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501.
海相碳酸盐岩层系深层-超深层油气形成机制是石油地质学研究的热点和难点。以川东北普光气田为例,通过烃源(岩)评价及其与原油、储层沥青和天然气之间的地球化学对比、油气藏形成演化与保存过程分析,结合不同类型天然气组分、流体包裹体以及多种烃源生烃模拟等实验数据,对油气来源和成烃成藏过程进行了系统分析。结果表明,在多期沉积构造活动背景下,海相深层烃源岩系和主力产层均经历过高温高压环境与高热演化,形成了不同类型的干酪根、以分散和富集状态赋存的可溶有机质,以及以有机酸盐形式存在的不溶有机质等多种形式烃源,并普遍存在不同类型烃源、不同成因油气的连续或叠置动态相态转化,及其对油气成藏贡献的接替过程,呈现出"来源的多样性、转化的接替性、过程的多期性和成因的复合性"之油气形成演化特点,提出"多源生烃动态转化"是深层油气形成演化的主要机制,将烃源生气过程延续到更高的演化阶段,有利于深层-超深层条件下油气藏的再充注和聚集保存。  相似文献   
502.
额济纳旗地区祥探9井揭示的石炭系—二叠系为火山岩+碎屑岩组合,火山岩锆石U-Pb谐和年龄分布在(302.2±7.8)-(319.9±4.5)Ma之间,对应的地层时代相当于晚石炭世,岩性组合特征与大狐狸山剖面干泉组(C2P1g)可以对比,确定为干泉组。该井揭示石炭系—二叠系1027.4m(未穿),其中4m和4m以上的暗色泥岩(或粉砂质泥岩)20层,累计厚度288.5m,占地层厚度的28.1%。少量钻井岩心样品进行的烃源岩地球化学特征分析表明,有机质丰度中等—好,干酪根类型为Ⅰ—Ⅱ1型,有机质演化进入成熟—高成熟阶段,显示了良好的生烃条件。与邻近的大狐狸山剖面干泉组烃源岩样品分析结果对比,祥探9井取得的样品有机质丰度显著高于地表剖面样品,TOC为地表剖面样品的1.8倍,热解产油潜量(S1+S2)为地表剖面样品的295.3倍,氯仿沥青"A"为地表剖面样品的32.8倍,总烃(HC)为地表剖面样品的42倍。干酪根类型评价指标分析,井下岩心样品H/C-O/C能较好地反映干酪根类型,地表剖面样品受风化作用的影响H元素显著降低,H/C-O/C无法进行干酪根类型评价,说明风化作用对烃源岩丰度和类型评价指标的影响较大。  相似文献   
503.
塔中地区中古44和中古10两条走滑断裂切割了塔中低凸起中古43井区,它们对油气输导具有控制意义。油气从中—下寒武统沿两条走滑断裂向上运移后,在下奥陶统鹰山组内向两侧输导,呈"T"字形的油气充注方式。从断裂向两侧,V/Ni值呈减小趋势,原油密度、黏度、含硫量和含蜡量等物性参数,距离断裂由近到远,均表现为逐渐变大的趋势,这些都证明油气是由走滑断裂向两侧运移的。水、油、气井的目的层海拔分别为-4 700 m以下、约-4 600~-4 500 m和-4 500 m以上;出油气层位在海拔-4500 m以上的井,平均气油比较高,在海拔-4 500 m以下的井,平均气油比较低。研究井区油气开发的连通半径平均约600 m,小于油气成藏的连通半径。在开发和成藏两种时间尺度下隔挡层的物性上限有着显著差别。  相似文献   
504.
赣东北上二叠统龙潭组为一个完整的准二级层序,含15个三级层序,按体系域分七个阶段描述了古地理特点。垂向上水体由浅至深再至浅,横向上南浅北深,有官山段上部、狮子山段、王潘里段上部三个障壁形成期。赣东北龙潭期含煤建造,多数是在潮汐为主的水动力条件下形成的,成煤环境与潮汐带伴生在一起,不同成煤环境形成不同的煤。退积型平缓潮坪,分内、中、外三种亚环境,分别形成富镜质组树皮煤、贫镜质组树皮煤、富镜质组含树皮煤;障壁后潮坪形成富镜质组富树皮煤;三角洲平原和滩脊带形成腐植煤。真正质量最好的乐平树皮煤,只发育在退积型平缓潮坪的中带。不同类型的煤,生烃条件大不相同。  相似文献   
505.
广饶潜山是东营凹陷南缘一个典型下古生界古风化壳型潜山,含油气规模较大,但油气富集规律复杂。结合勘探实践,本文利用大量钻测井、岩石矿物及油气测试资料阐明了广饶潜山差异性侵蚀特征及其对油气富集规律控制作用。岩性组合差异及内幕断裂带导致岩体结构弱化,从而下古生界呈现差异性侵蚀。高泥质含量岩性组合单元的差异侵蚀易形成粘土充填沟谷,对油气沿古风化壳侧向运移具有良好遮挡作用;沿内幕断裂带差异侵蚀的沟谷对油气侧向运移没有区域遮挡能力,但明显控制多个潜山带的油气独立富集。下古生界差异侵蚀与油气富集规律密切相关,这对该领域研究具有很好的借鉴意义。  相似文献   
506.
