Soap bubbles increase gas production

Adding soap to a gas production well increases its lifespan. Dutch gas company NAM expects a production increase between 5-15 %.

At the end of its lifetime, pressure goes down in a gas production well. Consequently, the water originating from the well is not blown upwards anymore but accumulates at the bottom of the pipe. Thus, the hydrostatic pressure builds up, and once it equals the pressure in the well, production comes to a halt.

Adding soap to the bottom of the well transforms water into course foam, which, due to its lower density, does get transported up the pipe. Thus, the water doesn’t pile up to smother gas production, and older production wells may be active for a longer time.

That’s good news for the Dutch gas company NAM since the technique allows them to continue producing gas from various small offshore fields in the North Sea. Most of these fields have been active since the 1970s and are prone to pressure falls. Currently, some 25% of NAM’s production comes from these small offshore fields. The lifetime of many fields can be extended by the use of soap.

“Every year, we’ll equip a minimum of ten production platforms with a soap installation”, said NAM’s public relations manager Willem Rogge at last week’s demonstration of the soap technology. He declined the suggestion that extra production from the North Sea could decrease NAM’s reliance on the Groningen gas fields.

Estimates of extra production due to the soap technology vary between 5 to 15 %. The higher estimate is based on a combination of enhancing technologies including soap injection.

“Normal soap will do the trick in the lab”, said TU researcher Dries van Nimwegen MSc. He worked on an 18-meter high demonstration pipe in the new lab for process and energy research at the faculty of 3mE. “But in the field, the surfactant needs to be stable over a large temperature range. Outside the pipe it may be freezing while deep down the temperature may get very high. You need special chemicals to do the job well.”

He doesn’t see risks for environmental pollution since the super soap solution that rises to the surface is biodegradable and will be separated from the gas and injected back into the gas reservoir.

“The technology is not new”, says Van Nimwegen who tells that Americans used to throw a stick of soap into an ailing well to recover the production. “What’s new is the systematic research into the technique.”

That research has led to two publications in the International Journal of Multiphase Flow with his Ph.D. supervisors Professor Ruud Henkes (3mE) and Dr. Luis Portela (TNW) as his co-authors. On June 15, 2015 Dries van Nimwegen will defend his Ph.D. thesis with the title The Effect of Surfactants on Gas-Liquid Pipe Flows.

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