EXPERIMENTAL STUDY OF A NOVEL ENVIRONMENTAL FRIENDLY DRILLING FLUID LOSS ADDITIVE WITH HIGH TEMPERATURE RESISTANCE PERFORMANCE

In order to minimize the adverse impact of drilling fluid on the environment, it is of great significance to realize the harmonious and sustainable development of protecting the natural environment and oil and gas exploration and development. And the construction of an environmental friendly water-based drilling fluid system on the basis of natural polymer modification is taken into account. In this paper, N-vinyl pyrrolidone (NVP) was used as a modifier to synthesize DFN-1, an environmental friendly fluid loss reducing agent for water-based drilling fluid with little influence on the rheological property of drilling fluid and high temperature resistance of 150 degrees C. The thermal stability of DFN-1 was evaluated by thermogravimetric analysis. The functional groups of the products were evaluated by infrared spectroscopy. The results showed that NVP was successfully grafted onto starch molecules, and the thermal degradation temperature is 320 degrees C. The experimental results show that DFN-1 has little effect on the rheological property of drilling fluid, and the salt resistance can reach saturation. The experimental results of biodegradability evaluation show that DFN-1 is easy to biodegrade and can be used as a high temperature fluid loss reducing agent for environmental protection drilling fluid.