Schlumberger

Case Study: VERSA-OUT Breaker Delivers Production Rate Beyond Customer’s Best Expectation

Challenge: In order to improve oil production of their offshore development field in Gabon, a customer requested M-I SWACO study possible oil based mud (OBM) reservoir drilling fluids and filter cake treatments. The completion method was a 7 in. slotted liner set below a 9 5/8 in. casing shoe in a horizontal drain.

Solution: After lab tests in Houston, M-I SWACO proposed to displace in the open hole a VERSA-OUT breaker pill for filter cake treatment of VERSAPRO LS drilling fluid system. The VERSA-OUT breaker is a water base breaker system designed for use in either injector or producer wells.

Result: When this well was started, oil production exceeded the highest expectation by more than 15%. No remedial jobs have been required, realizing rig time and cost savings for the customer. Due to that success, others applications will be run in the near future in West Africa to treat, dissolve and dismantle either VERSACLEAN oil based mud or VERSAPRO LS filter cake using VERSA-OUT technology.

The Details

After drilling the pilot hole to the top of formation to identify the current oil/water contact and run logs for reservoir quality information, the customer drilled 8 ½ in. section with a 1.03 - 1.05 s.g. (8.6 - 8.7 lb/gal) VersaPro LS oil based mud without any problem to reach TD at 8,328 ft (2,539 m). The operator circulated the hole clean and changed out shaker screens to 325 mesh (API 230). After the scraping operation, 28 m3 (176 bbl) of sieved mud was pumped and spotted covering the open hole plus 656 ft (200 m) inside 9 5/8 in. casing. The completion assembly with quantum packer, slotted liner and 2 7/8 in. wash pipe was run to 8,279 ft (2,524 m) with no problems. Cleaning pills were pumped in following order: 1 m3 (6.3 bbl) base oil, 8 m3 (50 bbl) transition spacer, 3 m3 (18.9 bbl) turbulent spacer, and 20 m3 (126 bbl) Versa-Out breaker. These pills were displaced through the liner/open hole annulus with 1.05 s.g. (8.7 lb/gal) inhibited KCl brine. The Versa-Out breaker was left inside the annulus and liner to soak while running the upper completion. No losses occurred while placing the breaker. The packer was set at 6,563 ft (2,001 m). The wash pipe and service tool were disnegaged from the packer.


Download: Versa-Out Breaker Delivers Production Rate (0.24 MB PDF)

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“M-I SWACO Smart RDF Technology demonstrates its highly efficient oil based mud filter cake treatment using VERSA-OUT system offshore West Africa.”
Benoît Allias
Business Development Manager
M‐I SWACO