Overview

Cesium formate brine is a heavy low-viscosity clear fluid, purpose-designed to provide the oil industry with a better and safer completion fluid for HPHT wells.

Cesium formate brines have been used as completion, well testing and suspension fluids in more than 80 challenging HPHT wells since 1999 and have demonstrated the following advantages over traditional high-density completion brines:

Reduced formation damage — cesium formate is essentially incapable of causing permanent formation damage. Most users report that after a few weeks of production their well productivity indices exceed expectations after drilling and/or completing in cesium formate brine. This is true both for perforated liner and open-hole sand-screen completions.

New improved HSE standards and reduced liability — no other high-density brines come close to matching the high HSE standards set by cesium formate brine. Using cesium formate brine greatly reduces the risk of creating long-term liability down the line.

Cesium formate brine

– made for challenging HPHT completions

Improved well integrity — the use of buffered cesium formate brine reduces the risk of catastrophic localised corrosion and stress corrosion cracking in well tubulars exposed to HPHT acid gas influxes.

Extreme durability — cesium formate brine can be safely deployed in extreme HPHT wells where traditional completion brines would cause major problems. Field experience in the Mako-6 well (BHST: 235˚C/455˚F) in Hungary has shown that suspension fluids based on buffered cesium formate brine will tolerate months of exposure to a combination of extreme temperatures/pressures and acid gas influxes.

The worth of cesium formate brines as HPHT completion fluids in dynamic underbalance perforating operations has been clearly shown in the Visund, Rhum, Braemar and Judy fields. In some cases, cesium formate brine has been successfully deployed as the emulsified internal brine phase of low-solids oil-based completion fluids.