The construction features of inactive wells which provide the mechanical barriers to fluid migration include: i) surface casing installed below all fresh water aquifers with cement circulated to the surface; 2) any intermediate casing installed and cemented, 3) production casing installed and cemented into the lowermost confining zone; and 4) any tubing and packer set in the well above the completion interval. The Christmas-tree or stuffingbox assembly isolates the wellbore fluids from the surface and provides readily accessible gauges on all tubing, casing, and annuli outlets for ease of monitoring pressures. The mechanical integrity of these well construction components is the key factor in their ability to provide a barrier to fluid migration. There are inactive wells which provide adequate protection against fluid migration into a fresh water aquifer or to the surface, but they may not have all of the construction details discussed above. By tailoring the monitoring program to a well’s construction, operators can increase monitoring frequency for inactive wells that have fewer barriers to fluid migration. Source: API BULLETIN E3, Environmental Guidance Document: Well Abandonment and Inactive Well Practices for U.S. Exploration and Production Operations, First Edition, January 1993 (Reaffirmed June 2000). Global Standards
A set of operations to be directed by the lease operator employing the drilling contractor and third-party services equipment and personnel.
Source: API Bulletin 97, Well Construction Interface Document Guidelines, First Edition, December 2013. Global Standards