Hydrocarbon Composition of Gas Condensates from the North Vasyugan and Luginets Fields of Tomsk Oblast
Abstract Generated abstract
This paper examines the group and structural group hydrocarbon composition of gas condensates from the Luginetskoye and Severo Vasyuganskoye fields in Tomsk Oblast. Fractions obtained by atmospheric vacuum rectification were analyzed using aniline point measurements, adsorption separation on silica gel, molecular sieves, urea complex formation, and the n-d-M method. The condensates are shown to be similar in composition, with high paraffinic hydrocarbon contents of about 67 to 69 percent, low aromatic contents of about 4 percent, and substantial naphthenic components, while the Severo Vasyuganskoye condensate appears less aromatized and somewhat richer in naphthenic structures. The study concludes that these condensates may be valuable feedstocks for petrochemical and refining processes, including reforming, pyrolysis, and production of kerosene, jet, and diesel fuels.
Full Text
HYDROCARBON COMPOSITION OF GAS CONDENSATES FROM THE SEVERO-VASYUGANSKOYE AND LUGINETSKOYE FIELDS OF TOMSK OBLAST
N. M. SMOLYANINOVA, G. B. NEMIROVSKAYA, M. E. SHLYKOVA
(Presented by the scientific-methodological seminar of the CTF)
The hydrocarbon composition is the most important qualitative characteristic of both oils and gas condensates, since it determines their principal properties and their value for chemical processing.
Below are presented the results of a study of the group and structural-group hydrocarbon composition of gas condensates from the Luginetskoye and Severo-Vasyuganskoye gas fields, located in the territory of Tomsk Oblast.
The composition of the gasoline fractions (initial boiling point—200°C) was determined by the aniline-point method with removal of aromatic hydrocarbons by adsorption on silica gel. The amount of normal paraffins was found using molecular sieves of the CaX type according to the procedure of [1].
Determination of the sum of paraffin-naphthenic and individual groups of aromatic hydrocarbons in gas-condensate fractions from 200°C and above was carried out by the adsorption method [2]. The separate contents of paraffins and naphthenes were determined by the aniline-point method in the paraffin-naphthenic portion obtained during adsorption separation of the fractions [3].
For the determination of normal paraffins, the method of complex formation with urea was used [4]. The structural-group composition of the fractions was calculated by the \(n—d—M\) method [5].
The fractions for investigation were obtained by atmospheric-vacuum rectification of gas condensates on an ARN-2 apparatus.
The results of determination of the group hydrocarbon composition are presented in Tables 1–3; data on the structural-group composition are given in Table 4.
It is seen from Table 1 that the gasoline fractions of the Luginetskoye gas condensate have a low content of aromatic hydrocarbons (0–8%), a considerable content of naphthenic hydrocarbons (34–24%), and a high content of paraffinic hydrocarbons (100–80%), with isoparaffins predominating among the latter.
The total gasoline distillate (initial boiling point—200°C) has a clearly expressed methane character.
