Point bloqué, terme synonyme de point de gel, désigne la profondeur dans un puits où la colonne de forage, le tubage ou le casing se bloquent, interrompant les opérations de forage ou empêchant l'achèvement du puits. Ce scénario frustrant représente un défi majeur pour les professionnels du forage et de l'achèvement de puits, nécessitant souvent des mesures correctives coûteuses et longues.
Causes du Point Bloqué :
Comprendre les causes profondes des points bloqués est essentiel pour les prévenir et mettre en œuvre des solutions efficaces. Parmi les causes courantes, on trouve :
Impact du Point Bloqué :
Les points bloqués peuvent avoir un impact important sur les opérations de forage et d'achèvement de puits, conduisant à :
Stratégies de Prévention et d'Atténuation :
La prévention des points bloqués nécessite une approche multiforme :
Actions Correctives :
Lorsqu'un point bloqué se produit, diverses mesures correctives peuvent être employées pour libérer le tube :
Conclusion :
Le point bloqué est un défi persistant dans le forage et l'achèvement de puits. Comprendre ses causes, mettre en œuvre des mesures préventives et employer des stratégies correctives efficaces sont essentiels pour minimiser l'impact de ce problème sur les opérations de forage et maximiser le succès des projets.
Instructions: Choose the best answer for each question.
1. Which of the following is NOT a common cause of a stuck point?
a) Differential sticking b) Key seating c) Torque and drag d) Wellbore lubrication e) Formation collapse
The correct answer is **d) Wellbore lubrication**. While lubrication is important in preventing stuck points, it is not a direct cause.
2. What is the most likely outcome of a stuck point?
a) Increased well productivity b) Drilling delays and increased costs c) Improved wellbore stability d) Reduced risk of formation collapse e) Faster well completion
The correct answer is **b) Drilling delays and increased costs**. Stuck points necessitate time-consuming and expensive remedial actions.
3. Which of the following is a preventive measure for stuck points?
a) Using a single type of drilling fluid throughout the wellbore b) Proper selection of drilling fluids c) Ignoring wellbore pressure fluctuations d) Relying solely on traditional drilling techniques e) Ignoring formation characteristics during wellbore design
The correct answer is **b) Proper selection of drilling fluids**. Using appropriate drilling fluids minimizes differential sticking and promotes wellbore stability.
4. Which remedial action is a last resort option for freeing stuck pipe?
a) Circulation b) Drilling out c) Sidetracking d) Fishing
The correct answer is **c) Sidetracking**. It involves drilling a new wellbore to bypass the stuck pipe, which is costly and time-consuming.
5. Which of the following tools can assist in preventing or mitigating stuck points?
a) Downhole cameras b) Specialized drilling techniques c) Both a and b d) None of the above
The correct answer is **c) Both a and b**. Downhole cameras provide valuable information about wellbore conditions, and specialized drilling techniques can help minimize the risk of stuck points.
Scenario: A drilling crew encounters a stuck point while drilling through a shale formation. The stuck pipe is located at 8,500 feet depth. The crew suspects differential sticking due to pressure differences between the wellbore fluid and the formation.
Task: Based on the information provided, list at least 3 possible remedial actions the crew could take to free the stuck pipe. Explain why each action might be effective in this specific scenario.
Here are three possible remedial actions and explanations:
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