A novel nano-sized polymer microsphere as a potential shale stabilizer in water-based drilling fluids

摘要

Borehole instability caused by pore pressure transmission and shale hydration gives rise to a number of problems, which has been a challenge during oil and gas drilling process for many years. In this paper, a novel nano-sized polymer microsphere as a potential shale stabilizer in water-based drilling fluids for drilling troublesome shale formations was successfully synthesized and characterized. Its shale inhibition characteristic was investigated with hot-rolling cuttings dispersion test and linear swelling test. The results indicated that it had good performance to prevent shale hydration. In addition, pressure transmission test was carried out to evaluate the sealing performance of the prepared polymer microsphere. The nano-sized polymer microsphere could effectively retard pore pressure transmission and reduce the permeability of shale samples. Hence, the prepared novel nano-sized polymer microsphere may be a potential stabilizer in the water-based drilling fluids for drilling troublesome shale formations.