Performance Report: FORM-A-SQUEEZE LC Plug Minimizes Mud Losses

Berland River

Challenge: A drilling break was recorded at 9,666 ft (2,948 m) at the top of the Spirit River formation resulting in 50 bbl of mud losses. At 9,705 ft (2,960 m), flow-back rapidly increased, and a kick was recorded, requiring well shut-in. Density was raised to 10.9 lb/gal (1,305 kg/m³) to handle the kick, which aggravated the losses. A conventional LCM pill was pumped unsuccessfully in an attempt to cure the mud losses.

Solution: FORM-A-SQUEEZE product was available on location and had worked with encouraging results on the previous section, while conventional LCM had not provided a great reduction in losses. So the decision was made at 9,813 ft (2,993 m) to initially mix a 19 bbl pill (12.5 bbl pumpable) covering 328 ft (100 m) of hole at 9,666 ft (2,948 m). The slurry was weighted at 50:50 ratio by volume with barite and calcium carbonate to 10.8 lb/gal (1,300 kg/m³) and spotted on bottom.

The annular preventer was closed after pulling up to 9,010 ft (2,748 m) and slowly breaking circulation. Then, the well was pressured to 217-290 psi (1,500-2,000 kPa). The annular pressure decreased to 0 after 30 seconds. The process was repeated over 1.25 hr, with the pressure eventually holding at 123 psi (850 kPa) each time. Approximately 6.3 bbl (1 m³) was lost during this time, after which the pill was left static for 1.25 hr.

Result: Mud losses were initially cured while drilling ahead to 9,280 ft (2,900 m). As the remainder of the section was drilled, levels of connection gas increased as did mud losses. Therefore, while tripping out for a new bit, the remaining 9.5 bbl (1.5 m³) FORM-A-SQUEEZE slurry was pumped at 9,459 ft (2,956 m) to cover from 9,443 to 9,672 ft (2,880 to 2,950 m). The density of the pill was 12.1 lb/gal (1,450 kg/m³) compared to the active system density of 11.5 lb/gal (1,375 kg/m³).

The Details

  • Calculated volume of open hole with string in: 52 bbl (8.2 m³)
  • Calculated volume from 7-in. (178 mm) casing shoe to assumed LC zone: 48 bbl (7.6 m³)
  • Calculated volume of pill: +/- 56 bbl (9.0 m³)
  • Pill formulation: 50 bbl HT 40 base oil and 100 sacks FORM-A-SQUEEZE product
  • LC pill densities: 10.8/11.1/12.1 lb/gal (1,300/1,330/1,450 kg/m³)

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