Description job: FRACSEAL application
Type of fluids: OBM
Phase: 121/4” directional hole
Potential problem: Loss Circulation / Sloughing Unconsolidated Sand
An 850bbl of active mud in a surface tank was pre-treated with 3ppb of FRACSEAL
(fine) and 220bbl of LCM pill was prepared containing 53ppb of blended conventional LCM and FRACSEAL to anticipate severe loss circulation while drilling expected loss zones. At a depth of 5,100ft, at approximately 200ft above expected top of loss zones, concentration of FRACSEAL fine was increased from 3ppb to 10ppb while drilling expected loss zones from 5,374ft to 5,915ft, also 2 sacks of FRACSEAL fine were added every hour into an active system to replace some of the FRACSEAL fine being screened out over shakers. No down-hole losses were experienced while drilling with mud weight of 81pcf.
The lithology at interval depth from 6,134ft to 6,670ft of Khafji formation is unconsolidated sand. Continued drilling through this section with 9ppb of FRACSEAL fine in the system, which was already pre-treated while drilling previous Wara formation (5,374ft) and Safaniya formation (5,740ft).
Khafji formation was stabilized from possibility of partially loss and differential sticking. Continued drilling 121/4” directional hole using oil base mud with mud weight at 81pcf containing 9ppb FRACSEAL fine from 6,670ft to casing point at 8,068ft without any down hole losses.