EXPERIMENTAL STUDY ON THE EFFECT OF WETTING AGENT ON OIL-BASED DRILLING FLUID PERFORMANCE AND RESERVOIR DAMAGE

摘要

Oil-based drilling fluids are widely used in the development process of a variety of complex geological conditions.As a key treatment agent in oil-based drilling fluids,wetting agents can improve the performance of oil-based drilling fluids by adjusting the wettability of the solid phase.In this paper,three different types of wetting agents are selected.First,the wetting performance of the wetting agent and the effect of the wetting agent on the performance of oil-based drilling fluids are studied.The results show that the wetting performance of the wetting agent is closely related to the type and concentration of the wetting agent.The cationic wetting agent has the best wetting reversal effect at a concentration of 1%.The addition of the wetting agent can significantly improve the settlement stability of the drilling fluid and the ability to resist pollution by bad soil such as drill cuttings.In addition,the addition of wetting agent will increase the viscosity of the drilling fluid.The effect of the oil-based drilling fluid system on the damage degree of the reservoir after adding the wetting agent was further evaluated.The results show that compared with the cationic wetting agent,the anionic wetting agent has a better effect on reducing the permeability damage of the reservoir.