摘要
燕辽裂陷带冀北坳陷中元古界(1 800~1 327 Ma)具有高于庄组黑色泥晶白云岩和洪水庄组黑色页岩2套烃源层,以及龙潭沟、双洞、卢家庄3处下马岭组底部沥青砂岩古油藏。沥青砂岩含有2期固体沥青组分:早期沥青组分反射率R_b值1.68%~2.52%;晚期沥青组分R_b值0.81%~1.01%。辉长辉绿岩岩床的侵位,导致早期古油藏蚀变成沥青砂岩;岩床围岩蚀变带的稠油油苗,提供岩浆冷凝后晚期石油充注的证据。沥青砂标志下马岭组底砂岩成岩作用初期(1 400 Ma),业已开始石油早期充注成藏过程;依据辉长辉绿岩侵位时间1 327 Ma,可厘定底砂岩古油藏的蚀变年龄。基于层序地层厚度分析,确定古油藏早期成藏的油源来自高于庄组烃源层,生烃门限深度约3 600 m;洪水庄组烃源层充注成藏时间应在中生代。冀北坳陷雾迷山组、铁岭组等液体油苗和下马岭组沥青砂岩晚期沥青的可溶烃组分源自洪水庄组烃源层。
As for the Mesoproterozoic strata(1 800~1 327 Ma) in Jibei Depression, Yanliao Faulted-Depression Zone, there are 2 sets of hydrocarbon source beds(i.e., Gaoyuzhuang Fm. black micritic dolomite and Hongshuizhuang Fm. black shale) as well as 3 sites of the basal bitumenous sandstone fossil-oil-reservoirs in Xiamaling Fm. respectively at Longtangou, Shuangdong and Lujiazhuang. The bitumenous sandstone has two phases of solid bitumen components(SBCs): the early SBC with 1.68%~2.52% in bitumen reflectance R_b and the late one with 0.81%~1.01%. Owing to emplacement of gabbro-diabase sills, palaeo-oil-reservoir had been alterated into bitumenous sandstone(i.e. fossil-oil-reservoir), whereas viscous oil seepages found within wall-rock alteration zone provide an evidence for late oil migration and filling after the magma cooling and consolidation. The discovery of bitumenous sands can indicate that early oil filling and entrapment process would be started at the early diagenetic period of basal sandstone in Xiamaling Fm.(~1 400Ma), while its alteration age would be determinated according to the emplacement age of Xlamaling Fm. gabbro-diabase(1 327Ma). Based on the stratigraphic sequence and stratum thickness analyses, it could be defined that early oil filling and entrapment of Xiamaling Fm. basal oil reservoir could only be sourced by the Gaoyuzhuang Fm. source bed, it's threshold depth of hydrocarbon generation would be around 3 600 m. On the basis of the threshold depth, the oil entrapment age from the Hongshuizhuang Fm. source bed should be at the Mesoproterozoic period. Oil correlation results show that all the oil-seepages found in the Wumishan and Tieling Fms. and the Late SBC extracts of Xiamaling Fm. basal bitumenous sandstone are sourced by Hongshuizhuang Fm..
出处
《石油科学通报》
2016年第1期24-37,共14页
Petroleum Science Bulletin
关键词
中元古界
下马岭组
底部沥青砂岩
古油藏
石油成藏年龄
生烃门限深度
mesoproterozoic
xiamaling formation
basal bitumenous sandstone
fossil-oil-reservoir
oil entrapment age
threshold depth of hydrocarbon generation
