Chalk emulsion: a new completion and workover fluid

Journal Article · Sat Jul 01 04:00:00 EDT 1972 · Pet. Eng.; (United States)

OSTI ID:5925035

Darley, H C.H.

Chalk emulsion is a water-in-oil emulsion developed at the Shell Development Co. research laboratory specifically for completion and workover operations. Oil muds have 2 advantages over water-base muds: the oil filtrate does not impair water-sensitive formations and low density fluids can be prepared for depleted reservoirs. The patented emulsion differs radically from conventional inverts in that it is stabilized by solids instead of organic emulsifiers. The solids are composed of finely divided chalk, treated so it will be adsorbed at the oil- water interfaces and form a skin around the water droplets. When the skin is dissolved by acid, the droplets coalesce and the emulsion breaks to clear oil and water. All other particles which may be included for bridging or weighting purposes also are carbonates and can be dissolved by acid. Furthermore, the emulsion is temperature-sensitive. It will break after standing a few days at reservoir temperature. Chalk emulsion is made with relatively inexpensive ingredients so the initial cost is low for an oil mud. The biggest cost item is the diesel oil. However, it can be made with almost any crude oil. The basic ingredients can be supplied as a treated powder in sacks. At the rig, the powder is added to the oil and water through the hopper and the emulsion made with the rig pumps.

• OSTI ID: 5925035
• Journal Information: Pet. Eng.; (United States), Journal Name: Pet. Eng.; (United States) Vol. 45:7; ISSN PENGA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
COLLOIDS
COST
DISPERSIONS
DRILLING RIGS
EMULSIONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PUMPS
RESERVOIR ROCK
TEMPERATURE DEPENDENCE
WELL COMPLETION