GATE-2018 (24) :Wyllie – Time average equation

CSIR-NET 2013

142. If the density of petroleum is 0.8 g/cc and density of saline formation water is 1.10 g/cc, then the buoyancy force on a 350m high continuous petroleum column would be 

A) 0.8 M Pa

B) 1 M Pa

C) 1.05 M Pa

D) 0.95 M Pa

Solution:

Buoyancy force (or) Buoyancy pressure (P_b) = ( ρ_w – ρ_p ) gh

P_{b –} buoyancy pressure

ρ_w and ρ_p – density of water and petroleum

g – acceleration due to gravity

h – height above the free water level

P_b = (1100 – 800) * 9.8 * 350 kg / m³ m/s² m

= 300 * 9.8 * 350 kg / m s²

= 1029000 kg / m s²

P_b = 1.03 MPa