在对地震、录井、测井、重力资料分析基础上,通过全三维构造精细解释、剩余重力异常综合分析等方法,对哈萨克斯坦南图尔盖盆地基底构造进行了推断解释。研究表明,该盆地具有双重基底,基底起伏十分剧烈,深大断裂发育,自西向东的4个北西—南东向展布的凹陷具有东断西超的特点。基底深度一般在1~5 km之间变化,表现为南部深度大、北部深度小的趋势,在北西向断裂系的作用下,基底局部构造大多呈北西向展布。在此研究基础上,从岩性、储集性能、生储盖配置关系及保存条件等方面进行了古潜山成藏条件分析,建立了南图尔盖盆地基岩油气成藏三种模式,突破了该区仅在古潜山风化壳含油的认识。  相似文献   
507.
基于地震地质解释,根据断裂带发育的位置、产状及构造样式,将琼东南盆地深水区中央坳陷自西向东划分为3个断裂体系:乐东—陵水伸展南倾调节断裂体系、北礁—松南—宝岛伸展北倾调节断裂体系以及宝岛—长昌张扭走滑断裂体系。断裂体系控制了生烃凹陷的分布和储集砂体的发育,形成了多种类型的圈闭,提供了油气垂向运移的通道,有利于油气聚集成藏。陵水凹陷—北礁凹陷结合部圈闭发育带、宝岛凹陷南部断阶带、长昌凹陷西部圈闭发育带是有利勘探区带。  相似文献   
508.
A Natural active oil seepage occurs at the intersection of the NW-oriented rift coastal fault and a NE-oriented cross fault which bound the southwest dipping Little Zeit tilted fault block at the southwestern side of the Gulf of Suez, Egypt. Detailed surface geological mapping followed by subsurface mapping using aeromagnetic, seismic and borehole data of Ras El Ush oilfield (the nearest oil field to the seepage) provide a reliable hydrocarbon migration pathway model of the area.The proposed model suggests that hydrocarbons migrated upward at the intersection of a NE-oriented and the NW-oriented rift coastal faults where they found their way to the surface. The Nubia Sandstone occurs south of Ras El Ush oilfield in a trap door structure and probably entrapped some of the migrating hydrocarbons while a probable oil-water-contact at −1000 m which resulted into the migration of hydrocarbon through the damage zone of the northeast fault.The original oil in place of the predicted reservoir is estimated to be more than 47.5 MMBO which encourages the design makers for more investigation of this reservoir to increase its certainty and putting it in the plan of the future investments.  相似文献   
509.
The largest condensate field of the Ordovician reef-shoal reservoirs, in China, was discovered along the N°1 fault zone in the Tarim Basin. However, current drilling activities are hindered by the low and unstable production from these carbonate reservoirs. A detailed structural analysis of 3-D seismic data identified three segments along the N°1 fault zone characterized by differences in structural geometry and evolution. Segmentation of the N°1 fault zone has resulted in the variation of characteristics and distribution of the Upper Ordovician carbonate reservoirs. Due to fault induced differential uplift before the Late Ordovician, a narrow and thick-rimmed platform margin rich in reefs has developed in the eastern segment, whereas wider and thinner shoals developed in the central and western segments. We clearly identified a fault block uplift related erosional unconformity, and associated karstification at the top of the Upper Ordovician carbonates in the eastern segment. In this segment, the karst caves resulted in the high and stable hydrocarbon production. In the central segment, good matrix reservoirs exist, but due to the lack of fault-related enhancement of the reservoirs quality, only relatively low production is observed. In the western segment, where fracture-vug reservoirs occurred in relation to later fault damage zones, production is much greater but unstable. Large-scale fracture-caves reservoirs related to fault activity, rather than the good unfaulted matrix reservoirs, lead to the high production of oil and gas. We classify these reef-shoal reservoirs as faulting modified reservoirs. Further exploitation should focus more on the fault damage zone beyond the platform margin rather than the microfacies in the Lower Paleozoic carbonates.  相似文献   
510.
In total, 2.37 million tons of marine crude oil originating from mixed source rocks has been discovered in the Tarim basin. Geological and geochemical analyses have confirmed that these mixed hydrocarbons are mainly from two sets of source rocks, including the Cambrian – Lower Ordovician and Middle-Upper Ordovician hydrocarbon source rocks. In this study, we determined the set of source rocks primarily responsible for the mixed hydrocarbons and the next location to be explored. Differences in n-alkane carbon isotopes in end-member oils from Cambrian–Lower Ordovician and Middle-Upper Ordovician source rocks were examined. A material balance model and simulation methods were used to evaluate the relative amounts contributed by each source. The results from known reserves in the Tazhong area show that the mixing ratio or contribution is up to 65% from Cambrian–Lower Ordovician source rocks and is generally higher than that from Middle-Upper Ordovician source rocks. The discovery of deep hydrocarbons has caused the total oil contribution from the Cambrian–Lower Ordovician to increase. The mixing ratio of Cambrian–Lower Ordovician oil varies depending on the well, formation, and block. It increases from west to east horizontally and from top to bottom vertically. Hydrocarbons from Cambrian–Lower Ordovician source rocks migrate upward along faults, and the mixing ratio decreases as the distance from the oil source fault increases. Favorable areas for Cambrian–Lower Ordovician hydrocarbon exploration are deep layers and areas near the fault zone that are connected to deep layers. The material balance model for carbon isotopes and evaluation methods for relative contributions considered differences in relative concentration and carbon isotope structure of n-alkanes. Herein, new methods for the identification and evaluation of hydrocarbons in the petroleum system of this superimposed basin are presented.  相似文献   
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