Impact of 3-D seismic data on the Nigerian National Petroleum Corporation/Chevron Nigeria Limited joint venture development drilling program
- Chevron Nigeria Ltd., Lagos (Nigeria)
The Nigerian National Petroleum Corporation/Chevron Nigeria Limited joint venture has been acquiring three-dimensional (3-D) seismic data over its concessions since 1984. To date, 1700 km[sup 2] have been recorded and processed at a cumulative cost of US $39 million. During 1991 - 1992, 20 development wells were drilled based directly on new 3-D seismic interpretations. These wells have added 148 million bbl of oil in new recoverable reserves, and to date have added 37,000 bbl/day to the joint venture's production. In addition, the 3-D interpretations have resulted in a sizable inventory of wells for future development drilling. The new 3-D interpretations provided more accurate pictures of fault patterns, fluid contacts, channel trends, stratigraphic continuity, and velocity/amplitude anomalies. In addition, the 3-D data were invaluable in designing low risk, directional well trajectories to tap relatively thin oil legs under large gas caps. Wells often were programmed to hit several objectives at their respective gas/oil contacts, resulting in maximized net oil sand pays and reducing the risk of gas production. In order to do this, directional [open quotes]sharpshooting,[close quotes] accurate depth conversion of the seismic time maps, was critical. By using the 3-D seismic, checkshot, and sonic data to develop a variable velocity space, well-top prognoses within 50 ft at depths of 6,000-10,000 ft were possible, and were key to the success of the program. As the joint venture acreage becomes more mature, development wells will be drilled for smaller numbers of stacked objectives, and sometimes for single sands. Highly accurate 3-D interpretations and depth conversions will become even more critical in order to tap thinner pay zones in a cost-effect manner.
- OSTI ID:
- 6964389
- Report Number(s):
- CONF-9310237-; CODEN: AABUD2
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 77:9; Conference: American Association of Petroleum Geologists (AAPG) mid-continent section meeting, Amarillo, TX (United States), 10-12 Oct 1993; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
Similar Records
Oil and gas developments in west coast in 1984
Oil and gas developments in central and southern Africa in 1987
Related Subjects
03 NATURAL GAS
DIRECTIONAL DRILLING
OPTIMIZATION
HYDROCARBONS
RESOURCE ASSESSMENT
RESERVOIR ROCK
RESOURCE POTENTIAL
SEISMIC SURVEYS
USES
COST
EXPLORATORY WELLS
MAPS
NATURAL GAS
NIGERIA
PETROLEUM
RESERVES
STRATIGRAPHY
THREE-DIMENSIONAL CALCULATIONS
AFRICA
DEVELOPING COUNTRIES
DRILLING
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
GEOLOGY
GEOPHYSICAL SURVEYS
ORGANIC COMPOUNDS
RESOURCES
SURVEYS
WELLS
020200* - Petroleum- Reserves
Geology
& Exploration
030200 - Natural Gas- Reserves
Geology
& Exploration