During the development of foreland basins, the intensive compressive stresses and typical orogen-basin relationship have resulted in complex sedimentary environments and structural deformations. And correspondingly, many geological activities may play important roles in pore pressure evolution. In this paper,the geological conditions favorable for overpressure generation and distribution of overpressures were analyzed. And then effects of some overpressuring mechanisms were simulated by using numerical basin modeling method, based on our understandings about various geological processes occurred in foreland basins, such as compaction ,fault opening, folding and erosion, etc. Simulated results demonstrate that lateral compaction caused by compressive tectonic stress, the intensive folding, as well as corresponding rapid deposition and erosion, are the typical geological effects that may cause high overpressures in a foreland basin. The extremely high overpressure in the southern margin of Junggar Basin, NW China, may be interpreted to have resulted from superimposition of allogenically-transmitted pressure along faults and dipping permeable sandstones under the background of high pressure generated by compaction and tectonic compression.
