H. Milton Hoff, Flow Control Equipment, Inc.
In 1992 and 1993, Huber began working with problem-solving teams of production supervisors, well attendants, engineers and buyers from major and independent oil companies to find ways to reduce operating costs by improving the performance of stuffing boxes. Huber, which has since become Flow Control Equipment, Inc. (FCE), a wholly-owned subsidiary of Huber, began research in 1993 to support this project. Most of the stuffing box improvements identified by the focus groups fell into one of six categories shown below: 1. Longer-lasting packing 2. Less demand on the well attendant's time 3. Better lubrication systems 4. Less inventory to support stuffing box maintenance 5. Reliable leak detection and fail-safe options 6. Rapid pay-out for investments in new equipment Early in the research project, it became apparent that improvements could be achieved in almost every one of the six categories by reducing the coefficient of friction between the stuffing box packing and the polished rod. Rubber, the most widely used packing material, was ideal for its flexibility and memory, but very undesirable for its high coefficient of friction. High coefficients of friction generate heat and result in more frequent stuffing box leaks. Progress to reduce the coefficient of friction was first reported at the 1994 Southwestern Petroleum Short Course at Texas Tech by Larry Angelo in a paper titled "Metal Film-Coated Stuffing Box Packing". Larry Angelo reported partial success using the MagionTM process to apply a molecular layer of metal over conventional cone rubber packing to reduce the coefficient of friction between the polished rod and stuffing box packing. Since then, Huber and subsequently FCE, has continued to pursue this objective and this paper is the second report on the progress of this research. The need to evaluate various stuffing box packing materials led to the development of laboratory test equipment shown in Figure 1 which could be used to measure the friction between the polished rod and packing. Tests were conducted on this equipment in non-lubricating environments - the most challenging of all conditions for testing the performance of packing. Metal film-coated rubber was partially successful. Combining PTFE with rubber, which is the subject here, was more successful.