Set-Through Completion

Test Your Knowledge

Set-Through Completion Quiz

Instructions: Choose the best answer for each question.

1. What is the primary characteristic of a set-through completion? a) The casing is perforated at the producing zone before cementing. b) The casing is run through the producing zone without perforating. c) Multiple casing strings are used for different zones. d) The production tubing is run outside the casing.

2. Which of the following is NOT an advantage of a set-through completion? a) Simplified operation b) Cost-effectiveness c) Enhanced zonal isolation d) Improved wellbore stability

3. What is a potential disadvantage of set-through completion? a) Limited production capacity b) Increased risk of wellbore collapse c) Cement squeeze into the producing formation d) Difficulty in running production tubing

4. In which scenario is set-through completion most likely to be suitable? a) A well with multiple producing zones at different pressures b) A well with a single, uniform producing zone c) A well with complex reservoir characteristics d) A well with a high risk of wellbore instability

5. Why is set-through completion considered a valuable technique in the oil and gas industry? a) It eliminates the need for cementing. b) It allows for greater flexibility in isolating different zones. c) It offers a simple, cost-effective, and flexible approach for many wells. d) It is the only suitable method for deep reservoirs.

Set-Through Completion Exercise

Scenario: You are a well engineer tasked with selecting a completion method for a new well. The well will target a single, shallow, and homogeneous oil reservoir. The production requirements are straightforward, and the focus is on minimizing costs.

Task:

1. Based on the information provided, would a set-through completion be a suitable option for this well? Why or why not?
2. Briefly discuss any potential concerns or challenges that might arise with using a set-through completion in this scenario.

Techniques

Set-Through Completion: A Detailed Exploration

Chapter 1: Techniques

Set-through completion involves running a single casing string through the entire productive interval, followed by cementing. The process can be broken down into several key steps:

1. Drilling and Casing Running: The well is drilled to the total depth, and the casing string is run through the entire productive zone. This requires careful planning to ensure sufficient casing strength and integrity. The casing is typically larger diameter to accommodate the production tubing.

2. Cementing: After the casing is run, a cement slurry is pumped down the annulus (the space between the casing and the wellbore). The cement displaces the drilling mud and creates a strong, impermeable seal around the casing. The quality of the cement job is crucial to prevent fluid migration and maintain wellbore integrity. Various cementing techniques (e.g., centralizers, spacers) are employed to ensure complete coverage.

3. Cementing Evaluation: After cementing, various techniques (e.g., cement bond logs) are used to evaluate the quality of the cement job. This ensures the cement has adequately sealed the annulus and prevents potential problems later.

4. Tubing Running: Once the cement has set, the production tubing is run inside the casing. The tubing conveys the produced hydrocarbons to the surface.

5. Perforating: Finally, perforations are created in the casing at the desired depth within the producing zone. This is done using shaped charges or other perforating methods to create channels for hydrocarbon flow into the wellbore. Precise perforation placement is crucial for optimizing production.

Chapter 2: Models

Predictive models are used to assess the feasibility and performance of set-through completions. These models consider several factors:

• Reservoir characteristics: Permeability, porosity, pressure, and fluid properties are key parameters. Numerical reservoir simulation can predict production rates and pressure responses.

• Wellbore stability: Models assess the risk of wellbore instability, such as shale swelling or sand production, due to the pressure changes caused by production. This often involves geomechanical modeling to determine the stress state around the wellbore.

• Cement behavior: Models predict cement properties, such as compressive strength and permeability, to ensure a sufficient seal. This helps prevent cement channeling or fluid migration.

• Tubing design: Models assess the integrity of the production tubing under various operating conditions, ensuring the tubing can withstand pressure and temperature changes.

These models often use Finite Element Analysis (FEA) or other computational methods to simulate the complex interactions between the reservoir, wellbore, and completion components.

Chapter 3: Software

Several software packages are used for planning and analyzing set-through completions:

• Reservoir simulators: These programs (e.g., Eclipse, CMG) model fluid flow and pressure behavior in the reservoir. They are used to predict production performance and optimize well placement and completion design.

• Geomechanical simulators: These programs (e.g., Abaqus, Rocscience) model the stress and strain in the wellbore and surrounding formation. They are used to assess the risk of wellbore instability and optimize casing design.

• Cement modeling software: Specific software packages are available to model the properties and behavior of cement slurries and predict the quality of the cement job.

• Completion design software: Software packages specifically designed for well completion design can streamline the process and integrate information from reservoir, geomechanical, and cement models.

Chapter 4: Best Practices

Optimal set-through completion requires adherence to several best practices:

• Thorough pre-job planning: Careful planning, considering reservoir characteristics, wellbore stability, and cement properties, is crucial.

• High-quality cementing: The cement job must be carefully executed to ensure a complete seal, preventing fluid migration and maintaining wellbore integrity. Careful selection of cement slurries and proper placement techniques are essential.

• Optimized perforation design: Perforation placement and density should be optimized to maximize hydrocarbon production while minimizing formation damage.

• Regular monitoring and maintenance: Post-completion monitoring, including pressure and production data, can help detect and address any potential problems.

• Continuous improvement: Lessons learned from previous completions should be used to improve future operations.

Chapter 5: Case Studies

(This section would contain examples of successful and unsuccessful set-through completions, highlighting the factors that contributed to the outcome. Each case study would ideally include details such as reservoir properties, completion design, operational challenges, and the overall results. Specific examples would be necessary to populate this section. For example, a case study could detail a successful completion in a shallow, homogenous reservoir, contrasting with a less successful outcome in a fractured reservoir with multiple zones requiring isolation.)