A Selective Plugging Agent for Horizontal Wells

The horizontal well suffers from serious water influx problems, so the development of efficient selective blocking agent becomes more and more important for water shutoff treatment in horizontal wells. In this paper, a novel selective water-blocking agent, emulsified asphalt, was used to solve the water production problem. For the emulsified asphalt, its rheological property, particle size distribution, stability and plugging capacity were discussed. The experimental results were as follows: The viscosity of emulsified asphalt was very low, and the frequency distribution of emulsified droplets with the size less than 3μm exceeded 80%. The emulsified asphalt had strong stability, keeping stable for at least 150 days. The heterogeneity of the reservoir was reduced significantly resulting from the plugging of the emulsified asphalt. Steam injection experiment showed that the blocking agent could also be used as a steam channel blocking agent in heavy oil thermal recovery wells. Hence, the emulsified asphalt was suitable to be used as blocking agent in horizontal wells and thermal recovery ones.