Petroleum Science >2013, Issue 3: 292-302 DOI: https://doi.org/10.1007/s12182-013-0278-1
Characteristics of the turbidite fan in the WenchangFormation of the Enping Sag, Pearl River MouthBasin, China and its hydrocarbon significance Open Access
文章信息
State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China 2 Basin Research Center, China University of Petroleum, Beijing 102249, China;3 CNOOC Research Institute, Beijing 100027, China;1School of Marine Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, China 2Guangdong University Key Laboratory of Offshore Oil Exploration and Development, Guangzhou, Guangdong 510006, China 3Guangdong Provincial Key Laboratory of Marine Reso;4Guangzhou Institute of Geochemistry, CAS, Guangzhou, Guangdong 510640, China;1School of Marine Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, China 2Guangdong University Key Laboratory of Offshore Oil Exploration and Development, Guangzhou, Guangdong 510006, China 3Guangdong Provincial Key Laboratory of Marine Reso;1School of Marine Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, China 2Guangdong University Key Laboratory of Offshore Oil Exploration and Development, Guangzhou, Guangdong 510006, China 3Guangdong Provincial Key Laboratory of Marine Reso
文章摘要
Mouth Basin (PRMB) has been studied using seismic, logging and borehole data. The fan is characterized
by parallel progradation on the dip seismic profile and is mound-shaped or lenticular-shaped on the strike
seismic profile. The study of the core and logging data from well EP17-3-1, which is located in the front
side of the turbidite fan, shows that this fan is a set of normal grading sand beds, interbedded within
thick dark grey mudstones of semi-deep to deep lake deposits in the Wenchang Formation. The fan is
interpreted as a sand/mud-rich turbidite fan that has an area of over 140 km2 and a maximum thickness
of over 340 m. Combined with a study of the regional geological background and previous provenance
analysis of the Eocene Wenchang Formation, the main potential provenances for the turbidite fan are
considered to be the Panyu low-uplift and northern fault terrace zone. The Enping Sag is considered to
be a half graben-like basin whose north side is faulted and whose south side is overlapped. Basement
subsidence in the Eocene was mainly controlled by boundary faults which dip relatively steeply on the
north side, causing the subsidence center of the Enping Sag in this stage to be close to the north boundary
faults. Sustained faults developed in the Enping Sag during the Eocene caused an increase of the relative
height difference between the north and the south uplift zone in the Enping Sag. Affected by the second
episode of the Zhuqiong movement (39-36 Ma) in late Eocene, sediments which had accumulated on the
Panyu low-uplift zone were triggered and moved toward the subsidence center of the Enping Sag and
formed the turbidite fan. The second episode of the Zhuqiong movement is the most important triggering
factor for the formation of the turbidite fan in the Wenchang Formation. Seismic attribute characterization
shows that the low frequency energy is enhanced and high frequency energy is weakened when seismic
waves propagate through the oil-bearing zone in this fan. Amplitude versus offset (AVO) anomalies
are observed in the seismic data and abnormally high pressure is encountered. The turbidite fan in the
Wenchang Formation has provided important information for sedimentary evolution in deep layers of the
Enping Sag and pointed to a new direction for the hydrocarbon exploration in the study area.
关键词
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Pearl River Mouth Basin, Enping Sag, Wenchang Formation, turbidite fan, hydrocarbonexploration