بررسی تجربی اثر شوری و نوع یون بر پایداری امولسیون‌های آب در نفت

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی شیمی، گروه نفت، دانشگاه تربیت مدرس، تهران، ایران

2 دانشکده مهندسی شیمی و نفت، دانشگاه صنعتی شریف، تهران، ایران

10.22078/pr.2019.3221.2487

چکیده

از میان روش‌های ازدیاد برداشت نفت، تزریق آب و بخصوص تزریق آب کم‌شور، روش ازدیاد‌برداشت کم‌هزینه‎ای محسوب می‌شود. در سال‌های اخیر مطالعات در این مورد بیشتر به بررسی اثر تزریق آب برروی برهم‌کنش سنگ/ نفت/ آب تخصیص داده شده است. هدف از انجام مطالعه پیش‌رو بررسی برهم‌کنش سیال/ سیال و بدون در نظر گرفتن وجود سنگ است که درمورد آن مطالعات کمی انجام شده است. در آزمایش‌های این پژوهش تعدادی تست بطری طراحی و انجام شده است که در آن 20% نفت خام مرده و 80% آب با شوری‌های مختلف از ppm000/6 تا ppm000/40 در مجاورت هم قرار گرفتند. با نمونه‌گیری از قسمت امولسیونی شده در سطح تماس بین آب و نفت، توزیع اندازه قطرات آب در نفت به‌دست آمد. اندازه قطرات آب از 02/0 تا mm 65/1 (با در نظر گرفتن داده‌هایی که مقادیر آنها خارج از محدوده دیگر داده‌ها بوده است) و فراوانی نسبی دسته‌بندی‌ها حداکثر mm 73/0 بود. نتایج نشان داد که با کاهش شوری اندازه قطرات نیز کاهش یافته و همچنین، از بین نمک‌های مورد آزمایش (سدیم کلرید، کلسیم کلرید، منیزم کلرید و سدیم سولفات)، کلسیم کلرید بیش از سه نمک دیگر توانایی در جذب مواد فعال سطحی طبیعی نفت به‌سمت سطح تماس و افزایش پایداری امولسیون را دارد. در آزمایش‌های مربوطه نشان داده شد که توان افزایش پایداری امولسیون توسط نمک‌ها (جذب مواد فعال سطحی طبیعی نفت مانند آسفالتین و رزین به‌سمت سطح تماس) به‌ترتیب کلسیم کلرید، منیزیم کلرید، سدیم سولفات و سدیم کلرید است. این امر به‌دلیل واکنش یون‌های نمک موجود در آب با نفت و تفاوت در چگالی بار هر یک از یون‌ها و فعالیت سطحی آن‌ها است.

کلیدواژه‌ها


عنوان مقاله [English]

Experimental Investigation of the Effect of Salinity and Type of Ion on the Stability of Water in Oil Emulsion

نویسندگان [English]

  • Ali Reza Roozbahani 1
  • Amir Hossein Saeedi Dehaghani 1
  • Shahab Ayatollahi 2
1 Petroleum Engineering Department, Faculty of Chemical Engineering, Tarbiat Modares University, Tehran, Iran
2 Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran
چکیده [English]

Water injection especially low-salinity water injection has provided a low-cost EOR method for more oil recovery. In recent years, most of the studies on low-salinity waterflooding have been focused on the investigation of the effect of water injection on rock/oil/water interaction. The purpose of this study is to investigate the fluid/fluid interaction which has received less attention in comparison with the rock/fluids interaction. In this experimental work, a series of bottle tests have been performed with 20 percent of crude oil and 80 percent of saline water (for five different common salts in the seawater) with different salinities from 6,000 to 40,000 ppm. By sampling the emulsified portion at the oil/water interface, the size distribution of the water droplets in oil has been obtained. Moreover, the size of water droplets have varied from 0.02 to 1.65 mm, and relative frequency of categories was 0.73 at its maximum. The size of water droplets decreases with a decease in the salinity. Among the salts, calcium chloride is more effective in comparison with others as the water droplet size is the lowest among three other salts, and consequently it could attract more natural surface active materials from oil to water-oil interface. The sorting of salts from highest to lowest stable emulsion is calcium chloride, magnesium chloride, sodium sulfate and sodium chloride. Ultimately, this is due to the interactions of ions in saline water with oil, charge density of ions and their surface activity.
 

کلیدواژه‌ها [English]

  • Emulsion
  • low-salinity water
  • stability
  • Oil
  • Types of Ions
  • Salinity

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