巴西萨利莫斯盆地油气地质特征及油气分布规律

基于萨利莫斯盆地基础地质条件,以石油地质理论为指导,对盆地的生储盖条件及成藏特征进行了研究,并利用多因素叠合的方法对盆地潜在有利区进行了预测。分析认为,萨利莫斯盆地是新元古代末期克拉通内断陷基础上形成的克拉通盆地,形成古生界和中-新生界两套沉积充填序列。盆地内主力烃源岩和储盖层均发育在古生界序列中。泥盆系然迪亚图巴组页岩是盆地中的主力烃源岩;石炭系朱鲁尔组砂岩和泥盆系俄勒组砂岩是最有利的储集层段,与石炭系卡让利组、朱鲁尔组的蒸发岩和页岩构成良好的储盖组合。受岩浆侵入的影响,烃源岩的生排烃分为岩浆侵入前和侵入后两个阶段,并以第二阶段为主生排烃阶段;受晚期构造运动的影响,盆地具有多期成藏的特征,最后一期成藏决定了油气的最终分布。盆地勘探经验表明,油气田往往位于断裂带周围,并受烃源岩的发育位置控制。因此,认为盆地中烃源岩发育区内的断裂带周围是油气田,特别是气田的有利勘探领域。

Petroleum Geology Characteristics and Hydrocarbon Distribution of Solimoes Basin,Brazil

Based on the geological characteristics,under the guidance of petroleum geology,characteristics of source rock,reservoir,cap rock,and hydrocarbon accumulation were studied.Superimposed method was adopted and favorable area of oil and gas exploration was forecasted.Solimoes Basin is a craton basin that originated from a rift in Amazon Craton.There are two main sequences in the basin,Paleozoic sequence and Mesozoic-Cenozoic sequence.The best source rock,reservoir and cap rock are all within the former one.The Devonian Jandiatuba Formation is the main source rock,and the Carboniferous Jurua Formation sandstone,Devonian Uere Formation sandstone are the main reservoirs.The evaporites of Carboniferous Jurua Formation and Carauari Formation are the cap rocks.Affected by the intrusion igneous rocks,generation of the hydrocarbon was separated into two phases,and the phase after the intrusion is more important.Due to the late Jurua tectonic movements,there were also two stages of the accumulation of hydrocarbon,and the later one controls the final distribution of the hydrocarbon.According to the experience of oil and gas exploration in the basin,oil and gas fields mostly locate around the faults,and are also controlled by the distribution of source rock.Hence,areas both with faults and good source rock are favorable areas of oil and gas,especially gas exploration.