Development of a New Inhibitive Fluid to Mitigate Shale Drilling Problems

Abstract

In oil and gas industry, drilling shale formations requires careful design of drilling fluids to control shale-fluid interactions and mitigate wellbore instability. As the aqueous phase of the fluid invades shale formations and contacts clay particles, that may cause shale swelling and disintegration. As a result, solids loading increase in the borehole and that might lead to tight holes and, eventually, stuck pipes. Also, the rate of penetration might be reduced due to low hole cleaning efficiency and bit balling. Therefore, differet types of inhibitive drilling fluids have been developed to counter act the interactions between the aquwous phase and clay particles. In order to develop an inhibitive water-based mud capable of mitigating the adverse effects of shale-mud interactions, it is important to characterize the shale sample in terms of mineralogical composition. Also, the shale-mud interactions should be studied through a series of experimental dispersion. This paper presents the results of characterization and testing one shale sample and its interactions with an inhibitive drilling fluid and a comparison to non-inhibitive drilling fluid.