通过地层异常压力的形成与演化研究可以了解油气的成藏过程,但目前缺乏对鄂尔多斯盆地中生界地层压力演化的定量研究。依据研究区声波时差测井曲线资料以及岩石与流体的物理数据,利用等效深度法和构造抬升剥蚀后地层流体压力的定量计算公式,分别计算了该盆地陇东地区在早白垩世末期最大埋深时地层压力和现今地层压力,确定了这2个重要时期地层压力变化特征;采用流体包裹体PVT热动力学模拟方法,获得了研究区不同地史时期古地层压力值,利用这些古地层压力值恢复了地史时期地层压力的演化规律。资料显示早白垩世末期鄂尔多斯盆地陇东地区中生界普遍存在剩余压力,长7油层组剩余压力最高,可达到14.50MPa;构造抬升剥蚀后,除长7油层组在部分地区仍然保留了异常高压外,研究层位普遍形成了异常低压,一般分布在-9.42~-2.25MPa之间。地层异常压力发育和演化经历了高压原始积累、高压消失和低压形成3个阶段,这种地层异常压力演化与该盆地中生界埋藏演化史、生烃史相一致。异常高压是油气初次和二次运移的主要动力,陇东大部分地区都满足了长7段烃源岩向长8段储层排烃的动力条件;长8段地层剩余压力较低区为油气运移成藏的指向地区。 Through the study of the formation and evolution of abnormal pressure in the strata, we can understand the hydrocarbon accumulation process, but there is no quantitative study on the evolution of the strata pressure in Mesozoic Ordos Basin. According to the data of acoustic logging from sonic time-difference and the physical data of rock and fluid, using the equivalent depth method and the quantitative formula of formation fluid pressure after uplift and denudation uplift, the maximum burial depth of Longdong area in the late Early Cretaceous The stratigraphic pressure and the current stratigraphic pressure in the deep area determine the characteristics of the stratigraphic pressure changes in these two important periods. Using the PVT thermodynamic simulation method of fluid inclusions, we obtain the paleostratigraphic pressure values ​​in different geological history periods of the study area, The value restored the evolution of formation pressure during the geodu period. The data show that the residual stress is generally present in the Mesozoic in the Longdong area of ​​Ordos Basin at the end of Early Cretaceous, and the residual pressure of Chang 7 reservoir is the highest, reaching 14.50MPa. After the tectonic uplifting and denudation, except for Chang 7 reservoir, abnormal pressure remained in some areas In addition, abnormal low pressure is generally formed in the research horizon, generally distributed between -9.42 ~ -2.25MPa. The development and evolution of abnormal pressure in the strata underwent three stages of high pressure original accumulation, high pressure disappearance and low pressure formation. The evolution of abnormal pressure in this formation is consistent with the buried evolution history and hydrocarbon generation history of Mesozoic in this basin. Abnormally high pressure is the main driving force for the primary and secondary migration of oil and gas. Most of Longdong have met the dynamic conditions of hydrocarbon expulsion from the Chang 7 member to the 8 member reservoir. The lower remaining pressure in the 8th member is Hydrocarbon migration and accumulation point to the area.