Use of polymer resins for surface annulus isolation enhancement

Abstract

Cementing is an extremely important task in oil/gas well drilling operations to ensure integrity of the well, and to prevent gas and oil migration through the cement matrix for an extended period. This could lead to sustained pressure in the casing annulus (CCA). Sometimes, cements or chemicals are injected from the surface to improve wellbore isolation. Two parameters control this surface operation success; injectivity and pressure. The objective of this paper is to demonstrate the ability of different types of resins in shallow remedial operations at different parameters of injectivity and pressures to improve wellbore isolation. Examples of these resins are epoxy resin system and polyester resins. Epoxy based resin is prepared by mixing an epoxy resin with an aromatic amine-curing agent. A polyester resin system is made by mixing polyester resin, norpol peroxide curing agent, filler, and silicon dioxide. Intensive lab testing and pilot testing were performed at shallow conditions to assess the limitation of each type of resin and to optimize on operational procedures. For such surface operations at low injectivity profile, it is expected to have solids free resin for deeper penetration. Short setting resins are desired over extended ones to allow for proper isolation and quick sealing. The paper will discuss best practices to perform the surface operations and will highlight limitations and benefits of both resins supported by intensive lab testing and field applications.