松辽盆地古龙凹陷葡萄花油层超压成因

钻井资料揭示松辽盆地古龙凹陷葡萄花油层存在超压现象，但不存在欠压实现象；葡萄花油层上覆的嫩江组--二段泥岩和下伏的青山口组泥岩存在明显欠压实.声波时差数据计算的泥岩层超压与储层地层测试压力对比，证实油层超压主要来自超压系统内部的压力传递.油气产能与压力测试数据统计表明油层内部原油的热裂解对油层超压也有一定贡献；统计的超压油层的压力梯度大于静水压力梯度，说明储层内存在流动压力，青山口组和嫩江组现今仍在向葡萄花油层提供流体.

Mechanism of Putaohua oil layer's overpressure in the Gulong Sag, Songliao Basin

Drilling data revealed there occurring overpressure in Putaohua oil layer in the Gulong Sag,Songliao Basin, but no undercompaction being discovered.On the contrary, the undercompaction existed in the overlying shales of Members 1 and 2, Nenjiang Formation and Qingshankou Formation.According to the comparison between reservoirs' testing pressure and the over-pressure calculated by interval transit time, the reason of the overpressure in oil layer might mainly be from the pressure transference of internal overpressure system.The statistics of oil-production capacity and test pressure data indicated that the oil cracking had some contribution to the overpressure of oil layer, and the pressure gradient of oil layer which existed overpressure was higher than that of hydrostatic pressure gradient.It comprehended that there might be flowing pressure in the reservoirs, and Qingshankou Formation and Members 1 and 2, Nenjiang Formation are still providing fluids to Putaohua oil layer nowadays.