Diagenesis and reservoir characterization of the Block V-Lamar field, Maracaibo basin, Venezuela

Conference · Fri Mar 01 04:00:00 EST 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5799111

Gonzales, C; Gustavo, F ^[1]

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1. INTEVEP, S.A., Caracas (Venezuela)

The Block V-Lamar field, located in the central portion of Maracaibo basin, Venezuela, is the subject of this study. The sedimentary section corresponds to a section of the Misoa Formation of early to middle Eocene age. These sediments were deposited in the upper delta plain as stacked distributary channel bars and associated facies and consist of relatively clean sandstones, fine to medium grained, with a sublitharenitic to subarkosic composition. The clay mineral assemblage is mainly composed of kaolinite, followed by chlorite and subordinate amounts of discrete smectite, discrete illite, and mixed-layer illite/smectite with order stratification with 20-30% of expandable layers, all of diagenetic origin. Even though there is a remnant of primary porosity reduced by silica cement, most porosity is secondary as a result of cement, matrix, and unstable grain dissolution. The petrographic XRD and SEM data obtained allow the authors to define the following paragenetic sequences: (1) mechanical compaction; (2) silica cementation; (3) patchy calcite cementation; (4) dissolution of matrix, cements, feldspars, and rock fragments; (5) kaolinite precipitation at or near feldspar intragranular pores; (6) matrix recrystallization to chlorite; (7) precipitation of second generation of kaolinite; and (8) precipitation of smectite. The porosity and permeability distribution in the reservoirs is the result of the net effect of the different diagenetic events that include early diagenesis, medium to late diagenesis, and telodiagenesis, mainly in response to basinwide tectonism.

• OSTI ID: 5799111
• Report Number(s): CONF-910403--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 75:3
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
CENOZOIC ERA
CLAYS
DEVELOPING COUNTRIES
DIAGENESIS
EOCENE EPOCH
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
LATIN AMERICA
MINERAL RESOURCES
MINERALOGY
PARAGENESIS
PETROLEUM DEPOSITS
POROSITY
RESERVOIR ROCK
RESOURCES
SEDIMENTARY BASINS
SOUTH AMERICA
TERTIARY PERIOD
VENEZUELA