This is actually one of the reasons the research is being done. Like it is clearly stated, not all clays are suitable or can be used in the formulation of drilling fluids. There are certain properties a particular clay should possess in order for it to be suitable for drilling fluid. A typical clay that has the required properties is bentonite.
So, the indigenous oil industries do not have confidence in the available local clays because most of them are unsuitable for use. So, the work aims at characterizing the clay deposits in terms of suitability. The suitable ones can then be recommended for use; additives can then be suggested for the unsuitable ones to make them useful.