Demand for fossil fuels will continue for a long time to come, especially from energy-intensive industries. Natural gas is the most green variant within this, but its production becomes more difficult as the gas reservoirs become depleted. One of the problems is liquid loading, the accumulation of liquids in the well. This can seriously disrupt or even stop gas production. Injecting soap is one of the solutions.

Although this technique has been used for some time, there are many ambiguities about the effects of using soap, which properties lead to which results and the quantities required. In the FOAM project, which was co-funded by RVO/TKI, TNO took up the gauntlet together with industry in order to gain more insight into this.

Effects not clear

After gas has been produced from a field for a long time, there comes a moment when liquids in the well block the flow of gas to a greater or lesser extent. By injecting so-called surfactants such as soap into the wells, the liquid is foamed so that gas production can continue unhindered. However, it is still not sufficiently clear which properties of the soap used are effective and to what extent. Any stagnation in production is extremely costly for the oil and gas industry. That is why we devised, described and carried out a comprehensive test procedure.

Ability to predict

We have developed a method to quantitatively predict the results of the injections. How effective is the soap you are going to use and how much do you need to maximise your output? Previous industry tests yielded contradictory results: soaps that were supposed to be effective often turned out not to be. We have carried out various laboratory-scale experiments to gain insight into the gas and fluid flow in the pipelines. We combined the results with the data on the production from the wells made available to us by the companies. We were able to identify qualitative trends and explain why a soap is or is not successful.

Calculation model and guidelines

The tool we have developed can be used by oil and gas companies for an initial assessment. The software is also relatively easy to build into the systems of the companies. In a second project we, together with TU Delft, will look in particular at issues such as thermal ageing and the impact of dissolved salts. We are also going to do the earlier tests on a larger scale. This should lead to an improved calculation model that can accurately predict the flow of gas and liquids and that only requires small-scale tests.
In addition to these predictive methods, we are also working on a guideline to test soap for oil and gas companies and their suppliers.

All in all, the predictive method will reduce the environmental impact and the costs of gas production. In this way, the production of natural gas will become as sustainable as possible.


In the two projects we worked together with NAM, TOTAL, Engie, ONE, TAQA, Wintershall, Petrogas, EBN and TUDelft. The projects were carried out with subsidies from the Ministry of Economic Affairs, National Ministry of Economic Affairs subsidy schemes, Energy Top Sector through the Netherlands Enterprise Agency.