Forage et complétion de puits

Kelly Cock

Le "Kelly Cock" : Un Composant Essentiel dans les Opérations de Forage

Le terme "Kelly Cock" peut sembler inhabituel, mais il désigne en réalité une partie cruciale du processus de forage. Ce type spécifique de valve est un composant essentiel du Kelly, un élément crucial du système d'une plateforme de forage.

Qu'est-ce qu'un Kelly ?

Le Kelly, également connu sous le nom de douille Kelly, est une pièce d'équipement cylindrique qui relie le top drive ou la table rotative au train de tiges. Cette connexion est essentielle pour transmettre la puissance de rotation de la plateforme de forage au trépan.

Le Rôle du "Kelly Cock" :

Le "Kelly Cock", une valve située sur le Kelly, joue un rôle vital dans le processus de forage. Il sert de mécanisme de contrôle pour le fluide de forage, qui est circulé à travers le train de tiges pour lubrifier le trépan, éliminer les déblais et maintenir la pression du puits.

Voici une ventilation des fonctions principales du "Kelly Cock" :

  • Contrôle de la circulation des fluides : Le "Kelly Cock" régule le flux de fluide de forage dans le puits. Cela permet des opérations de forage efficaces et évite les pertes de fluide indésirables.
  • Gestion de la pression : En contrôlant le flux de fluide, le "Kelly Cock" aide à maintenir la pression dans le puits. Cela évite l'instabilité du puits et les possibles éruptions.
  • Échantillonnage du fluide de forage : La valve permet aux opérateurs de prélever des échantillons du fluide de forage pour analyse. Ces données sont essentielles pour optimiser le processus de forage et garantir la stabilité du puits.

Types de "Kelly Cocks" :

Il existe plusieurs types de "Kelly Cocks", chacun avec sa propre conception et ses propres caractéristiques opérationnelles. Parmi les types courants, citons :

  • "Kelly Cock" rotatif : Ce type est généralement utilisé dans les opérations de forage rotatif et comporte une valve simple à commande manuelle.
  • "Kelly Cock" de top drive : Conçu pour une utilisation avec des systèmes de forage à top drive, ce type intègre souvent une valve à commande hydraulique pour un meilleur contrôle.

Importance du "Kelly Cock" :

Le "Kelly Cock" est un dispositif de sécurité essentiel et un composant vital pour des opérations de forage efficaces. Un bon entretien et un bon fonctionnement de cette valve sont primordiaux pour garantir la sécurité et la productivité du forage.

Conclusion :

Bien que le terme "Kelly Cock" puisse sembler inhabituel, il désigne une valve essentielle dans le processus de forage. Son rôle dans la régulation du flux de fluide, la gestion de la pression et la possibilité d'effectuer des prélèvements en fait un composant essentiel pour des opérations de forage sûres et efficaces. Comprendre son fonctionnement est crucial pour toute personne impliquée dans l'industrie pétrolière et gazière.

Test Your Knowledge

Kelly Cock Quiz:

Instructions: Choose the best answer for each question.

1. What is the primary function of the Kelly Cock?

a) Connecting the drill string to the rotary table.

Answer

Incorrect. This is the function of the Kelly, not the Kelly Cock.

b) Regulating the flow of drilling fluid.

Answer

Correct! The Kelly Cock controls the flow of drilling fluid into the wellbore.

c) Providing rotational power to the drill bit.

Answer

Incorrect. This is the function of the top drive or rotary table.

d) Supporting the weight of the drill string.

Answer

Incorrect. This is the function of the drilling rig's substructure.

2. What is NOT a function of the Kelly Cock?

a) Pressure management within the wellbore.

Answer

Incorrect. The Kelly Cock helps maintain pressure within the wellbore.

b) Sampling drilling fluid for analysis.

Answer

Incorrect. The Kelly Cock allows for drilling fluid sampling.

c) Providing lubrication to the drill bit.

Answer

Correct! The drilling fluid itself lubricates the bit, not the Kelly Cock.

d) Controlling the rate of penetration.

Answer

Incorrect. The Kelly Cock indirectly influences the rate of penetration by controlling fluid flow.

3. Which type of Kelly Cock is typically used with top drive drilling systems?

a) Rotary Kelly Cock.

Answer

Incorrect. Rotary Kelly Cocks are used with rotary drilling systems.

b) Top Drive Kelly Cock.

Answer

Correct! Top Drive Kelly Cocks are specifically designed for top drive systems.

c) Hydraulic Kelly Cock.

Answer

Incorrect. While some Top Drive Kelly Cocks use hydraulics, this is not a separate type.

d) Manual Kelly Cock.

