Physicochemical Characterization and Fractional Composition of Oil from the Sobolinskoye Field
Abstract Generated abstract
This study examines the physicochemical properties and fractional composition of oil from well 171 of the Sobolinskoye field in Tomsk Oblast, with attention to the quality of straight-run distillation fractions. Using general compositional measurements and atmospheric-vacuum distillation data, the authors characterize the oil as light, low in sulfur and vanadium, but relatively rich in paraffin, resins, asphaltenes, and water, with a tendency to form stable emulsions. The oil yielded 24.0 percent gasoline fractions, 42.0 percent distillate up to 300°C, and 72.0 percent total distillate to 432°C, after which residue decomposition limited further distillation. The results suggest that, despite lower distillate yields than Sovetskoye oil, Sobolinskoye oil is a potentially favorable refining feedstock because of its low sulfur content and appreciable light-fraction yield.
Full Text
PHYSICOCHEMICAL CHARACTERISTICS AND FRACTIONAL COMPOSITION OF OIL FROM THE SOBOLINSKOYE FIELD
S. I. SMOLYANINOV, N. M. SMOLYANINOVA, Z. I. TEREBYNKINA,
S. I. KHOROSHKO
(Presented by the scientific-methodological seminar of the CTF)
The present work is devoted to the study of the physicochemical properties, fractional composition, and evaluation of the quality of straight-run distillation fractions of oil from the Sobolinskoye field.
The Sobolinskoye oil field was discovered in April 1967. It is located in Tomsk Oblast, in the saddle between the Parabel megaswell and the Pudino arch. The structure is a linearly elongated anticlinal fold of general northwestern strike.
During testing of bed B-III (well No. 171, perforation interval 2139—2125 m), an industrial oil gusher was obtained with a production rate of 148.32 m³/day through an 8-mm choke and a gas factor of 23.3 m³/m³.
The oil sample for investigation was taken from well 171, located in the crest of the Sobolino structure.
The physicochemical characteristics of the sample are presented in Table 1. Table 2 gives data on the potential content of fractions in Sobolino oil, determined from the TBP curve (Fig. 1).
This oil belongs to the light type, although it differs from Soviet oil¹ by its higher density. It is characterized by a considerable content of paraffin (3.30%), resinous and asphaltene substances (silica-gel resins 6.18%, asphaltenes 2.21%), as well as by the absence of acidity.
Sobolino oil has a very low sulfur content (0.44%) and, during atmospheric-vacuum distillation (Table 2 and Fig. 1), gives a low yield of distillate cuts: final boiling point 432°C, amount of residue 28%. The yield of gasoline fractions is 24.0%; distillation up to 300°C amounts to 42.0%.
All attempts to increase the distillation of oil fractions proved unsuccessful—at temperatures above 430°C and a residual pressure of 2 mm Hg, vigorous decomposition of the residue occurred. It should also be noted that the oil has a high water content and that it tends to form stable emulsions. Dehydration of the oil proceeds with great difficulty, even in an autoclave.
The low vanadium content and low sulfur content are positive factors when using fractions of Soviet oil as feedstock for catalytic cracking.
¹ S. I. Smolyaninov et al. General study of oils from producing wells of the Sosnino-Sovetsko-Medvedevskoye field. In: Problems of the Geology and Development of Oil and Gas Fields of Tomsk Oblast. Tomsk State University Press, Tomsk, 1969.
General study of Sobolinsk oil
Table 1
| Indicator | Temperature, °C | Temperature, °C | Temperature, °C | Temperature, °C | Temperature, °C |
|---|---|---|---|---|---|
| Indicator | 10 | 20 | 30 | 40 | 50 |
| Density of the oil at the given temperature relative to the density of water at 4°C, \(P_4^{20}\) | 0.8611 | 0.8545 | 0.8480 | 0.8412 | |
| Kinematic viscosity, cSt | 15.13 | 12.72 | 9.20 | 6.85 | 4.34 |
Continuation of Table 1
| M. W. | Pour point, °C | Pour point, °C | Saturated vapor pressure, mm Hg | Saturated vapor pressure, mm Hg | Content, % | Content, % | Content, % | Content, % | Content, % | Content, % | Content, % |
|---|---|---|---|---|---|---|---|---|---|---|---|
| M. W. | with heat treatment | without heat treatment | 38°C | 50°C | water-soluble acids | mercaptans | silica-gel resins | paraffin, \(T_{\mathrm{mp}}\), °C | cokeability, % | ash, % | acid number, mg KOH per 1 g oil |
| 209 | −22 | −4 | 374 | 439 | 22 | 2.21 | 6.18 | 3.30; 47°C | 3.20 | 0.007 | 0 |
Continuation of Table 1
| Content, % | Content, % | Content, % | Content, % | Content, % | Content, % | Content, % | Elemental composition, % | Elemental composition, % | Elemental composition, % | Elemental composition, % |
|---|---|---|---|---|---|---|---|---|---|---|
| mechanical impurities, % | naphthenic acids | phenols | water | vanadium, % | salts, mg NaCl per 1 l oil | flash point, °C | C | H | N | S |
| 0.58 | 0.003 | 0.016 | 8.0 | 0.0004 | 25.03 | −12 | 85.60 | 12.70 | 0.79 | 0.44 |
Fig. 1. Distillation curves of Sobolinskaya oil.
