Development of Smart Drilling Fluids Using Nano-Materials

  • Shulian Li

    Student thesis: Master's Thesis

    Abstract

    Drilling fluids used while drilling unconventional reservoirs need new focus, hence new formulations. The major concern is the swelling of shales (hole stability). The swelling of shales results in strength loss, wellbore collapse, dispersion of shale cuttings and at times loss of the well. Wellbore instability problems may occur during drilling process when shales are exposed to drilling fluids, which result in high drilling costs. This wellbore instability problem is best solved by selection of excellent smart drilling fluids. Due to the limited functional ability of conventional additives and the size effect of the materials, conventional water-based drilling fluid systems with macro or micro material-based additives, are not usually successful in solving instability problems. Nanoparticles can physically plug the nano-sized pore throats of shale and prevent water intrusion into them; thus prevent shale swelling. The purpose of this thesis was to develop smart drilling fluids using nano materials. Rheology, pH and filtration tests were carried out to evaluate the smart drilling fluids. Two rock samples were tested against the formulated smart fluids with nano materials. The first was man-made gunk squeeze and the second was shale cuttings from rig site in Abu Dhabi. The rocks were characterized by the following tests: scanning electronic microscope (SEM), cation exchange capacity test (CEC), and adsorption test. All selected smart drilling fluids were tested against gunk squeeze and shale cutting rock samples. Dispersion tests and barite sag test were performed. After comparing all the test results, the conventional inhibited potassium chloride drilling fluid system with 0.2 gram Nano-silica Aerosil 90 was the best formulation. The use of this formulation resulted in thin, tight, and well textured mud cake. Mud cake thickness was reduced a lot after adding nano materials. Out of the eight smart drilling fluids used for the dispersion tests, the best fluid was the one with Nano-silica Aerosil 90. The barite sag tests also indicated the fluid to be good for cutting suspension. No sedimentation was observed after monitoring for three days, which indicated a good cleaning efficiency. The rheology and filtration properties of smart drilling fluid system remained stable under static condition after three days of aging. The cost comparison between smart drilling fluid system and base (generic) drilling fluid system shows that smart drilling fluid system is economically applicable.
    Date of Award2016
    Original languageAmerican English
    SupervisorSamuel osisanya (Supervisor)

    Keywords

    • Applied sciences
    • Dispersion test barite sag test
    • Nano-material
    • Smart drilling fluid
    • Petroleum engineering
    • 0765:Petroleum engineering

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