In the fractions of the gas condensate boiling above 200°C (Tables 2, 3), the content of aromatic hydrocarbons is considerably higher than in the gasoline fractions and amounts to 12–15%. In their composition, representatives of group 1 predominate—benzene derivatives with refractive index \(n_D^{20}\) lying within the range 1.4556–1.5214; representatives of group 4 are absent—
Table 1
Group hydrocarbon composition of gas-condensate fractions from b.p. to 200°C
| Temperature range of fraction collection, °C | Condensate yield, wt% | Refractive index $n_D^{20}$ | Density $d_4^{20}$ | Aromatic, wt% | Naphthenic, wt% | Paraffinic, total wt% | Paraffinic, normal structure wt% |
|---|---|---|---|---|---|---|---|
| Luginetskoye field | |||||||
| 28–60 | 13,8 | 1,3634 | 0,6251 | 0 | 0 | 100 | 50 |
| 60–95 | 29,0 | 1,3913 | 0,7119 | 1 | 34 | 65 | 31 |
| 95–122 | 15,8 | 1,4082 | 0,7309 | 2 | 37 | 61 | 25 |
| 122–150 | 12,0 | 1,4187 | 0,7510 | 5 | 29 | 66 | 23 |
| 150–200 | 14,6 | 1,4310 | 0,7725 | 8 | 24 | 68 | 22 |
| 28–200 | 78,2 | 1,4036 | 0,7307 | 3 | 22 | 75 | 33 |
| Severo-Vasyuganskoye field | |||||||
| 28–60 | 15,9 | 1,3547 | 0,6244 | 0 | 0 | 100 | 50 |
| 60–95 | 22,4 | 1,3983 | 0,7132 | 1 | 40 | 59 | 23 |
| 95–122 | 16,9 | 1,4119 | 0,7382 | 3 | 46 | 51 | 18 |
| 122–150 | 10,1 | 1,4208 | 0,7518 | 5 | 34 | 61 | 18 |
| 150–200 | 13,0 | 1,4310 | 0,7717 | 9 | 23 | 68 | 21 |
| 28–200 | 78,3 | 1,4020 | 0,7309 | 3 | 29 | 68 | 26 |
Table 2
Group hydrocarbon composition of gas condensates boiling from 200°C to the final boiling point, wt.%
| Temperature limits of fraction collection, °C | Yield on condensate, % | Methane–naphthenic hydrocarbons, $n_D^{20}$ | Methane–naphthenic hydrocarbons, % | 1st group of aromatic hydrocarbons, $n_D^{20}$ | 1st group of aromatic hydrocarbons, % | 2nd group of aromatic hydrocarbons, $n_D^{20}$ | 2nd group of aromatic hydrocarbons, % | 3rd group of aromatic hydrocarbons, $n_D^{20}$ | 3rd group of aromatic hydrocarbons, % | Sum of aromatics, % | Intermediate fractions and resins, % |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Luginetskoye field | |||||||||||
| 200–250 | 7.6 | 1.4331–1.4400 | 88 | 1.4556–1.5214 | 9 | 1.5445 | 2 | 1.5560 | 1 | 12 | — |
| 250–319 | 3.4 | 1.4424–1.4650 | 85 | 1.4900–1.5176 | 9 | 1.5491 | 3 | 1.5718–1.5780 | 3 | 15 | — |
| Severo-Vasyuganskoye field | |||||||||||
| 200–250 | 6.6 | 1.4314–1.4435 | 89 | 1.4783–1.5248 | 8 | 1.5303–1.5398 | 1 | 1.5530–1.5731 | 2 | 11 | — |
| 250–300 | 4.0 | 1.4405–1.4540 | 87 | 1.4833–1.5185 | 7 | — | — | 1.5550–1.5880 | 6 | 13 | — |
Table 3
Group composition of fractions of gas condensates from fields of Tomsk Oblast
| Fraction distillation temperature limits, °C | Aromatic hydrocarbons, % | Naphthenic hydrocarbons, % | Paraffinic hydrocarbons, total, % | Paraffinic hydrocarbons, n-structure, % |
|---|---|---|---|---|
| Luginetskoye field | ||||
| 28–200 | 3 | 22 | 75 | 33 |
| 200–250 | 12 | 36 | 52 | |
| 250–b.p. | 15 | 13 | 72 | |
| 28–b.p. | 4 | 29 | 67 | |
| Severo-Vasyuganskoye field | ||||
| 28–200 | 3 | 29 | 68 | 26 |
| 200–250 | 11 | 30 | 59 | 31 |
| 250–300 | 13 | 14 | 73 | 33 |
| 28–300 | 4 | 27 | 69 | 29 |
Table 4
Structural-group composition of fractions above 200°C (by the n–d–M method)
| Fraction distillation temperature limits, °C | Specific gravity, $d_4^{20}$ | $n_D^{20}$ | Molecular weight | $C_A$ | $C_N$ | $C_{\mathrm{ring}}$ | $C_P$ | $K_A$ | $K_K$ | $K_0$ |
|---|---|---|---|---|---|---|---|---|---|---|
| Luginetskoye | ||||||||||
| 200–250 | 0.7986 | 1.4457 | 172 | 7 | 26 | 33 | 67 | 0.17 | 0.54 | 0.71 |
| 250–b.p. | 0.8216 | 1.4622 | 223 | 15 | 9 | 26 | 74 | 0.39 | 0.34 | 0.73 |
| Severo-Vasyuganskoye | ||||||||||
| 200–250 | 0.7945 | 1.4415 | 174 | 2 | 31 | 33 | 67 | 0.06 | 0.68 | 0.74 |
| 250–300 | 0.8160 | 1.4525 | 203 | 4 | 34 | 38 | 62 | 0.09 | 0.87 | 0.96 |
... The latter fraction (250–b.p.°C) is distinguished by a low content of naphthenic hydrocarbons (13%) and a high content of paraffinic hydrocarbons (72%).
