WATER BLOCK DAMAGE IN YC GAS RESERVOIR AND ITS PREVENTION MEASURES

YC gas field is the largest reserve found to date in Jiangsu Oilfield. Formation characteristics analysis and test study show that YC gas reservoir is a low permeable gas reservoir, and water blocking in this area is very severe, especially the inflowing fluid water blocking. Technologies for gas reservoir protection are investigated, and such methods as using an oxidizer to remove the filtrate cake blockage on borehole surface, using high inhibitative low-interface tension water base drilling fluid and completion fluid, and speeding the discharge of inflowing fluid in the formation, etc. are proposed to minimize the water blocking damage. The combined method of oxidizing and acidizing is recommended for plugging removal, so as to improve the acidizing effect.