Lake-type controls on petroleum source rock potential in nonmarine basins
Lake-type controls on petroleum source rock potential in nonmarine basins
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DOI：
10.1306/8626ca5f-173b-11d7-8645000102c1865d
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发表时间：
2001-06
期刊：
影响因子：
3.5
通讯作者：
A. Carroll;K. Bohacs
中科院分区：
文献类型：
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作者：
A. Carroll;K. Bohacs
在大量湖盆地层经验观察的基础上，提出了湖相组合的三重分类，解释了湖相油源岩的最重要特征，并为湖相圈定不完整的陆相盆地的勘探提供了预测框架。(1)河流-湖泊相组合以淡水湖相泥岩与河流-三角洲沉积互层为特征，通常含煤。海岸线进积以盆地充填为主，导致10米厚的模糊表达旋回的叠加。从地图上看，沉积可能在区域上广泛分布，但在横向上不连续，并包含强烈的相对比。运输的陆源有机质有助于形成混合的I-III类干酪根，从而产生蜡质油(I类干酪根富氢，易油；III类干酪根贫氢，主要倾向于天然气)。绿河组(怀俄明州)的鲁曼舌和霍尼扬池组(准噶尔盆地，中国)提供了这种相组合的例子，这种相组合也存在于中国东北部的松辽盆地、苏门答腊岛中部盆地和中西部的白垩纪多巴/多索盆地。(2)起伏的深部相组合代表了进积型和加积型盆地充填的组合，包括一些世界上最丰富的烃源岩。从地图上看，矿床在区域上分布广泛，具有相对均一的源相，含有倾向于石油的I型干酪根。例子包括绿河组(怀俄明州)的莱尼成员、芦草沟组(准噶尔盆地，中国)、布科马子组(西非近海)和拉戈亚费亚组(巴西坎波斯盆地)。(3)蒸发相组合主要表现为与盐湖-高盐湖干化旋回有关的沉积充填，可能包括蒸发岩和古潜流沉积。滨浅海富含有机质的泥岩相相对较薄，但可能(开始页1034)相当丰富和广泛。最高的有机质富集度与最深的湖泊阶段相吻合。低投入的陆地植物有机质导致有机含量的横向差异最小。在某些情况下，一种独特的I-S(富硫)干酪根可以在低至0.45%镜质组反射率当量的热成熟度下生成石油。例如，绿河组(怀俄明州)的威尔金斯山顶段，准噶尔盆地的井井子沟组(中国)，江汉盆地和柴达木盆地(中国)，以及阿根廷的布兰卡里拉组。
Based on numerous empirical observations of lacustrine basin strata, we propose a three-fold classification of lacustrine facies associations that accounts for the most important features of lacustrine petroleum source rocks and provides a predictive framework for exploration in nonmarine basins where lacustrine facies are incompletely delineated. (1) The fluvial-lacustrine facies association is characterized by freshwater lacustrine mudstones interbedded with fluvial-deltaic deposits, commonly including coal. Shoreline progradation dominates basin fill, resulting in the stacking of indistinctly expressed cycles up to 10 m thick. In map view, the deposits may be regionally widespread but laterally discontinuous and contain strong facies contrasts. Transported terrestrial organic matter contributes to mixed type I-III kerogens that generate waxy oil (type I kerogen is hydrogen rich and oil prone; type III kerogen is hydrogen poor and mainly gas prone). The Luman Tongue of the Green River Formation (Wyoming) and the Honyanchi Formation (Junggar basin, China) provide examples of this facies association, which is also present in the Songliao basin of northeastern China, the Central Sumatra basin, and the Cretaceous Doba/Doseo basins in west-central Africa. (2) The fluctuating profundal facies association represents a combination of progradational and aggradational basin fill and includes some of the world's richest source rocks. Deposits are regionally extensive in map view, having relatively homogenous source facies containing oil-prone, type I kerogen. Examples include the Laney Member of the Green River Formation (Wyoming), the Lucaogou Formation (Junggar basin, China), the Bucomazi Formation (offshore west Africa), and the Lagoa Feia Formation (Campos basin, Brazil). (3) The evaporative facies association represents dominantly aggradational fill related to desiccation cycles in saline to hypersaline lakes and may include evaporite and eolianite deposits. Sublittoral organic-rich mudstone facies are relatively thin but may be (Begin page 1034) quite rich and widespread. The highest organic enrichment coincides with the deepest lake stages. Low input of land plant organic matter results in minimal lateral contrasts in organic content. In some cases a distinctive type I-S (sulfur-rich) kerogen may generate oil at thermal maturities as low as 0.45% vitrinite reflectance equivalent. Examples include the Wilkins Peak Member of the Green River Formation (Wyoming), the Jingjingzigou Formation (Junggar basin, China), the Jianghan and Qaidam basins (China), and the Blanca Lila Formation (Argentina).