Oriented Coring improves recovery rate from 35% to over 90%
The recovery of sidewall-cores has historically been very low in Mexico, specially in large holes, where a large hole kit (LHK) needs to be run. The protuberance created by this LHK causes the tool to lean on its side, which creates an oblique contact between the coring bit and the borehole wall (specially in deviated wells) and has a negative impact on the recovery rate.
In an attempt to improve the recovery rate, one of the operators decided to convey the HRSCT with Tool Taxis so that the coring bit would penetrate the formation perpendicular, while keeping the tool firmly set.
Core recovery on this job was 80.6% with 29/36 cores
recovered. In the following eight months, Petromac performed another six jobs, reaching an average core recovery of 91.2%, with a total of 197 recovered cores out of 216 attempts.
CHALLENGE
When running HRSCT in 12.5” holes or more, a large hole kit needs to be installed. This causes the tool to lean on its side and creates an oblique contact between the coring bit and the borehole wall, which translates into a very poor core recovery.
SOLUTION
Petromac Tool Taxis were installed on the HRSCT, to orient the coring bit perpendicular to borehole wall.
RESULTS
The operator obtained high quality cores while improving the recovery rate from 35% to over 90%.