Challenging tax assessment in county where one has no mineral rights - Texas?

In Texas, I own royalties on an abstract in Midland county. 7 wells pass thru this abstract and other abstracts ending in Martin county. My royalty revenue is based solely on my Midland county holdings, but I have been notified of an assessment for taxation in Martin county. Has anyone successfully challenged a similar situation? Can you cite an appropriate law or ruling that I might use in a challenge?