Yes, they did, not sure if they have kept up the patent fees though. Also doubt they are worth the paper they were written on, as they tried to sue Haliburton about 4 years ago and then both sides dropped the suits around the time crude oil crashed in 2014 like it is doing again this year. Their nitch was fracking water recycling which the recent trumplican team has eliminated the need for by legalizing waste dumping in our back yards....
I called the stock here overvalued about 6-7 years ago at about .70/share. Looks like I was right.
I watch it out of curiosity since this is one of the fields I work in.
All of my posts are strictly opinions and should not be considered to be facts, or investment advise. They are for entertainment purposes only.