准噶尔盆地腹部深层构造特征与油气前景

The Deep Structural Features and Hydrocarbon Prospect in Hinterland of Junggar Basin

准噶尔盆地腹部深层发育逆冲断裂体系和古隆起两类构造,北部埋藏较浅,呈现出凹凸相间的构造格局,南部埋藏较深,为相对独立的古隆起构造。深层(C-P)油气源较为充足,储集层物性能够得到有效保存:下石炭统发育海陆过渡相暗色泥质烃源岩,资源量大,有利于自生自储;石炭系火山岩特殊储集层不受埋深限制,深部发育相对优质储集层,并经历了晚海西、晚印支、中燕山和晚燕山运动等4期成藏及其破坏与调整,深层目的层埋藏越深,离烃源岩越近,越易自生自储,围绕继承性古隆起可以形成深盆高温高压天然气藏成藏组合模式。石炭系火山岩厚度大,分布广,且发育一系列大型正向构造,是十分现实的勘探领域。莫索湾凸起莫深1井钻达7500m,钻揭石炭系700m,证实腹部深层石炭系发育火山岩特殊储集层,展示出良好的勘探前景。

Thrust-fauh system and palaeohighs are developed in deep structures in hinterland of Junggar basin. In the north the burial depth of them is shallower and characterized by concave-convex structural framework; in the south that is deeper and features relatively independent palaeohighs. The oil sources of the deep strata （C-P） are adequate, and the petrophysical properties of reservoirs can be conserved effectively. In the Lower Carboniferous occur dark argillaceous source rocks of transitional facies, which are favorable for self- generation and self-preservation due to rich resources; while the special volcanic reservoirs of Carboniferous are not restricted by burial depth, thus relatively premium reservoirs are developed in deep strata which undergo such four-stage reservoir formations, destructions and adjustments as Late Hercynian, Late Indosinian, Middle Yanshan and Late Yanshan orogenic movements. The deeper the deep target strata, the more adjacent they from the source rocks, and the easier the self-generation and self-preservation becomes, even they could form deep-basin natural gas reservoir combination patterns with high temperature and high pressure around inherited palaeohighs. It is concluded that the volcanic rocks of Carboniferous will be a most realistic domain for petroleum exploration for their big thickness, wide distribution and a series of giant forward structures. The Moshen^l Well in Mosuowan swell drilled 7 500 m in depth and penetrated 700 m of Carboniferous indicates that in hinterland of Junggar basin, deep volcanic reservoirs of Carboniferous are developed, revealing bright prospects for exploration.