Heat-Exchanger Deposition in an Inverted Steam-Assisted Gravity Drainage Operation. Part 1. Inorganic and Organic Analyses of Deposit Samples

Abstract

Heat-exchanger fouling is a severe operational problem in steam-assisted gravity drainage (SAGD) processes. In an effort to better understand which species are prone to deposit and gain insights into means for mitigating SAGD heat-exchanger deposition, analyses were performed on a series of heat-exchanger deposit samples from an inverted SAGD operation in Canada. Deposit samples were obtained from each of five heat-exchanger banks used in the operation of the facility: exchangers heating the produced raw bitumen reverse emulsion coming from the wells (two exchanger banks in series) and exchangers cooling separated produced water leaving the high-temperature separator (HTS) (three exchanger banks in series). The separated produced water leaving the facility HTS was also analyzed. The analyses focused on determining the overall inorganic and organic elemental compositions, as well as providing general information on the type of chemical species predominately present. The analyses performed on the deposits and solids from the produced water included (1) carbon, hydrogen, and nitrogen analyses, (2) X-ray fluoresence, (3) X-ray diffraction, (4) thermogravimetric analyses, (5) chloroform/methanol/toluene solubilities, and (6) Fourier transform infrared spectroscopy. Ion chromatography and inductively coupled plasma analyses were also run on the water sample. Analyses indicated preferential deposition of particular species and potential causes of deposition in certain exchangers. For the SAGD operation, at that time, a periodic slop-tank recycle containing warm lime softener sludge was indicated as a source of a significant amount of fouling in the heat exchangers handling the produced bitumen reverse emulsion and the initial exchanger cooling separated produced water leaving the HTS. High Mg +2 and Si +4 compositions were detected in these deposits. Magnesium silicates were indicated in Fourier transform infrared spectroscopy analyses. Deposition of additional other sand/silicates was also indicated. For the organic portion of these deposits, significant concentrations of organic acids and organic acid salts were indicated within the deposit hydrocarbons. Although all deposits contained both inorganic and organic components, the deposits in the last two exchangers cooling the produced water were found to be predominately organic. Significant concentrations of organic acids and organic acid salts were also indicated in these deposits. The indications of a significant organic acid/acid salt content led to collaboration work with the National High Magnetic Field Laboratory to study these components in detail. Electrospray ionization Fourier transform ion cyclotron resonance mass spectroscopy work performed at the National High Magnetic Field Laboratory is discussed in the part 2 companion paper (

Treatment of anin situoil sands produced water by polymeric membranes

“…(2015) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] www.deswater.com doi: 10.1080/19443994.2015.1069216 pumped to the surface where the bitumen and water are separated and the water is treated for reuse as boiler feedwater (BFW).…”

“…The economics of an SAGD process depend on the energy consumed for steam generation as well as the energy consumed for produced water deoiling and treatment and blowdown disposal [1,2].…”

“…The high levels of DOM and TDS in the OTSG feedwater can cause numerous operational problems like fouling of pipelines and equipment, and clogging of injection wells [2][3][4]. To reduce the injection water volume, evaporators are sometimes used as a downstream BBD recovery process.…”

Application of a New Method in Identifying the Sludge Deposits from Refineries and Gas Plants: A Case of Laboratory-Based Study

“…Sludge deposits are the semisolid mixture and formed by the combination of liquid (e.g., oil and water), hydrocarbon (e.g., grease and lubricant), and nonhydrocarbon or inorganic compounds of solids [1,2] in the forms of scale deposits and corrosion products. The sludge deposits, which are mixture of solid and viscous material, are formed at the different parts of equipment in refineries and gas plants.…”

Dissolved organic compounds in reused process water for steam-assisted gravity drainage oil sands extraction

“…By repeated recycling, contaminants such as dissolved organic compounds (DOCs), which include significant amounts of organic acids and organic acid salts, accumulate in the process water, severely interfering with subsequent reuse due to scaling and corrosion (Jennings and Shaikh, 2007). To prevent the accumulation of these organic contaminants in the process water, water recycling technology is being rapidly developed to meet the water management needs of SAGD processes (Allen, 2008b;Heins, 2010).…”