A new type of reservoir rock in volcaniclastic sequences

Journal Article · Fri Jun 01 00:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6201441

Vernik, L ^[1]

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1. Stanford Univ., CA (USA)

Development of pronounced secondary porosity and permeability, accompanied by dramatic changes in wave propagation velocity and other physical properties, in laumontite tuffs occurs in the oil fields of eastern Georgia, Soviet Union. These rocks originated during intense hydrothermal alterations of andesite tuffs and comprise local (few meters thick), commonly lens-shaped bodies. Hydrothermal alteration was lithologically and structurally controlled, resulting in the formation of specific reservoir rocks identifiable on geophysical logs and capable of producing oil and gas. The considerable relief of the in-situ stress within these bodies was estimated from differential velocity analysis using sonic-log and laboratory data. This stress relief, as well as borehole enlargements (accompanied by the development of zones of nonelastic deformation around the hole) tends to enhance near-well permeability and, hence, the productive potential of these uncommon and poorly studied reservoirs. 6 figs., 3 tabs.

• OSTI ID: 6201441
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (USA), Vol. 74:6; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
NATURAL GAS DEPOSITS
RESERVOIR ROCK
PETROLEUM DEPOSITS
HYDROTHERMAL ALTERATION
LITHOLOGY
PERMEABILITY
POROSITY
TUFF
USSR
ASIA
EASTERN EUROPE
EUROPE
GEOLOGIC DEPOSITS
MINERAL RESOURCES
RESOURCES
020200* - Petroleum- Reserves
Geology
& Exploration
030200 - Natural Gas- Reserves
Geology
& Exploration