This document discusses different types of subsurface waters and their origins. It defines four main types: 1) Meteoric waters which occur near the surface and are involved in the hydrological cycle. 2) Formation waters (connate waters) which are trapped in sedimentary basins and have evolved over time through water-rock interactions. 3) Juvenile waters of igneous or metamorphic origin. 4) Mixed waters. It also discusses settings of earth's water, how water moves between settings like oceans, lakes, rivers, atmosphere, and groundwater, and reduction potential as a measure of water quality.

1. The Subsurface Environment

2. Revision:
1. Seal
2. Structural trap
3. Stratigraphic trap

3. Introduction
 We shall discuss about subsurface waters
 The effects of pressure and temperature on the
condensation and evaporation of gas and oil.
 Fluid dynamics in sedimentary basins

5. Genetic Classification
Normally, four types of subsurface water can be defined according to
their genesis:
1. Meteoric waters: Occur near the earth surface. Involved in
hydrogeological cycle.
2. Formation waters (connate waters): water trapped in the pore
spaces or rocks in sedimentary basins, and have not recently
been involved in the hydrogeological circle. These waters evolve
with time as a result of water-rock interactions and gain high
salinity.
3. Juvenile waters: These are igneous or metamorphic origin
4. Mixed water
Meteoric
Mixed
Juvenile Connate

6. Settings of Earth’s
Water Observe all the places where
water is present
Oceans: 96.5% of
near-surface water
Rivers
Lakes: fresh or
salty
Swamps
and wetlands
Atmosphere
Glaciers: 69% of
freshwater
Biological water
Water in minerals:
may be large
amount
Groundwater: 30% of freshwater
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7. How Does Water Move? Observe how water moves
between settings
Air currents
Evaporation
(oceans, lakes,
rivers,…)
Condensation Precipitation
(rain, snow, hail)
Runoff
Infiltration:
water seeps
into
ground
Groundwater flows
Groundwater flows onto
surface
Most precipitation
into ocean; some
evaporates on way down
Transpiration
from plants
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9.  Reduction potential (also known as redox potential,
oxidation / reduction potential, ORP, pE or Eh) is a
measure of the tendency of a chemical species to
acquire electrons and thereby be reduced.
Reduction potential is measured in volts (V), or
millivolts (mV).
 Each species has its own intrinsic reduction
potential; the more positive the potential, the
greater the species' affinity for electrons and
tendency to be reduced. ORP is a common
measurement for water quality

22. Note: Conductivity increases
and gradient decreases with
depth & declining porosity

25. Regional
variations in
heat flow affect
petroleum
generation. In
areas of high
heat flow & high
geothermal
gradient, the
optimal tempt.
Will be reached
at shallower
depth.

26. Questions?