Technology Lost Circulation Cure is one of EverGreen key Technologies. Generally lost circulation comes from the following formations： -Non consolidated sand -Water sensitive shale -Fracture and cavern carbonate -Anomaly pressure zones A combination of materials to cure lost circulation are：  DrilXpress – A liquid chemical that can pump with mud into hole. It strongly inhibits shale water sensation and clay reaction. There is no “Gumbo” and “fish-eye” that are often found in conventional Bentonite Based System. It is 100% compatible with various WBM/OBM/BBM.
USM – Synthetic Fiber system that combine fiber and a proprietary high expanding polymer to seal various kinds of fracture and filtration in formation. USM has a proprietary fiber distribution and polymer that can seal large aperture fracture up to 1/8”. It often combined with DrilXpress and pumped into hole with Mud. It is 100% compatible with various WBM/OBM/BBM. PGS – A proprietary gelling sealant to cure heavy/total/whole mud loss. It is pure liquid but has to independently pump into hole and take rig time for crosslink. It is 100% compatible with various WBM/OBM/BBM. Mud loss can be classified into： Seepage Loss – Mud loss rate is less than 10 BPM while return will be a bit less than pumped. Depending on formation characteristic, zone will trigger heavy loss in future drilling or cementing. sweeping of DrilXpress fluid and USM. DrilXpress: min. 30 bbl USM: min. 15 sacks First slug sweeps into hole to cure the lost circulation and second slug will be swept with new hole drilling at 10-15 bbl’s per 100’ until seepage zone is passed. Sweeping of DrilXpress and USM costs very little rig time. Partial Loss – Mud loss rate is between 10 BPM and 60 BPM while less return is obviously observed. Depending on formation characteristic, zone will trigger heavy loss in future drilling or cementing. sweeping of DrilXpress fluid and USM. DrilXpress: min. 50 bbl USM: min. 50 sacks First slug sweeps into hole to cure the lost circulation and second slug will be swept with new hole drilling at 10-15 bbl’s per 100’ until partial loss zone is passed. Sweeping of DrilXpress and USM costs very little rig time. Heavy Loss– Mud loss rate is over 60BPM while return is greatly less. sweeping of DrilXpress fluid and USM. DrilXpress: min. 100 bbl USM: min. 100 sacks First slug sweeps into hole to cure the lost circulation. If lost circulation still persists, second and more slugs sweep into hole until LC is cured. It is recommended to attempt to fill the backside and kick the mud pumps on slowly until circulation is established. Sweeping of DrilXpress and USM costs very little rig time. Total Loss – Mud loss rate is far over 60BPM while return is little. sweeping of DrilXpress fluid and USM. DrilXpress: more than 100 bbl USM: more than 100 sacks First slug sweeps into hole to cure the lost circulation. If lost circulation still persists, second and more slugs sweep into hole until LC is cured. It is recommended to attempt to fill the backside and kick the mud pumps on slowly until circulation is established. Sweeping of DrilXpress and USM costs very little rig time. Whole Mud Loss – No return at all Deploy PGS sealant to cure the whole mud loss. sweeping of 100 bbl or more PGS sealant Place bit 10 bbl atop of lost zone and monitor return when PGS reaches the bit. If returns are observed, pick bit to top of PGS. Document bbl’s and clear bit by 5 bbl’s and shut down. If returns were not observed, shut down and wait on (8) hours for PGS to cross-link before attempting to establish circulation. Second slug may be applied if LC is mitigated but still exists after crosslink. Pumping of PGS sealant will take some rig time. |