New Nanoparticle Water-based Drilling Fluid Formulation with Enhanced Thermal Stability and Inhibition Capabilities in the Woodford Shale

Book excerpt: "Drilling fluid design for unconventional reservoirs aims at preventing formation instability problems associated with fluid invasion, shale swelling, and cuttings dispersion. Although oil-based mud (OBM) can be used to achieve these goals, environmental and economic concerns limit its application. This experimental study evaluated the potential use of nanoparticles (NP) to improve water-based mud (WBM) inhibition capabilities and its ability to enhance the overall drilling fluid thermal stability while providing a cleaner technology to the industry. Characterization of Woodford shale was completed with X-ray diffraction, cation exchange capacity, and scanning electron microscopy, silica, and graphene NP were characterized with aqueous stability tests and zeta-potential. Selected NP were added at a low concentration (0.1 - 1 % wt.), and standard filtration (LTLP & HTHP), rheology, dispersion and swelling tests were conducted to investigate the inhibition improvements of the new NP-WBM. In addition, optimum formulation of the new NP-WBM was aged at different conditions (150°F, 200°F, 250°F) for thermal and rheological stability. Conventional KCL/PHPA fluid was used for comparison purposes. The NP showed a reduction of the chemical interactions between the WBM and Woodford shale samples, reducing the swelling and dispersion effects. Also, a synergistic effect was observed between NP and conventional additives indicating that NP had the capability to improve the WBM temperature resistance. Thus, offering an eco-friendly alternative with enhanced thermal and rheological stability of the overall WBM formulation and providing more efficient drilling and wellbore stability"--Abstract, page iii.