【作者】 何争光；

【导师】 刘池阳；

【作者基本信息】 西北大学 ， 矿产普查与勘探， 2009， 硕士

【摘要】 周口坳陷位于华北地块东南缘,为一稳定克拉通基础之上形成的中新生代叠合盆地的一部分,该区后期改造强烈,现今周口坳陷及其邻区古生界热演化差异大,其形成机制与热演化过程尚不明确。此外,周口坳陷古生界具备良好的生烃条件,但至今尚未发现来自古生界油气源的大型油气藏。因此,对周口坳陷古生界热演化史及其油气地质意义进行研究,具有较重要的科学与实际意义。本文坚持含油气盆地研究中“整体、动态、综合”的分析原则,以周口坳陷古生界热演化史分析为主线,研究了古生界埋藏史、热演化特征、热演化阶段划分与古、今地温特征等,最终动态模拟了该区古生界的热演化史与生烃史并对古生界生烃区进行评价。主要得出以下几点认识与结论:1、周口坳陷中新生代演化划分为:三叠纪、早—中侏罗世、晚侏罗—早白垩世、晚白垩世末—古近纪与新近纪—第四纪。三叠纪主要以区域沉降为主,侏罗纪—早白垩世为差异演化阶段,以多数地区隆升剥蚀与局部沉降为主,新生代主要为伸展沉降阶段。2、周口坳陷现今地温梯度平均为2.44℃/100 m,大地热流值平均为48.4 mW/m²,与中国其它含油气盆地相比,具有“温盆”的特征,其控制影响因素为现今岩石圈厚度、构造特征、地下水活动。3、周口坳陷古生界山西组热演化平面分布总体呈“北高南低”的特征。古生界热演化在空间分布上极不均一,不同地区的热演化程度差别很大。北部凹陷带（鹿邑凹陷等）古生界经历中生代中晚期（J₃-K₁）的构造热事件,达到最高热演化阶段,古地温梯度为5.3℃/100m,其形成背景与北部邻区太康热力构造有关。中南部热演化程度相对较低,以埋藏增温作用为主。中南部多数凹陷带在晚三叠世达到最高热演化阶段,古地温梯度为3.6～3.9℃/100m,谭庄-沈丘凹陷在晚白垩世达到最高热演化阶段,古地温梯度为4.3℃/100m左右。4、结合研究区沉降史、古今地温场,对周口地区古生界热演化史与生烃史进行模拟。周口坳陷古生界生烃存在早期生烃与早、晚期生烃两种类型。综合烃源岩特征、埋藏史、热演化史等因素将古生界生烃区进行评价,指出谭庄—沈丘凹陷东部为古生界生烃较有利区;鹿邑凹陷南部、倪丘集中西部、谭庄—沈丘凹陷西部为古生界生烃潜力中等区;襄城凹陷为生烃潜力区较差区。更多还原

【Abstract】 The Zhoukou depression is a part of Cainozoic Era superimposed basin which formed on the stabilize cratonic. The Paleozoic group experiences Indo-Chinese, Yanshan and the Himalayas tectonic movement with varying degrees of transformation. Nowadays (The distribution plane of thermal evolution between Zhoukou depression and neighbouring area paleozoic is different) , but the thermal evolution of Zhoukou depression’s formation mechanism and process is not clear. In addition, The paleozoic group of Zhoukou depression have good conditions for hydrocarbon generation, but yet has not found the reservoir of the source of paleozoic source rocks. Therefore, the research for the paleozoic group of Zhoukou depression’s thermal evolution history and geological significance of oil and gas has a certain scientific and practical significance. In my paper, I insist on the principle of "overall, dynamic, comprehensive" to analyse oil and gas basin and take the thermal evolution of Zhoukou depression and the paleozoic group of neighbouring area as a main line. We study the burial history of Paleozoic, the characteristic of the thermal evolution, stages of the thermal evolution’s division, temperature characteristic for ancient, now ground and so on. We also dynamically simulate the thermal evolution history and hydrocarbon generation history at the Paleozoic area, and evaluate favorable hydrocarbon-generating area of Paleozoic group in Zhoukou depression. We mainly obtain the following several understandings:1. The evolution for the Paleozoic group of Zhoukou depression is divided into Triassic,Early-Middle Jurassic, Late Jurassic-Early Cretaceous, Late Cretaceous- Paleogene and Neogene-Quaternary. In Triassic period it is mainly regional subsidence, In Jurassic-Early Crataceous it become as difference evolution stage, In Cenozoic it become as fault depression stage.2. The average geothermal gradient is 2.44℃/100 m. The value of average heat flow is 48.4 mW/m~2 in Zhoukou depression. The geothermal field of studied area belongs to the transitional type between the hot basin in eastern and cold basin in western China. The controlling facors are the lithospheric thickness, structural characteristics, groundwater activities.3. The characteristics of overall thermal evolution distribution at the Zhoukou depression and the Paleozoic group of neighboring area is " North higher than south ". The space distribution of Paleozoic thermal evolution is very different in different areas. The Paleozoic experienced the late Jurassic-early cretaceous tectono-thermal event in north depression zone(such as Luyi bag), and reached to the highest stage of thermal evolution, and it’s geothermal gradient reached to 5.3℃/100m. The formation background have relationship with the Tai-kang thermal structure. The central-southern part’s thermal evolution degree is relatively lower than Luyi bag, its thermal evolution action mainly is buried-warming effect. Southern depression zone and most of central depression zone reach to the highest thermal evolution stage in late triassic, It’s geothermal gradient reached to 3.6～3.9℃/100m. The Tanzhuang-Shenqiu Paleozoic bag reach to the highest thermal evolution stage in late cretaceous, and its geothermal gradient reached to 4.3℃/100m.4. Combining subsidence histroy of research area and the geothermal field, the paleozoic hydrocarbon generated histroy and termal evolution histroy have be simulated in Zhoukou area. We figured out that The Zhoukou depression have two type of hydrocarbon generated, one is early hydrocarbon generated and early, secondary hydrocarbon generated. Integrated the characteristic of hydrocarbon source rock, tectonic development history and termal evolution histroy, we valuated the Paleozoic generation as three degree. the most favorable zone of hydrocarbon generation are in east area of Tanzhuang-shenqiu bag. The more favorable zone of hydrocarbon generation are in southern area of Luyi bag, west area of Tanzhuang-shenqiu bag as well as middle-west of Niqiuji bag, and the source rocks in Xiangcheng bag have poor hydrocarbon generation potential.更多还原