Dans le monde de l’exploration pétrolière et gazière, l’accès aux précieux hydrocarbures piégés dans les profondeurs de la terre nécessite un processus soigneusement orchestré. L’une des étapes cruciales de ce processus est la **complétion**, qui consiste à préparer le puits à la production après le forage. Une technique de complétion courante et efficace est la **complétion gainée et perforée**.
Le processus :
Interprétation des diagraphies et ciblage :
La clé du succès d’une complétion gainée et perforée réside dans l’**interprétation des diagraphies**. Divers outils de diagraphie sont utilisés pour recueillir des données sur la formation pendant le processus de forage. Ces diagraphies fournissent des informations sur :
Ces informations sont ensuite utilisées pour déterminer les **zones productives** les plus prometteuses, c’est-à-dire les intervalles de la formation où les hydrocarbures sont les plus susceptibles d’être présents en quantités significatives. Les perforations sont placées stratégiquement dans ces zones productives pour maximiser la production.
Avantages de la complétion gainée et perforée :
Conclusion :
La complétion gainée et perforée est une technique largement utilisée et efficace dans la production pétrolière et gazière. Elle combine les avantages du gainage pour la stabilité et l’isolation du puits avec l’approche ciblée des perforations, maximisant la production des zones les plus prometteuses. En utilisant l’interprétation des diagraphies pour identifier ces zones, les opérateurs peuvent assurer une extraction efficace et durable des hydrocarbures.
Instructions: Choose the best answer for each question.
1. What is the primary purpose of the casing in a cased and perforated completion? a) To prevent the wellbore from collapsing. b) To isolate different geological zones. c) To protect the wellbore from corrosion. d) All of the above.
d) All of the above.
2. How are perforations used in a cased and perforated completion? a) To create a pathway for drilling fluid to flow. b) To allow hydrocarbons to flow from the reservoir into the wellbore. c) To strengthen the wellbore. d) To prevent the casing from corroding.
b) To allow hydrocarbons to flow from the reservoir into the wellbore.
3. What information is used to determine the best locations for perforations? a) Seismic data. b) Wellbore pressure readings. c) Log interpretation data. d) Fluid flow rates.
c) Log interpretation data.
4. What is a "pay zone" in the context of a cased and perforated completion? a) The section of the wellbore where the casing is cemented. b) The interval within the formation where hydrocarbons are most likely to be present in significant quantities. c) The depth at which the wellbore intersects the target reservoir. d) The zone where the perforations are created.
b) The interval within the formation where hydrocarbons are most likely to be present in significant quantities.
5. Which of the following is NOT a benefit of using a cased and perforated completion? a) Increased production. b) Reduced wellbore instability. c) Enhanced well control. d) Increased risk of wellbore collapse.
d) Increased risk of wellbore collapse.
Scenario: You are an engineer working on a new oil well. The log interpretation data shows a thick, porous and permeable reservoir at a depth of 3,500 meters. The reservoir contains a high percentage of oil saturation.
Task: Design a cased and perforated completion strategy for this well. Consider the following factors:
Here's a possible completion strategy: **Casing size and type:** A 9 5/8" casing with a high yield strength steel (e.g., J-55) would be suitable for this depth and expected pressures. **Cementing:** A class "H" cement with a high density would be used to ensure good cement bond and zonal isolation. Special considerations include using a cement slurry with a low water content and adding a retarder to allow for proper placement. **Perforation intervals:** Based on the log data, the perforations should be placed within the entire thickness of the reservoir (3,500 meters). **Perforation design:** The perforation size should be large enough to allow for efficient flow but small enough to prevent excessive damage to the formation. A 0.50 inch diameter perforation with a 12 shots per foot density could be used. This is just an example, and the actual design would depend on more specific factors like formation characteristics and operational requirements.
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