oil based mud

Roughly 75% of the formations drilled contain reactive shale and over 90% of wellbore stability problems are related to the inability of drilling fluids to control reactive shale. The most important variable in maintaining shale stability is preventing pore pressure invasion into the shale matrix. Pressure invasion alters the near wellbore stress state and can induce failure. Shale stability is achieved when pressure invasion is reduced and differential pressure support is maintained.

TERRA-MAX is a high-performance water based mud (HPWBM) with performance approaching
an oil-based mud (OBM). Developed by Baker Hughes Drilling Fluids, it balances reduced environmental impact with increased operational efficiency. The system inhibits reactive formations encountered in onshore and inland water applications.

The HPWBM incorporates a micronized deformable sealing polymer that mechanically bridges shale micro-pores and micro-fractures.

Additionally, the deformable nature of the polymer allows the “mold” along fractures and pores to effect better bridging of shale matrix or other low porosity formations such as tight gas permeable sands. This sealing effect reduces pressure invasion thus maintaining borehole integrity.