A method having the following steps: running a circulation valve comprising a reactive material into the well bore on the casing; reverse-circulating an activator material in the well bore until the activator material contacts the reactive material of the circulation valve; reconfiguring the circulation...http://www.google.com/patents/US20080060803?utm_source=gb-gplus-sharePatent US20080060803 - Casing Shoes and Methods of Reverse-Circulation Cementing of Casing
