China Petroleum Exploration ›› 2018, Vol. 23 ›› Issue (3): 28-34.DOI: 10.3969/j.issn.1672-7703.2018.03.004

• PETROLEUM GEOLOGY • Previous Articles     Next Articles

Overpressure structure in Dongying sag and its controlling factors

Qiu Yibo   

  1. Exploration and Development Research Institute, SINOPEC Shengli Oilfeld Company
  • Received:2017-08-25 Revised:2018-03-31 Online:2018-05-15 Published:2018-05-15
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Abstract: Overpressure is quite common and pressure structures are complex in Dongying sag. The overpressure structures are obviously diverse at different depth in different strata and different tectonic belts. The differences of overpressure structures in Dongying sag and their controlling factors were analyzed in detail by investigating the measured formation pressure, the acoustic log response characteristics of mudstone and the overpressure characteristics of seismic velocity spectrum in this sag. It is shown that the overpressure structures in Dongying sag present obvious zoning characteristics. Vertically, the overpressure is mainly developed in the depth of 2200-4500 m, and its main bodies are mainly developed in Es3 and Es4. Areally, the overpressure is mainly developed in Lijin, Niuzhuang, Boxing and Minfeng subsags. The overpressure amplitude is the highest in Lijin subsag, secondarily in Minfeng and Niuzhuang subsags and the lowest in Boxing subsag. The diversity of overpressure structures is closely related to the structural pattern, the evolution degree of source rocks and the activity of faults. The spatial variation of pressure feld is controlled by the structural pattern of salient alternating with subsag, and the distribution and amplitude of overpressure are dependent on the distribution and thermal evolution degree of source rocks, and the boundary of overpressure system is dominated by long-term inherited major faults.

 

Key words: formation pressure, over-pressure structure, controlling factor, Dongying sag

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