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Naturally propped fractures caused by quartz cementation preserve oil reservoirs in basement rocks
Author(s) -
Baba Mas'ud,
Parnell John,
Bowden Stephen A.
Publication year - 2019
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12385
Subject(s) - geology , quartz , cementation (geology) , geochemistry , sedimentary rock , petroleum reservoir , petrology , petroleum engineering , cement , composite material , paleontology , materials science
Much silica precipitation in oil reservoirs occurred in the presence of hydrocarbons, evidenced by the entrapment of oil fluid inclusions in quartz. Also, silica in sedimentary basins is commonly precipitated at oil‐window temperatures. This spatial and temporal relationship between oil and quartz precipitation aids the entry of oil into fractured reservoirs, including fractured basement. Where quartz is precipitated as fracture linings, the fractures are propped open by bridging quartz crystals, creating high fracture porosity and permeability. Evidence from fossil fractured reservoirs shows a large proportion of oil residue is in such propped open fractures.