Cellulose isolated from Eichhornia crassipe (Water hyacinth) and Pennisetum purpureum (elephant grass) were evaluated using Fourier Transform Infra-Red spectroscopy and standard analytical methods for production of drilling mud. The physico-chemical analyses were carried out after chlorination and alkaline process using sodium chlorite and sodium hydroxide for the extraction of cellulose from the two biomass samples under same experimental conditions. Results of physico-chemical analysis of Eichhornia crassipes showed pH: 7.30; conductivity 0.028; bulk density 0.1097g/ml. Pennisetum purpureum showed pH: 7.50; conductivity 0.192; bulk density 0.1378g/ml. Pennisetum purpureum has a higher cellulose yield of 31.39% compared with Eichhornia crassipes with a percentage cellulose yield of 21.88%. Both biomass samples have Herzberg strain of Violet-blue. The results of the Fourier Transform Infra-Red spectroscopy showed prominent peaks at 3353-3164, 1655, 1629, 1320, 1033 and 1019 cm-1. The broad absorption bands around 3353-3164 cm-1 indicated stretching of –OH groups due to inter-molecular and intra-molecular hydrogen bonds of polymeric compounds. The sharp bands at 1655 cm-1 and 1629 cm-1 showed C=C stretch of aromatics. The sharp absorption bands observed at 1320, 1019 and 1033 cm-1 were characteristic of C—O stretch and C—O—C asymmetric stretch of cellulose. The FTIR results proved that the products extracted from the two samples were aromatic hydroxyl compounds. The results of the physicochemical analyses showed that cellulose isolated from the biomass samples which are persistent noxious weeds that invade the aquatic and terrestrial environment can be utilized in industrial applications for drilling fluid production.