate was generated by chemical reaction. Mechanisms by which a precipitate reduces permeability include solids deposition on the pore walls due to attractive forces between the particles and the surfaces of the pores, individual particles blocking pore throats, and several particles bridging across a pore throat. The characteristics of the precipitate influence the extent of formation damage. Conditions such as large degree of supersaturation, presence of impurities, change in temperature, and rate of mixing controls the quantity and morphology of the precipitating crystals. Introduction The formation of mineral scale associated with the production of hydrocarbon has been a concern in oilfield operation. Depending on the nature of the scale and the fluid composition, the deposition can take place within the reservoir which causes formation damage [14, 17, 20, 25] or in the production facilities where blockage can cause severe operational problems. The two main types of scale which are commonly found in the oilfield are carbonate and sulphate scales [19–20, 27–30, 32, 36, 39–44]. Whilst the formation of carbonate scale [3, 42–43] is associated with the pressure and pH changes of the production fluid, the occurrence of sulphate scale is mainly due to the mixing of incompatible brines, [21–23, 25–26, 43–44] i.e. formation water and injection water. In the oilfield, the universal use of sea water injection as the primary oil recovery mechanism and for pressure maintenance means that problems with sulphate scale deposition, [25–26] mainly calcium and strontium, are likely to be present at some stage during the production life of the field. A field example is the Iranian offshore of Siri field [25] in the southern Persian Gulf. The oil in this field comes from a formation called Mishrif; this formation is common between Iran and the United Arab Emirates. Water injection into the Siri field was started in 1984 with 9100 bbl/day in order to maintain the pressure and to increase the oil recovery. But the injectivity decreased rapidly by 1990 the water injection was only 2200 bbl/day, and subsequently the water injection was stopped. The history of water injection in the Siri field is shown in Fig.1 [25] with a drop in injectivity of approximately 7000 bbl/day over a period of six years.
- North America > United States > Texas (0.93)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean (0.74)
- Europe > Denmark > North Sea > Danish Sector (0.74)
- Asia > Middle East > Iran > Arabian Gulf (0.74)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Europe > Denmark > North Sea > Danish Sector > Norwegian-Danish Basin > Siri Canyon > Block 5604/20 > Siri Field (0.99)
- Africa > Middle East > Egypt > Gulf of Suez > Gulf of Suez Basin > Morgan Field (0.99)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Waterflooding (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene (1.00)
Scale Formation in Oil Reservoir and Production Equipment during Water Injection (Kinetics of CaSO4 and CaCO3 Crystal Growth and Effect on Formation Damage)
Moghadasi, J. (Petroleum University, University of Surrey) | Jamialahmadi, M. (Petroleum University, University of Surrey) | Müller-Steinhagen, H. (Stuttgart University) | Sharif, A. (University of Surrey)
Abstract In the oilfield, due to the extensive use of water injection for oil displacement and pressure maintenance, many reservoirs experience the problem of scale deposition when injection water starts to breakthrough. In most cases the scaled-up wells are caused by the formation of sulphate and carbonate scales of calcium and Strontium. Due to their relative hardness and low solubility, there are limited processes available for their removal and the preventive measure such as the ‘squeeze’ inhibitor treatment has to be taken. It is therefore important to have a proper understanding of the kinetics of scale formation and its detrimental effect on formation damage under both inhibited and uninhibited environment. This paper presents an experimental and theoretical study of permeability reduction of porous medium caused by scaling. Two incompatible solutions, calcium and sulfate/carbonate rich ions were injected into and calcium sulphate or carbonate generated within the porous medium by chemical reaction. Mechanisms by which a precipitate reduces permeability include solids depositing on the pore walls because of attractive forces between the particles and the surface of the pore, a single particle blocking a pore throat, and several particles bridging across a pore throat. The characteristics of the precipitate influence the extent of formation damage. Conditions such as large degree of supersaturation, presence of impurities, a change in temperature, and the rate of mixing control the quantity and morphology of the precipitating crystals. Introduction The formation of mineral scale associated with the production of hydrocarbon has been a concern in oilfield operation. Depending on the nature of the scale and the fluid composition, the deposition can take place within the reservoir which causes formation damage [10, 13, 15, 20] or in the production facilities where blockage can cause severe operational problems. The two main types of scale which are commonly found in the oilfield are carbonate and sulphate scales [14–15, 22–24, 27–28, 31–35]. Whilst the formation of carbonate scale [2, 34–35] is associated with the pressure and pH changes of the production fluid, the occurrence of sulphate scale is mainly due to the mixing of incompatible brines, [16–18, 20–21, 35–36] i.e. formation water and injection water. In the oilfield, the universal use of sea water injection as the primary oil recovery mechanism and for pressure maintenance means that problems with sulphate scale deposition, [20–21] mainly calcium and strontium, are likely to be present at some stage during the production life of the field. A field example is the Iranian offshore of Siri field [20] in the southern Persian Gulf. The oil in this field comes from a formation called Mishrif; this formation is common between Iran and the United Arab Emirates. Water injection into the Siri field was started in 1984 with 9100 bbl/day in order to maintain the pressure and to increase the oil recovery. But the injectivity decreased rapidly by 1990 the water injection was only 2200 bbl/day, and subsequently the water injection was stopped. The history of water injection in the Siri field is shown in Fig.1 [20] with a drop in injectivity of approximately 7000 bbl/day over a period of six years. Table 1 shows the various types of scales that are commonly found in oilfield [21]. Table 2 shows the major components of scales found in the Iranian oilfield [21]. The deposits are seldom pure calcium sulphate or calcium carbonate, but are usually a mixture of two or more of the inorganic components plus corrosion products, congealed oil, paraffin, silica and other impurities. These materials are trapped in the inorganic lattice and frequently complicate the removal of the deposit. Of all the scales, calcium sulphate and calcium carbonate have been singled out for study in this work.
