What is Enhanced Oil Recovery?
When the conventional extraction of oil from a reservoir has been completed, as much as two-thirds of the oil is typically left behind. Enhanced Oil Recovery (EOR), also known as tertiary recovery, can then be used to get substantially more of the crude oil out of the reservoir.
EOR describes a range of techniques that use steam, gas or water to push the oil out from where it is trapped in the pores of the rock. In the case of water, extraction can be further improved by adding small amounts of detergents and other additives.
Shell Chemicals, with strong cooperation from Shell Upstream, has developed these detergents – and has the required manufacturing capacity to make them. We market the Enhanced Oil Recovery Detergents under the ENORDET name.
How do ENORDET products work?
Oil and water don’t mix. That’s why adding water alone to an oil reservoir is never fully effective in extracting the oil. To improve this, chemicals can be added to the water. Three components work together: soda-ash (Alkali), detergent (Surfactant) and a thickener (Polymer). When this ‘ASP’ combination is used, it’s described as chemical EOR (cEOR).
The ENORDET surfactants enable the oil and water to mix due to the creation of a so-called ultra-low interfacial tension between the oil and water. The alkali and polymer add to the effectiveness of the process.
Why Shell Chemicals?
Shell Chemicals manufactures and sells large volumes of the oil-loving part of EOR surfactants, known as ‘hydrophobes’. We already sell these materials to some of the world’s largest detergent makers and many other leading global companies.
We have substantial manufacturing capability offering essential security of supply to our customers. We sell the ‘hydrophobes’ as a raw feedstock for others to further process, or contract a third party to convert them into the finished EOR surfactants.
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Product range & applications
We offer two types of dedicated enhanced oil recovery surfactants: alcohol alkoxy sulfates (AAS) and internal olefin sulfonates (IOS). Correct blending of these surfactants allows the (Alkaline) Surfactant Polymer solution to be matched to the reservoir conditions, so achieving optimal oil recovery performance.
The benefits of each surfactant type can be summarised as follows:
EOR Surfactant type benefits
Developing the correct combination of surfactants prevents the formation of viscous micro-emulsions, which may otherwise hamper efficient transport of oil through the reservoir pores and to the producing wells.
Sometimes, the use of a co-solvent (such as IBA or SBA) in combination with ENORDET surfactants can help in reducing micro-emulsion viscosities and so improve the sweep efficiency and ultimate oil recovery.
Key data for ENORDET surfactants
Carbon number chain length
PO/EO per alcohol unit (mol/mol)
Applicable temperature range
Di-valent ion tolerance
|O242||IOS||C20-24||low/med||N/A||ambient to 200°C||limited|
|O332||IOS||C15-18||high||N/A||ambient to 200°C||limited|
|O342||IOS||C19-23||medium||N/A||ambient to 200°C||limited|
|O352||IOS||C24-28||low ||N/A||ambient to 200°C||limited|
|LTS-18||LTS||C18 (25)||low||NA||ambient to 250° C||limited|
|J771||AAS||C12-13||low/med||7 PO||ambient to 60°C or 80°C* ||excellent|
|J13131||AAS||C12-13||low/med||13 PO||ambient to 60°C or 80°C* ||excellent|
|C031||AAS||C12-15||high||3 EO||ambient to 60°C or 80°C* ||excellent|
- IOS: internal olefin sulfonate
- AAS: alcohol alkoxy sulfate, or alkyl ether sulfate
- LTS: Linear alkyl Toluene Sulfonate. Applicable for steam-foam and (A)SP formulations.
- Applicable salinity: the range of salinities where a surfactant can be applied is formulation dependent
- Recommended applicable temperature range for the AAS is formulation dependent: Up to 60°C for the AAS alone, up to at least 80°C for an AAS/IOS combination. ASP formulations will have higher stability than SP formulations.
- Di-valent tolerance: effective di-valent ion tolerance is formulation dependent
Concentrated ENORDET surfactants: cutting logistic costs
For large scale commercial application it is preferable to ship concentrated surfactants thus minimising transport costs and reducing storage space. Depending on the concentration and surfactant type, the ENORDET surfactants can range in physical properties from low viscosity liquids to higher viscosity pastes.
To simplify operations in the field, it may be desirable to ship the surfactant system as a concentrated blend rather than ship the single surfactants. This has the advantage of only needing one surfactant storage tank and removes the need for on-site surfactant mixing. An additional benefit is that a combination of IOS and AAS surfactants often results in a lower viscosity liquid, which is easier to handle than a paste.
We can support you in developing a surfactant formulation for your oil field. For this we would need a crude-oil sample that is representative for your reservoir.
Crude-oil parameters like total acid number (TAN) and viscosity may be taken into account when formulating, as well as brine composition - salinity and hardness. The specific reservoir conditions, such as temperature, permeability and rock type, as well as practical considerations such as the availability of fresh water or softened (saline) water will also need to be discussed.
Additional practical considerations to include are the constraints posed by the location of your field. For example, off-shore locations often have limited storage space, weight and power availability.
Core flood testing using the customer’s crude-oil and brine under the prevailing reservoir conditions can be arranged in cooperation with selected independent laboratories.
Concentrated ENORDET surfactant blends
To simplify operations in the field, it may be preferable to ship the surfactant system as a concentrated blend rather than ship the single surfactants.
