Spear Fishing: The Art of Retrieving Lost Pipe in the Oil and Gas Industry
The oil and gas industry is a complex and challenging one, with many risks and uncertainties. One of the most challenging aspects of drilling and well completion is the potential for equipment loss, specifically the loss of pipe within the wellbore. This can happen for a variety of reasons, such as:
- Stuck Pipe: Pipe may become stuck due to various factors, such as differential sticking, torque and drag, or unexpected formation conditions.
- Pipe Breakage: Stress on the pipe due to extreme conditions, corrosion, or mishandling can lead to pipe breakage.
- Part of the string becoming detached: A connection failure, or improper installation can lead to a portion of the drilling string becoming detached.
When this happens, it can cause significant delays and expenses, as well as posing safety risks. Fortunately, a range of specialized tools and techniques have been developed to address this problem. One such tool is the spear, a simple but effective fishing tool designed to retrieve lost pipe.
Spear Fishing: A Targeted Approach
A spear is a simple, yet powerful tool used in fishing operations. It consists of a body with multiple prongs or tines that extend out. The spear is lowered down the hole and into the pipe being fished. The prongs are designed to engage with the lost pipe, often the tool joint, allowing it to be retrieved back to the surface.
Here's a simplified breakdown of the process:
- Lowering the Spear: The spear is attached to a wireline or coiled tubing and lowered down the wellbore.
- Engagement: The spear is guided into the open end of the lost pipe, engaging with the tool joint using its prongs.
- Retrieving the Pipe: The spear is then lifted, pulling the lost pipe with it back to the surface.
Types of Spears
There are several types of spears, each designed to suit different situations:
- Single-tine spear: This type features a single, large prong for engaging the tool joint.
- Multi-tine spear: These spears have multiple prongs for a more secure grip on the pipe.
- Swivel spear: This type features a swivel head that allows for a wider range of engagement angles.
Advantages and Limitations of Spear Fishing
Spear fishing offers several advantages:
- Simple and Effective: Spears are relatively simple to use, yet very effective in retrieving lost pipe.
- Versatility: Spears can be used in a variety of well conditions and with different types of lost pipe.
- Cost-effective: Compared to other fishing techniques, spear fishing can be more cost-effective, particularly for less complex situations.
However, spear fishing also has some limitations:
- Limited Application: Spears are primarily effective for retrieving pipe that is relatively accessible and intact.
- Risk of Damage: If the spear is not correctly engaged, it can damage the lost pipe, making retrieval more difficult.
- Risk of Dropping: If the connection fails, the spear and the lost pipe could be lost again.
Conclusion
Spear fishing is an important tool in the oil and gas industry for retrieving lost pipe. While it is not a foolproof solution, it offers a simple and effective approach for many situations. Understanding the advantages and limitations of spear fishing, as well as the various types of spears available, allows for informed decision-making in the complex and challenging world of well completion.
Test Your Knowledge
Spear Fishing Quiz
Instructions: Choose the best answer for each question.
1. What is the primary purpose of a spear in the oil and gas industry? a) To drill new wells. b) To retrieve lost pipe. c) To stimulate oil production. d) To prevent pipe corrosion.
Answer
b) To retrieve lost pipe.
2. Which of the following is NOT a reason why pipe might become lost in a wellbore? a) Stuck pipe. b) Pipe breakage. c) Excessive well pressure. d) Part of the string becoming detached.
Answer
c) Excessive well pressure.
3. What is a key advantage of spear fishing compared to other pipe retrieval techniques? a) It is the most reliable method for retrieving lost pipe. b) It can be used in any well condition. c) It is generally more cost-effective. d) It is less likely to damage the lost pipe.
Answer
c) It is generally more cost-effective.
4. What type of spear would be most suitable for retrieving a lost pipe with a complex tool joint? a) Single-tine spear. b) Multi-tine spear. c) Swivel spear. d) None of the above.
Answer
b) Multi-tine spear.
5. What is a potential limitation of spear fishing? a) It requires specialized equipment that is not widely available. b) It is only effective for retrieving pipe that is relatively intact. c) It can only be used in shallow wells. d) It is a very slow process.
Answer
b) It is only effective for retrieving pipe that is relatively intact.
Spear Fishing Exercise
Scenario:
A drilling crew has lost a section of pipe in the wellbore. The lost pipe is approximately 100 feet down and appears to be intact. The crew wants to attempt to retrieve the lost pipe using a spear.
Task:
- Identify the type of spear most appropriate for this situation.
- Explain why you chose this particular type of spear.
- List two potential risks associated with using a spear to retrieve the lost pipe.
Exercice Correction
**1. Type of Spear:** A **multi-tine spear** would be the most appropriate for this scenario. **2. Explanation:** A multi-tine spear offers a more secure grip on the tool joint of the lost pipe compared to a single-tine spear. This is especially important if the pipe is intact and the tool joint is relatively accessible. **3. Potential Risks:** * **Damage to the lost pipe:** If the spear isn't correctly engaged, it can potentially damage the tool joint or the pipe itself, making retrieval even more difficult. * **Loss of the spear and lost pipe:** If the connection between the spear and the wireline fails, the spear and the lost pipe could be lost again.
Books
- "Petroleum Engineering: Drilling and Well Completions" by Robert C. Earlougher Jr. and Thomas K. F. Klett (This book provides comprehensive coverage of drilling and completion operations, including sections on fishing and retrieval techniques.)
- "Well Completion Design and Operations" by Michael J. Economides and Kenneth G. Nolte (This book offers detailed information on well completion practices, including chapters on fishing tools and methods.)
- "Oil Well Drilling and Production" by William C. Lyons (This book covers various aspects of drilling and production, including a chapter dedicated to fishing techniques.)
Articles
- "Fishing Tools and Techniques" by The American Petroleum Institute (API) (Search for specific API publications on fishing operations for detailed information on tools and practices.)
- "Lost Circulation Control and Fishing" by SPE (Society of Petroleum Engineers) (Search for SPE publications on fishing operations for case studies and technical papers.)
- "A Review of Fishing Tools and Techniques" by Journal of Petroleum Technology (Search for articles on fishing operations in JPT for a review of existing technologies and innovations.)
Online Resources
- API (American Petroleum Institute): www.api.org
- SPE (Society of Petroleum Engineers): www.spe.org
- IADC (International Association of Drilling Contractors): www.iadc.org
- Schlumberger: www.slb.com
- Halliburton: www.halliburton.com
- Baker Hughes: www.bakerhughes.com
Search Tips
- Use specific keywords: Include terms like "fishing tools," "lost circulation control," "retrieval techniques," "spear fishing," "oil and gas drilling," etc.
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- Use quotation marks: "spear fishing" will only show results with that exact phrase.
- Refine your search with operators: Use "site:" to search within a specific website (e.g., "site:spe.org fishing tools").
- Use advanced search operators: Explore Google's advanced search options for further refinement.
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