海拉尔盆地热演化史与油气成藏史研究

【作者】 崔军平；

【导师】 任战利；

【作者基本信息】 西北大学 ， 地球探测与信息技术， 2004， 硕士

【摘要】 本论文按照盆地分析整体、动态、综合的原则，综合应用地质、数学、地球物理及地球化学新方法，对海拉尔盆地热演化史及油气成藏历史进行了深入的研究，取得了一些新的认识。 通过对大量的测温资料回归分析，认为海拉尔盆地现今地温梯度变化不大，平均为3.0℃／100m，现今大地热流平均为59mWm^-2，海拉尔盆地为一个中温型盆地。海拉尔盆地的地温梯度的分布受大的走滑断裂和凹陷拉张程度的控制，盆地南部凹陷拉张量较大，地温梯度也较高。 海拉尔盆地相同层位热演化程度总体上具有南高北低的特点，在各个凹陷中心部位相同层位烃源岩热演化程度高于凹陷边缘部位。海拉尔盆地北部绝大部分地区大磨拐河组烃源岩未成熟，南部大磨拐河组烃源岩普遍进入低成熟生油阶段。在海拉尔盆地北部凹陷南屯组烃源岩处于未成熟-低成熟阶段；南部凹陷南屯组热演化程度较高，普遍处于成熟生油阶段，局部已处于高成熟生油阶段。南屯组是海拉尔盆地的主力生油层位，是海拉尔盆地主要找油区。 应用多种古地温方法恢复了海拉尔盆地古地温及古地温梯度，盆地平均古地温梯度在3.46～4.20℃／100m之间，明显高于现今地温梯度，平均古大地热流高于现今大地热流值，古今地温对比表明部分凹陷古地温高于今地温，烃源岩最大古地温是在伊敏组末达到的，烃源岩热演化程度受古地温场控制。 在镜质体反射率Ro演化史和干酪根成烃演化史的基础上分析了烃源岩成烃过程，在部分凹陷新生代以来烃源岩有二次生烃过程。 应用饱和压力法、储层伊利石测年法及流体包裹体测温法等方法并结合热史模拟、埋藏史，分析了海拉尔盆地油气成藏期次。海拉尔盆地油气成藏期次主要分为两大阶段：第一阶段在伊敏组沉积晚期；第二阶段在青元岗组沉积以来。伊敏组沉积晚期是海拉尔盆地最重要的成藏时期。青元岗组沉积以来发生过近东西向的挤压反转，使已形成的油气藏重新调整及二次生成的油气二次注入成藏。现今的油气藏是青元岗组沉积以来油气藏重新调整的结果，这一阶段油气成藏对海拉尔盆地油气勘探很重要。更多还原

【Abstract】 By principles of integrated, dynamic and comprehensive basin analysis, research were made in Hailaer basin using geological, mathematical, geophysical and geochemical methods. Progresses are made according to research of thermal evolutional history and oil-gas reservoirs generation history in the Hailaer basin.On the regression analysis from large numbers of thermometric data, results show that the Hailaer basin is a middle-temperature style basin, present geothermal gradients change little in different areas, average value is 3.0℃/100m, average value of thermal flux is 59mw/m2. The thermal gradient distribution in Hailaer basin is controlled by large-scale strike-slip fault and depression extension. In the Southern depression, the depression extension is large and thermal gradient value is higher.Thermal evolutional degree of contemporary layer in the south basin is higher than that in the north. In different depression, thermal evolutional degree in the center part of contemporary layer is higher than that in the fringe part. Large depressions in northern basin, the hydrocarbon source rocks of Damoguaihe formation is in immature-stage, while in the southern basin, the same hydrocarbon source rocks is in the low mature-stage. Similarity, hydrocarbon source rocks of Nantun formation in northern depression, its maturity is in the immature to low mature stage, partly in high-mature stage, becomes the main oil production layer in the Hailaer basin and southern depression is the main oil-gas prospecting areas.The average paleogeothermal gradient in the Hailaer basin is between 3.46-4.20 ℃/100m, which is obvious higher than present thermal gradient due to the recovery of thermal evolutional history by means of many kinds of paleothermometric methods, results also indicate that the values of paleothermal flux is higher than that of present values, and temperature contrasts between historic and present implies that the paleothermal in lager depressions are higher that the present.The max paleogeothermal values of hydrocarbon source rocks were reached in the late Yimin formation period, paleogeothermal field controlled maturity of hydrocarbon source rocks.Analysing generation hydrocarbon process of hydrocarbon source rocks on reflectance of vitrinite evolutional history and caseate generation hydrocarbon history, hydrocarbon source rocks in most of depressions have experienced two oil and gas generation periods. Research were made on the oil-filling history of the Hailaer basin, using the methods of the dating of illite, saturation pressure and homogenization temperatures fluid inclusion combining with thermal evolutiona history and burial history research . Results show that the forming time of oil-gas reservoirs have two stages: the first is in the late Yimin formation sedimentary stage; the second is from Qinyuangang formation sedimentary to now. The first stage is the most important oil and gas generation stage hi Hailaer basin. Since Qinyuangang formation sedimented, oil and gas have happened to be adjusted again due to the east-west directional extrusion and reversion, and secondary generation oil and gas poured into the traps and formed new oil-gas reservoirs,, Present oil-gas seservoirs are the adjustive result since Qinyuangang formation sedimented, this stage is important for oil and gas exploration in Hailaer basin.更多还原