Characterization of fracture networks applied to optimize well tracks in deep Cretaceous reservoirs of Lake Maracaibo, Venezuela

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

OSTI ID:5575745

Franssen, R C.M.W.; Vahrenkamp, V C ^[1]; Van De Graaff, E W.J.E. ^[2]; Munoz, P J ^[3]

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1. KSEPL, Rijswijk (Netherlands)
2. Shell Expro, Aberdeen (United Kingdom)
3. Maraven S.A., Caracas (Venezuela)

Cretaceous Cogollo Group carbonates in the Lake Maracaibo basin, Venezuela produce mainly from fractures. Any improvement in production rate requires an effective assessment of the open fractures. This has been done using two paleomagnetically oriented cores from Lake Block 9 (Central Lake Maracaibo). Wells SVS-225 and SVS-229 respectively represent the west and east flank of a structure defined by the left-lateral Icotea fault. Open fractures on both sides of the Icotea fault are subvertical. In the west flank the open fractures trend WSW-ENE and in the east flank the trend is WNW-ESE. For maximum rates of open fracture intersection the optimum well tracks are towards azimuth 330{degree} and deviation 60{degree} in the west flank and towards azimuth 030{degree} and deviation 60{degree} in the east flank. The open fracture networks consist of incompletely cemented or leached fractures which contain a 'channel and island' structure of interconnected porosity. This 'channel and island' structure of the open fractures, in combination with the high rock matrix strength and the subparallel E-W trend of the present-day maximum horizontal stress indicate that it is unlikely that the individual fracture conductivity is reduced drastically upon depletion. The structural model established for wells SVS-225 and SVS-229 is consistent with data obtained from wells VLA-711 and VLA-722 in the west flank of Block 1, some 40 km to the north. This indicates that the reservoir model has regional validity and that the well track recommendation of azimuth 330{degree} should also apply to the west flank of Lake Block 1.

• OSTI ID: 5575745
• 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
020300 -- Petroleum-- Drilling & Production
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
030300 -- Natural Gas-- Drilling
Production
& Processing
CARBONATE ROCKS
CRETACEOUS PERIOD
DEVELOPING COUNTRIES
DIRECTIONAL DRILLING
DRILLING
FRACTURED RESERVOIRS
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
LATIN AMERICA
MESOZOIC ERA
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NATURAL GAS WELLS
OIL WELLS
OPTIMIZATION
PETROLEUM DEPOSITS
RESOURCES
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SOUTH AMERICA
VENEZUELA
WELLS