Integrated Technology of Water Plugging and Acidizing of Hydrofractured Oil Wells

摘要

An integrated technology combining water plugging and acidizing in the same flooded oil well is studied with the goal of controlling the water content of the oil and attaining a comprehensive synergy. For this, a micro- and macro-fracture porosity model and four models with other kinds of fractures are built. The feasibility of application of gel water plugging system in this integrated technology is evaluated. The experimental results show that the gel system is effective in high-permeability interlayer plugging (plugging degree > 99%), but not very effective in low-permeability interlayers. Multi-slug injection reduces the impact of subsequent acidizing on the effectiveness of the pugging material. At the same time, the degree of oil recovery by displacement with water for the fracture porosity model is not high, but after polymer plugging system injection, recovery increases, reaching more than 60%. The proposed integrated technology was applied in two wells in the Chongqing oilfield. Oil production of each well increased on an average by 1 ton/day for more than one year.