塔里木盆地北部塔河油田油气藏成藏机制

从储层沥青、流体包裹体、油气藏饱和压力/露点压力等研究认为,塔河油田及邻区油气藏的形成主要有4期,海西早期以破坏为主;海西晚期成藏与改造并存;燕山-喜马拉雅早期以正常油藏为主;喜马拉雅晚期保存条件最好,以轻质油和气藏为主。塔河油田油气藏成藏机制为:(1)海西期以来下古生界长期持续供油,为塔河油田多期成藏及油气的叠加、复合改造提供了条件;(2)塔河地区长期处于斜坡区,在不同的地史时期始终是古生界海相油气的运移必经之地,是大规模油气聚集和多期成藏的重要条件;(3)多层位有效储盖组合及在时间、空间上分布的差异,是塔河油田多期成藏及成藏后油气性质变化的重要原因;(4)成藏封闭系统的演化对油气保存、破坏和改造的作用巨大,早期封闭系统的形成与破坏,为寻找重质海相原生油藏指明了方向,晚期封闭系统的重建,为寻找次生、原生轻质油气藏及天然气指明了勘探方向。 

FORMING MECHANISM OF HYDROCARBON POOLS IN TAHE OILFIELD OF THE NORTHERN TARIM BASIN

On basis of studies of reservoir bitumen, liquid inclusion, saturation pressure/bubble point pressure of hydrocarbon pools, there are 4 stages of formation of hydrocarbon pools in Tahe Oilfield and its adjacent: (1) the destruction of pools was occurred in the Early Hercynian, pool forming and modification in the Late Hercynian, formation of oil pools in the Yanshanian-Early Himalayan, and formation of light oil and gas pools in the Late Himalayan. The forming mechanism of hydrocarbon pools of the Tahe Oilfield can be superimposition, combination and modification of pools in the Tahe Oilfield were supported by the continuous supply of oil and gas from the Lower Paleozoic source rocks since the Hercynian; (2) the Tahe area was long located in a slope, where was the only way of hydrocarbon migration and provided basic condition for large scale of accumulation and multiple pool forming; (3) efficient combination of reservoirs and seals in various level and the difference of hydrocarbon distribution in time and space resulted in multiple pool forming and changes of oil and gas properties after pools were formed; (4) evolution of sealing system of pools played very important role in hydrocarbon preservation, destruction and modification. The formation and destruction of early sealing system provided clues for discovery of marine heavy primary oil reservoirs; and reconstruction of late sealing system was important factors for preservation of secondary and primary light oil reservoirs and especially gas reservoirs.