Abstract
Hundreds of depleted shallow gas wells in the Saco, Montana area of the Northwestern United States have been found to have bypassed pay that until recently was believed uneconomical to recover. Wells in the area were traditionally completed with one production zone and were fractured by conventional means down the casing. The pay zones were then efficiently depleted through the use of siphon strings and flow line compression. Upon review of the well logs, it was determined there may be enough bypassed pay within the existing wellbore to continue producing the well as a multi-zone completion.
This paper outlines the logistics, execution, and evaluation of coiled tubing conveyed fracturing for depleted gas wells. Formations that were stimulated in this study appear to have similar characteristics to the thin producing lenses typically treated in Southeastern Alberta, Canada. The majority of the wells treated received up to six fractures and averaged 100,000 lbs of sand placed into each wellbore. The challenges and results from an initial pilot project are reviewed along with the subsequent multi-well project that followed.
