GIS-based Wellbore Geometry Analysis: Evaluating Recompletion Potential in the Eagle Ford Play

Christian McLellan

May 31, 2019

Introduction

• Geospatial Analyst – ConocoPhillips – Geospatial and Information Management• Master of Geoscience GIST – Texas A&M University• Hail from San Antonio• I have a dog named Cooper• Sagittarius• May 2019 horoscope: “Expect life to be busy in May, with sudden developments that

push your boundaries and shake up the natural order of things or your routines. But there will be plenty of moments of passion and excitement and time to savor life and enjoy the process. ”

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Background Information and Terms

• Completing a well (hydraulic fracturing) varies in results for hydrocarbon recovery.• One factor in the success or failure can be the wellbore geometry.• A wellbore’s geometry looks at the as-drilled pathway of the well drilled in the

subsurface.• Tortuosity Index is a calculated value that ranks the quality of a wellbore’s geometry.• The tortuosity index calculation requires amplitude where the wave is the as-drilled

path of the well and the base is the desired well plan (straight path).

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Y = Amplitude

Project Forecast

• In this project, GIS is used to evaluate the wellbore geometry of every well in the Eagle Ford.

• The process includes spatial data gathering, processing with Python & FME and visualizing in ArcGIS.

• Why evaluate wellbore geometry?• Competitor Analysis.

• Evaluate drilling practices.• Acquisition assessment for recompleting drilled wells.

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Timeline of a Well

• Planning• Well plans dictate where a well is going to drill.

• Drilling• Directional survey is collected during drilling.

• Completions• Hydraulic fracturing

• Completions and Recompletions can be negatively impacted by a wellbore’s geometry.

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https://www.croftsystems.net/oil-gas-blog/conventional-vs.-unconventional

• 27 counties total in southern Texas have Eagle Ford wells.

• The path of a drilled unconventional well (i.e. directional survey) is public data made available by the Texas Railroad Commission.

• The directional survey dataset is approximately 3 million points.

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http://www.rrc.state.tx.us/oil-gas/major-oil-and-gas-formations/eagle-ford-shale-information/

The Challenge

• Can geospatial analysis be used to evaluate wellbore geometry at a field-wide scale?• Tortuosity Index calculated from the number waves in a well path and the average amplitude of

those waves. The index value lets you know how much risk there will be in mechanically recompleting a wellbore.

• Can a 2D map view approach tell us enough about a wellbore’s geometry?• Do we need to examine the 3D subsurface direction of a wellbore? Inclination and Azimuth.

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X, Y, MD, Inclination, Azimuth2D

Data Collection and Processing

• Collect and groom directional surveys from data vendor.• Filter out the vertical section of the well.• Create a baseline to determine the amplitude of survey

points with geoprocessing .• Calculate 2D and 3D tortuosity index with Python script

going through the ~3 million points.• Create visualizations with ArcGIS.

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Azimuth Waves

• The amount of Azimuth waves are used to calculate the 2D and 3D tortuosity

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Number of AZM Waves

Low AZM Waves

High AZM Waves

Medium AZM Waves

Eagle Ford – South TX CountiesEach point represents a well

Amplitude Distance by Survey

• The distance between the survey point and the baseline.

• Shows a more detailed look at a well.

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Amplitude Distance

Low Distance

High Distance

Medium Distance

3D Tortuosity Index

• 3D tortuosity shows geologic trends.• Southern Eagle Ford is

known to have more faults.

• This can cause a biased data set across the region.

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Eagle Ford – South TX CountiesEach point represents a well

3D Tortuosity Index

Good 3D Index

Bad 3D Index

Cross Section

2D Tortuosity Index

• 2D tortuosity does not factor in geologic complexity and shows wellbore complexity caused by other issues such as bad drilling practices.

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2D Tortuosity Index

Good 2D Index

Bad 2D Index

Eagle Ford – South TX CountiesEach point represents a well

2D vs 3D Tortuosity Index

• 2D and 3D tortuosity can be used together to evaluate the geometry.

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Project Summary

• GIS can be used to evaluate wellbore geometry at a field-wide level.• The 2D and 3D index show a decent correlation together.• However, the 3D tortuosity index can cause a bias in the data when

analyzing a whole field with different ranges of geologic complexity.• The 2D index would be best used for field-wide evaluations.

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Future Work

• Incorporate additional datasets such as production data.• Increase the scope.

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https://pubs.usgs.gov/dds/dds-069/dds-069-q/text/introduction.htm

Thank you

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