博兴洼陷东南部石油运移的地球化学标志

通过对烃源岩和油藏中原油正构烷烃的色谱分析发现,研究区存在四种类型的色谱峰型:(1)单峰型,主峰碳为nC23;(2)双峰型,前主峰碳以nC2o为主,后主蜂碳为nC23,后主峰碳强度大于前主峰碳;(3)双峰型,前峰碳为nC16或nC17,后主峰碳为nC23,前主峰碳强度高于后主蜂碳强度;(4)单蜂型,主蜂碳为nC16.同源油藏流体的运移导致色谱峰型产生变异.在运移路径上,随着运移程度的增强,色谱峰型由第一种类型演变为第四种类型;正烷烃碳数分布范围将减小;主蜂碳前移,从以后主峰碳为主演变为以前主峰碳为主,nC21-/nC22 从0.42～0.60增大到1.36～2.33.利用色谱蜂型特征可以判定油气运移方向和估量运移程度,从而有助于油气勘探目标的选择.

Geochemical signature of oil migrationin in Southeast Boxing depression, Jiyang, China

Based on chromatographic analysis of crude oil normal alkane from hydrocarbon-bearing source rock and oil pool, four types of chromatographic peak are identified according to carbon number (arrangement). Type 1 is single peak with the main peak carbon of nC_(23). Type 2 is double peak, in which the former and back main peak carbons are nC_(20) and nC_(23), respectively; the intensity of nC_(23) is higher than that of nC_(20). Type 3 is also double peak, in which the former and back main peak carbons are nC_(16) or nC_(17) and nC_(23), respectively; but the intensity of the back main peak carbon is lower than that of the former one. Type 4 is single peak with the main peak carbon of nC_(16). The fluid migration of oil pool with same source is responsible for difference of chromatographic spectrum type. With increase of migration intensity on the migration path, the chart of chromatographic spectrum changes gradually from type 1 to type 4 while the carbon number arrangement of the normal alkane decreases and the main peak carbon migrates forward, the predominance of the back peak carbon will be replaced gradually by that of the former peak carbon; nC_(21)~-/nC_(22)~ will increase from 0.42~0.6 to 1.36~2.33. The characteristic of chromatographic spectrum can be used to determine the path of oil migration and evaluate the possible intensity of the (migration). This is helpful for choice of exploration target.