克拉通盆地基底结构特征及油气差异聚集浅析

THE PRIMARY STUDY OF BASEMENT STRUCTURE AND DIFFE- RENCE OF HYDROCARBON RESERVOIR IN CRATONIC BASIN

克拉通盆地分布广泛,面积巨大,油气资源潜力和富集程度差异性也很大。把世界主要克拉通盆地按照其基底不均一特性划分为4种类型:裂谷拉张型(北美密歇根和伊利诺斯盆地)、拼接缝合型(中国塔里木和俄罗斯东西伯利亚盆地)、褶皱造山型(北美威利斯顿盆地)和稳定结晶型(澳洲卡奔塔里亚湾盆地等)。在对各类盆地深部基底结构和油气富集规律比较分析的基础上,初步认为发育在活动构造基底(裂谷、褶皱带、缝合线)上的克拉通盆地油气资源远远好于稳定结晶基底上形成的盆地,各类盆地的油气丰度排序为:裂谷型>褶皱型>拼接型>稳定结晶型,不同类型的克拉通盆地油气成藏的主控因素也各有差异。

The Cratonic basins are abundant in petroleum deposition and becoming the future field of oil and gas resource exploration with unequal hydrocarbon accumulation and distribution. According to the difference of basement under interior cratonic basin, four types of basin can be identified: rift basement(Michigan and Illinois Basins in north America), orogeny fold basement (Williston basin, between the Canada and US), jointing suture basement (Tarim and Eastern Siberia basins) and stable crystal basement(Carpentaria basin in Australia and Parana basin in south Americ). This classification emphasizes control action of different structure basements to formation and evolution of interacratonic basins, such as Reelfoot rift in Illinois basin, Keweenawan rift in Michigan basin, Mgrich Mafic suture in Tarim basin, KotujAngaraLena folded belt in east Siberia basin and Transhudson orogenic zone in Williston basin. The development of cratonic lithosphere tends to become simple and thin with geological time. Based on the study of deep structure and the rule of reservoir formation, we can find the abundance of oil and gas in basins which have active structures is more better than that in stable crystallization basins. This geological background is highly advantageous to generation and accumulation of hydrocarbon. The oil and gas enrichment degree of cratonic basin is riftbased basin> orogeny foldbased basin>jointing suturebased basin>stable crystalbased basin. Furthermore, the main control factor of reservoir formation is also different among these variety interior cratonic basins.