Question:
Which of the following offshore drilling platform(s) has/have legs on the seabed?
Which of the following offshore drilling platform(s) has/have legs on the seabed?
Show Hint
- Jack-up rigs and gravity-based platforms rest on the seabed.
- Tension leg and semi-submersibles are floating systems, held by tethers or anchors.
Updated On: Aug 24, 2025
- Jack up
- Tension leg
- Concrete gravity
- Semi-submersible
Show Solution
Verified By Collegedunia
The Correct Option is A, C
Solution and Explanation
Step 1: Jack-up rigs.
Jack-up rigs are mobile platforms with extendable legs that can be lowered to the seabed. Once in place, the platform is jacked above sea level for stable drilling. Hence, they definitely have legs resting on the seabed. Step 2: Tension leg platforms.
Tension leg platforms are floating structures tethered to the seabed by vertical tensioned tendons or tethers. These are not "legs resting on seabed" but mooring elements providing vertical stability. Hence, option (B) is incorrect. Step 3: Concrete gravity platforms.
Concrete gravity-based structures (GBS) rest directly on the seabed. Their enormous weight (gravity base) provides stability. They have large "legs/shafts" rising above the seabed. Hence, (C) is correct. Step 4: Semi-submersibles.
Semi-submersibles float on partially submerged pontoons and are held in place by anchors or dynamic positioning systems. They do not have legs resting on the seabed. Thus, (D) is incorrect. Final Answer: \[ \boxed{\text{(A) Jack up and (C) Concrete gravity platforms}} \]
Jack-up rigs are mobile platforms with extendable legs that can be lowered to the seabed. Once in place, the platform is jacked above sea level for stable drilling. Hence, they definitely have legs resting on the seabed. Step 2: Tension leg platforms.
Tension leg platforms are floating structures tethered to the seabed by vertical tensioned tendons or tethers. These are not "legs resting on seabed" but mooring elements providing vertical stability. Hence, option (B) is incorrect. Step 3: Concrete gravity platforms.
Concrete gravity-based structures (GBS) rest directly on the seabed. Their enormous weight (gravity base) provides stability. They have large "legs/shafts" rising above the seabed. Hence, (C) is correct. Step 4: Semi-submersibles.
Semi-submersibles float on partially submerged pontoons and are held in place by anchors or dynamic positioning systems. They do not have legs resting on the seabed. Thus, (D) is incorrect. Final Answer: \[ \boxed{\text{(A) Jack up and (C) Concrete gravity platforms}} \]
Was this answer helpful?
0
0
Top GATE PE Oil and Gas Well Drilling Technology Questions
- Which ONE of the following options is CORRECT in relation to the standard drill pipe?
- Which of the following offshore drilling platform(s) has/have legs on the seabed?
- The hoisting system of a drilling rig contains seven ideal sheaves with hook load of \( 3.0 \times 10^5 \) kg. The static derrick load is .......... × \( 10^5 \) kg (rounded off to one decimal place).
- A drilling fluid with time-dependent rheology is used for the rotary drilling of a reservoir. The following equation describes the dependence of shear stress (\( \tau \)) on shear rate (\( \dot{\gamma} \)):
\[ \tau + \frac{\mu_0}{\alpha} \frac{d\tau}{dt} = \mu_0 \dot{\gamma} \] where \( \mu_0 \) and \( \alpha \) are constants.
If the rotation of the drill pipe is stopped at time \( t = 0 \), then the relaxation behavior of the fluid stress with time is: - The hydrostatic pressure gradient in a vertical well drilled in a relaxed depositional basin is 0.452 psi/ft. Assume that the gradient of effective horizontal stress with depth is constant in the drilling zone and has a value of 9.96 × 10⁻² psi/ft. The casing shoe is at 4000 ft depth.
While drilling the bore hole below the casing shoe with 10 ppg mud, the maximum allowed standpipe pressure is .......... psi (rounded off to one decimal place).
View More Questions
Top GATE PE Drilling Method and Machines Questions
- Which ONE of the following options is CORRECT in relation to the standard drill pipe?
- Which of the following offshore drilling platform(s) has/have legs on the seabed?
- The hoisting system of a drilling rig contains seven ideal sheaves with hook load of \( 3.0 \times 10^5 \) kg. The static derrick load is .......... × \( 10^5 \) kg (rounded off to one decimal place).
- A drilling fluid with time-dependent rheology is used for the rotary drilling of a reservoir. The following equation describes the dependence of shear stress (\( \tau \)) on shear rate (\( \dot{\gamma} \)):
\[ \tau + \frac{\mu_0}{\alpha} \frac{d\tau}{dt} = \mu_0 \dot{\gamma} \] where \( \mu_0 \) and \( \alpha \) are constants.
If the rotation of the drill pipe is stopped at time \( t = 0 \), then the relaxation behavior of the fluid stress with time is: - The hydrostatic pressure gradient in a vertical well drilled in a relaxed depositional basin is 0.452 psi/ft. Assume that the gradient of effective horizontal stress with depth is constant in the drilling zone and has a value of 9.96 × 10⁻² psi/ft. The casing shoe is at 4000 ft depth.
While drilling the bore hole below the casing shoe with 10 ppg mud, the maximum allowed standpipe pressure is .......... psi (rounded off to one decimal place).
View More Questions
Top GATE PE Questions
- Four fair coins are tossed simultaneously. The probability that at least one tail turns up is:
- Let \( \vec{A} = 2\ell - \mathbf{j} + \mathbf{k} \) and \( \vec{B} = \ell + \mathbf{f} \), where \( \ell, \mathbf{f}, \) and \( \mathbf{k} \) are unit vectors. The projection of \( \vec{B} \) on \( \vec{A} \) is:
- The value of \( \lim_{x \to \frac{\pi}{2}} \left( \frac{\cos x}{x - \frac{\pi}{2}} \right) \) is:
- Which ONE of the following CANNOT be obtained from pressure transient analysis in well testing?
- The primary objective of the electrostatic grid in electrostatic heater-treater used in crude oil processing is to
View More Questions