More than 50% of the petroleum resources on the Norwegian continental shelf is still unused. Most simple wells are already drilled and drilling is becoming increasingly complex, either due to reduced drilling window in mature fields with depletion or injection for production support, or due to targeting reserves in more difficult reservoirs, such as high pressure, high temperature, extended reach, or karstified carbonate reservoirs. Developing improved technology for pressure control in drilling is therefore one of the most important measures for improved recovery on the Norwegian continental shelf. Currently, no technology exists that is capable of reliably monitoring the integrity of the mud barrier in case of gas expanding in the riser while drilling. This is a critical uncertainty when drilling in formations with losses, where a loss may mask gas displacing the mud column in the riser and compromising the integrity of the mud barrier. Tracking expansion of gas is key to distinguish gas expanding in annulus from simultaneous losses or influx while drilling, and is vital to be able to assess the integrity of the mud column. We will in this project solve fundamental challenges related to enable reliable real-time monitoring the integrity of the mud barrier in case of gas influx. This will result in new technology that will remove considerable uncertainty associated with the handling of well control incidents in drilling, which will be invaluable for HPHT (high pressure, high temperature) and deep water operations in order to prevent influx scenarios from escalating into severe incidents. In particular, the project will bridge the lack of technology for reliable monitoring gas migration when drilling in formations with losses, such as e.g. karstified carbonates.
Project leader: Geir Arne Evjen
Institution: KELDA DYNAMICS AS