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.

Successful stimulation and increased production

A wellbore drift and perforation wash was performed as a prerun using the Jet Blaster jetting scale removal service. Depth correlation was performed and the packer was set the first time at the required setting depth. The full treatment was pumped below the packer at 3,500 psi [24 MPa] differential pressure. Nitrogen was pumped to lift the well while the packer was retrieved. This solution allowed correlating and lifting the well on the same run as setting the packer, saving two runs. Post-treatment production was sustained at more than three times the original production level.

The treatment solution allowed correlating and lifting the well on the same run as setting the packer, saving two runs. Post-treatment production was usstained at more than three times the original production level.