Seismic characters of subtle stratigraphic traps in Erchungchui formation: Application for evaluation of hydrocarbon potential of future prospects
The Erchungchui reservoir within the hydrocarbon bearing zone produces a strong reflection or {open_quotes}bright spot{close_quotes} which is strongly associated with tuning effect caused by thin layer less than 5 meters. The bright spot has a consistent amplitude character over the major part of the gas field covering an area of 6 km{sup 2}. A quantitative analysis system was developed to resolve thin porous sands. Seismic characteristic analyses were applied to reveal characters of gas sand and stratigraphic modeling study were carried out with results matching perfectly to seismic sections. A stratigraphic model of thin washover fan buried in thin lagoon mud was proposed. In addition to {open_quotes}bright spot{close_quotes}, polarity reverse, conspicuous low frequency content of waveform and time sag in strata underneath the gas revoir are seismic characters of the stratigraphic trap in Erchungchui Formation. The modeling demonstrates that polarity reverse is strongly related to lateral variation of tuning conditions: seismic responses of two peaks of thin layer changes from equal polarity to opposite polarity reflectivity series, corresponding to thin lagoon mud and gas sand respectively. The production field is concluded to be stratigraphic traps rather than structural traps as interpreted previously. Seismic characters analyzed in this study are criteria to locate future potential prospects, reflection events containing Erchungchui Formation is suggested to be zoomed in to identify these criteria. Distribution area of gas sand is estimated to be 2 km{sup 2} and maximum thickness of it is suggested to be in the area between shot point 110 and 220 of line DR, where strong seismic characters analyzed in this study are observed.
- OSTI ID:
- 542881
- Report Number(s):
- CONF-951013-; TRN: 97:004463-0069
- Resource Relation:
- Conference: SEG `95: 65. annual meeting and international exposition of the Society of Exploration Geophysicists (SEG), Houston, TX (United States), 8-13 Oct 1995; Other Information: PBD: 1995; Related Information: Is Part Of SEG/Houston `95 - technical program; PB: 1623 p.
- Country of Publication:
- United States
- Language:
- English
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