Abstract:

The reasons for anomalous pore pressure are analyzed in this paper. The methods of equivalent depth to predict pore pressure from well logging data and Fillippone’ formula based on seismic velocity are introduced and compared with the results from MDT pressure data. The results of prediction of pore pressure from well sonic data in the Tahe oilfield TPT area shows that this area pressure coefficient change from 1.0 to 1.2, can be classified as normal pressure system. The maximum error between MDT and predicted pore pressure by Fillippone’ formula reaches 5% as predictied pore pressure by equivalent depth method reaches 15%, so Fillippone’ formula has high precision and reliability than the equivalent depth method. This study show that prediction of pore pressure using seismic velocity can predict the layer pressure which embodies the pressure change trend of a heavy layer and design the mud density before drill. It can also can improve the drill productivity and approve the support for safe drill.

Key words:  , Key words：abnormal compaction, velocity spectrum, pressure coefficient,prediction of pore pressure, anomalous formation pressure, Tahe oilfield