- North America > United States > Texas (0.93)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean (0.74)
- Europe > Denmark > North Sea > Danish Sector (0.74)
- Asia > Middle East > Iran > Arabian Gulf (0.74)
- Geology > Mineral > Sulfate (1.00)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.40)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > United States > Texas > Permian Basin > Area Formation (0.99)
- Europe > Denmark > North Sea > Danish Sector > Norwegian-Danish Basin > Siri Canyon > Block 5604/20 > Siri Field (0.99)
Scale Formation in Iranian Oil Reservoir and Production Equipment During Water Injection
Moghadasi, J. (Petroleum University, University of Surrey) | Jamialahmadi, M. (Petroleum University, University of Surrey) | Müller-Steinhagen, H. (Stuttgart University) | Sharif, A. (University of Surrey) | Ghalambor, A. (U. of Louisiana) | Izadpanah, M.R. (Kerman University) | Motaie, E. (Petroleum University )
Abstract 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.
- North America > United States (1.00)
- Asia > Indonesia (1.00)
- Africa > Middle East > Egypt (1.00)
- (3 more...)
- Research Report (0.46)
- Overview (0.34)
- Geology > Mineral > Sulfate (1.00)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.40)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > United States > Texas > Permian Basin > Area Formation (0.99)
- Europe > United Kingdom > North Sea > Central North Sea > Forties Formation (0.99)
- Europe > Denmark > North Sea > Danish Sector > Norwegian-Danish Basin > Siri Canyon > Block 5604/20 > Siri Field (0.99)
- (17 more...)
Formation Damage in Iranian Oil Fields
Moghadasi, J. (Petroleum University) | Jamialahmadi, M. (Petroleum University) | Müller-Steinhagen, H. (Stuttgart University) | Sharif, A. (University of Surrey) | Izadpanah, M.R. (Kerman University) | Motaei, E. (Petroleum University) | Barati, R. (Petroleum University)
Abstract The 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. Introduction The success of oil recovery is strongly influenced by whether the reservoir permeability can be kept intact or even improved. Permeability changes in petroleum reservoirs have received a great deal of concern by the oil and gas industry. This problem is termed as "formation damage". It can occur during almost any stage of petroleum exploration and production operations. Attempting to understand formation damage is becoming an important task for reservoir engineers, oilfield chemists, and decision-makers in business, because it is first step to be taken to prevent and further alleviate this problem. Formation Damage Mechanisms - Two phenomena can change the permeability of the rock. One is change of porosity. This phenomenon is due to the swelling of clay minerals or deposition of solids in the pore body. The other is the plugging of pore throats. The narrow passages govern the ease of fluid flow through porous media. If they are blocked, the permeability of the porous rock will be low even though the pore space remains large. Either organic or inorganic matter may cause the plugging of pore throats. The organic induced damage is due to the formation of high viscosity hydrocarbon scale when temperature and pressure conditions in the reservoirs are changed. The inorganic damage involves release and capture of particulate including in situ fines and precipitates from chemical reactions. The mechanisms that trigger the formation damage can be categorized into three major processes (Leone and Scott, Hydrodynamic- A mechanical force mobilizes loosely attached fine particles from the pore surface by exerting a pressure gradient during fluid flow. The movement of clay minerals, quartz, amorphous silica, feldspars, and carbonates may cause mechanical fine migration damage.
- North America > United States (1.00)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean (0.67)
- Europe > Denmark > North Sea > Danish Sector (0.67)
- Asia > Middle East > Iran > Arabian Gulf (0.67)
- Research Report (0.46)
- Overview > Innovation (0.34)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (0.75)
- Asia > Middle East > Qatar > Arabian Gulf > Arabian Basin > Arabian Gulf Basin > Block 6 > Al Khalij Field > Mishrif Formation (0.99)
- Asia > Middle East > Iran > Arabian Gulf > Arabian Basin > Arabian Gulf Basin > Sirri Field (0.99)