While drilling in the lateral section of well in Howard County, Texas, an operator experienced oil-based mud (OBM) losses at a rate of 30-40 barrels per hour. The losses were occurring in the fractured Spraberry formation directly above the Wolfcamp formation. The well started ballooning while making connections which led to excessive non-productive time (NPT) and potential well control issues.
The operator pumped a ROCKBLOCK 3 LCM pill at 20 lb/bbl in 30bbls of OBM. As the pill crossed the thief zone the losses decreased. A second ROCKBLOCK 3 LCM pill consisting of 40lb/bbl in 40 bbls was pumped and as the pill crossed the thief zone, the annular pressure increased and full returns were achieved. The well was drilled to total depth (TD) with no further lost circulation or ballooning events.
ROCKBLOCK 3 sealed the fractured formation and eliminated OBM losses and wellbore ballooning. This allowed the operator to drill to TD and successfully cement casing on bottom. The operator described the product as successful in stopping the losses to the troublesome formation. The operator will continue to use this formulation when drilling in this region.