Effect of Mantle-Derived CO2 on Hydrocarbon Accumulation in Central African Rift System: A Case Study of Palogue Oilfield
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摘要: Melut盆地Palogue油田的发现打开了中非裂谷系古近系勘探新方向，证实了Melut盆地北部凹陷为富油气凹陷.Palogue油田以下白垩统为主力烃源岩，古近系为主力油藏的成藏组合，幔源CO2气体对油气的聚集和改造具有不可忽略的作用.通过对CO2气体、原油特征、包裹体特征进行研究，结合构造和烃源岩演化，分析CO2气体与Palogue油气成藏之间的关系.结果表明：古近纪末-新近纪发生的幔源CO2运移热事件对Palogue油田油气充注成藏具有重要影响.在构造-热事件作用下，烃源岩热演化迅速进入成熟阶段，发生强烈的生排烃作用，生成大量原油并融入超临界CO2中，饱含原油的超临界CO2快速穿层运移，发育大量高温混合烃类包裹体，即表现为异常高热事件下的快速成藏事件；饱含超临界CO2的原油进入Palogue圈闭后，因地层温压条件的变化，CO2气体开始向上逐层从原油中析出，携带轻质组分融入上层油藏中发生混合作用，由此导致垂向上原油物性发生一系列变化.Abstract: The discovery of Palogue oilfield in Melut Basin has opened a new exploration direction of the Central African Rift Paleogene and confirmed that the northern sag of Melut Basin is rich in oil and gas resources. The Lower Cretaceous source rock is the major source rock of Melut basin, the Palaeogene is its main seal⁃reservoir assemblage. The formation mechanism and model of oil and gas accumulated were proposed based on the specific tectonic-stratigraphic assemblages and evolution history of the Melut Basin. Oil and gas accumulations were influenced of mantle CO2. Relationship between CO2 and hydrocarbon accumulation was investigated using a suite of hydrocarbon generation and expulsion history, tectonic evolution history, fluid inclusions, CO2 and crude by taking Palogue oil reservoir as an example. The results show that the Late Paleogene-Neogene, the occurrence of the mantle source CO2 migration tectonic thermal event have an important influence on oil and gas accumulation in Palogue oilfield. Under the action of tectonic-thermal events, the thermal evolution of source rocks rapidly enters the mature stage, and intense hydrocarbon generation and expulsion occurs, CO2 in supercritical state quickly blends into crude oil. The crude oil saturated with supercritical CO2 quickly migrated through the reservoir and developed a large number of high-temperature mixed hydrocarbon inclusions, which showed the rapid accumulation event under the abnormal high heat event. After the crude oil full of supercritical CO2 entered the Palogue trap, CO2 gas began to separate out from the crude oil layer by layer due to the change of formation temperature and pressure conditions, CO2 gas carries light components into the upper reservoir for mixing. This results in a series of changes in vertical physical properties.
