Research Of The Anti-swelling Agent In Ji Zhong Sha-ao Oilfield

Clay minerals are easy to swell,disperse and migrate in the water, thereby blocking the throat of pore structure, reducing formation permeability, ultimately, affecting well yield and water injection. In order to solve problems of high injection pressure and difficult injection proration caused by serious water sensitivity, the technology of anti-swelling was studied in this paper. 16 different types of anti-swelling agents were collected in this paper. Those anti-swelling agents were selected and compounded by the centrifugal method to form four kinds of formulas whose swelling prevention ratio may achieve 96%. Evaluations showed that these formulas had high anti-washing capacity and can effectively inhibit the damage of core in the process of water injection. Moreover, injection time, injection cycle and injection rate of anti-swelling agents were studied which possess guiding significance to the field use of anti-swelling agents. In addition, a formula consisting of ZYKM-01, FG and ZJ was designed for the purpose of anti-swelling and shrinkage performance in this paper, anti-swelling rate could reach 92.5% and shrinking rate 68% on average. The principle of well selection applicable for anti-swelling and shrinking technology, and design basis of parameters in field testing project were summarized. The anti-swelling agent studied in this paper has been used in 30 wells of JiZhong Shaao field, of which 21 wells'injection pressure were brought under effective control. The application in Zhou 16-9 field showed that anti-swelling and shrinking technology was effective in augmented injection.