Известия Томского политехнического университета: Инжиниринг георесурсов (May 2019)
Gas chromatographic determination of alcohols as tracers in monitoring oil fields with polymethylsilicone phase modified by cobalt acetylacetonate
Abstract
The relevance of the discussed issue is caused by the need to improve the reliability and accuracy of the tracers for monitoring oil fields. Tracer analysis allows us to determine the direction of the main filtration flows during flooding. This is important for taking necessary technological solutions for oil production. Separating tracers, such as alcohols, have the property of component distribution between water and oil fraction that allows estimating the heterogeneity of oil reservoirs. The main aim of the research is to study the regularities of the chromatographic separation of aliphatic alcohols on the binary phase combined polymethylsiloxane PMS-100 modified with cobalt acetylacetonate Co(acac)2; to optimize the composition of liquid stationary phase for capillary columns and to select the conditions of separation when oil components do not interfere to accurate and reproducible determination of microconcentrations C3-C5 alcohols. The methods used in the study: capillary gas chromatography. Equipment. Chromatographic research was carried out using gas chromatograph "Agilent Technologies-6890 N" with a flame ionization detector and headspace sample introduction. Capillary column DB-1 of 30 m length, 0,25 mm internal diameter and 0,3 micrometers film thickness was used for comparison. Working silica capillary column 20 m ´ 0,25 mm were prepared under the same conditions to obtain an identical phase film thickness of 0,30 microns with a content Co(acac)2 in a liquid stationary phase PMS-100 10...80 % weight. The effectiveness of the speakers was 3900-4200 t.p./m. The results. Use of cobalt acetylacetonate additives into polymethylsiloxane nonpolar phase allows increasing the selectivity of the chromatographic separation of aliphatic alcohols in drilling and petroleum drilling fluids. It is shown that in the region of 40 wt. % of modifier additives the extrema of retention and values of adsorption energy of aliphatic alcohols are observed. The advantage of the recommended liquid stationary phase for capillary gas chromatography is the decrease of the matrix effect of the sample by separating the chromatographic peaks at different speeds of reducing the elution time components.
