0 引言
1 地质概况
图1 川中地理位置及侏罗系主要含油气构造分布Fig.1 Generalized map showing the main oil or gas fields structures distribution and geographic position in the central Sichuan Basin |
2 样品及实验方法
表1 川中地区侏罗系原油和天然气轻烃地球化学参数Table 1 Light hydrocarbons data for Jurassic oil and gas samples from the central of Sichuan Basin |
井号 | 层位 | 类型 | MCH 指数 | C7化合物含量/% | CH 指数 | C6化合物含量/% | K 1 | Ctemp/℃ | ||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
MCyC6 | DCyC5 | nC7 | MCyC5 | CyC6 | nC6 | |||||||
H5 | J2 s 2 | 凝析油 | 69.5 | 69.5 | 11.5 | 19.0 | 51.9 | 18.6 | 51.9 | 29.6 | 1.13 | 134.1 |
Q8 | J2 s 2 | 凝析油 | 61.6 | 61.6 | 14.1 | 24.3 | 56.0 | 16.9 | 56.0 | 27.1 | 1.14 | 132.5 |
J71H | J2 s 2 | 凝析油 | 68.0 | 68.0 | 8.7 | 23.3 | 54.5 | 12.4 | 54.5 | 33.1 | 1.12 | 135.0 |
G16 | J2 s 1 | 轻质油 | 50.0 | 50.2 | 11.3 | 38.5 | 29.0 | 20.3 | 29.5 | 50.2 | 1.01 | 135.0 |
GH16 | J2 s 1 | 轻质油 | 46.9 | 46.9 | 10.2 | 42.9 | 25.5 | 15.2 | 25.5 | 59.3 | 1.03 | 135.4 |
GH18 | J2 s 1 | 轻质油 | 47.1 | 47.1 | 10.9 | 42.0 | 25.6 | 15.7 | 25.6 | 58.7 | 1.03 | 135.1 |
G108X | J1 dn | 轻质油 | 46.3 | 46.3 | 11.2 | 42.5 | 28.5 | 17.3 | 28.5 | 54.2 | 1.04 | 131.1 |
J94 | J1 dn | 轻质油 | 44.9 | 44.9 | 12.5 | 42.6 | 29.1 | 17.8 | 29.2 | 53.0 | 1.12 | 127.0 |
H5 | J2 s 2 | 天然气 | 76.6 | 76.6 | 15.0 | 8.4 | 43.8 | 22.7 | 43.8 | 33.5 | 1.16 | 138.1 |
Q8 | J2 s 2 | 天然气 | 68.7 | 68.7 | 15.7 | 15.6 | 43.9 | 19.6 | 43.9 | 36.5 | 1.16 | 136.7 |
J71H | J2 s 2 | 天然气 | 74.9 | 74.9 | 12.0 | 13.1 | 48.7 | 15.2 | 48.7 | 36.1 | 0.98 | 141.4 |
G16 | J2 s 1 | 天然气 | 43.2 | 43.2 | 19.3 | 37.5 | 16.7 | 19.1 | 16.7 | 64.2 | 1.13 | 136.0 |
GH16 | J2 s 1 | 天然气 | 48.2 | 48.2 | 12.4 | 39.4 | 15.2 | 14.2 | 15.2 | 70.5 | 1.03 | - |
GH18 | J2 s 1 | 天然气 | 39.4 | 39.4 | 17.4 | 43.2 | 12.8 | 13.9 | 12.8 | 73.3 | 1.07 | 141.6 |
G108X | J1 dn | 天然气 | 48.3 | 48.3 | 13.1 | 38.7 | 19.1 | 16.8 | 19.1 | 64.1 | 1.17 | - |
J94 | J1 dn | 天然气 | 46.5 | 46.5 | 15.8 | 37.7 | 21.2 | 16.5 | 21.2 | 62.2 | 1.12 | 132.6 |
MCH指数=MCyC6/(nC7+MCyC6+1,1⁃DMCyC5+1,c3⁃DMCyC5+1,t3⁃DMCyC5+1,t2⁃DMCyC5)×100;CH指数=CyC6/(nC6+CyC6+MCyC5)×100;K 1=(2⁃MC6+2,3⁃DMC5)/(3⁃MC6+2,4⁃DMC5);Ctemp(℃)=140+15×(Ln[2,4⁃DMC5/2,3⁃DMC5)] |
3 结果与讨论
3.1 油气轻烃分布
图3 川中地区Q8井沙二段凝析油和天然气气相色谱(a) 凝析油全油气相色谱;(b) 凝析油轻烃分布;(c)天然气轻烃分布iC4: 异丁烷;nC4: 正丁烷;iC5: 异戊烷; nC5: 正戊烷;2,2-DMC4: 2,2-二甲基丁烷;CyC5: 环戊烷;2-MC5: 2-甲基戊烷;3-MC5: 3-甲基戊烷;nC6: 正己烷;2,2-DMC5: 2,2-二甲基戊烷;MCyC5: 甲基环戊烷;2,4-DMC5 : 2,4-二甲基戊烷;Benz: 苯;3,3-DMC5: 3,3-二甲基戊烷;CyC6: 环己烷;2-MC6: 2-甲基己烷;2,3-DMC5: 2,3-二甲基戊烷;1,1-DMCyC5: 1,1-二甲基环戊烷;3-MC6: 3-甲基己烷;1, c3-DMCyC5: 顺-1,3-二甲基环戊烷;1, t3-DMCyC5: 反-1,3-二甲基环戊烷;nC7:正庚烷和反-1,2-二甲基环戊烷交换位置;1, t2-DMCyC5: 反-1,2-二甲基环戊烷;MCyC6: 甲基环己烷;ECyC5: 乙基环戊烷;Tol: 甲苯 Fig.3 Gas chromatogram of the condensate and nature gas from Well Q8 in J2 s 2 of the central of Sichuan Basin |
图4 川中地区侏罗系原油与天然气轻烃组成分析(a) iC4/nC4 vs. iC5/nC5; (b) 2-MC5/nC6 vs. 2-MC6/nC7 Fig.4 The light hydrocarbon compositionof natural gas and oil in Jurassic reservoirs of the central of Sichuan Basin |
3.2 蒸发分馏作用对轻烃参数的影响
图6 川中地区原油与天然气轻烃参数对比横坐标所代表的轻烃参数(参数比值中组成分子与分母的化合物的沸点之差)分别为:1:1, c3-/1, t2-DMCyC5 (1.1℃);2:2-MC6/3-MC6 (2.0 ℃);3:2-MC5/3-MC5 (3.0 ℃);4:3-MC5/nC6 (5.7 ℃);5:3-MC6/nC7 (6.5 ℃);6:iC5/nC5 (8.1 ℃);7:2-MC6/nC7 (8.5 ℃);8:2-MC5/nC6 (8.7 ℃);9:iC4 /nC4 (11.5 ℃) Fig.6 Comparison of light hydrocarbon parameters between natural gas and crude oil from the central of Sichuan Basin |