Research And Application Of Water Soluble Shielding Temporary Plugging For Chengdao Oil Field

Temporary blocking technology is widely used in the oil industry to prevent well leaking. In recent years, in order to satisfy the needs which include preventing the killing fluid, flushing fluid, cementing slurries and other exotic fluid invading into reservoir and preventing harmful acid flow to the high permeability interlayer,etc, more and more temporary blocking technology methods have been applied in oil production. The most commonly used one is oil-soluble temporary blocking technology, but in high water production wells and injuction wells this method could not be than effective. As the oil field production develops, reservoir pressure will gradually decline, water content will gradually increase, so it is of great urgent need to use water-soluble temporary blocking technology,taking advantage of its easy to use, cost-effective, convenient to plug which make it more suitable for our old oilfield development post high water feature.In this paper, Chengdao offshore oilfield of Shengli Oilfield is choosed as test area.Water-soluble temporary plugging material type, water-soluble, temperature resistance,sealing performance and other aspects are studied, for the purpose of finding preferably suitable water-soluble blocking material. And make water-soluble temporary blocking agent and rock hole roar compatibility studies, selecting water-soluble temporary blocking material suitable for different sizes of pore-throat. Developed a temporary blocking agent suspension which has high dispersed suspension ability, does no harm after entering the reservoir reservoir and protects the oil-contain layer. Water-soluble temporary blocking system plugging ability, plugging valid time, the permeability recovery performance are studied. Indoor simulation experiments show that when the experimental preferred water-soluble temporary blocking formulations are used in sealing, pressure withstand reaches 10 MPa or more, temporary blocking stabile, plugging smooth application and temporary blocking acidification can adjust the wash acid profile better, to ensure acidifying effect of heterogeneous reservoir.Field application shows that temporary blocking acidification technology has these following superiorities, construction is simple and easy, no additional stratification measures, the amount of fluid needed is less than general acidification, plugging effect isbetter; also, temporary blocking acidification takes the anvantages of simple construction,low cost, high success rate, economic effective, no environmental pollution and so on; using temporary blocking acidification can ease the contradiction between layers. The application of temporary plugging acidizing technology can effectively overcome the shortcomings of the traditional acidification, achieve the effcct of uniform acid spread, increased acid absorption profile, uniformly improve layers permeability, and further improve the acidifying effect. Water-soluble temporary blocking technology in such reservoirs has good promotional value.