A novel bio-based deflocculant for bentonite drilling mud

Abstract The physical and chemical properties of bentonite, a widely utilized drilling fluid additive, in the aqueous phase could potentially change when encountering drilling fluids contaminants. Therefore, prior to encountering an excepted contaminant, it is mandatory that one treat the bentonite mud by an appropriate deflocculant. This study assesses for the first time the performance of Oak seed extract (OSE) as a novel bio-based deflocculant in bentonite drilling mud through some extensive experiments. After being exposed to high temperatures and contaminants, the value of rheological parameters and fluid loss of bentonite mud free from any additives changed remarkably. The OSE kept the stability of bentonite in aqueous phase by restraining the capacity of bentonite to form a flocculated structure, decreasing rheological parameters and fluid loss value. From bentonite inhibition tests, the incapacity of OSE to reduce the magnitude of plastic viscosity was fairly clear. Based on particle size measurements, OSE had a significant impact in reducing particle size of contaminated bentonite muds. According to SEM observations, no remarkable difference was seen between the morphological features of modified bentonite with and without OSE, indicating particle delamination in both cases and no inhibitive property of OSE. The findings verify that OSE can act as a superior deflocculant. The deflocculating performance of OSE was more drastic in the case of cement-contaminated mud owing to its acidic nature (pH = 4.58 at 1 mass%). Therefore, this study proposes the pre-treat of the bentonite mud with OSE for encountering ultra-high pH condition generated by cement. The deflocculation mechanism is believed to be a neutralization of the positive edges of montmorillonite (Mt, dominant mineral in bentonite) by tannins (dominant constituent in OSE), destroying the ability of Mt layers to link one another. In addition to high performance, environmentally friendliness and cost effectiveness are characteristics which can be considered as other fascinating aspects of OSE.