Well Annular Isolation

Introduction 

An operator engaged NEXUS OFS to support a well integrity investigation for a suspended land-based producer showing sustained annulus pressure and surface gas venting. The client required a clear, data-driven recommendation on how to restore isolation—without mobilizing a rig—while meeting regulatory requirements and minimizing surface impact. 

Scope of Work 

• Evaluation of historical well files, cement bond logs, and annular pressure trends 

• Identification of potential leak paths (e.g., micro-annulus, poor cement, shallow gas) 

• Feasibility assessment of rigless intervention options 

Solution 

Based on data analysis and diagnostic evidence, NEXUS OFS recommended a three-phase approach: 

1. 1. Focused Diagnostics

• • • Deploy multi-finger caliper and ultrasonic tools to assess casing condition 

• • • Run noise and temperature logs to localize active gas channels 

1. 2. Remedial Strategy (Rigless)

• • • Utilize CT with inflatable straddle packer 

• • • Pump a gas-tight polymer sealant into the suspected leak zone 

• • • Avoid high-pressure operations to prevent further casing damage 

1. 3. Verification Plan

• • • Perform staged pressure testing of the A and B annuli 

• • • Monitor the casing vent over 72 hours post-sealant cure 

Value Delivered by NEXUS OFS 

• • Independent expert review free of operational bias 

• • Fit-for-purpose solution balancing technical, regulatory, and logistical constraints 

• • Accelerated decision-making through structured diagnostics and tool selection 

NEXUS OFS provides specialized consultancy in well integrity, completions, and subsurface diagnostics—helping operators reduce risk and optimize solutions before committing to costly interventions.