ENORDET product overview

What is enhanced oil recovery?

Enhanced oil recovery (EOR) is a term that describes a group of technologies designed to increase the recovery of oil from oil reservoirs. When an oil field reaches the end of its normal life, as much as two-thirds of the oil can be left in the ground because it is too difficult or too expensive to get out. By recovering just 1% of that extra oil, it is estimated that the equivalent of 88 billion barrels of oil would become available.

One of the EOR technologies is Alkaline Surfactant Polymer flooding or ASP-flooding. The ASP ingredients are dissolved in water and used to flood the oil reservoir. Shell Chemicals supplies surfactants used in this technology. 

What are ENORDET surfactants for enhanced oil recovery?

ENORDET* is short for ENhanced Oil Recovery DETergents. These materials are surfactants, based on alcohol alkoxy sulfates (alkyl ether sulfates) and internal olefin sulphonates.

Shell Chemicals is building on long-standing experience in surfactant manufacturing to develop and manufacture high-performing EOR surfactants.

How are ENORDET surfactants used?

The oil reservoir is first flooded by adding water containing a small percentage of surfactant. Surfactants can lower the crude oil/water interfacial tension (IFT) to an ultra-low level allowing oil globules in the reservoir to flow through rock pores and coalesce to form a clean bank of oil. To make this work, specific surfactants need to be selected and matched to specific reservoir conditions, taking into account:

• Temperature
• Water salinity and divalent ion (Ca, Mg) concentration
• Crude oil type (total acid number, viscosity, etc)

Selection of the right surfactant is important in preventing the formation of higher viscosity emulsions, which would otherwise become trapped and prevent effective transport of the surfactant solution through the reservoir.

Alkali, usually in the form of sodium carbonate (soda-ash), is often added to the aqueous solution to increase efficiency. It generates natural soaps through reaction with acids in the crude oil and also reduces surfactant absorption on rock surfaces. A water-soluble polymer is usually added to increase the viscosity of the water phase.

The ASP solution is usually followed by a polymer solution that acts as a piston to push the oil through the reservoir to the producing wells. 

What are our key strengths as a supplier of enhanced oil recovery surfactants?

Supply Security: Shell is the largest integrated producer of internal olefins, alcohols and ethoxylates globally. Our manufacturing processes, which are ISO 9001 and ISO 14001 certified, have proven themselves over decades.

Proven technology: the Shell Higher Olefin Process (SHOP) underpins the manufacture of cost effective high molecular weight internal olefin sulfonates. The Shell Hydro Formylation (SHF) process offers unique alcohol manufacturing flexibility.

Technical support: our technical specialists, located in Houston and Amsterdam, work closely with customers to identify the appropriate products for their needs, and to optimise customer formulations. See also ‘Customer formulation support'.

Flexible solutions: by making a crude-specific formulation, comprising two or three ENORDET surfactants, a wide range of crude oils and reservoir conditions can be matched.