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Key words:
- Melut basin /
- Palogue oilfield /
- accumulation process /
- evaporative fractionation /
- petroleum geology
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图 1 Melut盆地构造单元划分及地层综合柱状图
Fig. 1. Classification of structural units and strata column of Melut Basin
图 3 W-1井埋藏热演化史及Palogue油田成藏事件图
Fig. 3. Burial-thermal history in well W-1 and accumulation event of the Palogue oilfield
图 4 原油中正构烷烃、藿烷、甾烷分布
Ts. 18α-C27三降藿烷；Tm. 17α-C27三降藿烷；25-NHC29. 25-降藿烷；C30H. C30藿烷；G. 伽马蜡烷；C27、C28、C29. 20R-αααC27、20R-αααC28、20R-αααC29
Fig. 4. The distribution of alkanes and hopane and sterane in crude oil
图 5 Palogue油藏分布及物性特征
①A（43.6）；w（15.0）；G（91）；CO2：（37）. ②A（24.0）；W（17.8）；G（85）；CO2（45）. ③A（24.5）；w（/）；G（87）；CO2（51）. ④A（23.3）；W（26.6）；C（2.3）；G（47）；CO2（33.6）. ⑤A（22.7）：W（30.2）；C（1.5）；G（52）；CO2（39.6）. ⑥A（21.8）；W（25.8）；C（/）；G（56）；CO2（45.0）. ⑦A（19.2）；W（4.8）；C（1.2）；G（55）；CO2（54.1）. ⑧A（18.2）；W（3.1）；C（/）；G（64）；CO2（56.4）；⑨A（14.5）；W（3.0）；C（1.1）；G（74）；CO2（63.8）. A.API度；W.含蜡量（%）；C.C21+22/C28+29；G.气油比（cf/bbl）；CO2含量（%）
Fig. 5. Distribution and physical characteristics of Palogue oilfield
图 7 Palogue油田原油正构烷烃摩尔浓度与碳数分布关系
Fig. 7. Correlation between molar concentration and carbon number disrtibution of Palogue oilfield
图 8 Melut盆地Palogue油田油气充注演化模式
Fig. 8. Oil and gas accumulation model for the Palogue oilfield in the Melut basin
表 1 Palogue油田原油物性
Table 1. Physical properties of crude oil in Palogue oilfield
井位 深度(m) 气油比(m3/m3) API度 倾点(℃) 含蜡量(%) 粘度(cp) CO2含量(%) TSE-1 1 956 9.69 29.62 35.50 17.26 32.38 F-5 1 362 11.60 33.00 20.00 909.30 48.25 F-7 1 373 13.03 39.00 27.60 532.60 56.48 T-2 1 232 16.37 25.20 42.00 31.20 203.90 63.40 T-3 1 209 14.52 22.70 41.11 31.31 389.00 63.04 A-1 1 206 14.69 23.00 37.50 30.00 89.16 62.00 A-3 1 220 20.27 22.50 39.00 36.42 110.00 57.25 
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Da, J. X., Dai. Y., Song, C. S., 1996. Geochemistry and Accumulation of Carbon Dioxide Gases in China. AAPG Bulletin, 80(10): 1615-1626. https://doi.org/10.1306/64eda0d2-1724-11d7-8645000102c1865d Dou, L. R., 2005. Formation Mechanism and Model of Oil and Gas Accumulations in the Melut Basin, Sudan. Bulletin of Mineralogy, Petrology and Geochemistry, 24(1): 50-57(in Chinese with English abstract). Dou, L. R., Cheng, D. S., Li, M. W., et al., 2008. Unusual High Acidity Oils from the Great Palogue Field, Melut Basin, Sudan. Organic Geochemistry, 39(2): 210-231. https://doi.org/10.1016/j.orggeochem.2007.09.001 Dou, L. R., Xiao, K. Y., Cheng, D. S., et al., 2007. Petroleum Geology of the Melut Basin and the Great Palogue Field, Sudan. Marine and Petroleum Geology, 24(3): 129-144. https://doi.org/10.1016/j.marpetgeo.2006.11.001 Gao, Y. Q., Liu, L., 2007. Time Recording of Inorganic CO2 and Petroleum Infilling in Wuerxun Depression, Hailaer Basin. Acta