Oil & Gas Geology ›› 2004, Vol. 25 ›› Issue (1): 81-87.doi: 10.11743/ogg20040115

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Reservoir dynamic monitoring: a commentary on time-lapse (or 4-D) seismics

Cui Yongqian1, Liu Chiyang1, Zhang Yiming1,2   

  1. 1. Northwest University, Xi'an, Shaanxi;
    2. Huabei Oilfield Company of PetroChina, Renqiu, Hebei
  • Received:2003-09-18 Online:2004-02-25 Published:2012-01-16

Abstract:

Time-lapse seismic (4D seismic) technology, a reservoir dynamic monitoring technology rapidly developed in recent years, has become a new tool for reservoir management,and has widely been applied in many oilfields,especially offshore oilfields. The application of this technology is continuously enlarging and the accuracy is continuously increasing with the deepening of study on petrophysical properties and the development of relevant technologies. Currently, time-lapse seismic technology is used to monitor changes of oil recovery, oil displacement efficiency and fluid front, to identify areas with bypassed oil, as well as to monitor sealing capacity or leakage of faults. The key to seismic acquisition is to improve repeatability and signal-to-noise ratio. New technologies,such as cross equalization, normalization and bin parameter recombination and the principle of synchronous processing of new and old data,are applied so as to ensure that the final seismic differences are the only results of fluid flow changes in reservoirs. Based on direct interpretation, reversion and property analysis, seismic history match and dynamic reservoir description are developed as seismic interpretation technologies and are used in combination with other subjects and technologies to reduce non-uniqueness of interpretation. Remarkable progresses have also been made in respect of lowering investment risk of projects and feasibility study. The application conditions and limitations of the technology should be considered when carrying out time-lapse seismic projects. With the deepening of research on time-lapse seismic techniques and enriching of experiences, time-lapse seismic reservoir monitoring will progress more rapidly and will more widely be applied.

Key words: time-lapse (4D) seismics, reservoir monitoring, repeatability, petrophysical properties, fluid flow, cross equalization, differential images

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