Abstract
Eliminating or controlling lost circulation during drilling or cement operations is a costly and time-consuming process. Water-absorbent resins play an important role in mud loss control for their deformability and water-absorbable and expandable properties. This paper developed a new kind of water-absorbent resin, Double Network Water-absorbent Resin(DNWR), which could be used in deep well or ultra deep well to solve loss problems.
The most difference between DNWR and traditional water-absorbent resins is that DNWR has excellent mechenical properties and good thermal stability; it can be used at the temperature of 150°C for more than 30 days, while the later only could be used below 120°C. The properties and the mechanism of controlling mud loss of DNWR were discussed, after being pumped and squeezed into the formation fracture, DNWR could expand 5–10 times of its original volume, adsorb on the fracture surface, and form a compact sealing layer. Laboratory tests had shown the effectiveness of DNWR in plugging different borehole sizes with a high temperature. The efficiency of this system was enhanced in the laboratory when combined with other inorganic bridge materials which have good thermal stability and optimized particle size distribution.
