Case History

Eliminating Wellbore Instability in Mechanically Weak Formations in Kuwait

Kuwait
Challenge

For one operator, drilling operations recently moved into increasingly challenging formations in Kuwait. The operator set out to prevent wellbore instability in known problematic formations which included the Mauddud (limestone) and Wara (sandstone). The operator was seeking to produce in the Burgan Field, while eliminating costly wellbore instability and improving safety performance.

Solution

One approach to drilling micro-fractured shale, weak sands, depleted formations, or highly inter-bedded sequences is to mitigate and prevent the invasion of drilling fluids into the formation. Invasion of fluids causes changes in pore pressure, increases micro-fractures, and is a common trigger for wellbore instability events. Thus, stopping the pressure invasion of fluids is a key to mitigating wellbore instability and other drilling problems. FLC 2000, a specially designed low-invasion additive protects the formation and allows normal drilling operations to continue. The operator adopted the use of the technology.

Results

Field data demonstrated the successful application of FLC 2000 to meet challenging key performance indicators (KPI) in the Burgan Field. Using the low-invasion additive, drilling operations reported no differential sticking, torque-and-drag problems, sloughing or hole closure, whereas offset wells experienced common incidences of differential sticking, pack-offs, and tight hole. Drilling with FLC 2000 allowed control of the micro-fractured and tectonically stressed formations. Furthermore, the low-invasion additive did not significantly change the rheological profile of the drilling fluid. Meeting these goals through the use of FLC 2000 reduced both costly non-productive time and formation damage and reduced the overall cost to drill these wells.