TY - JOUR
T1 - Characterisation of oil and potential source rocks in the northeastern Song Hong Basin, Vietnam: indications of a lacustrine-coal sourced petroleum system
AU - Petersen, Henrik I.
AU - Nytoft, Hans P.
AU - Nielsen, Lars H.
N1 - Funding Information:
This study is a contribution to the establishment of a regional source rock database in Vietnam as described in the DANIDA-sponsored ENRECA project “Integrated analysis and modelling of geological basins in Vietnam and an assessment of their hydrocarbon potential”. The Quattro Micro GC mass spectrometer was partly financed by the Danish Natural Science Research Council. Extraction and MPLC-separation was done by D. Kiel-Dühring (GEUS). J. Halskov (GEUS) is thanked for drafting the figures and tables. J.R. Ineson (GEUS) improved the English. We also appreciate the useful reviews of R. Lin (Unocal Thailand Ltd.) and A. G. Holba (ConocoPhillips, TX). The paper is published with permission from PetroVietnam, Vietnam Petroleum Institute and the Geological Survey of Denmark and Greenland (GEUS).
PY - 2004/4
Y1 - 2004/4
N2 - Oil discovered in the B10-STB-1x well in the northeastern Song Hong Basin, Vietnam, has typical lacustrine-coaly geochemical features, indicating the existence of a principally lacustrine sourced petroleum system with minor contributions from a coal source. The presence of lacustrine source rocks in the basin is indicated by distinct high-amplitude seismic reflectors in undrilled half-grabens and outcrops of Oligocene immature mudstones and humic coals at Dong Ho and on Bach Long Vi Island. The mudstones from Dong Ho generally have a TOC content of 8-17 wt.% and HI values >500 mg HC/g TOC. The organic matter is principally composed of fluorescing amorphous organic matter and liptodetrinite; alginite with Botryococcus-morphology is present. The organic matter corresponds to type I kerogen. The Bach Long Vi Island mudstones contain 2-7 wt.% TOC and have HI values from 200-700 mg HC/g TOC. The organic matter is largely similar to that in the Dong Ho mudstones, but in addition may contain some marine organic material. The B10-STB-1x oil shows features common to both the Dong Ho and Bach Long Vi Island mudstones, but was probably principally generated from a source similar to the Dong Ho mudstones with contributions from higher land plant organic matter. A prominent activation energy peak dominates the activation energy distributions of the mudstones, and upon artificial maturation (hydrous pyrolysis) the mudstones show extensive hydrocarbon generation over a narrow temperature range. Hydrocarbon expulsion has been estimated to occur at a vitrinite reflectance of ∼0.75%R
o. The source of the B10-STB-1x oil may be located in the Thuy Nguyen Graben, and maturity modelling shows that the lacustrine mudstones will be thermally mature in this graben.
AB - Oil discovered in the B10-STB-1x well in the northeastern Song Hong Basin, Vietnam, has typical lacustrine-coaly geochemical features, indicating the existence of a principally lacustrine sourced petroleum system with minor contributions from a coal source. The presence of lacustrine source rocks in the basin is indicated by distinct high-amplitude seismic reflectors in undrilled half-grabens and outcrops of Oligocene immature mudstones and humic coals at Dong Ho and on Bach Long Vi Island. The mudstones from Dong Ho generally have a TOC content of 8-17 wt.% and HI values >500 mg HC/g TOC. The organic matter is principally composed of fluorescing amorphous organic matter and liptodetrinite; alginite with Botryococcus-morphology is present. The organic matter corresponds to type I kerogen. The Bach Long Vi Island mudstones contain 2-7 wt.% TOC and have HI values from 200-700 mg HC/g TOC. The organic matter is largely similar to that in the Dong Ho mudstones, but in addition may contain some marine organic material. The B10-STB-1x oil shows features common to both the Dong Ho and Bach Long Vi Island mudstones, but was probably principally generated from a source similar to the Dong Ho mudstones with contributions from higher land plant organic matter. A prominent activation energy peak dominates the activation energy distributions of the mudstones, and upon artificial maturation (hydrous pyrolysis) the mudstones show extensive hydrocarbon generation over a narrow temperature range. Hydrocarbon expulsion has been estimated to occur at a vitrinite reflectance of ∼0.75%R
o. The source of the B10-STB-1x oil may be located in the Thuy Nguyen Graben, and maturity modelling shows that the lacustrine mudstones will be thermally mature in this graben.
UR - http://www.scopus.com/inward/record.url?scp=1842431604&partnerID=8YFLogxK
U2 - 10.1016/j.orggeochem.2004.01.011
DO - 10.1016/j.orggeochem.2004.01.011
M3 - Article
SN - 0146-6380
VL - 35
SP - 493
EP - 515
JO - Organic Geochemistry
JF - Organic Geochemistry
IS - 4
ER -