关键词: 大庆油田, 嫩二段, 嫩二标志层, 套管损坏, 视电阻率, 地质因素

Abstract: The analysis on accurate location by lead pattern and multi-arm calliper shows that damage points of casing in the member Ⅱof Nenjiang Formation in Daqing Oilfield are mainly concentrated on N₂ marker bed.The damage pattern is shear casing damage.The most serious casing damage sheared at the bedding plane which corresponds to the highest peak of six peaks of 2.5 meters apparent resistivity in N₂ marker bed.The N₂ marker bed is a set of fossil assembly.The six peaks of 2.5 meters apparent resistivity is closely related to fossil quantity.The more fossil in N₂ marker bed,the higher apparent resistivity peaks.Since the N₂ marker bed is a kind of hard rock mainly consisting of CaCO₃ and SiO₂ and also the fossils densely distributed along bedding which would have the weakest plane at the highest peak of apparent resistivity,both hard rock and weak plane are the key geological factors resulting in batch casing damage in N₂ marker bed.The N₂ marker bed deposited in the period of the largest lake transgression in the Cretaeous,so its depositional environment and characteristics have regional consistent,which is the geological base for resulting in casing damage in the same layer but in different areas in Daqing Oilfield.

Key words: Daqing Oilfield, member Ⅱ of Nenjiang Formation, N₂ marker bed, casing damage, apparent resistivity, geological factor