Sedimentologica Sinica, 25(4): 574-582(in Chinese with English abstract). doi: 10.3969/j.issn.1000-0550.2007.04.011 Genik, G. J., 1993. Petroleum Geology of Cretaceous-Tertiary Rift Basins in Niger, Chad, and Central African Republic. AAPG Bulletin, 77(8): 1405-1434. https://doi.org/10.1306/bdff8eac-1718-11d7-8645000102c1865d Gerlach, T. M., 1991. Present-Day CO2 Emissions from Volcanos. EOS, Transactions American Geophysical Union, 72(23): 249-255. https://doi.org/10.1029/90eo10192 Gui, L. L., Liu, K. Y., Liu, S. B., et al., 2015. Hydrocarbon Charge History of Yingdong Oilfield, Western Qaidam Basin. Earth Science, 40(5): 890-899(in Chinese with English abstract). He, J. X., Xia, B., Liu, B. M., et al., 2005. Origin, Migration and Accumulation of CO2 in East China and Offshore Shelf Basins. Petroleum Exploration and Development, 32(4): 42-49(in Chinese with English abstract). Jin, Z. K., Bai, W. H., Zhang, X. X., 2005. Genetic Types and Distribution of CO2 Gases in the Huanghua Depression. Petroleum Science, 2(2): 25-30. Kissin, Y. V., 1987. Catagenesis and Composition of Petroleum: Origin of N-Alkanes and Isoalkanes in Petroleum Crudes. Geochimica et Cosmochimica Acta, 51(9): 2445-2457. https://doi.org/10.1016/0016-7037(87)90296-1 Li, W., Dou, L. R., Wen, Z. G., et al., 2021. Rearranged Hopane: Molecular Tracers for Filling Pathway in Oil Reservoirs. Earth Science, 46(7): 2507-2514(in Chinese with English abstract). Li, W., Dou, L. R., Wen, Z. G., et al., 2022. Genetic Origin of CO2-Rich Oil Reservoirs and Pool-Forming Period in Melut Basin, Southern Sudan. Earth Science, 47(4): 1459-1469(in Chinese with English abstract). Li, W., Xu, J. Y., Liu, Z. F., et al., 2023. Influence of Mantle-Derived CO2 on Hydrocarbon Accumulation in Qinhuangdao 29 Tectonic Zone, Bohai Sea. Oil & Gas Geology, 44(2): 418-428(in Chinese with English abstract). Liu, X. Y., Chen, H. H., Xiao, X. W., et al., 2022. Overpressure Evolution Recorded in Fluid Inclusions in the Dongpu Depression, Bohai Bay Basin, North China. Journal of Earth Science, 33(4): 916-932. https://doi.org/10.1007/s12583-020-1375-x Losh, S., Cathles, L., Meulbroek, P., 2002. Gas Washing of Oil along a Regional Transect, Offshore Louisiana. Organic Geochemistry, 33(6): 655-663. https://doi.org/10.1016/s0146-6380(02)00025-6 Lu, X. S., Song, Y., Liu, S. B., et al., 2008. Progress in the Studies of Mantle-Derived CO2 Degassing Mechanism, Degassing Model and Pool-Forming Mechanism. Earth Science Frontiers, 15(6): 293-302(in Chinese with English abstract). Ma, A. L., Sun, H. J., Zheng, L., et al., 2017. A Study on Forming Mechanisms of CO2-Rich Reservoirs in Jupiter Oilfield, Santos Basin, Brazil. Oil & Gas Geology, 38(2): 371-378(in Chinese with English abstract). Mango, F. D., 1997. The Light Hydrocarbons in Petroleum: A Critical Review. Organic Geochemistry, 