Coating Development for High Temperature Dissolvable Rubber Element in Dissolvable Plug Applications

Dissolvable tools have been used more in unconventional oil and gas operations in recent years. Currently, more and more wells in Southwest of China requires high temperatureHigh temperature (HT) dissolvable plugDissolvable plug. The HT dissolvable plugDissolvable plug needs to hold 70 Mpa pressure differential in water at 150 °C for 24 h. On the other hand, after the pressure holding test, the dissolvable plugDissolvable plug needs to be dissolved in 1% KCl at 95 °C in less than 15 days. These requirements put big challengesChallenges on dissolvable rubberDissolvable rubber sealing materialsSealing materials. To meet the industrial challengesChallenges, several special HT coatingsCoating were developed to delay the dissolution time of the HT dissolvable rubbersDissolvable rubber. Two coatingsCoating delayed the dissolution time of dissolvable rubberDissolvable rubber coupons from 16 h to 14 days. Two dissolvable plugsDissolvable plug with coatingCoating B coated dissolvable rubberDissolvable rubber element passed the testing requirements. Based on our knowledge, this is the first time in the industry a HT dissolvable plugDissolvable plug with dissolvable rubberDissolvable rubber sealing element passed the requirements.