Ultra-Seal Plus, Ultra Seal TG, Drill-Xpress RHODEN 7-15 1-8

Well Information

Searcy, Arkansas Fayetteville Shale
9-7/8
OBM
10.0 PPG
150 F
2 hrs

Challenge

Wells in the Fayetteville Shale are air drilled to ± 4,000’. A typical well is air drilled
with a 10 ¾” bit to ± 1,000’ and surface casing is then run and cemented. Air drilling
continues to ± 4,000’ or until water sands are encountered. Once the water sands
have been encountered, mud up occurs with oil base mud. Typical oil to water
ratio’s are 80/20. The vertical section of the well is continued to kick of point. While
drilling the vertical section, loss circulation occurs up the hole in the “Hell Sand” and
in the shale/sand interfaces. This particular well experienced total lost circulation
while drilling ahead at ± 4,500’. The system was treated with 12 ppb of conventional
LCM (Cedar Fiber) and circulation was established, but the well was still loosing 25
bbl’s/hour of oil base mud. In order to keep the conventional LCM in the mud
system, the shakers had to be bypassed. After several days with oil base mud
losses of 25 bbl’s/hour, the decision was made to try Ultra Seal®. With both
shakers running with 70 mesh screens, the cedar fiber was removed from the
system. Ultra Seal® TG was added to the circulating system at a concentration of
8 ppb. Ultra Seal® TG was added for daily maintenance. Sweeps with 30 ppb
Ultra Seal® Plus were also run. While drilling the lateral section of the well, three
sweeps with Dril-Xpress® were run for hole cleaning. Compatibility between the
oil base mud and Dril-Xpress® was maintained with the addition of two gallons
per barrel of Ultra Surf S.

Results

The remaining vertical section along with ± 5,000’ of lateral were drilled
without further incidence of loss circulation or documented seepage
losses. Prior to treating the circulating system with Ultra Seal®, daily
losses averaged 600 bbl’s.