26(7-8): 417-440. https://doi.org/10.1016/s0146-6380(97)00031-4 Meulbroek, P., Cathles, L. Ⅲ, Whelan, J., 1998. Phase Fractionation at South Eugene Island Block 330. Organic Geochemistry, 29(1-3): 223-239. https://doi.org/10.1016/s0146-6380(98)00180-6 Qu, X. Y., Liu, L., Yang, H. D., et al., 2011. Genesis of Oil-Associated CO2 and Its Significance in Petroleum Geology. Journal of China University of Petroleum (Edition of Natural Science), 35(4): 41-46(in Chinese with English abstract). Shi, B. Q., Li, Z., Xue, L. Q., et al., 2014. Petroleum Accumulation Pattern and Exploration Targets in Hydrocarbon-Rich Sags of Melut Basin, Southern Sudan. Xinjiang Petroleum Geology, 35(4): 481-485(in Chinese with English abstract). Shi, Z. S., Wang, T. Q., Xue, L., et al., 2017. Reservoir Characteristics and Enrichment Rule of Highly Sandy Formation in Melut Basin, Central Africa. Natural Gas Geoscience, 28(2): 262-271(in Chinese with English abstract). Thompson, K. F. M., 1979. Light Hydrocarbons in Subsurface Sediments. Geochimica et Cosmochimica Acta, 43(5): 657-672. https://doi.org/10.1016/0016-7037(79)90251-5 Tian, L. X., Yang, H. F., Wang, D. Y., et al., 2013. Study on Genesis of High Contents of CO2 and Hydrocarbon Accumulation Period in Paleogene, Bohai Sea: An Example in Q Oil-Gas Field of Qinnan Sag. Journal of Central South University (Science and Technology), 44(2): 673-678(in Chinese with English abstract). Wang, L., Tian, W., Wei, Z. H., et al., 2018. Volcanic Conduits of the Tarim Flood Basalt Province: 3D Structure and Thermogenic Gas Release. Acta Petrologica Sinica, 34(1): 75-90(in Chinese with English abstract). Wang, W. B., Su, S. G., Wang, N., et al., 2021. The Possible Coupling Relationship among Large-Scale Magmatic Activity, Iron Deposit Formation and Global Climate Change in the Early Cretaceous. Acta Petrologica Sinica, 37(7): 2234-2244(in Chinese with English abstract). Wang, Z. F., He, J. X., Zhang, S. L., et al., 2004. Genesis of Carbon Dioxide and Geological Significance for Carbon Dioxide Infilling and Oil Displacement in the Northern Marginal Basin of South China Sea. Acta Petrolei Sinica, 25(5): 48-53(in Chinese with English abstract). Wilson, M., Guiraud, R., 1992. Magmatism and Rifting in Western and Central Africa, from Late Jurassic to Recent Times. Tectonophysics, 213(1-2): 203-225. https://doi.org/10.1016/0040-1951(92)90259-9 Yang, J., Huang, H. P., Zhang, S. C., et al., 2003. Semi- Quantitative Evaluation of Mixed Oil in Northern Uplift of the Tarim Basin. Geochimica, 32(2): 105-111(in Chinese with English abstract). Yu, L. D., Li, S. H., Zhang, J., et al., 2022. Experimental Study on the Effective Measurement of the Total Homogenization Temperature of High Internal Pressure CO2-Rich Fluid Inclusions in Orogenic Gold Deposits: A Case Study of the Yufeng Gold