The release affected 42 ha and has been contained. Apache raised its estimate of the volume of produced water, from which hydrocarbons had been removed, to 15,400 cu m from an original estimate of 9,500 cu m. It has begun soil remediation.
Apache said sulfur gas from the produced water permeated an inner plastic liner of the pipeline, which is less than 5 years old, and attached to the four layers of steel bands protecting it. The pipe has an exterior plastic liner.
“Apache believes a pinhole in the exterior plastic liner allowed water to leak into the pipe, which mixed with the sulfur gas, causing stress corrosion cracking and the sudden failure of the pipe,” the company said in a statement. It said the failure occurred on May 5.
The company has treated more than 110,000 cu m of water from the area and released it to the environment. It has injected 80,000 cu m of affected water into the producing formation.
Zama is a carbon-dioxide enhanced oil recovery project.