Ultra-Seal Plus, Ultra Seal TG MIZE #2H
Well Information
Wise County, Tx Barnett Shale Fort Worth Basin
WBM
12.0 PPG
160 F
2 hrs
Challenge
Wells in the Wise County, Texas are drilled to ± 3,000’using gel base spud mud and
a surface string of casing is run and cemented. The surface casing is drilled out
with water base mud and water base mud is continued to TD. Various additives
are added to the water base mud to inhibit the shale sections. A typical well
encounters total lost circulation in the vertical section while drilling through the
“Pregnant Shale” at ± 5,500′ and also into a conglomerate formation just above the
Barnett Shale. Conventional methods using cotton seed hulls, cedar fiber and nut
plug have been used to try and control whole mud losses into the referenced
formations. Rig time lost from each occurrence of lost circulation using conventional
methods average five days. When these methods are unsuccessful, then cement
plugs are pumped. Two cement plugs were pumped in the offset well to control lost
circulation resulting in additional lost time. For this well, drilling continued until total
lost circulation was encountered, ± 5,500′. A pill of Ultra Seal® Plus was mixed at a
concentration of 40 lbs/bbl and pumped down hole. After 25 bbl’s of pill was out of
the drill pipe, full returns were observed. At this point, Ultra Seal® XP was added to
the circulating system at 4 ppb. Drilling commenced without losses through the
“Pregnant Shale” while circulating at a maximum drill rate of 11 BPM. While drilling
through the “Conglomerate” formation, total lost circulation occurred three times.
This was to be expected due to the litho logy of this formation (rubble zone). Pill’s
of Ultra Seal® Plus were mixed ahead of time and were ready to be pumped when
lost circulation occurred. The concentration of the Ultra Seal® Plus pill’s was 40
ppb. Each time total loss circulation was encountered, the pill was pumped and
circulation regained after 10-15 of pill had exited the bit. While drilling the horizontal
section of the well, Ultra Seal® XP was maintained in the system at 4 ppb.
Results
The use of Ultra Seal® products saved over 2,000 bbl’s of mud and an
estimated 6 days of rig time.