ENORDET product overview

Enhanced oil recovery comprises 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, the bulk of its oil (as much as two-thirds) is left in the ground because it is too difficult or too expensive to get out. It is estimated that by recovering just 1% extra throughout the world, the equivalent of 88 billion barrels of oil would be available. 

Surfactant-based enhanced oil recovery utilises surfactant with polymer (SP) and often with the addition of alkali (ASP) to increase the recovery of oil.

ENORDET surfactants are a range of products specifically developed for enhanced oil recovery. They are based on alkoxy sulfates and internal olefin sulphonates.

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

In surfactant-based enhanced oil recovery, the oil reservoir is flooded by pumping in water containing a small percentage of surfactant(s). The surfactant(s) overcome natural capillary forces by lowering the crude oil/water interfacial tension (IFT) to an ultra-low level which allows oil globules (ganglia) in the reservoir to flow through rock pores and coalesce to form a clean oil bank. To achieve this, particular surfactant(s) need to be selected and matched to particular reservoir conditions:

• temperature
• water salinity and divalent ion concentration
• crude oil type (total acid number, viscosity, etc)

Selection of the correct chemical structure of surfactant(s) is important to prevent the formation of higher viscosity emulsions, which would otherwise become trapped and prevent effective transport of the surfactant solution through the reservoir. Alkali is often added to the aqueous solution of surfactant(s) to increase efficiency.

Alkali generates additional natural surfactants through reaction with acids in the crude oil and also reduces surfactant absorption on rock surfaces. A water-soluble polymer (HPAM) is usually added to increase the viscosity of the water phase.

The alkali surfactant polymer (ASP) slug is usually followed by a slug of polymer solution that acts as a piston to push the oil bank through the reservoir to the producing wells. Once mobilised, the oil (and surfactant solution) flow out of the reservoir in a way that is related to how conventional laundry detergents shift soil from clothing and carry it away in the waste water.

• Shell is the largest integrated producer of alcohols and ethoxylates globally, offering unmatched security of supply.
• The Shell Higher Olefin Process (SHOP) allows the manufacture of cost competitive high molecular weight internal olefin sulfonates. Our NEODENE product range is manufactured using the same SHOP process.
• The Shell Hydro Formylation (SHF) process offers unique manufacturing flexibility, with a wide variety of alkoxy alcohols and carbon number chains. Our NEODOL product range is manufactured using the SHF process.
• Our technical product experts, located in Houston and Amsterdam, work closely with customers to identify the appropriate products for their needs, and to optimise customer formulations.
• The Shell team offers a depth of knowledge and experience gained over more than 50 years.