Answer

Incorrect. Manual Kelly Cocks are usually associated with rotary drilling systems.

4. What is the significance of the Kelly Cock in drilling operations?

a) It is a purely decorative component.

Answer

Incorrect. The Kelly Cock has a critical role in drilling operations.

b) It is essential for drilling safety and efficiency.

Answer

Correct! Proper Kelly Cock function is crucial for both drilling safety and productivity.

c) It is only used in specific drilling environments.

Answer

Incorrect. The Kelly Cock is a standard component in most drilling operations.

d) It is a recent innovation in drilling technology.

Answer

Incorrect. The Kelly Cock has been a vital part of drilling operations for decades.

5. Which of the following is NOT a reason why maintaining a functional Kelly Cock is important?

a) Preventing fluid loss from the wellbore.

Answer

Incorrect. The Kelly Cock helps control fluid flow and prevent loss.

b) Ensuring accurate drilling fluid analysis.

Answer

Incorrect. The Kelly Cock allows for drilling fluid sampling.

c) Preventing blowouts.

Answer

Incorrect. The Kelly Cock helps maintain pressure and prevent blowouts.

d) Increasing the rate of penetration.

Answer

Correct! While the Kelly Cock indirectly influences the rate of penetration by controlling fluid flow, its primary function is not to increase drilling speed.

Kelly Cock Exercise:

Scenario:

You are a drilling supervisor on a rig using a top drive system. The drill string is stuck, and you suspect it's due to a problem with the Kelly Cock.

Task:

  1. Identify three possible causes for the stuck drill string related to the Kelly Cock.
  2. Explain how each cause could lead to the drill string getting stuck.
  3. Describe the steps you would take to troubleshoot and potentially resolve the issue.

Exercice Correction

Here's a possible solution:

1. Possible Causes:

  • Kelly Cock Valve Stuck Closed: The Kelly Cock valve may be stuck in the closed position, preventing the flow of drilling fluid and creating a pressure differential between the wellbore and the drill string, leading to the string becoming stuck.
  • Kelly Cock Valve Not Fully Open: The valve may not be completely open, restricting fluid flow and causing a build-up of pressure above the stuck point.
  • Kelly Cock Internal Damage: There may be damage or debris within the Kelly Cock valve itself, obstructing fluid flow and causing pressure build-up.

2. How Each Cause Leads to Stuck Drill String:

  • Stuck Closed: When the valve is closed, fluid pressure in the wellbore can build up, pressing the drill string against the walls and causing it to get stuck.
  • Not Fully Open: Restricted fluid flow creates a pressure difference between the wellbore and the annulus, leading to pressure build-up and potential sticking.
  • Internal Damage: The obstruction in the valve creates a blockage, preventing fluid circulation and leading to pressure build-up and sticking.

3. Troubleshooting Steps:

  • Check for Proper Valve Operation: Verify that the Kelly Cock valve is open and operates smoothly. This may involve manually opening and closing the valve, ensuring it moves freely.
  • Check for Pressure Build-Up: Monitor the pressure gauge on the mud pump and compare it to the pressure in the wellbore to determine if there is a pressure difference.
  • Inspect for Damage: Visually inspect the Kelly Cock for signs of damage or debris.
  • Attempt to Flush the Valve: Try to flush the Kelly Cock with fluid to clear any obstructions.
  • Replace the Valve (If Necessary): If damage is suspected, replace the Kelly Cock with a new one.

Note: This is a simplified exercise. A real-world situation would require further investigation and potentially involve specialists. It's important to follow proper safety procedures and adhere to the rig's emergency procedures when dealing with stuck drill strings.

Books

  • Petroleum Engineering: Drilling and Well Completions by John Lee
  • Drilling Engineering: Principles, Practices and Applications by M.K. Chatterjee
  • Modern Drilling Fluids by Robert F. Mitchell

Articles

  • Drilling Fluid Systems and Practices by SPE (Society of Petroleum Engineers)
  • Drilling Basics: The Anatomy of a Drilling Rig by Schlumberger
  • Understanding Drilling Fluid and Its Importance by Oilfield Technology

Online Resources

  • SPE website: https://www.spe.org/
  • Schlumberger website: https://www.slb.com/
  • Oilfield Technology website: https://www.oilfieldtechnology.com/

Search Tips

  • Use specific keywords like "Kelly Bushing", "Drilling Rig Components", "Drilling Fluid Control Valves".
  • Include keywords related to drilling operations, like "rotary drilling", "top drive drilling".
  • Use "site:" to specify websites, like "site:spe.org drilling fluid".

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