DRILLING MUD DISPLACEMENT FROM THE WELL DURING CEMENTING

Currently, almost all researchers believe that turbulent flow is the most preferred displacement mode. However, in regard to cementing, where practical limitations prevent obtaining turbulent flow, opinions begin to differ. In general, either "protracted" flow or "rapid" flow is recommended for all annular cementing of the wells. A new and very affordable composition of the buffer liquids has been proposed in this paper to reduce price and unevenness in the cement slurry distribution. Studies have shown that adding specialized structure-forming additives to the developed cement slurries helps to form sediment-resistant cement systems. This improves the strength characteristics of the cement stone and increases the overall quality of lining of inclined wells. Analysis of the rheological properties of the new cement slurries demonstrates that these systems have a high yield point at elevated temperatures and pressures. The developed aqueous spacer fluids help to more effectively clean both casing strings and rocks from drilling mud residues and clay cake, which in turn improves the quality of cementing oil and gas wells. It was also revealed how the composition and properties of the components affect the washing ability of the spacer fluids and the strength characteristics of the cement stone. Keywords: buffer fluid, drilling fluid, cement mortar, turbulent flow, mode of motion, mud cake, centralizer, casing string.