Authors:
Yong Yang
1
;
Aifang Bie
1
;
Hanyu Bie
2
;
Ming Zhang
1
and
Zhaohui Xia
1
Affiliations:
1
Research Institute of Petroleum Exploration and Development and Petrochina, China
;
2
School of Energy Resources and China University of Geosciences (Beijing), China
Keyword(s):
Geometry, coal ply, coalbed methane, sedimentary facies, geological model
Abstract:
The Walloon Coal Measures(WCM) is the main producing formation in Tipton coalbed methane(CBM) field in the Jurassic Surat basin of the southeast Queensland, Australia. The numerous, thin, pinching out, merging, and splitting coal seams in the WCM show highly variable in the spatial continuity. Accurate determination of the facies, lithological attributes and geometries is important in the CBM exploration and development planning for Tipton field. In the paper, high resolution sequence stratigraphy is used to build an isochronal stratigraphic framework of sublayers and coal plies by utilizing all available data from cores and logs. The key methodology in this procession is to identified single fining-upwards cycles with sandstone at the bottom and coal, siltstone or shale at the top. Five lithologies of coal, shaly coal, sandstone, siltstone and shale are classified by density and gamma ray well logs. Six members, 20 sublayers and 125 single coal plies are picked and correlated for th
e whole WCM. The distributions and geometries of coal and channel are analysed for each sublayer. The characteristics of the following depositional facies are interpreted: coal swamp and swamp, major channel, minor channel, floodplain, lacustrine. A concept model of sedimentation is reconstructed to emphasize the relationships of major facies which is essential for the further geological modelling, potential sweet spots determining and filed development of the Tipton field.
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