Case Study: Verifying Subsurface Safety for Commercial Redevelopment – Placentia, CA
Turnkey Oil Well Excavation, Methane Sniff Testing, and CalGEM Compliance Alignment
THE CHALLENGE
A commercial redevelopment site required confirmation that buried oil wells posed no active gas leak risk.
Complications:
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Deeply Buried Assets: Wells were buried ~11.5 feet below grade.
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Strict State Mandates: Required strict adherence to California Geologic Energy Management Division (CalGEM) guidelines.
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Multi-Agency Oversight: Additional oversight from local fire authority and state regulators.
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Development Viability at Stake: Risk of methane or H2S leakage impacting site safety and development viability.
SOLUTION
Terra-Petra managed the process from location through validation.
Key Actions:
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Wellhead Exposure Support: Directed excavation to accurately locate buried well casings.
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Regulatory Standard Inspections: Performed leak testing and emissions monitoring per regulatory standards.
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Comprehensive Field Diagnostics: Conducted:
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Combustible gas testing at well heads
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Background air sampling
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Bubble leak testing to detect pressure-driven gas release
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Agency Coordination: Coordinated all work under CalGEM supervision to ensure compliance.
OUTCOME
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Zero Combustible Gas Detection: No detectable combustible gas at the well heads (< 1 ppmv).
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Normal Ambient Baselines: Background levels confirmed at 0.1–0.2 ppmv (within normal range).
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No Toxic Hydrogen Sulfide: No hydrogen sulfide detected.
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Total Casing Integrity: No evidence of pressure leaks (no bubble formation).
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Building Permit Hold Released: Site cleared from a soil gas risk standpoint, supporting redevelopment
THE TAKEAWAY
You don’t guess on subsurface risk — you prove it.
Terra-Petra brings precision testing + regulatory alignment to validate site conditions, so developers can move forward with confidence, not assumptions.
Explore our complete suite of Oil Well Due Diligence Services to map out your site’s path forward.