WorldOil

Seven years of successfully constructing difficult North Sea HPHT wells using cesium formate brine

Formate brines have a long history of successful use as reservoir drill-in, completion, workover and suspension fluids in High Pressure/High Temperature (HPHT) well construction operations. These applications have included about 120 cases in which high downhole pressures have necessitated the use of cesium formate brines for well control purposes. With its superior HSE profile and low corrosiviness, cesium formate has proven to be an excellent replacement for the traditional zinc bromide brine, and is now the only high-density (i.e., specific gravity greater than 1.72) clear brine completion fluid used in North Sea HPHT wells. Statoil (now StatoilHydro) has deployed cesium formate brines as well construction fluids in 57 HPHT operations in the North Sea since early 2001, including the drilling and completion of the reservoir sections of 13 high-angle HPHT development wells in Huldra and Kvitebjørn Fields.