YM32下古生界潜山油气藏是受断裂控制的低幅度油气藏,油气运聚复杂.结合新钻井的地球化学分析数据,对研究区油气藏油气运移规律进行剖析.依据YM32下古生界潜山气田藏的原油及抽体物样品中的饱和烃的烷烃、甾藿烷,芳烃的萘与菲、烷基二苯并噻吩、三芳甾烷等生物标志化合物进行系统分析,优选油气示踪参数,并归一化,结合族组分分析结果,形成了油气运移示踪二步法.综合研究发现,YM32下古生界潜山油气藏有YM342-YM343和YM322两个油气充注点,以及YM342-YM 343→YM 34-1H→YM 32、YM342-YM343→YM34-7H→YM33、YM342-YM343→YM37-YM35,以及YM322→YM321→YM32共4条油气运移路径,并在YM342-YM343→YM37-YM35油气运移路径上,发现2个资源量超过1.00×106t的潜力圈闭.单参数与油气运移示踪二步法都可以反映油气运移路径,而后者具有全面、直观、准确地表征油气运移路径的特点.

During the study of oil and gas geochemistry, analysis of big data must be experienced, and there are some abnormal values in tremendous amount data, which will affect the analysis results of oil and gas migration. On the basis of geochemical big data of YM32 buried hill reservoirs in Tarim Basin, the mean value and standard deviation of hydrocarbon compound parameters reflecting the direction of hydrocarbon migration in the samples are analyzed, and the outliers, which less than X̅ −2D and great than X̅ +2D, are excluded. According to the content of saturated hydrocarbon and aromatics, the hydrocar bon migration factors are calculated and analyzed, and a three-step method of hydrocarbon migration tracer is formed. It is inferred that there are two oil and gas filling points of YM342-YM343 and YM50 in the YM32 buried hill reservoir, as well as four migration paths of YM342-YM343 to YM34, YM342-YM343 to YM37 to YM35, YM342-YM343 to YM33, and YM50 to YM321. The method can be used for reference in the evaluation of oil and gas reservoirs and in the search of remaining oil enrichment areas.

The accumulation mechanism of hydrocarbons in the Yingmai 2 Oilfield of the Tabei Uplift in the Tarim Basin is not well understood. Here, the characteristics and formation of Paleozoic faults in the Yingmai 2 Oilfield are studied with new 3D seismic data and regional geologic data. Inclusion features and geochemical parameters are used to investigate the faults controlling the oil and gas compositions. The results indicate that three fault systems developed in the Yingmai 2 Oilfield: a NNW-trending strike slip fault system that formed in the middle Caledonian, a NW-trending strike-slip fault system that formed in the Caledonian-late Hercynian and a NE-trending thrust fault system that formed in the late Hercynian-Indosinian, which was associated with volcanic activity. The two strike-slip fault systems were important early hydrocarbon migration pathways in the late Caledonian-early Hercynian, late Hercynian, and Himalayan accumulation periods. The NE-trending thrust faults were sealed by volcanics, and divided the originally uniform oilfield into two accumulation systems during the Himalayan. This finding is supported by the differences in the compositions of the oils and gases in the eastern (YM area) and the western (YG area) Yingmai 2 Oilfield. The oil density, iC(4)/nC(4), Ph/nC(18), and V/Ni ratios of the oils in the reservoirs in the YM area are lower than those in the YG area, whereas the TMNr, TeMNr, 4-1/DBT, Pr/Ph, C-29-diasterane/C-29-regular sterane ratios, H2S content, and the content of Himalayan hydrocarbon inclusions are higher. The hydrocarbon accumulation in the Yingmai 2 Oilfield is attributed to multiple episodes of hydrocarbon charging and suggests that the YM area has greater exploration potential than the YG area. (C) 2018 Elsevier Ltd. All rights reserved.