Snubbing has recently been implemented as a method of routine well-control during workovers and completions at the Anschutz Ranch East (ARE) field in Summit County, Utah. This action was taken in response to poor post-workover performance caused by a water retention problem in the Nugget sandstone formation with the use of water-base well-control fluids. The incremental expense of snubbing at ARE averaged 25–40% of the cost of a standard workover and was considered reasonable in view of the alternative of poor well performance with existing well-control methods.
The concept of snubbing as a "commonplace" well-control method at ARE represents a major departure from historical control methods employed there. The new experience gained with surface control of potentially high-rate, medium-pressure, retrograde gas wells may benefit other operators in planning and executing safe, efficient snubbing operations in wells with similar conditions.
A review of the decision logic which chose snubbing versus other alternative well-control methods is presented. In addition, an overview of job pre-planning activities is provided. Finally, a detailed discussion of actual implementation problems and solutions is given with particular emphasis on underbalanced drilling of plugs and fill.