Assessment of CO2 Storage Resources in Depleted Oil and Gas Fields in the Ship Shoal Area, Gulf of Mexico

The Gulf of Mexico is one of the most important regions in the United States for energy resources and infrastructure. Gulf of Mexico federal offshore oil and gas production accounts for 17% of total U.S. crude oil production and 5% of total U.S. gas production.  Over 45% of total U.S. petroleum refining capacity is located along the Gulf coast, as well as 51% of total U.S. natural gas processing plant capacity.  This region presents an excellent combination of high need and significant opportunity for large scale geologic storage of CO₂.

 The primary goal of this project is to characterize the Pliocene and Miocene sediments of the depleted oil/gas fields of the Ship Shoal Area for high volume CO₂ storage.  The Ship Shoal Area is located about 20 miles offshore Louisiana, in federal waters.  It is part of a very extensive trend (more than 400 square miles) of significant hydrocarbon bearing sediments.  This area contains a number of depleted oil and gas fields either currently abandoned, or planned for abandonment by 2025, which provide very significant potential CO₂ storage capacity.  These fields are related to anticlines formed by deep seated diapiric movement of salt. 

 GeoMechanics Technologies is nearing the end of a two-year research project supported by the Department of Energy under Award Number DE-FE0026041.  We have performed a detailed geologic review of the northern Ship Shoal region, consulting publically available geologic literature, horizon maps and well logs.  We have analyzed the CO₂ storage potential of Ship Shoal Block 84 and 107 fields, by developing high resolution 3D geologic models and integrated fluid flow and geomechanical models for the fields.  

 Many of the depleted oil and gas fields in the Ship Shoal area and other GOM areas are found in structural traps related to salt domes. Repressurization due to CO₂ injection may modify stresses and pore pressure in bounding faults, introducing some risk for fault reactivation.  These geomechanical effects are important factors in assessing risk and safe injection volume for such structures, thereby improving the accuracy of the prospective storage resource estimation. 

 The objective of this project was to characterize in detail the Neogene delta sands of the northern Ship Shoal area for large scale CO₂ sequestration through a research program that included:

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Comprehensive evaluation of storage capacity, seals, and risk assessment for the Ship Shoal area,

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Evaluation of all available well logs from exploration and development wells, and all available geologic and geophysical data in the public domain,

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Development of 3D geologic models to depict as accurate as possible a representation of the subsurface geology, to support the prediction of CO₂ storage capacity,

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Development of CO₂ injection model to simulate CO₂ migration and containment,

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Development of 3D geomechanics modeling to simulate induced stresses due to CO₂ injection on surrounding area, and study the potential of fault reactivation risk,

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Analysis of existing infrastructure of oil and gas for CO₂ transportation from source to sink and recommendation of a transportation pipeline corridor.