An operator was drilling a challenging horizontal well section when communication with the RSS was lost. After pulling out of hole to change out the BHA, the operator resumed drilling to reach the planned 3,585-m MD. While drilling the next section, gamma ray readings from the adnVISION™ azimuthal density neutron service increased from 24 to 105 gAPI, suggesting the well was deviating from the planned trajectory. To stay in the zone of interest, the operator dropped the inclination from 90° to 87°. However, when GR logs continued to show a relatively poor reservoir, the operator decided to stop drilling at 4,215 m and POOH. While POOH, the string encountered tight spots and became stuck twice. After many failed attempts to release the stuck pipe, the operator wanted to retrieve the nuclear source before any further intervention attempts.
The BHA included the MUDGARD workstring filter, which provided the critical throughbore access the drilling team needed for source retrieval. Designed to capture foreign debris, protect equipment, and mitigate jamming events during drilling, the MUDGARD workstring filter also facilitated a contingency central bypass, allowing complete and immediate wireline and coiled tubing access. This bypass feature enabled SLB to recover the radioactive source contained within the drill collar without requiring the recovery of additional drillstring components. The successful retrieval of the source reduced HSE risk and avoided source damage during subsequent intervention operations, which included acid treatment, packoff, and fishing.