Labels in the figure:
- \(\eta_D^{20}\)
- \(\rho_4^{20}\)
- \(t,^\circ\mathrm{C}\)
- Mol. wt.
- \(V,\ \mathrm{cm^3}\)
- \(\eta_D^{20}\)
- \(d_4^{20}\)
- Ts.T.N.
- M.w.
- \(t_{\mathrm{flash}}\)
- \(t_{\mathrm{visc}}\)
- Sulfur content
- \(V_{20}\)
- \(V_{50^\circ}\)
- \(V_{100^\circ}\)
- Pour point, \(^\circ\mathrm{C}\)
- Paraffin content, %
- Sulfur content, %
- Yield on oil, wt. %
Table 2
Potential fraction content in oil from the Sobolinskoye field (well 171)
| Fraction cut temperature limits, °C | Yield of fractions from oil, wt % (individual) | Yield of fractions from oil, wt % (cumulative) | Fraction cut temperature limits, °C | Yield of fractions from oil, wt % (individual) | Yield of fractions from oil, wt % (cumulative) |
|---|---|---|---|---|---|
| Gas to C₄ | 200—210 | 1,6 | 25,6 | ||
| a) propane | — | — | 210—220 | 1,6 | 27,2 |
| b) iso-butane | 0,2 | 0,2 | 220—230 | 1,6 | 28,8 |
| c) n-butane | 0,4 | 0,6 | 230—240 | 1,6 | 30,4 |
| 28—60 | 2,0 | 2,6 | 240—250 | 1,6 | 32,0 |
| 60—62 | 0,1 | 2,7 | 250—260 | 1,8 | 33,8 |
| 62—70 | 1,0 | 3,7 | 260—270 | 2,0 | 35,8 |
| 70—80 | 1,2 | 4,9 | 270—280 | 2,2 | 38,0 |
| 80—85 | 0,7 | 5,6 | 280—290 | 2,0 | 40,0 |
| 85—90 | 0,6 | 6,2 | 290—300 | 2,0 | 42,0 |
| 90—95 | 0,7 | 6,9 | 300—310 | 2,2 | 44,2 |
| 95—100 | 0,7 | 7,6 | 310—320 | 2,2 | 46,4 |
| 100—105 | 0,7 | 8,2 | 320—330 | 2,0 | 48,4 |
| 105—110 | 0,8 | 9,0 | 330—340 | 1,9 | 50,3 |
| 110—120 | 1,5 | 10,5 | 340—350 | 2,0 | 52,3 |
| 120—122 | 0,3 | 10,8 | 350—360 | 2,3 | 54,6 |
| 122—130 | 1,4 | 12,2 | 360—370 | 2,6 | 57,2 |
| 130—140 | 1,6 | 13,8 | 370—380 | 2,6 | 59,8 |
| 140—145 | 0,8 | 14,6 | 380—390 | 2,7 | 62,5 |
| 145—150 | 1,0 | 15,6 | 390—400 | 2,5 | 65,0 |
| 150—160 | 1,8 | 17,4 | 400—410 | 2,4 | 67,4 |
| 160—170 | 1,6 | 19,0 | 410—420 | 2,3 | 69,7 |
| 170—180 | 1,6 | 20,6 | 420—430 | 2,0 | 71,7 |
| 180—190 | 1,7 | 22,3 | 430—432 | 0,3 | 72,0 |
| 190—200 | 1,7 | 24,0 | Residue | 28,0 | 100,0 |
Thus, in terms of its quality, Sobolinskaya oil is inferior to the oil of the Sovetskoye field, since it has a significantly lower yield of distillate fractions; however, it compares favorably with the main oils of the Volga–Ural region because of its low sulfur content and high content of light cuts, which makes it possible to regard it as a favorable feedstock for industrial refining.