Effect of Polymer Additives on the Rheology and Fluid Loss of Water Based Muds

In drilling operations, the effects of filter cake properties and filtration control on drilling fluid cannot be undermined in the process of wellbore construction and stability in order to obtain a successful drilling activity. This paper used experimental approach to investigate the effect of filter cake on fluid loss and formation damage using the formulated environmentally friendly water base polymers. Four mud samples were formulated separately, the first four mud sample were prepared with Acrylamide monomer (AAM) while the other four mud sample were done with Carboxylmethyl cellulose (CMC) by-polymer. The polymers varied for each sample from 5g-20g while other composition remain constant. High pressure high temperature fluid loss test was conducted on the formulated mud sample.

The results obtained with Acrylamide monomer (AAM) looks more interesting, giving a reduced fluid loss of about 8. lcm³ and a reduced filter cake thickness of about 0.042cm3 this means formation damage reduction with Acrylamide monomer (AAM) based mud. The Carboxylmethyl cellulose (CMC) fluid was found to be pseudo-plastic with shear thinning behavior, the fluid experienced a drastic decrease in plastic viscosity of 11 cp and yield point of about 351b/ 100fta, Acrylamide monomer (AAM) showed the higher shear rate and shear stress than Carboxylmethyl cellulose (CMC), it also acted as a better viscosifier. This can be attributed to the OH branches on the glucose rings, because of the negative charge it carries. The Acrylamide monomer (AAM) gave a relatively lower fluid loss with an increase in the polymer concentration and also gave lower filtration values at increased temperature and pressure conditions. Results shows that AAM reduces fluid loss better than CMC