The Paleogene lacustrine mudstone is one of the most important sets of source rocks in Termit Basin, Niger. However, studies on the Paleogene source kitchen are scarce. In this study, the source rock types, spatial distribution and their hydrocarbon generative potential within the Paleogene Sokor-1 and LV formations are systematically evaluated. A total of two third-order sequences (SSQ1 and SSQ2, from the bottom to top) and six systems tracts were identified in the Sokor-1 Formation, while the LV Formation mainly comprises pure shale and is regarded as a compositive stratigraphic sequence with no need of subdivision. Six types of source rocks could be distinguished within the three depositional environments of the sequence stratigraphic framework: (1) deep lake mudstones and shale deposited in the lacustrine deep-water facies, (2) shallow lake mudstones and carbonaceous mudstones occurring in the shallow lake environment, and (3) deltaic-front mudstones and prodeltaic mudstones developed in the deltaic facies. Deep lake mudstones/shale, which mainly occurred in the SSQ1-TST (transgressive systems tract), SSQ2-TST and LV Formation, are considered organic-rich source rocks with oil-prone generative potential. The shallow lake mudstones and deltaic mudstones were predominantly distributed in the tectonic slope and marginal areas of the Agadem Block within the lowstand systems tract and high stand systems tract of the SSQ1 and SSQ2. Nevertheless, geochemical results indicated that the deltaic mudstones are good gas-prone source rocks but the shallow lake mudstones were classified as poor potential source rocks. The variance in organic matter accumulation and preservation conditions within different depositional facies and the fluctuation of relative lake level are the controlling factors for the occurrence and distribution of high-quality source rocks. The effective Paleogene source kitchen is limitedly distributed around the depocenter of the Dinga Depression within a small scale, and therefore exploration for oil and gas resources from the Paleogene source kitchen should focus on the eastern Dinga fault-step zone adjacent to the depocenter of the Dinga Depression.

中文翻译：

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尼日尔 Termit 盆地古近系 Sokor-1 和 LV 地层烃源岩类型、分布及其生烃潜力

古近系湖相泥岩是尼日尔 Termit 盆地最重要的一组烃源岩。然而，对古近纪源灶的研究很少。在这项研究中，系统评估了古近系 Sokor-1 和 LV 地层内的烃源岩类型、空间分布及其生烃潜力。Sokor-1组共识别出2条三级层序（SSQ1和SSQ2，自下而上）和6条体系域，而LV组以纯页岩为主，属于复合地层层序，无细分的需要。在层序地层格架的三种沉积环境中可区分出六类烃源岩：（1）湖相深水相沉积的深湖泥岩和页岩；(2) 浅湖环境发育的浅湖泥岩和碳质泥岩； (3) 三角洲相发育的三角洲前缘泥岩和前三角洲泥岩。深湖泥岩/页岩主要产于SSQ1-TST（海侵系统域）、SSQ2-TST和LV组，被认为是具有生油潜力的富有机质烃源岩。浅湖泥岩和三角洲泥岩主要分布在SSQ1和SSQ2低位体系域和高位体系域内的Agadem块体构造斜坡和边缘区。尽管如此，地球化学结果表明，三角洲泥岩是良好的易气烃源岩，而浅湖泥岩被归类为较差的潜在烃源岩。不同沉积相有机质积累和保存条件的差异和相对湖泊水位的波动是优质烃源岩发生和分布的控制因素。古近系有效源灶在丁加坳陷沉积中心周围小范围分布，因此古近系源灶油气资源勘探应重点在丁加凹陷沉积中心附近的东丁加断阶带沮丧。