In these circumstances, Shell Chemicals can develop a customer-specific, concentrated blend. The parameters to be taken into account will be discussed with you. These can include prevailing climate, storage options, logistic challenges (e.g. off-shore supply), modes of shipment, product unloading and mixing into the water stream. Given the many possibilities, blend development will need to be done in close collaboration with our customer.
Manufacturing & supply
Manufacturing & supply security
Shell Chemicals companies are large volume suppliers of surfactants and surfactant feedstock to major detergent manufacturers. We operate world class production facilities in Geismar, Louisiana (USA) and in Stanlow (UK), that are ISO 9001 and ISO 14001 certified. By being fully integrated with the ethylene feedstock supply chain, we offer a strong record of reliable supply to our customers.
We serve customers globally; products can be shipped using isotanks, railcars and trucks. Smaller quantities, typically for field tests such as single-well test (SWT) or multiple well pilot (MWP), can be arranged in intermediate bulk containers (IBC) or drums.
We work continually to reduce transport costs for our customers by offering more shipping options. Examples of our innovative approach include: high active matter (HAM) liquids and pastes and effective means to dilute these concentrates down to the required concentration in the final ASP solution.
Health, Safety, Security & Environment (HSSE)
Shell chemicals companies are committed to complying with all regulations during manufacture, transport, storage and use of our ENORDET surfactant products. HSSE specialists are available to support our customers in meeting their HSSE requirements.
- Application of Internal Olefin Sulfonates and Other Surfactants to EOR - Part 1: Industrial Production, Structure Performance Relationships, Handleability
Presented by Julian Barnes, Principal Researcher Higher Olefins and Derivatives/Chemical Enhanced Oil Recovery, Shell Global Solutions International
- Application of Internal Olefin Sulfonates and Other Surfactants to EOR - Part 2: The Design and Execution of an ASP Field Test
Presented by Marten Buijse, Principal Research Chemist for Enhanced Oil Recovery, Shell Global Solutions International
- Alkaline-surfactant-polymer flooding - Laboratory and single well chemical tracer test (SWCT) results
Presented by Rien Faber, Principal Research Chemist for Enhanced Oil Recovery, Shell Global Solutions International
Shell Chemicals presentations
A variety of documents are available on the OnePetro website of technical documents and journal articles serving the oil and gas exploration and production industry.
|SPE number||Title||Date||Published by|
|SPE-190453-MS||Large Scale EOR Projects: Cutting Costs on Surfactant Supply Logistics. This paper was prepared for presentation at the SPE EOR Conference at Oil and Gas West Asia held in Muscat, Oman.||26-28 March 2018||Shell|
|SPE-179573-MS||Essentials of Upscaling Surfactants for EOR Field Projects”. This paper was prepared for presentation at the SPE Improved Oil Recovery Conference held in Tulsa, Oklahoma, USA.||11–13 April 2016||Shell|
|SPE-177613||Quality Assurance and Control of Surfactants for Field Scale EOR Pilot Projects. This paper was prepared for presentation at the Abu Dhabi International Petroleum Exhibition and Conference held in Abu Dhabi, UAE.||9–12 November 2015||Shell|
|SPE- 169096||Effects of Hardness and Co-surfactant on Phase Behavior of Alcohol-Free Alkyl Propoxylated Sulfate Systems. Presented at the 2014 SPE Improved Oil Recovery Symposium held in Tulsa, Oklahoma, USA. ||12-16 April 2014||Shell |
|SPE-159620||A New Approach to Deliver Highly Concentrated Surfactants for Chemical Enhanced Oil Recovery. Presented at the SPE Annual Technical Conference and Exhibition held in San Antonio, Texas, USA||8-10 October 2012||Shell |
|SPE-154084||Controlled Hydrophobe Branching to Match Surfactant to Crude Oil Composition for Chemical EOR. Presented at the 2012 SPE Improved Oil Recovery Symposium held in Tulsa, Oklahoma, USA||14-18 April 2012||Shell |
|SPE-129769-PP||Application of Internal Olefin Sulfonates and Other Surfactants to EOR. Part 2: The Design and Execution of an ASP Field Test". Presented at the 2010 SPE Improved Oil Recovery Symposium held in Tulsa, Oklahoma, USA||24–28 April 2010||Shell |
|SPE-129766-PP||Application of Internal Olefin Sulfonates and Other Surfactants to EOR. Part 1: Structure - Performance Relationships for Selection at Different Reservoir Conditions. Presented at the 2010 SPE Improved Oil Recovery Symposium held in Tulsa, Oklahoma, USA||24–28 April 2010||Shell |
|SPE-129675-PP||Surfactant systems for EOR for high salinity, high temperature environments. Presented at the 2010 SPE Improved Oil Recovery Symposium held in Tulsa, Oklahoma, USA||24–28 April 2010||Rice University and Shell|
|SPE-113314-PP||Phase Behaviour Methods for the Evaluation of Surfactants for Chemical Flooding at Higher Temperature Reservoir Conditions. Presented at the SPE Improved Oil Recovery Symposium held in Tulsa, Oklahoma, USA||19–23 April 2008||Shell and Rice University|
|SPE-113313-PP||Development of Surfactants for Chemical Flooding at Difficult Reservoir Conditions. Presented at the SPE Improved Oil Recovery Symposium held in Tulsa, Oklahoma, USA||19–23 April 2008||Shell and Rice University|
|SPE-100089||Identification and Evaluation of High Performance EOR Surfactants. Presented at the 2006 SPE/DOE Improved Oil Recovery Symposium held in Tulsa, Oklahoma, USA||22-26 April 2006||University of Texas|