WP5 Impact mitigation and remediation

photo credit - Jirapong Manustrong

The potential environmental impacts of geoenergy projects are always a consideration. These impacts relate to leakage from wells including CO2 and methane, or naturally occurring permeable pathways, or the potential for induced seismicity.

We will make use of a network of commercial, pilot and research-scale sites in Europe and internationally in order to demonstrate best practice and investigate new methods for predicting, avoiding or reversing environmental impacts.

Our research will be underpinned by laboratory measurements, which will be used to model field-scale scenarios. We will look at pipeline integrity and resilience, and ways to minimise damage to wells and rock, as part of geoenergy operations. The use of sealants and other remediation strategies will also be considered.

 

Outputs

Report on remediation strategies for tubings and casings (D5.3)

This report addresses several potential casing and tubing failure mechanisms in CO2 and shale gas wells, and will describe remediation strategies to maintain well integrity. The objectives of this report are to:

  • Describe the most common well barrier envelopes used for CO2 and shale gas wells based on the NORDSOK STANDARD D-010 concerning well integrity.
  • Review different casing and tubing failure mechanisms. The different mechanisms considered in the report are: abrasion, corrosion and mechanical loads during hydraulic fracturing in unconventional oil and gas operations
  • Review different remediation methods and technologies for failure of tubing and casing.
  • Outline planned laboratory testing to investigate tubing mechanical strength after remediation by cement squeeze. This activity will complement similar tests investigating cement fracturing and remediation, outlined in WP5 Deliverable D5.1.

Report on experiment-based knowledge on acoustic emission characteristics of CCS and shale gas operations and suggestions on how to mitigate seismicity for both (D5.2)

This report reviews Acoustic Emission (AE) laboratory tests designed to investigate mechanisms by which micro-seismicity arises in CCS and shale gas operations. The differences between the two subsurface operations are reviewed, in terms of the stress path leading to rock failure and acoustic emission.

Report on remediation strategies for tubings and cement sheaths (SECURe Report D5.1)

Well integrity is a relevant topic to the oil and gas industry and is equally important for CO2 storage projects. This report describes the well barrier approach to well integrity using the NORSOK D-010 standard, reviews possible leakage scenarios for CO2 wells and uses the same approach to address possible leakage scenarios from shale gas wells. Remediation strategies and technologies that can be applied to failure of tubing, casing and cement sheath are reviewed, including squeeze cementing; alternative sealing materials; and casing and tubing repair. Finally, the novel aspects of this work related to leakage remediation and alternative sealing materials are discussed, along with the experimental plan for the combined tasks in WP2 on risk assessment strategies and WP5 related to leakage remediation and testing of alternative sealants.

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