Deposit, Eastern Tianshan Orogen. Acta Petrologica Sinica, 38(1): 267-280(in Chinese with English abstract). Zhang, C., Wei, K. S., 2005. Sequence Characteristics and Reservoir Formation Condition in the Southern Wuerxun Depression. Acta Petrolei Sinica, 26(2): 47-52(in Chinese with English abstract). Zhang, G. Y., Huang, T. F., Liu, J. G., et al., 2019. Multi-Cycle Evolution of the Intracontinental Passive Rift Basins and Its Controlling on Accumulation of Oil & Gas: Taking Muglad Basin in Africa as an Example. Acta Petrologica Sinica, 35(4): 1194-1212(in Chinese with English abstract). Zhang, S. C., 2000. The Migration Fractionation: An Important Mechanism in the Formation of Condensate and Waxy Oil. Chinese Science Bulletin, 45(14): 1341-1344. https://doi.org/10.1007/BF03182916 Zhang, S. C., Zhang, B., Yang, H. J., et al., 2012. Adjustment and Alteration of Hydrocarbon Reservoirs during the Late Himalayan Period, Tarim Basin, NW China. Petroleum Exploration and Development, 39(6): 712-724. https://doi.org/10.1016/s1876-3804(12)60096-2 Zhao, W. B., Guo, Z. F., Liu, J. Q., et al., 2021. Fluxes and Genesis of Carbon Dioxide Emissions from Cenozoic Volcanic Fields in NE China. Acta Petrologica Sinica, 37(4): 1255-1269(in Chinese with English abstract). 窦立荣, 2005. 苏丹迈努特盆地油气成藏机理和成藏模式. 矿物岩石地球化学通报, 24(1): 50-57. 高玉巧, 刘立, 2007. 海拉尔盆地乌尔逊凹陷无机CO2与油气充注的时间记录. 沉积学报, 25(4): 574-582. 桂丽黎, 刘可禹, 柳少波, 等, 2015. 柴达木盆地西部英东地区油气成藏过程. 地球科学, 40(5): 890-899. 何家雄, 夏斌, 刘宝明, 等, 2005. 中国东部及近海陆架盆地CO2成因及运聚规律与控制因素研究. 石油勘探与开发, 32(4): 42-49. 李威, 窦立荣, 文志刚, 等, 2021. 重排藿烷: 示踪油藏充注途径的分子标志物. 地球科学, 46(7): 2507-2514. 李威, 窦立荣, 文志刚, 等, 2022. Melut盆地富含CO2油气藏的成因及期次. 地球科学, 47(4): 1459-1469. 李威, 徐建永, 刘志峰, 等, 2023. 幔源CO2对渤海海域秦皇岛29构造带油气成藏的影响. 石油与天然气地质, 44(2): 418–428. 鲁雪松, 宋岩, 柳少波, 等, 2008. 幔源CO2释出机理、脱气模式及成藏机制研究进展. 地学前缘, 15(6): 293-302. 马安来, 孙红军, 郑磊, 等, 2017. 桑托斯盆地Jupiter油气田富含CO2油气藏形成机制. 石油与天然气地质, 38(2): 371-378. 曲希玉, 刘立, 杨会东, 等, 2011. 油伴生CO2气的成因及其石油地质意义. 中国石油大学学报(自然科学版), 35(4): 41-46. 史卜庆, 李志, 薛良清, 等, 2014. 南苏丹迈卢特盆地富油气凹陷成藏模式与勘探方向. 新疆石油地质, 35(4): 481-485. 史忠生, 王天奇, 薛罗, 等, 2017. 中非Melut盆地高砂地比地层成藏特征与富集规律. 天然气地球科学, 28(2): 262-271. 田立新, 杨海风, 王德英, 等, 2013. 渤海海域古近系油气藏高含量CO2的成因及成藏期研究: 以秦南凹陷Q油气田为例. 中南大学学报(自然科学版), 44(2): 673-678. 王磊, 田伟, 魏子寒, 等, 2018. 塔里木溢流玄武岩火山通道的三维结构及其热成因气体释放. 岩石学报, 34(1): 75-90. 王文博, 苏尚国, 王娜, 等, 2021. 全球早白垩世大规模岩浆活动、铁矿床形成及与气候变化的可能耦合关系. 岩石学报, 37(7): 2234-2244. 王振峰, 何家雄, 张树林, 等, 2004. 南海北部边缘盆地CO2成因及充注驱油的石油地质意义. 石油学报, 25(5): 48-53. 杨杰, 黄海平, 张水昌, 等, 2003. 塔里木盆地北部隆起原油混合作用半定量评价. 地球化学, 32(2): 105-111. 于立栋, 李胜虎, 张静, 等, 2022. 造山型金矿中富CO2高内压流体包裹体完全均一温度的有效测定实验研究: 以东天山玉峰金矿床为例. 岩石学报, 38(1): 267-280. 张成, 魏魁生, 2005. 乌尔逊凹陷南部层序地层特征及成藏条件. 石油学报, 26(2): 47-52. 张光亚, 黄彤飞, 刘计国, 等, 2019. 非洲Muglad多旋回陆内被动裂谷盆地演化及其控油气作用. 岩石学报, 35(4): 1194-1212. 赵文斌, 郭正府, 刘嘉麒, 等, 2021. 中国东北新生代火山区CO2释放规模与成因. 岩石学报, 37(4): 1255-1269. -
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