In December 1999, UPRI and Search Energy combined their resources to drill an exploration well south and east of Fort Nelson, British Colombia. An unusual chain of events combined to result in loss of control and a blowout. Located in an environmentally sensitive area, containing the blowout was a most important priority and a difficult challenge. The very high flow rate, hydrogen sulfide content, large volume of water and freezing temperatures made work at the well slow and difficult. This paper chronicles the unusual chain of events that preceded the blowout and the equally unusual approach to recovery. The lessons learned at the Klua blowout will be of benefit to the entire industry worldwide.


The Klua d-27-J/94-J-8 (Klua), located approximately 25 miles southeast of Fort Nelson, British Columbia, was spudded at 1900 hours on 29 October 1999. The project was jointly owned by Union Pacific Resources, Inc. (UPRI) and Search Energy Corporation (Search). UPRI was the operator.

Due to problems with the terrain, the well had to be directionally drilled. However, the fact that the well was directionally drilled is not significant to subsequent events. For the sake of simplicity and clarity, all figures depict a vertical wellbore. All depths and measurements given in this discussion are measured depths, unless otherwise noted.

The wellbore schematic is presented as Figure 1. Pursuant to the plan and procedure, 339.7 mm (13 ⅜ in) surface casing was set at 226 m (741 ft) on 30 October 1999. The well was intentionally deviated at 285 m (935 ft) and reached a maximum deviation angle of 23 degrees at 800 m (2624 ft) measured depth.

As illustrated in Figure 1, the 311.2 mm (12 ½in) intermediate hole was drilled without incident and 244.5 mm (9 ⅝ in) casing was routinely run to 1522 m (4993 ft). The 244.5 mm (9 ⅝ in) casing was cemented with the top of the cement calculated to above the 339.7 mm (13 _ in) casing shoe.

A 222.3 mm (8 ¾in) hole was drilled below the 244.5 mm (9 ⅝ in) casing. On 26 November 1999, a 177.7 mm (7 in) drilling liner was set and cemented at 2105 m (6906 ft). The top of the 177.7 mm (7 in) liner is at 1411 m (4629 ft).


A 158.8 mm (6 ½in) hole was drilled below the 177.7 mm (7 in) drilling liner. In the early hours of 1 December, while drilling at 2234 m (7329 ft), the complete loss of circulation was encountered. The pumps were shut off and a lost circulation pill was prepared. Within one hour of shutting down the pumps, the well began to flow. The blowout preventers were closed and the well was monitored while the lost circulation pill was prepared.

After the lost circulation pill was prepared and pumped, circulation was regained and the well was circulated without significant losses.

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