Scorpion Plot

Test Your Knowledge

Scorpion Plot Quiz:

Instructions: Choose the best answer for each question.

1. What does the "tail" of a Scorpion Plot represent?

a) The cost of the workover b) The well's production after the workover c) The well's production before the workover d) The overall production decline of the well

2. What does a long, impactful "stinger" in a Scorpion Plot indicate?

a) The workover was unsuccessful b) The workover was highly profitable c) The workover cost more than the production gains d) The well's production declined rapidly after the workover

3. Which of the following is NOT a factor to consider when evaluating a Scorpion Plot?

a) The well's production history b) The type of workover performed c) The oil price at the time of the workover d) The reservoir characteristics of the well

4. A Scorpion Plot with a "flat stinger" might suggest that:

a) The workover effectively addressed the production decline b) The workover was extremely expensive c) The workover did not address the root cause of the decline d) The well is nearing the end of its production life

5. Why is the Scorpion Plot a valuable tool for workover analysis?

a) It simplifies the analysis of complex well data b) It visually displays the economic impact of a workover c) It predicts future production trends after a workover d) It eliminates the need for detailed well history analysis

Scorpion Plot Exercise:

Scenario:

You are reviewing two Scorpion Plots for different wells that underwent workovers.

• Well A: Shows a gradual decline in production before the workover (tail), a significant investment in the workover (body), and a steep increase in production immediately after the workover, followed by a gradual decline (stinger).
• Well B: Shows a steep decline in production before the workover (tail), a moderate investment in the workover (body), and a slight increase in production after the workover, followed by a continued decline (stinger).

Task:

Analyze the two Scorpion Plots and answer the following questions:

1. Which well experienced a more successful workover based on the Scorpion Plot?
2. What insights can you draw about the potential causes of the production decline in each well before the workover?
3. Which well would you recommend for further investment in workovers based on the Scorpion Plots?

Techniques

Chapter 1: Techniques for Constructing Scorpion Plots

The Scorpion Plot, as described previously, is a valuable tool for workover analysis. This chapter delves into the specific techniques used to construct these insightful plots.

1. Data Gathering:

• Production Data: Obtain historical production data for the well, including oil, gas, or water rates. This data should span a sufficient period before and after the workover.
• Workover Costs: Collect a detailed breakdown of all costs associated with the workover, including labor, materials, equipment, and permits.
• Time Stamps: Ensure accurate time stamps for both production data and workover costs, aligning them to provide a clear chronological representation.

2. Data Preparation:

• Normalizing Production Data: Standardize production rates to a common unit (e.g., barrels of oil equivalent per day). This enables consistent comparison across different wells or workovers.
• Cost Aggregation: Summarize the total workover cost into a single value representing the investment.
• Data Visualization Software: Utilize suitable software (e.g., Excel, MATLAB, Python) to handle data manipulation, plotting, and visualization.

3. Plot Construction:

• X-Axis: Represent time, spanning a period before and after the workover. This axis allows for the visualization of production trends over time.
• Y-Axis: Plot production rate on the left y-axis, and cost on the right y-axis. Ensure consistent scaling for both axes.
• Pre-Workover Tail: Plot production data prior to the workover, representing the well's declining performance.
• Workover Body: Mark the workover time period on the x-axis. Represent the total workover cost as a vertical bar extending upwards from the x-axis.
• Post-Workover Stinger: Plot production data post-workover, showcasing the impact of the intervention. The length and direction of this section reveal the workover's success.

4. Plot Interpretation:

• Stinger Length: A long, upward-trending stinger indicates significant production improvement, justifying the workover cost.
• Stinger Slope: A steep upward slope suggests a rapid production increase. A gradual slope suggests a slower recovery.
• Body Height: A high body indicates a significant investment in the workover. It must be accompanied by a substantial production increase for profitability.
• Flat Stinger: A flat stinger suggests the workover failed to address the production decline.
• Declining Stinger: A rapidly declining stinger indicates a short-term improvement followed by further production loss, suggesting underlying issues.

5. Additional Considerations:

• Data Quality: Ensure data accuracy and completeness. Poor data can lead to misleading plots and inaccurate conclusions.
• Well Specifics: Consider factors like reservoir characteristics, well completion, and production history. This context helps interpret the plot effectively.
• Sensitivity Analysis: Varying workover costs and production projections can assess the robustness of the economic decision.

Conclusion:

Constructing a Scorpion Plot requires careful data collection, preparation, and visualization. By mastering these techniques, operators gain valuable insights into workover performance, enabling informed decisions that maximize economic value.