Application of Micro-fracturing and Chelate Acidizing Compound Technology in Bohai Oilfield

With the development of Bohai Oilfield, the incompatibility between injected water and reservoir water cause corrosion and scaling of downhole string, resulting in reservoir pollution, plugging and water injection pressure increasing. Conventional single pressurize and acidizing methods can not solve the secondary precipitation problem of scaling ions. Consequently, period of validity is short and multiple plug removal is needed, which causes high expense. In order to reduce the pressure and increase the injection of water injection wells, referring to the principle of oil well fracturing stimulation, this paper tries to form micro-fractures near the reservoir by water micro pressure cracking plugging without adding sand, then compound boiling acidification technology to improve the sweep efficiency and fingering of acid solution, and prevent the secondary precipitation of scaling ions. The application in Bohai water injection well shows that the water injection pressure has decreased obviously, and the daily water injection volume and apparent water absorption index have increased greatly. After 7 months of production, the daily water injection is still stable without obvious fluctuation, which indicates that the micro fracturing and acidizing technology is capable of improving reservoir permeability, reducing injection pressure, increasing water injection, and long action cycle. It has a good prospect of popularization and application.