The significance of a piecemeal geometric model of mudstone compaction: Pinghu Slope, Xihu Depression, Eastern China

• Published in: Marine and petroleum geology 2021-09, Vol.131, p.105138, Article 105138
• Main Authors: Fan, Changyu, Wang, Gang
• Format: Article
• Language: English
• Subjects: Chemical compaction; Compaction; Overpressure; Pressure prediction
• ISSN: 0264-8172; 1873-4073
• DOI: 10.1016/j.marpetgeo.2021.105138

The geometric model of the loading curve used to express mudstone compaction behaviour profoundly influences the quantitative estimation of pore-pressure and identification of the origin of overpressure. The verification of field data from the Pinghu Slope Belt indicates that as burial depth increased, the compaction process was divided into three sections of mechanical compaction fitted by a convexity function, chemically enhanced mechanical compaction fitted by a concavity function, and stable compaction fitted by a convexity function. The piecemeal geometric model of mudstone compaction expressed by the loading curve is more appropriate than previous monotonous loading curves for characterising compaction behaviour, amplifying the effect of chemical compaction, and expressing chemical compaction behaviour. The piecemeal geometric model of mudstone compaction behaviour yields more precise results of formation pressure prediction and overpressure origin identification. •The compaction process was divided into three sections of mechanical, chemically enhanced mechanical and stable compaction.•The piecemeal loading curve is more appropriate for expressing compaction behavior.•The piecemeal geometric model can effectively predict formation pressure and identify the origin of overpressure.