Customized NAF, optimized solids control, and STOPPIT® LCM

Overview: Operator needs to economize on drilling costs due to lower oil prices

An operator in north the Middle East wanted to lower drilling costs and prevent severe lost circulation. A non-aqueous fluid (NAF) system was used on these wells, with an average of 140 wells drilled per year. The Baroid technical team was asked to identify ways to decrease NAF costs, optimize solids control efficiency for improved base oil and whole mud recovery, and implement a rapid cure for downhole losses.

Soltion: Solutions target base oil consumption, whole mud recovery, and LCM

Baroid personnel recommended changing the NAF oil/water ratio (OWR) to 70/30. The reduction in base oil content would provide immediate cost benefits with low- to mediumdensity fluid. Next, optimizing shaker and centrifuge processing rates would result in lower dilution requirements and less base oil consumption. Additional whole mud could be recovered in two ways: 1) treat NAF spacers contaminated during cementing jobs, and return them to the treated volume to the active system; and 2) capture and reuse mud remaining in surface tanks and the rig cellar by using a BaraStream™ SV60 portable cuttings and fluid transfer unit. The Baroid team also proposed controlling the rate of penetration (ROP) and pumping sweeps while drilling the surface hole to help eliminate gumbo attacks that had been causing significant nonproductive time (NPT). 

To cure downhole losses in large and/or vugular fractures, the Baroid team recommended spotting 100-bbl pills containing 80 lb/bbl STOPPIT® lost circulation material (LCM). The STOPPIT LCM pills could be pumped through the bottomhole assembly (BHA) with no issues, eliminating the need to trip out of the hole.

Result: Estimated savings in one year exceed USD 1 million

These efforts to reduce costs and optimize drilling performance helped the operator save an estimated USD 1,213,000 over the course of 140 wells drilled in one year. The use of STOPPIT LCM pills, combined with careful mud density management, reduced downhole losses by 45 percent compared to the previous year. The pills were effective in curing losses in 90 percent of loss zones encountered.