Emulsifiers

The objective of acidizing treatments is to create new pathways and enhance the permeability to improve the connectivity of the reservoir to the wellbore, increasing production. In carbonate environments or low permeability reservoirs with limited injection rates, it is necessary to control the acid reaction rate, to inhibit the acid from reacting too quick and close to the wellbore. Emulsifiers can be used to mix “acid-inside” emulsions with an oil phase on the outside. The overall effect of this emulsion reduces the acid reaction rate, allowing for further penetration of the acid into the reservoir, and creation of effective wormholes. Emulsions for treatments must also be able to withstand the reservoir temperature, as well as having the correct oil to acid ratio, and appropriate viscosity for its purpose, and therefore thorough laboratory testing is required. Typically, emulsions for treatments are prepared with Hydrochloric acid, and emulsifying agents may include surfactants.