Home Work # 3 (02%)
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Subsidence
1.
Beneath the Ghawar Field, the basement is found about 7 km beneath the
surface. It is covered with sediments (3 km is carbonates and the other part is
clastics). Calculate the crustal
thickness by assuming Airy Isosticy method.
Support your answer with drawing.
Hint:
Compensating depth is
80 km
Initial crustal thickness is
35 km.
Clastics sediments density is
2.60 gm/cm3
Carbonate sediment density is 2.80 gm/cm3
Crust density is
2.92 gm/cm3
Mantle
density is
3.35 gm/cm3
2.
Repeat the above calculation using densities 2.5, 2.7, 3.0, and 3.2
respectively. Also assume the compensating depth and the initial crustal
thickness are 80 km. Compare between the two answers. What is your opinion of this comparison?
Time-Average
Equation
3.
You have a piece of sandstone whose fractional porosity is 0.25 and whose
water-saturated velocity is 4000 m/s.
Calculate the sandstone velocity at zero porosity, its air-saturated
velocity, and its ice-saturated velocity.
Hint:
Velocity
of Air is
330 m/s
Water
1500 m/s
Ice
3150 m/s
GOOD LUCK