Technology Well integrity behind casing is highly related to cement bond quality. Poor bond often leads to cross flow, sustained casing pressure and reduced production. Even a good bond may not prevent from a gas migration. Conventionally, section milling is deployed to fix the integrity. Section milling means multiple runs of tubing deployment and debris wash out operations. And it is also risk concern to accidently break the formation during the cement squeeze. In general, operator dare not to deploy section milling unless it has to. EverGreen deploys PWC to replace section milling. PWC is a terminology of a sequence of perforation, wash out and cement displacement in one run. When PWC is deployed,  Casing is not milled but kept a barrier to protect integrity
A 50m poor bond section will be selected to 2nd cementing After perforated, cement debris behind casing will be fully washed out And cement will be displaced into the perf zones without any squeezing After cementing, the integrity behind casing is re-established Only 12 hours for whole PWC operation Application Over 100 jobs have been performed and save operator rig time and investment. Risk assessment is greatly improved. |