HOUSTON (AP) _ Oil industry supplier ABB Vetco Gray has sued FMC Corp. to stop its rival from infringing on intellectual property rights covering subsea wellhead systems, the company said Monday.

In the suit filed in U.S. District Court, Houston-based ABB Vetco Gray accused Chicago-based FMC of infringing on patents for a subsea wellhead system.

The two companies compete worldwide in the wellhead equipment market.

``This relates to a patent claim which we thought we had resolved with Vetco Gray in 1992,'' said FMC spokeswoman Pat Brozowski. ``We don't think it has any merit.''

She said FMC would file a response in early June.

ABB Vetco Gray said it developed the system and introduced it to the subsea completion market in May 1990.

ABB Vetco Gray also accused FMC of plagiarizing and distributing a manual for the equipment.