Performance and application of high-strength water-swellable material for reducing lost circulation under high temperature

Mud loss has a significant effect on drilling operation and reservoir formation damage. Bridge plug and quick-drying cement plug are widely used to control mud loss during drilling operation. However, the leakage of variable and useful materials would impair the loss control effect. In this paper, DPP was adopted by choosing suitable monomers, crosslinking agents, initiators and optimum dosage, which would react at 60°Cand dry at 120 °C. To verify the plugging performance of the DPP, tests were conducted both in laboratory and in field. The experimental results display that the swelling ratio of the DPP in bentonite slurry and clean water is 16 times and 22.8 times, respectively after 6 h, while the swelling ratio of the DPP is unstable in different formulations. The slurry was formulated as substrate +4%DPP with a constant filtration rate as 0. The plugging paste formula is base paste +5%DPP+10% additive, and the plugging strength can reach more than 10 MPa. DPP still has remarkable effect when the temperature is up to 150 °C. The application of DPP in 8 wells of a gas field in China is one of the most notable cases of this work, which demonstrates that the success rate of one operation increases from 33% to more than 90%, and the formation ability is obviously improved after leak plugging operation. DPP meets the design and construction requirements for loss control in gravel, coal and buried hill strata. Therefore, the positive plugging strength and high temperature tolerance of DPP can provide strong technical support for the safety drilling. •The expansion coefficient of DPP in bentonite slurry and water reached 22.8 times, the constant filtration rate reach 0. In high-temperature formation, the formula plugging strength reach 10 MPa.•This plugging agent can be made according to different particle sizes and proportions requirements.•The application results show that the new expansion resin has a good pressure plugging ability in different wells.