Improved Techniques to Alleviate Sustained Casing Pressure in a Mature Gulf of Mexico Field

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe objective of this paper is to highlight the techniques used during a recent workover program to alleviate sustained casing pressure in a Gulf of Mexico field. Discussion will include cement and workover fluid programs, hole preparation before milling and cementing operations, and improved milling procedures.

Specification for Permanent Plugging Materials

“…The inclusion of latex additives to cement slurry lowers the surface tension between the slurry and casing and helps cement adhere to casing while setting. Surfactants treat the oil-wet surfaces by removing oil and allow better bonding contact [20].…”

Design and field-scale demonstration of the buoyant-kill process for restoring integrity of wells with sustained casing pressure

“…Sustained Casing Pressure (SCP) is the pressure at the top of well's annulus that cannot be permanently bled off as it is caused by the loss of well's integrity-gas migration in the annular fluid above the top of degraded and leaking cement sheath. Cement degradation is a time-dependent and complex process resulting from variety of physical, chemical and microbial reactions (Achang et al, 2020;Seyyedi, et al, 2020;Taleghani and Santos, 2023;Yan et al, 2023). Disintegrated cement provides flow pathways for gas escape from the cement top into the annular fluid.…”

“…The technique is effective but, reportedly, can only be used in wells with no cement sheath outside the upper section of inner casing (Milanovic and Smith, 2005). The reported most effective use of the downhole-intervention method for successful SCP removal in twelve wells in the Gulf of Mexico was to employ a site-specific combination of the above techniques to stop gas migration in the affected annuli (Soter et al, 2003).…”