I am an oil well integrity engineer. Need help in understanding gas solubility in oil-based drilling mud (OBM) when the mud is gelled. Normally, oil based mud is an emulsion, where continuous phase is some type of oil (~70%), and remaining is dispersed water/brine droplets, various additives to get to desired drilling mud properties. Gas is highly soluble in OBM, mostly due to base oil is it's main component. However, drilling mud is thixotropic and becomes like a gel when static. Don't know exact mechanism, but something like molecules connect to create long chain polymers, thus forming gel (?).

I am trying to understand, if gas is diffused into the mud after it has become like gel, would the gas dissolve in the same way as it would in thin mud (before it's gelled). Considering, how non-polar molecules dissolve in non-polar solvents, I tend to think that not as much gas would dissolve, but I might be wrong. Please, help me.

  • $\begingroup$ That is not how a "gas kick" type incident happens in a well ,if that is what you are after. $\endgroup$ – blacksmith37 Mar 18 '20 at 1:17
  • $\begingroup$ No, I am not interested in drilling at this point. I am interested in very low rate gas entry (leak) into well annulus space during production. $\endgroup$ – NailaS Mar 18 '20 at 4:38

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