Polymer matrix particles for inhibiting scale formation in oil and gas wells

1. A coated substrate, consisting essentially of:

a coating disposed on an interior wellbore surface of a tubing, drill pipe, or casing of a wellbore; or on an interior wellbore surface of a collection of pipes and valves on top of a wellbore; wherein the coating comprises:

a continuous oil phase suitable for forming a coating on an interior surface of a well; and

polymer matrix particles dispersed in the continuous oil phase for inhibiting scale formation, each particle comprising a water-insoluble, porous, crosslinked polymer matrix, the polymer matrix comprising a polymer backbone and ionic functional groups covalently bonded to the backbone, the ionic functional groups comprising quaternary ammonium groups being capable of selectively attracting and binding salt scale-forming ions when in contact with a liquid containing such ions.

2. The coated substrate of claim 1 wherein the quaternary ammonium groups comprise tetrabutylammonium groups.

3. The coated substrate of claim 1 disposed in a brine comprising sodium chloride.

4. The coated substrate of claim 1 disposed in an oil or gas well.

5. The coating of claim 1 wherein the continuous phase comprises vegetable oil.

6. The coating of claim 1 wherein the coating is disposed in contact with the interior surface of a tubing, drillpipe, or casing of a wellbore; and further comprises a corrosion inhibitor.

7. The coating of claim 1 , wherein the polymer backbone of the polymer matrix is selected from the group consisting of polyacrylates, polyurethanes, polyesters and polystyrenes.

8. The coating of claim 1 , wherein the polymer matrix has a polyacrylate backbone.