Subsurface Containment Assurance Program - Key Element Overview and Best Practice Examples

Abstract

The goal of Subsurface Containment Assurance is to ensure that no environmental damage, damage to operated assets, or impacts on well operations (drilling or production) are incurred by leakage of production or injection fluids from their intended zones. Subsurface Containment Assurance involves the integrated efforts of the subsurface (reservoir and overburden characterization), the wells (planning, construction, well integrity and abandonment) and the operations (process and well operations and management of change) teams. Disciplines must act together to develop and implement a surveillance plan to proactively monitor containment during well and injection operations. The paper will describe the elements of a Subsurface Containment Assurance Program that are required for business units operating across the entire life cycle from exploration to mature developments. The program is designed to be comprehensive yet flexible, and focuses on the critical elements and risks for individual operating units. A consistent framework has been created and implemented that draws from existing tools for reservoir and overburden characterization and field management, and combines these tools to reduce the risk of unintended subsurface fluid containment loss. Specific assessment criteria and ranking approaches and tools for qualitative and quantitative estimation of containment risks will be reviewed. Lastly, practices for deepwater subsurface containment and implications for the oil and gas industry will be discussed.

An Independent Scientific Assessment of Well Stimulation in California Volume II: Potential Environmental Impacts of Hydraulic Fracturing and Acid Stimulations

“…Analysis discussed above has shown that induced fractures that connect with highpermeability structures, such as adjacent wells, are a potential pathway for the contamination of groundwater or the ground surface. Clearly, to avoid problems with leakage along these types of structures, careful characterization of the system is necessary to identify any wells or geologic features within the area expected to be affected by the well stimulation treatment (Shultz et al, 2014). Bachu and Valencia (2014) recommend conducting hydraulic fracturing from offset wells at a safe distance, which is not specified, but would need to be evaluated using fracture modeling and field experience.…”

General Principles of Well Barriers

“…One may claim that the subject of subsurface containment assurance fulfills the well integrity requirements, however, in fact it is more comprehensive than the well integrity. It includes well integrity, subsurface integrity, and any aspect of deepwater and surface facilities which are directly relevant to upstream exploration, production, and abandonment operations [25]. As an example the well integrity of abandoned wells or fields might be influenced by nearby injector wells influencing the pressure regime.…”