Drill an extended-reach well through a difficult shale environment where BHA balling is common

An operator planned to drill an extended-reach well to reach a reservoir located under an environmentally sensitive area. To achieve this, the customer built a location near a swamp to start the operations. Environmental licenses precluded the use of oil- and synthetic-based fluids; instead the operator planned to use a water-based mud (WBM).

The operator used information from an offset well drilled in 2011 to supplement the development plan. While drilling the offset well, the operator had experienced several complications, including constant packoffs and tripping issues. First, the highly heterogeneous formations demanded different drilling fluid approaches to ensure wellbore stability and shale inhibition. The tough shale environment tended to create BHA balling events, making additional trips necessary to clean the BHA. And, based on the challenges encountered while drilling the offset well, the operator anticipated experiencing several torque issues even with a highly lubricious fluid.

Use the HydraGlyde system to combat issues experienced while drilling the offset

Based on prior experience in similar wells, M-I SWACO, a Schlumberger company, decided that the HydraGlyde* high-performance water-based drilling fluid system would be the best replacement for the WBM used in the offset wells. Because the system can compete with oil-based muds in terms of penetration rates and wellbore stability, the HydraGlyde system was ideal for preventing the challenges experienced while drilling the offset well, helping the operator minimize the risk of environmental impact and save of dilution and disposal costs. In addition, the operator used the PRESSPRO RT* real-time downhole performance measurement software to enable decision making based on real-time drilling parameters and practices. Together, these technologies enabled efficient drilling and hole cleaning operations.

Prevent BHA balling, stick/slip, and torque issues

The most challenging shale section of the well—the 17½-in section from 800–7,450-ft [244–2,271-m] MD—was drilled in a single run without any BHA balling. The BHA came up clean after drilling the section. The well also experienced zero packoff events in the 12¼-in section— from 7,450–15,830-ft [2,271–4,825-m] MD—during drilling or tripping. Drilling torque remained at low levels throughout the entire well with values below the simulations, without any stick/slip events. In addition, the operator was able to run the casing to TD without issues, a marked contrast compared to the offset well experience with stuck casing.