Lipophilic Rheology Modifier And Its Application In Oil-Based Drilling Fluids

Control of rheological behavior plays an important role in the process of wellbore construction and ensure the success of drilling operation. This paper reports for the first time the use of poly-amide (SMN) and poly-ester (SMO) as potential rheology modifiers. Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance, and thermogravimetric analysis have been carried out to confirm the chemical structures and properties of SMN and SMO. The results from environmental scanning electron microscope (ESEM) illustrated that SMN and SMO are lamellar structures formed by the stacking or interpenetrating of thin sheets. The atomic force microscope test results show that the network structure is formed after dissolving rheology modifier in diesel oil. Combining with the rheology and suspension measurements, it can be determined that the addition of rheology modifier exhibited obvious influence on the viscosity, thixotropy, and settlement factor of W/O emulsion. The rheology control properties and suspension stability between two rheology modifiers and traditional rheology modifier organoclay were compared. After hot rolling at 180 degrees C, the base mud containing organoclay exhibited excellent suspension stability, but the fluid had completely lost fluidity and consolidated into a block. For SMN and SMO addition into the base formula, the rheological parameters of base mud changed moderately and the settlement of barites was not observed after standing for 24 h.