The volume of cuttings and produced waste, particularly produced water, will increase as brownfield developments progresses. Missing environmental and economic targets represent a major investment exposure. As a resut, there is an increasing demand on engineering to mitigate process risks and ensure injection and sound subsurface waste management.
This paper describes the outcome of pressure analysis successfully used for Cuttings Re-Injection (CRI) and disposal of produced water resulting from closely monitoring pressure injection and decline. It addresses proper root-cause engineering diagnostic processes that were implemented during abnormal pressures increases and restrictions observed during annulus injection in North Sea projects.
Severe risks were mitigated with injection pressures observed, on occasion above overburden, to maintain safe injection assurance. A methodology was developed and implemented, as a result of process mapping based on signature pressures from pressure decline. Their characterization represents a major step in mitigating risks posed by waste injection, providing not only engineering understanding valuable to overall drilling operations planning, but also minimizing potential environmental impact with sound engineering subsurface waste management.