Professionals of TatNIPIneft have developed a new technology of well casing and elimination of production tubing leaks using polymer/cement slurry.
The proposed technology is protected by RF patent No.2382172. The method implies that a polymer composition, cement slurry and at the final stage of cementing a polymer/cement mixture are sequentially injected in the amount sufficient to fill the annular space in the productive layer interval.
Fragility of the resulting synthetic resin based polymer/cement stone is lower in comparison with the cement stone. This increases the resistance of the polymer/cement stone to alternating loads, which the cement sheath in the annulus of the pay zone is constantly exposed to in the process of perforation and operation of wells. The cured polymer/cement stone demonstrates high corrosion resistance in corrosive reservoir fluids.
Various synthetic resin based polymer/cement compositions are used as a plugging material, which cure in the cement slurry environment.
The injection of the polymer composition prior to the cement mortar is necessary for the polymer composition to evenly distribute and solidify after penetration into the rock and the mud cake, forming a solid impermeable barrier in the near-wellbore part of the rock. The developed method improves the structural and mechanical properties of the filter cake and the rock contacting with the cake. This saves the reservoir properties due to the formation of the impermeable polymer based barrier in the near-wellbore part. Filling of the reservoir interval annulus with 10-20 m of polymer/cement material overlap in the final stage of cementing provides for high sealing contact of the polymer/cement slurry with the polymer/cement cake crust and the casing metal.
Application of the polymer/cement slurry for the production string sealing will allow the Company's professionals to effectively carry out both sealing and additional sealing of production strings as the resulting polymer/cement slurry filtrate has a high penetrating power, while the cement slurry does not penetrate into the formation pores and fractures. Therefore, the filtrate containing resin penetrates and cures in tight channels and eliminates leakage, while the formed polymer/cement stone prevents squeezing of the filtrate in the process of its curing. Moreover, the resin specifically gets into the leak channels and is not diluted with the reservoir fluids on the way to the wellbore, which typically occurs when pumping pure resins as their density is less than the density of the reservoir fluids.
For more information about related Opportunities and Key Players visit Caspian Region Projects