Abstract:
Abstract Seawater for water flooding has been in use for many years. It is obviously the fluid of choice in coastal or offshore locations. Seawater differs from surface waters in the concentration of dissolved salts and trace metals. shows a typical seawater analysis. The total dissolved solids (salinity) is high (38,000 ppm) compared to most surface waters which usually have salinities ranging from 500 – 1000 ppm. This paper addresses the analysis and treatment requirements for seawater for water injection as well as provide operating conditions for some seawater treatment plants around the world particularly with respect to scale control.Cite
Abstract Seawater breakthrough percentage monitoring is critical for offshore oil reservoirs as seawater fraction is an important parameter for estimating the severity of many flow assurance issues that caused by seawater injection and further developing effective strategies to mitigate the impact of those issues on production. The validation of using natural ions as tracer to calculate seawater fraction was investigated systematically by studying the natural chemical composition evolution in porous media using coreflood test.Results indicate that chloride, bromide and sodium can be regarded as conservative tracers to calculate seawater fraction as long as there is considerable concentration difference between seawater and formation water.Behavior of calcium shows acceptable error in seawater fraction calculation especially at high temperature and low clay content reservoirs. Application of barium and sulfate reaction model in coreflood test works not as well as in bottle test because of not taking account of fluid flow in porous media.Magnesium,potassium, and boron have significant interactions with core matrix, and thus cannot be used as tracers directly to calculate seawater fraction. Behavior of all ions gives a guideline on selecting suitable ions as tracer. Besides, ions evolution is helpful in understanding the mechanisms of low salinity waterflooding.
Fraction (chemistry)
TRACER
Mass fraction
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Summary Seawater breakthrough percentage monitoring is critical for offshore oil reservoirs because seawater fraction is an important parameter for estimating the severity of many flow assurance issues caused by seawater injection and further developing effective strategies to mitigate the impact of those issues on production. The validation of using natural ions as a tracer to calculate the seawater fraction was investigated systematically by studying the natural chemical composition evolution in porous media using coreflood tests and static bottle tests. The applicable range of ions was discussed based on the interaction between ion and rock. The barium sulfate reactive model was improved by integrating interaction between ions and rock as well as fluid flow effect. The results indicate that chloride and sodium interact with rock, but the influence of the interaction can be minimized to a negligible level because of the high concentrations of chloride and sodium. Thus, chloride and sodium can be used as conservative tracers during the seawater flooding process. However, adsorption/desorption may have a large influence on chloride and sodium concentrations under the scenario that both injection water and formation water have low chloride and sodium content. Bromide shows negligible interaction with rock even at low concentrations and can be regarded as being conservative. The application of a barium and sulfate reaction model in coreflood tests does not work as well as in bottle tests because fluid flow in porous media and ion interaction with rock is not taken into account. Although sulfate and barium adsorption on clay is small, it should not be neglected. The barium sulfate reaction model was improved based on the simulation of ion transport in porous media. Cations (magnesium, calcium, and potassium) are involved in the complicated cation-exchange process, which causes large deviation. Therefore, magnesium, calcium, and potassium are not recommended to calculate seawater fraction. Boron, which exists as anions in formation water and is used as a conservative tracer, has significant interactions with core matrix, and using boron in an ion tracking method directly can significantly underestimate the seawater fraction. The results give guidelines on selecting suitable ions as tracers to determine seawater breakthrough percentages under different production scenarios.
Barium chloride
Barium
Sodium sulfate
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Content (measure theory)
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해수 중 용존 영양염은 해양 내 물질순환을 이해하는 가장 기초적인 자료로 전 지구적 환경변화를 감지하는데 필수 생지화학 성분으로 그 중요성이 인식되고 있다. 분석능력이 다양한 연구자들에 의해서 상이한 시공간에서 측정된 용존 영양염 자료의 상호 비교를 위해 영양염 표준물질의 필요성이 증가하고 있다. 본 연구는 경기도 시화호 내측연안, 울진의 인근 연안 표층수와 동해 울릉분지 표층과 1500m에서 채취된 해수를 여과, 멸균하여 제조한 영양염 표준물질의 균질성과 안정성에 대하여 다루었다. 본 연구에서 제작된 영양염 표준물질은 해외에서 제조되는 영양염 표준물질과 유사한 균질성을 가지고 있다. 제조 후 3-13개월 동안 영양염 농도가 일정한 방향으로 감소하거나 증가하는 경향이 관측되지 않았으며 이 보다 더 긴 기간 동안의 안정성은 지속적인 모니터링이 필요하다. Dissolved nutrients in seawater are recognized as an essential biogeochemical factor for detecting global environmental changes. The importance of nutrient reference material for seawater has been increased greatly for the comparison of nutrient data, measured in different time and space in global ocean by various researchers with different levels in nutrient analysis skill. In this study, we described the homogeneity and stability of nutrient reference material for seawater using natural seawater, collected at a station of Shihwa Lake, at a coastal station near Uljin (surface water), and at a station over the Ulleung Basin (surface water and 1500 m depth water) and sterilized. Based on the homogeneity data, the nutrient reference materials has similar homogeneity compared to other nutrient reference materials. During 3-13 month period, there was no unidirectional trend of increase or decrease in nutrient concentration of newly developed nutrient reference material for seawater. However, a sustained measurement is required to check stability for longer period.
Biogeochemical Cycle
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Current economic and ecological analyses of the various processes available for recovery of minerals from seawater favor ion exchange and sorption technology. The steam power stations in some countries which border the sea use seawater for cooling the turbine stream. Traditional methods for producing magnesium by processing hydromineral sources fail to satisfy the newer ecological standards. Potassium is the fourth most abundant macroelement in the sea. It is produced on a small scale from seawater by evaporation and crystallization methods. The ion-exchange capacity of clinoptilolite in extracting potassium from seawater reaches a value of 30 mg/g, which far exceeds the capacity values quoted for the much more costly zirconium phosphate. The air-stripping production of bromine from seawater is effective only under relatively high seawater temperatures and sufficient bromine concentration.
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Seawater is a solution of salts of nearly constant composition, dissolved in variable amounts of water. It is denser than fresh water. It is risky to drink seawater because of its high salt content. More water is required to eliminate the salt through excretion than the amount of water that is gained from drinking the seawater. Seawater can be turned into potable water by desalination processes or by diluting it with freshwater. The origin of sea salt is traced to Sir Edmond Halley, who in 1715 proposed that salt and other minerals were carried into the sea by rivers, having been leached out of the ground by rainfall runoff. On reaching the ocean, these salts would be retained and concentrated as the process of evaporation removed the water. There are more than 70 elements dissolved in seawater as ions, but only six make up more than 99 percent of all the dissolved salts; namely, chloride (55.04 weight percent [wt%]), sodium (30.61 wt%), sulphate (7.68 wt%), magnesium (3.69 wt%), calcium (1.16 wt%), and potassium (1.10 wt%). Trace elements in seawater include manganese, lead, gold, and iodine. Biologically important elements such as oxygen, nitrogen, and iron occur in variable concentrations depending on utilization by organisms. Most of the elements occur in parts per million or parts per billion concentrations and are important to some positive and negative biochemical reactions. Properties such as salinity, density, and pH could be used to highlight the composition of seawater.
Artificial seawater
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Coastal sea
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