Page 206 - Geochemistry of Oil Field Waters

Chapter 7. ORIGIN OF OILFIELD WATERS

The five spheres of the earth are the lithosphere (rocks), the pedosphere
(soils, till, and other surficial materials), the hydrosphere (natural waters),
the atmosphere (gases), and the biosphere (living organisms). Oilfield waters
are a part of the hydrosphere, and petroleum is a product of the biosphere.
The total volume of water in the hydrosphere is about 1,338 x 10'' liters,
and about 8.4 x 10" liters is ground water (Skinner, 1969). Most of the
water, 1,300 x 10" liters, is in the oceans. Less than 50% of the total
ground water is in strata below 1 km. The total amount of water in sedimen-
tary rocks and associated with liquid and gaseous hydrocarbons is less than
1.3 x 1OI8 liters.
All of the petroleum recovered to date has been taken from oil wells
drilled into the upper 8 km of the earth's crust. The average thickness of the

0 km
I7 km
400km
1,000 km

2.900km

5,000km
6,371 km

Fig. 7.1. Regions of the interior of the earth.