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Making a full recovery
A chemical Enhanced Oil Recovery (EOR) technique, which uses novel surfactant molecules to flush out difficult to reach reserves, could provide one solution to the global energy challenge by significantly increasing oil recovery rates.
We are building an understanding of how to design surfactants for different oil reservoir conditions.
Watch a short film on the story behind the development of the surfactants used in Enhanced Oil Recovery.
There are still significant reserves of oil yet to be harvested across the globe - the problem is getting them out of the ground. In a typical oil field, conventional production methods extract, on average, about one third of the oil. The rest stays in the ground because it is too costly or too technically difficult to extract.
When an oil well is drilled it is not just like tapping into a vast underground lake. The oil may be contained within a variety of complex geological rock structures.
As reserves decline, it becomes more costly and more complicated to reach the remaining oil and bring it to the surface.
At a time of surging global energy demand, Shell and other oil companies are actively looking at ways to squeeze extra barrels from ageing oilfields. One of the latest techniques relies on the unique molecular structure of Shell Chemicals surfactants, more typically found in household detergents and soaps, to literally wash the oil out.
In this technique, the oil reservoir is flooded with water containing a small percentage of surfactant and other additives. This solution reacts with natural acids in the trapped oil, creating a micro-emulsion similar to soap lather.
The surfactant is key to the formation of the exact type of micro-emulsion that will break down the interfacial tension with the target oil. This is critical to both mobilise the oil and enable it to escape from the rock.
Each reservoir has different characteristics in terms of permeability, porosity, crude oil type, temperature and water composition and so the surfactant has to be closely matched to the specific conditions in order to achieve the desired interaction.
Once mobilised, the oil is able to flow out of the reservoir, in a similar way to how conventional laundry detergents shift soil from clothing and carry it away with the wastewater.
Research teams in Shell’s Amsterdam and Houston laboratories are developing and testing new surfactant molecule designs specifically for EOR. By studying the behaviour of these molecules when they interact with oil we are building an understanding of how to design optimum surfactants for different reservoir conditions.
EOR has the potential to add significantly to the amount of oil that can be extracted from fields. If recovery from existing reservoirs globally could be increased by just one percent, it could deliver 88 billion barrels of additional oil. Experts estimate that around 750 billion BBL of oil could potentially be recovered by chemical EOR.
This feature was added to the Innovations section in August 2008.