Since the dawn of rotary drilling, engineers and scholars have persevered, through study and research, to formulate an optimum inhibitive drilling fluid for the shale formations. Although fluids with acceptable performance in shale have been formulated, one only needs to examine the word “acceptable” in the context above to realize that the industry has ongoing activities to formulate an optimum inhibitive fluid for the Marcellus Shale. In accordance, this research seeks to fabricate a means of reducing formation damage (permeability reduction), stuck pipe incidences, heaving, sloughing and caving which are all due to the swelling of Smectite clay and shale. The ultimate achievement in reducing formation damage would consequently lead to an augmentation in oil and natural gas production from the Marcellus Shale.
This research paper, in its infinite practicality, illustrates the problems associated with swelling and dispersion of shale. The chemistry behind the swelling/dispersion of shale validates this research with respect to inhibition/swelling. Also, presented are the experimental procedures performed in the formulation of an optimum inhibitive drilling fluid 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. The study utilizes a novel chemical in the industry: α–ω Diamino Alkanes (Diamino Butane and Diamino Hexane) as well as comparing the inhibitive capability of two familiar chemicals in conjunction with Chlorides and Hydroxides of Alkali metals, Alkaline earth metals and Transition metals (K+, Na+, Zn+, 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 in West Virginia and similar shale formations throughout the globe. Universally acceptable filtrate loss correlations have been formulated, during the course of this research, for various base drilling fluids.
API standard procedures were utilized in the evaluation of rheological and filtration properties of base drilling fluids and the results obtained from the rheological and filtration experiments are independent of shale formation characteristics. However, the inhibition/Swelling test was limited to the Marcellus Shale formation in the State of West Virginia and the results obtained for inhibition/swelling may not be universally acceptable in the evaluation of other shale formations.