Did you mean difference between IADC & IWCF? I may have interpreted the question wrong, but it is a valid question that comes up frequently... "which is optimal, IADC or IWCF?". To be clear, it is not that the IADC Well Control certs are not authentic and/or accedited, they most certainly are. However, some operators prefer IWCF due to its more stringent testing requirements, which allow less room for errors in order to pass.
That said, IADC is striving to improve this; this is evident in the rollout of the IADC WellSharp program, which is more comprehensive than the regular course and has added a few parameters to the traditional program, notably more robust, standardized modules and testing, and an addition of Human Factors theory into it. It is and has been known that human factors play a significant part in preventing and responding to Well Control incidents and Blowouts, and Drilling & Wells emergencies in general.
When we inspect a rig or do a well control audit, we do check the WC certificates, and typically they are a mix of IADC and IWCF depending on company and contractors. Assistant Drillers on up to OIM (and company men of course) shall have valid certificates from either entity, as this is the minimum requirement for these roles.
Hope that answers at least part of it.
All the best,
Eric S. Roth, RSP, MIIRSM
Managing Director - S-energy Consultants and Rig Integrity Global Services (RIGS)