Analysis on Plugging Measures for Leakage in Liujiagou Formation of Dongsheng Gas Field

Abstract:

Dongsheng gas field stepped into the development period in 2013. Along with gradual increase of horizontal well construction, lost circulation accidents occur frequently, single well plugging time in drilling cycle was roughly 8%～50%, which greatly restricted the drilling efficiency. The main leakage zone was in Liujiagou formation, the permeability loss happened when drilling fluid density was low with 3～5m3/h leakage velocity and crack leakage occurred when drilling fluid density was high with 20m3/h leakage velocity until annular return lost. The cracks would expand with the increase of the borehole liquid column pressure, which would cause repeated lost circulation. By the analysis on the leakage characteristics in J58P13H and plugging effect, the adaptability of the composite plugging method, plugging materials for large crack expansion and expansion pipe plugging method in fractured leakage plugging were explored in order to promote these methods in Dongsheng gas field.