Writing and Publications

Chevron Safely Disposes One Million Barrels of NORM in Louisiana Through Slurry Fracture Injection

Reed , A . C ., Mathews , J . L ., Bruno , M . S ., Olmstead , S . E ., SPE 71434 Proc. 2001 Annual Tech. Conference, September 30 - October 3, 2001.

Abstract

During the past 50 years, storage pits and adjacent land around the Bay Marchand facility near Port Fourchon, Louisiana, had accumulated large deposits of non-hazardous drilling and production waste containing naturally occurring radioactive material (NORM). This material primarily included drill cuttings, drilling mud, produced sand, saltwater, pipe scale, crude oil and precipitates. To remediate this site, Chevron chose to re-inject the material into the deep subsurface through on-site Slurry Fracture Injection (SFI). This process provided greater environmental security than alternative surface pit or landfill disposal, and at much lower cost than off-site transport and disposal options.

More than 1 million barrels of pit soil and canal bottoms was safely disposed into a single well during two years of injection concluding in March 2000. Solid waste was mixed with water to create a slurry and injected down-hole above formation parting pressure into a weakly consolidated sandstone formation at depths from 4400 to 5000 feet. Injection operations were episodic, generally taking place for 11 hours per day, 5 days per week. This allowed formation pressure to decline each day to initial reservoir pressure. The project was designed and extensively monitored to maintain and verify containment within the permitted interval. Down-hole pressure was continuously monitored, allowing analysis of daily fall-off pressure. Waste containment was confirmed through a combination of shut-in pressure analysis, periodic step-rate tests, and periodic gamma logs and temperature surveys.

In addition to improved environmental protection provided by this technology, the on-site operation was a fraction of off-site disposal costs to Chevron. This paper describes the project design and permitting, injection operations, containment monitoring and analysis, and project economics.

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