250+ TOP MCQs on Mechanisms of Hydraulic Fracturing and Answers

Petroleum Production Operations Multiple Choice Questions on “Mechanisms of Hydraulic Fracturing”.

1. Effective compressive stress increases when the formation has porosity and contains fluid.
a) True
b) False
Answer: b
Clarification: The statement is false. The corrected statement is that effective compressive stress decreases when the formation has porosity and contains fluid. As pore pressure affects the matrix stress.

2. In which of the following the environmentalists are more concerned with due to fracking?
a) Seismic activity
b) Air quality
c) Endangered species
d) Groundwater
Answer: d
Clarification: Groundwater is more concerned with due to fracking. No one has the right to destroy the natural groundwater irrespective of whether producing oil or gas. The government has some rules and regulations which the company must follow up.

3. How can the vertical stress be calculated by considering the pore P_ressures?
a) σ = 0.007ρD – P_r
b) σ = 0.07ρD
c) σ = 0.009ρD
d) σ = 0.72ρD – P_r
Answer: a
Clarification: The vertical stress can be calculated by the formula σ = 0.007ρD – P_r considering the pore pressures. Pore pressure affects matrix stress. Effective compressive stress decreases when the formation has porosity and contains fluid.

4. How can effective horizontal comP_ressive stress be calculated?
a) 0.007ρD – P_r
b) (ρ_v– P_r) .ν/ (ν-1)
c) 0.07ρD
d) 0.72ρD – P_r
Answer: b
Clarification: The effective horizontal comP_ressive stress can be calculated by using the formula ( ρ_v– P_r) .ν/ (ν-1). Where ν is the Poisson’s ratio. On laboratory-based experiments, it is found that the Poisson’s ration can range from 0.15 to 0.40.

5. What will be the vertical stress (without considering the pore pressures) if the average rock density if 100 lb/ft³ and depth is 5000 ft?
a) 3500
b) 4000
c) 3254
d) 5454
Answer: a
Clarification: The vertical stress can be calculated by using the formula σ_v = 0.007ρD i.e. σ_v = (0.007).(100). (5000)= 3500, without considering the pore pressures. Pore pressure affects matrix stress. Effective compressive stress decreases when the formation has porosity and contains fluid.