Has anyone sold easements in Karnes County to Enterprise Pipeline?

About a month ago, I received a call from what I would term an "oil well services" representative who wanted permission to perform four types of surveys on my land to determine if it would meet Enterprise's criterion to purchase 40 acres. He indicated that they were surveying several sites in order to select two. He later mailed a description of their plans. I told him no. I can only speculate what they wanted with 40 acres. Has anyone heard anything else about this? Or about Enterprise or other pipeline companies buying easements?

I fully realize that the companies are scrambling to build the infrastructure for current and anticipated production and that it is in all landowners' best interests for this to be done sooner rather than later. And I know that easements can be taken under eminent domain. But...