Relationships among oils and water compositions in Niger delta

Journal Article · Thu Oct 01 00:00:00 EDT 1987 · AAPG Bull.; (United States)

OSTI ID:6916335

Dickey, P A; George, G O; Barker, C

In some fields of the Tertiary Niger delta of Nigeria, heavy, asphaltic oil is found in shallow reservoirs and light, waxy oil is found in deeper reservoirs in the same field. Both oils appears to have had the same source. The change with depth from heavy to light oil is usually abrupt and occurs at a reservoir temperature between 150/sup 0/ and 180/sup 0/F (66/sup 0/ and 82/sup 0/C). In other areas similar degradation of oil has been ascribed to bacteria brought into the oil reservoir by invading meteoric water. In Nigeria, meteoric water is low in dissolved solids and high in bicarbonate, whereas connate water is saltier and contains more chloride. Samples of both types of oil and associated water from six fields were analyzed and compared with previously acquired analyses from these fields. No clear relationship between meteoric water and degraded oil was found. Degraded oil may occur with either meteoric or connate water, and undegraded oil is sometimes found with meteoric water. This suggests extensive secondary migration of oil from one structure to another as well as deep penetration of meteoric water. 14 figures, 1 table.

• OSTI ID: 6916335
• Journal Information: AAPG Bull.; (United States), Vol. 71:10
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
NIGERIA
OIL FIELDS
RESERVOIR ROCK
METEORIC WATER
PETROLEUM
WATER INFLUX
AFRICA
DEVELOPING COUNTRIES
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOLOGIC DEPOSITS
GROUND WATER
HYDROGEN COMPOUNDS
MINERAL RESOURCES
OXYGEN COMPOUNDS
PETROLEUM DEPOSITS
RESOURCES
WATER
020200* - Petroleum- Reserves
Geology
& Exploration