Study of Drilling Fluid Additives and their Impact on Smectite Inhibition, Marcellus Shale Inhibition and Filtration & Rheological Properties of Bentonite Based Drilling Fluids

Abstract

AbstractShale makes up 75% of drilled formations and causes over 90% of wellbore instabilities. Although drilling fluids with acceptable performance in Shale have been formulated, the industry is still endeavouring to formulate an optimum inhibitive drilling fluid for the Marcellus Shale. In accordance, this research seeks to fabricate a means of reducing formation damage (permeability reduction leading to poor hydrocarbon production), stuck pipe incidences, heaving, sloughing and caving which are all due to the swelling of Smectite clay and shale.This research paper, in its infinite practicality, expounds upon the predicaments associated with swelling and dispersion of shale, the chemistry behind the swelling/dispersion of shale, justification of this research and the results obtained from laboratory work and experiments, experimental procedures performed in the formulation of an optimum inhibitive drilling fluid for the Marcelus Shale such as rheological, filtration and linear swelling experiments.Most importantly, this paper introduces a novel approach and experiment towards the development of an optimum inhibitive drilling fluid, utilizing a novel chemical in the industry: ω-α Diamino Alkanes (Diamino Butane and Diamino Hexane) as well as comparing the inhibitive capability of two familiar chemicals in the industry in conjunction with Chlorides and Hydroxides of numerous Alkali metals, Alkaline earth metals and Transition metals (K+, Na+, Ca2+, Mg2+, Li+ etc) in various concentrations.The rheological, shale inhibition and filtration effects of the aforementioned Hydroxide and Chloride chemicals were tested and examined which led to the subsequent elimination and selection of certain fluids which this research has recommended for testing in Marcellus Shale formations in West Virginia and similar shales in the globe. Universally acceptable filtrate loss correlations have been formulated, during the course of this research, for various base drilling fluids.Finally, it was observed that a drilling fluid system comprising of KCl, Diamino Hexane and Bentonite was effective in reducing shale and Smectite swelling when compared to the currently leading inhibitive mud currently used in drilling shale formations. This research project was limited to the Marcellus Shale formation in the State of West Virginia and the results obtained from the inhibition/swelling tests may not be universally acceptable in the evaluation of other shale formations. However, the generated rheological and filtrate loss results and correlations may be universally applied.