Average Co-Inventor Count = 19.01
ph-index = 1
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. China National Petroleum Corporation (1 from 81 patents)
2. China University of Petroleum (1 from 25 patents)
3. Cnpc Bohai Driling Engineering Company Limited (1 from 1 patent)
1 patent:
1. 12000222 - Pressure compensation device with accumulator group for controlled pressure drilling