RT Journal Article
T1 Destruction of a fluvial reservoir by hydrothermal activity(Cameros Basin, Spain)
A1 Ochoa, M.
A1 Arribas Mocoroa, José
A1 Mas Mayoral, José Ramón
A1 Goldstein, Robert H.
AB This study provides an example of a high-quality fluvial hydrocarbon reservoir that was completely destroyed by hydrothermalprocesses. The reservoir unit was deposited in the Cameros Basin, located in the NW sector of the Iberian Chain (Spain). The basinwas filled with clastic fluvial deposits (sandstones and conglomerates) between Late Berriasian and Early Aptian times. Provenanceof sands was mainly from coarse crystalline rocks. A humid tropical climate produced intense weathering of K-feldspar duringtransport from source to basin. Thus, a mineralogically mature rigid framework with high porosity existed at the time of deposition,which would have constituted a high-quality hydrocarbon reservoir. At present however, the porosity of the reservoir is negligible.Porosity was reduced by a sequence of diagenetic processes: (1) mechanical compaction (i.e. crushing of metamorphic lithic grains)and chemical compaction, (2) kaolinite and siderite cementation, and (3) early quartz cementation. Hydrocarbon emplacementprobably occurred between phases (2) and (3). A low-grade metamorphic (hydrothermal) event, reaching greenschist facies, tookplace during the Late Cenomanian. It dramatically reduced the remaining porosity of the reservoir and destroyed the hydrocarboncharge. Hydrothermal processes which affected the sandstones include (1) re-compaction; (2) late quartz cementation andsilicification of remaining feldspars; (3) carbonate cementation; (4) chloritization of feldspars, metamorphic lithic fragments andintrabasinal argillaceous grains; and (5) growth of pyrite and chloritoid crystals on argillaceous material of intrabasinal,extrabasinal or even diagenetic origin. Hydrocarbons that migrated to the margins of the basin escaped these hydrothermalmodifications and were preserved. The results of this study may be used to predict the diagenetic and hydrothermal evolution ofother potential reservoirs in similar tectonic settings.
PB Elsevier
SN 0037-0738
YR 2007
FD 2007
LK https://hdl.handle.net/20.500.14352/49684
UL https://hdl.handle.net/20.500.14352/49684
LA eng
DS Docta Complutense
RD 2 may 2024