water based drilling mud

I am hearing that 88e used water based drilling mud in WINX1. Normally water based drilling fluids are not used on formations where clays are present. Water and clay form slurries which can significantly reduce flow since pores in reservoir rock become blocked. Oil based synthetic drilling fluids are the preferred option
when clay is present in formation rocks. Obviously 88 were not aware of clays present within the sandstone but had OBS fluids been used the near bore rock may not have blocked
with clay. What's done is done re the current drill, I suppose if the above is indeed correct there is a small chance of a side track as there is still time, just. Probably wont happen though
as the thinking is there may well be better reservoir Updip, closer to Horseshoe and once all the data is reprocessed we will drill next year. Thoughts?