Oil Exploration Game
(Basic concepts)
-Sedimentary rocks-Shale - Very fine grained sedimentary rock composed mainly of clays with
little/no porosity and impermeable. Comprises cap rock, traps in oil and
gas, and keeps from escaping, and usually source rock, from which the oil
and gas are derived.
-Sandstone – Medium – coarse grained sedimentary rock composed mainly of
quartz grains. Highly porous and permeable, contains the oil and gas,
Host rock.
-Halite - (rock salt) – Non-porous/permeable rock which can form ‘salt domes’,
which form large up-welling, dome-shaped features where gas and oil tend
to migrate towards, and get trapped against.
Porosity – Empty ‘pore’ spaces between individual grains in which gas, oil, water
can be stored.
Permeability – The extent to which pore spaces are connected, such that
gases/fluids are able to migrate through a particular medium (i.e. rock
type).
-Structural Geology-Faults - Planar feature in which rock units are offset from each other and varying
units are juxtaposed against each other.
-Folds – Contorted features caused by compression of a body of rock forming
anticlines (concave up folds) and synclines (concave down folds). The
peak (high spots) in an anticline is usually where gas and oil migrate to
and are trapped.
-Geophysics-Seismic reflection - Non-invasive technique used to image subsurface geologic
structures by sending a single seismic signal (sound wave, usually an
explosion) into the Earth, and recording the time it takes for the sound
wave to return to the surface after bouncing of many interfaces of different
rock types, allowing for the imaging of the subsurface after much
processing.
-Densities – Differences between gas, oil, and water (least to most dense), why they will
always separate out in that order (least dense on top).