Multifunctional High Temperature Water-Based Fluid System

The development of deep oil and gas reservoirs requires high temperature stable drilling fluid systems. The properties of conventional polymers in water-based systems decline above 300°F which led to the development of the new high temperature water-based system. The high temperature water-based system, featuring a newly developed synthetic polymer, has been developed to provide enhanced rheological profiles and fluid loss control, along with long-term stability under elevated temperature and pressure conditions. The system has been designed to minimize formation damage by forming a thin and ultra-low permeable filter cake. The versatility of the developed polymer allows the new system to be formulated at a wide range of densities using most conventional oilfield brines including monovalent and divalent halide and formate brines. The clay-free high temperature drilling fluid has stable rheological properties, no gelation and low sag tendencies which are ideal for high temperature logging applications. Also, the highly branched nature of the polymer provides a rheological profile suitable for coil tubing applications. A new breaker package was developed along with the high temperature water-based system to slowly and uniformly clean-up its deposited filter cake, reducing near wellbore damage and maximizing production when the system is used to drill open-hole completion wells. This paper summarizes the fluid design in the lab and recent field applications, where the new high temperature polymer-based system was successfully deployed in different locations around the world.