Filtration control has a considerable impact on drilling fluid properties & performance, on drilling costs and on well productivity. The requirements for filtration control, with regard to optimisation of the various stages of drilling a well, are ambiguous. This is largely due to the lack of understanding of the functionality of the mud components and on imprecise definition of demands.
Multi-Core Dynamic Filtration equipment has been designed to study static- and dynamic filtration (including spurt loss conditions) and assess their effect on return permeability for up to 4 core samples at a time. Several core samples in one experiment will enable us to evaluate the effect of permeability variation on clean-up efficiency. In another development, equipment has been designed for continuous measurement of cake thickness during filtration.
Polymer systems have been identified that effect acceptable fluid loss without solid particle additions. Apparently, the micelles formed have the dual functionality of solids to plug the pores and polymers to reduce cake permeability. This line of investigation may have potential in the development of truly solids free drilling fluid systems based on high density brines (e.g. Formates).