Collision between wells while drilling leads to blowout (onshore, location not provided)

20 February 2015

IOGP Safety Alert no. 265 describes the sequence of events, the causes and recommendations.

17 wells had been drilled in 3 clusters, including 4 wells with the current rig and personnel. A 23” section was being drilled, there were various minor deviations from the documented drilling programme. At 600m depth there was a metal proximity alarm, the drill team decided this was from an abandoned branch of another well and continued drilling ahead. An obstruction was then encountered.

After a phone discussion with base it was decided to sidetrack the well from 3m above the obstruction. There was then a shift change, high torque and vibration were experienced, but they continued drilling ahead, penetrating two casings and then the production string of a live well that had been drilled from another cluster – its details were not included in the data used to plan the directional drilling.

See the full Safety Alert for more details.

If you have a current drilling programme, are you confident that your drilling personnel would have stopped and fully risk assessed their options, as didn’t happen for this well?

Have they already seen and discussed this Safety Alert?