Patent ID: 8267170

Claim:
A method of positioning wellbores for forming a double barrier for at least a portion of a treatment area, comprising: forming a plurality of first barrier wells in the formation for a first barrier, wherein a substantially constant spacing separates adjacent first barrier wells; analyzing the formation to determine the principal direction of water flow in at least one layer of the formation; determining an offset distance of the second barrier wells relative to the first barrier wells based on the principal direction of water flow in at least one layer to limit a maximum separation distance between a closest barrier well and a theoretical breach extending from the first barrier to the second barrier along the principal direction of water flow to a distance of less than one half of the spacing that separates adjacent first barrier wells; and forming a plurality of second barrier wells in the formation for a second barrier to a side of the first barrier wells by a substantially constant separation distance, wherein the second barrier wells are offset from the first barrier wells by a distance that is at least substantially the same as the offset distance.