开封坳陷构造特征、形成演化与油气远景

STRUCTURAL FEATURES,EVOLUTION AND OIL AND GAS PROSPECTS OF KAI FENG DEPRESSION

开封坳陷是南华北盆地北部一个主要呈ＮＷＷ向展布，而局部地段ＮＮＥ－ＮＥ向构造格局又具明显优势的中新生代断陷型勒陷。其形成是由于早白垩世晚期、古新世晚期到渐新世发生的ＮＷＷ向断裂作左行剪切拉张平移运动与ＮＮＥ－ＮＥ向断裂作右行剪切拉张平移运动联合作用的结果。该坳陷共发现了－Ｏ、Ｃ－Ｐ、Ｊ＿３－Ｋ＿１和Ｅ四套生油层系。油气资源评价表明，中新生界仅具有形成小型油气藏地质条件，而古生界具有形成较大型的油气藏地质条件。

Kaifeng depression,situated in the northern part of the southern North China basin,mainly extending in NWW direction structurally and in the NNE-NE directions in some seg-ments,is a fault-subsided Meso-Cenozoic depression. Its formation was resulted from theNWW faulting with sinistral shear-extensional movement and the NNE-NE faulting withdextral shear-extensional movement,which occurred in the late stage of the early Cretaceous,through the late stage of the Palaeocene and the Eocene.16 wells have been drilled in the depression,4 source bed systems of-O,C-P,J-K andE have been identified.Petroleum resource evaluation showed that there are geological condi-tions for only small-sized pools in Meso-Cenozoic,and for larger sized pools in Palaeozoic.