巴西塞尔西培-阿拉戈斯盆地油气地质特征及勘探方向

PETROLEUM GEOLOGICAL FEATURES AND EXPLORATION POTENTIAL OF THE SERGIPE-ALAGOAS BASIN OF BRAZIL

塞尔西培-阿拉戈斯盆地是巴西东部重要的含油气盆地,经历了3期构造-沉积演化阶段。根据已掌握的资料,全面总结了盆地的油气地质特征及油气成藏模式,预测了勘探方向:①盆地发育3套烃源岩,其中过渡期烃源岩最为重要,裂谷期次之,漂移期烃源岩生烃潜力最小。②盆地发育3套储层,分别为裂谷早期的三角洲-风成砂岩、裂谷晚期的河流-三角洲相砾质砂岩或砾岩和漂移期的浊积砂岩。目前3套储层均已证实。③最终优选出2套潜力层系的有利区带:盐下裂谷层系有利区带在北部和中央隆起带;盐上漂移层系有利区带在塞尔西培次盆地南部深水以及Sao Francisco河口外深水区域。

The Sergipe-Alagoas Basin is an important petroliferous basin in eastern Brazil, and has undergone three tectonic and sedimentary evolution stages. According to the data available, petroleum geological features and the hydrocarbon accumulation model of the basin are comprehensively summarized, and the exploration potential predicted in this paper. ①There are three sets of source rocks developed in the basin, of which the source rocks formed in the transitional period are the most important, followed by that formed in the rift period. The source rock deposited in the drift period is the one with lowest hydrocarbon generation potential. ②There are three sets of reservoirs confirmed in the basin, i.e. the deltaic-aeolian sandstone deposited in the early rift period, the fluvial-deltaic pebbly sandstone or conglomerate in the late rift period, and the sandstone in the drift period. ③Finally, two favorable exploration zones are predicted, which includes the favorable zone of the subsalt rift system in the north of the basin and on the central uplift, and the favorable zone of the drift system in the deep water of the southern part of the Sergipe sub-basin and deep water area outside the Sao Francisco river mouth.