苏丹富油气凹陷岩性油气藏区带评价探讨——以Muglad盆地Fula凹陷为例

Play evaluation on lithologic reservoirs in hydrocarbon-rich sags in Sudan:a case study on Fula sag,Muglad Basin

苏丹Muglad盆地Fula凹陷是一个陆相被动裂谷盆地内发育的富油气凹陷,经过多期次勘探后,目前已进入新的以岩性圈闭为目标的勘探阶段。以"满凹含油理论"、"构造—层序区带聚集理论"为指导,以岩性油气藏"四图叠合"区带评价方法为手段,对Fula凹陷三级层序内构造、沉积、有效烃源岩、运移条件的配置关系进行了综合分析,并结合现今油气发现,预测了Fula凹陷内岩性油气藏有利勘探区带。分析结果认为:Abu Gabra组AG2段是岩性油气藏发育最有利层段,Jake区扇三角洲前缘相带是目前最有利的岩性油气藏勘探区带,Baleela区曲流河三角洲前缘相带次之,Moga区曲流河三角洲前缘相带再次之,Fula区断裂坡折带上盘岩性油气藏勘探潜力有限。

The Fnla sag in the Muglad Basin is a hydrocarbon-rich sag in a passive continental rift basin. Currently, its exploration focuses on lithologic traps. According to the ＂sag-wide oil-bearing theory＂ and the ＂tectonic-sequence zone accumulation theory＂, the matching relationship among structures, sedimentations, effective source rocks and migration conditions in third-order sequences of Fula sag was analyzed comprehensively by means of ＂fottr-map overlying＂ play evaluation method for lithologic reservoirs. Then, combined with existing oil and gas discoveries, the favorable plays of lithologic reservoirs in the Fula sag were predicted. It is indicated that AG2 Member of Abu Gabra Formation is the most favorable interval for the development of lithologic reservoirs, and the fan delta front within the Jake area is currently the most favorable lithologic reservoir exploration zone, followed by the meandering delta front within the Baleela area and then the meandering delta front within the Moga area. The lithologic reservoirs at the upper wall of fracturing slope break belt in the Fula area are limited in exploration potentials.