乍得Bongor反转裂谷盆地中生界剥蚀厚度恢复及勘探启示

Mesozoic erosion thickness restoration and its implication to exploration in Bongor inverted rift basin, Chad

综合利用泥岩声波时差法、镜质组反射率（Ro）法和地层对比法对Bongor盆地中生界剥蚀厚度进行了恢复，恢复结果表明Bongor盆地中生界的剥蚀厚度在1000--2000m之间，呈现出南北大、中间小的特征。快速而剧烈的抬升剥蚀使得该盆地下成藏组合P组砂体的储集能力得以保存;反转期的挤压应力导致了盆地地层的褶皱变形，形成了一系列断背斜、断鼻构造，为油气成藏提供了良好的圈闭条件；反转引起的断层活化为Bongor盆地中油气的运移提供了通道。

Mesozoic erosion thickness of Bongor Basin was restored using mudstone acoustic time difference method, vitrinite reflectance （Ro） method, and stratigraphic correlation method. Result showed that the erosion thickness ranged from 1000 to 2000 m, thick in northern and southern slope while thin in central sag. The quick but intense uplift preserved the good reservoir quality of the P Formation sand body in the lower play. The compressive stress during inversion folded the strata and contributed to the formation of a lot of faulted anticlines and noses which were excellent traps for hydrocarbon accumulation. The fault reactivation triggered by inversion promoted the hydrocarbon migration in Bongor Basin.