Texas Natural Resources Code - NAT RES § 91.012. Water in Wells

(a) In boring any well for oil or gas, if a person pierces any cap rock or other geological formation in a manner that will cause a flow of salt water or fresh water injurious to an already bored oil well or any oil or gas deposits and that will probably result in the injury of the oil or gas field or already bored oil or gas well, the person shall abandon immediately all work on the well if the flow of water cannot be cased off and shall plug and fill the well in a manner and with materials that will stop the flow of the water.

(b) No well owner or person boring a well described under Subsection (a) of this section may remove the casing from the drilled well until the flow of water is stopped either by casing off or plugging the well.

(c) The provisions of this section apply only if the cap rock or other formation is pierced at a depth below the horizon at which oil or gas has been discovered already.