Average Co-Inventor Count = 3.43
ph-index = 2
The patent ph-index is calculated by counting the number of publications for which an author has been cited by other authors at least that same number of times.
Company Filing History:
1. Duhn Oil Tool, Inc. (2 from 11 patents)
2. Shell Western E&p Inc. (1 from 22 patents)
2 patents:
1. 5303774 - Ring seal packer
2. 4974676 - Ground subsiding wellhead