Isolation and stimulation of two intervals
An operator drilling in Algeria needed to isolate two separately
perforated intervals to stimulate the underperforming bottom interval of the
well. The fractured top interval was highly permeable, and the less-permeable
bottom interval was the stimulation target zone.
When the two zones were completely isolated, the bottom zone was to be
stimulated through coiled tubing (CT) below the packer with organic mud acid.
The CoilFLATE high-pressure, high-temperature (HPHT) through-tubing inflatable
packer was selected for the project because CoilFLATE HPHT packers are designed
for extended assembly exposure at 375 degF [191 degC] in harsh wellbore
conditions and almost any chemical environment.
Depth accuracy for optimum packer positioning
Only 10 ft [3 m] of wellbore was available to set the CoilFLATE HPHT
packer (a window of between 11,253 ft and 11,263 ft [3,430m and 3,433 m]) and
isolate the top zone.
Depth accuracy is key to success when setting the packer between zones,
and the CoilFLATE HPHT system ensured absolute depth control through wireless
real-time casing collar log correlation for optimum packer positioning.
After the CoilFLATE HPHT packer was inflated, the 120-bbl [19,080 l]
organic mud acid treatment was successfully pumped at a maximum differential
pressure of 3,500 psi [24 MPa] across the packer. Then the CoilFLATE HPHT
packer was deflated, allowing nitrogen to be pumped and to flow back the acid
while pulling the CT and bottomhole assembly to the surface.