Size-exclusion chromatography in the measurements of concentration and molecular weight of some EOR polymers
Procedures that involve the use of size exclusion chromatography (SEC) for the measurement of concentration and weight-averaged molecular weight, M-bar/sub w/, of some EOR polymers were developed and found to give improved detectability, accuracy, and/or efficiency. The separation of polymer from low-molecular-weight impurities by size allows unambiguous detection of polymer properties such as concentration and M-bar/sub w/. A combination of an SEC column of a pore size small enough to exclude the polymer totally and a mobile phase of ionic strength of 1.5 was found suitable for the separation of polyacrylamide, partially hydrolyzed polyacrylamide, cationic polyacrylamide derivative, and xanthan polysaccharide from impurities. Concentration detection of the separated polymer sample with a variable-wavelength ultraviolet (UV) detector was found to give superior detectability over detection by refractive index difference. A wavelength of 214 nm (2,140 A) was used for the detection of these polymers on the basis of the spectra of samples purified by dialysis. With the active polymer assay determined by reprecipitation into a nonsolvent, the detection limit by UV was determined to be <0.1 ..mu..g/cm/sup 3/ for polyacrylamide and a cationic polyacrylamide derivative, <0.2 ..mu..g/cm/sup 3/ for partially hydrolyzed polyacrylamide, and <0.7 ..mu..g/cm/sup 3/ for a xanthan polysaccharide. The linear calibration range was up to 500 ..mu..g/cm/sup 3/. The precision of the concentration measurement was better than 4% for polyacrylamide and its derivative and 5% for polysaccharide at a 95% confidence level.
- Research Organization:
- Univ. of Kansas (US)
- OSTI ID:
- 6658236
- Journal Information:
- SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States), Journal Name: SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States) Vol. 3:3; ISSN SREEE
- Country of Publication:
- United States
- Language:
- English
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ACRYLAMIDE
AMIDES
CALCULATION METHODS
CHEMICAL REACTIONS
CHROMATOGRAPHY
COLLOIDS
DISPERSIONS
DISPLACEMENT FLUIDS
ENERGY SOURCES
ENHANCED RECOVERY
FLUIDS
FOSSIL FUELS
FUELS
GELS
HYDROPHYLIC POLYMERS
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OIL WELLS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PERFORMANCE TESTING
PETROLEUM
POLYMERS
RECOVERY
SCATTERING
SEPARATION PROCESSES
TECHNOLOGY ASSESSMENT
TESTING
WELLS