Patch (tubular)

Test Your Knowledge

Tubular Patches Quiz

Instructions: Choose the best answer for each question.

1. What is the primary purpose of a tubular patch? a) To replace a damaged section of tubing string. b) To prevent corrosion in tubing strings. c) To increase the production rate of a well. d) To repair localized damage in a tubing string.

2. Which of the following is NOT a common type of tubular patch? a) Sleeve patch b) Ring patch c) Full-bore patch d) Connector patch

3. How are tubular patches typically installed? a) Using a crane to lift the patch into the wellbore. b) Through a wellhead connection using wireline or coiled tubing. c) By drilling a new hole next to the damaged section. d) By connecting a new section of tubing to the existing string.

4. What is a key advantage of using tubular patches over pulling the entire tubing string? a) They are more effective at repairing severe damage. b) They are more environmentally friendly. c) They are more expensive than pulling the entire string. d) They require more time to install than pulling the entire string.

5. Which of the following factors can limit the effectiveness of tubular patching? a) The diameter of the tubing string. b) The depth of the wellbore. c) The severity of the damage to the tubing. d) The location of the well.

Tubular Patches Exercise

Scenario: An oil well is experiencing a production decline due to a pinhole leak in the tubing string. The leak is located 2,000 feet below the surface. The well operator is considering using a tubular patch to repair the leak.

Task:

1. Identify the type of tubular patch that would be most suitable for this scenario. Explain your reasoning.
2. Describe the installation process of the chosen patch.
3. List three potential benefits of using a tubular patch in this situation.
4. Identify one potential limitation of using a tubular patch for this specific leak.

Techniques

Patching Up Trouble: Understanding Tubular Patches in Oil & Gas

This document expands on the provided introduction, breaking down the information into separate chapters focusing on techniques, models, software, best practices, and case studies related to tubular patches.

Chapter 1: Techniques

Tubular patch installation involves several key techniques, the choice of which depends on factors like well conditions, the severity of damage, and available equipment. The primary methods include:

• Wireline deployment: This is a common method for deploying patches, especially in deeper wells. A wireline unit lowers the patch into the wellbore, positioning it accurately over the damaged section. The patch is then expanded or secured using a variety of mechanisms.

• Coiled tubing deployment: Coiled tubing offers greater flexibility and maneuverability, particularly useful in deviated wells or for accessing challenging locations. The patch is conveyed downhole on a continuous coil of tubing and then deployed.

• Mechanical Expansion Techniques: Many patches rely on mechanical expansion to create a tight seal against the tubing wall. This might involve hydraulic expansion, using internal mandrels or inflatable elements, or mechanical expansion using tapered sleeves or wedges. The chosen method depends on the patch design and the available equipment.

• Elastomeric Sealant Application: In some cases, an elastomeric sealant is used in conjunction with the mechanical expansion or as a primary sealing mechanism. This sealant conforms to the irregularities of the tubing surface, ensuring a secure, leak-proof seal. The sealant's properties are critical to its success in high-pressure, high-temperature environments.

• Patch Setting and Verification: After deployment, the successful setting of the patch needs to be verified. This usually involves pressure testing to ensure the integrity of the seal. Downhole tools may be used to inspect the patch's placement and condition.

Chapter 2: Models

Various models of tubular patches exist, each designed for specific applications and damage scenarios. Key distinctions are based on:

• Sleeve Patches: These are cylindrical sleeves that encapsulate the damaged area. They are typically used for relatively minor corrosion or wear issues. They come in various lengths and diameters.

• Ring Patches: Used for localized defects, like pinholes or small cracks. These are smaller than sleeve patches and offer a more targeted repair.

• Full-Bore Patches: These patches completely encircle the tubing's interior diameter. They are ideal for substantial damage or when multiple repairs are necessary within a short section of tubing.

• Expandable Patches: These utilize a mechanism (hydraulic, mechanical, or thermal) to expand and create a tight seal once in place. This is advantageous in situations where precise placement is challenging.

• Material Considerations: Patch materials vary based on the well's environment. Common materials include high-strength alloys (stainless steel, duplex stainless steel), composite materials (fiberglass-reinforced polymers), and elastomers (for sealing). The selection of materials must account for corrosion resistance, high-temperature tolerance, and pressure limitations.

Chapter 3: Software

Software plays an important role in planning and executing tubular patch interventions. Specialized software packages can:

• Simulate patch deployment: Modeling the deployment process helps optimize placement and predict potential challenges.

• Assess patch performance: Simulate the patch's behaviour under varying pressure and temperature conditions.

• Analyze wellbore geometry: Software can integrate wellbore data to ensure accurate patch placement and proper sizing.

• Design custom patches: Some software enables the design of custom patches tailored to specific well conditions and damage types.

• Optimize intervention planning: Software helps optimize the overall operation, minimizing non-productive time and associated costs.

Chapter 4: Best Practices

Successful tubular patching requires adherence to best practices:

• Thorough pre-job planning: This includes careful assessment of the damage, selection of the appropriate patch type, and detailed planning of the deployment procedure.

• Accurate damage assessment: Employing advanced inspection techniques (e.g., caliper logging, ultrasonic inspection) is crucial for accurately characterizing the extent and nature of the damage.

• Proper patch selection: The patch must be compatible with the tubing material, well conditions (temperature, pressure, corrosive environment), and the type and severity of the damage.

• Rigorous quality control: Ensuring the quality of the patch materials and its proper installation is vital for the long-term success of the repair.

• Post-intervention monitoring: Regular monitoring of the well after the patch installation is crucial to detect any potential problems.

Chapter 5: Case Studies

(This section would include specific examples of successful and unsuccessful tubular patch deployments. Each case study should detail the well conditions, type of damage, the patch used, the intervention process, and the outcomes. This section requires specific data which isn't available in the provided text.) For example, a case study might cover:

• Case Study 1: A successful repair of corrosion damage in a high-pressure well using an expandable sleeve patch. Details would be included on the patch material, deployment method, and long-term performance.

• Case Study 2: A challenging intervention where initial attempts to patch a severely corroded section failed. The reasons for failure and the ultimate successful repair strategy would be analyzed. This would highlight the importance of proper pre-job planning and risk assessment.

This expanded structure provides a more comprehensive understanding of tubular patches in the oil and gas industry. Remember that the Case Studies chapter requires specific real-world examples to be truly informative.