Safe disposal of one million barrels of NORM in Louisiana through slurry fracture injection

During the past 50 years, storage pits and adjacent land around the Bay Marchand facility near Port Fourchon, Louisiana, had accumulated large deposits of nonhazardous drilling and production waste containing naturally occurring radioactive material (NORM). This material primarily included drill cuttings, drilling mud. produced sand. salt water, pipe scale. crude oil, and precipitates. To remediate this site, the operator chose to reinject the material into the deep subsurface through on-site slurry fracture injection (SFI). This process provided greater environmental security compared to alternative surface pit or landfill disposal and at a much lower cost than off-site transport and disposal options. More than 1 million barrels of pit soil and canal bottoms were safely disposed into a single well during 2 years of injection that concluded in March 2000. Solid waste was mixed with water to create a slurry and injected downhole at greater than the formation parting pressure into a weakly consolidated sandstone formation at depths from 4,400 to 5,000 ft. Injection operations were episodic, generally taking place for 11 hours per day, 5 days per week. This allowed the formation pressure to decline each day to the initial reservoir pressure. The project was designed and extensively monitored to maintain and verify containment within the permitted interval. Downhole pressure was continuously monitored, allowing analysis of daily falloff pressure. Waste containment was confirmed through a combination of shut-in pressure analysis and periodic step-rate tests, gamma logs, and temperature surveys. In addition to the improved environmental protection provided by this technology, the on-site operation was a fraction of the off-site disposal costs, This paper describes the project design and permitting, injection operations. containment monitoring and analysis, and projects economics.