Overall, the gas condensate of the Luginetskoye field contains 4% aromatic, 29% naphthenic, and 67% paraffinic hydrocarbons.
The data in Tables 1–3 show that, in hydrocarbon composition, the gas condensate of the Severo-Vasyuganskoye field is very similar to the Luginetskoye condensate, differing from the latter by a somewhat higher content of naphthenic hydrocarbons both in the gasoline fractions and in the higher-boiling fractions.
Data on the structural-group composition of the condensates of both fields (Table 4) show that the Severo-Vasyuganskoye gas condensate is characterized by a lower degree of aromatization: the amount of carbon accounted for by aromatic structures ($C_A$) is 2–4%, as against 7–15% for the Luginetskoye condensate, and the average number of rings in the molecule ($K_A$) is 0.06–0.09, as against 0.17–0.39 for the Luginetskoye condensate. At the same time, the Severo-Vasyuganskoye condensate has a considerably larger amount of naphthenic structures ($K_N$).
On the basis of data on the hydrocarbon composition of fractions of gas ...
condensates, a preliminary conclusion can be drawn about their exceptionally high value as feedstock for petrochemistry and petroleum refining.
The high yields of gasoline cuts (more than 78%), the absence of sulfur compounds in their composition, and also the significant content in some fractions of naphthenic hydrocarbons and the small amount of aromatics make it possible to assess them as favorable feedstock for catalytic reforming and pyrolysis.
Because of the high content of paraffinic hydrocarbons and the low aromatic content, these fractions will, in all likelihood, not have high octane numbers, which will not permit their use for improving commercial gasolines of modern grades.
Cuts boiling above 150° may prove to be excellent feedstock for obtaining illuminating kerosene, jet and diesel fuels, and also, if necessary, feedstock for obtaining lower olefinic hydrocarbons by pyrolysis.
Conclusions
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The group hydrocarbon composition of gas condensates from the Luginetskoye and Severo-Vasyuganskoye fields of Tomsk Oblast has been studied.
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It has been shown that they are characterized by a high content of paraffinic hydrocarbons (67–69%) and a low content of aromatic hydrocarbons (4%). The amount of naphthenics is, respectively, 29 and 27%.
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A conclusion has been drawn regarding the high value of gas condensates as feedstock for petrochemistry and petroleum refining.
Literature
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L. P. Kvitkovskii, E. V. Grushetskaya, Chemistry and Technology of Fuels and Oils, No. 3, 1962.
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Methods for the Investigation of Petroleum and Petroleum Products. Gostoptekhizdat, Moscow, 1955.
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Chemical Composition of Petroleums and Petroleum Products. NKTP USSR, ONTI, 1935.
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K. Van Nes and H. Van Westen. Composition of Oil Fractions of Petroleum and Their Analysis. IL, Moscow, 1954.