www.ijemr.net ISSN (ONLINE): 2250-0758, ISSN (PRINT): 2394-6962 247 Copyright © 2016. Vandana Publications. All Rights Reserved. Volume-6, Issue-5, September-October 2016 International Journal of Engineering and Management Research Page Number: 247-256 Kinetic Modeling of Drilling Mud Treated with Local (Cassava) and Imported Polymers Harry, T.F. 1 , Oduola, K. 2 , Ademiluyi, F.T. 3 , Joel, O.F. 4 1,4 World Bank African Centre of Excellence for Oil Field Chemicals Research, University of Port Harcourt, NIGERIA 2 Department of Chemical Engineering, University of Port Harcourt, NIGERIA 3 ABSTRACT Department of Chemical/Petrochemical Engineering, Rivers State University of Science and Technology, Port Harcourt, NIGERIA The reaction rate constant of bentonite polymer drilling mud was expressed in terms of apparent viscosity and used to evaluate the thermal stability and effectiveness of aged muds. The muds were formulated from two local cassava starches and two imported polymers. The rheological performances of the muds were determined. Model equation was developed to relate the apparent viscosity of bentonite muds before and after 16 hours aging. Model rateconstants were determined for the bentonite- polymer muds at 80 o F, 120 o F, 150 o F and 190 o I. INTRODUCTION F. The model for apparent viscosities before and after aging fitted with good correlations, ranging from 99.6 to 99.9 percent. The local cassava starch treated bentonite muds were better in withstanding temperature variations, while the imported polymers muds were more stable after aging. Polymer concentration was found to influence the rate constant of the muds, however, the influence was not significant with the local starches treated muds. The kinetic model, half- lifeand activation energies determined could be used to evaluate the thermal stability of polymer based bentonite muds and predict the performance of aged muds. Keywords--- Cassava starch, reaction rate constant, half- life, viscosity, thermal stability Starch was the first polymer used for drilling fluid (Xiuhua and Xiaochun, 2010). Starchis used in the formulation of drilling fluid for viscosity enhancement and fluid loss reduction. The performance of starch in drilling mud depends on temperature which the mud is subjected to, starch concentration, age of the mud and the source of starch (Ismail and Idris, 1997). Starch sources from local cassava varietieswere investigated as drilling fluid additive (Akintola and Isehunwa, 2015; Ademiluyi et al., 2011; Oriji and Joel, 2012; Samavati et al., 2014).The primary compositions of drilling mud are water and bentonite (Abdou et al., 2013). Chemistry associated with bentonite hydration and swelling facilitatesmudphysical performance for drilling;however the starch treatment of bentonite mud enhances the viscosity and fluid loss control properties. 1.1 Starch Chemistry in Solution The decomposition of starch occurs whenever starch is made into solution. The rate at which reaction occurs is a function of the temperature at which the solution is used. Natural polymers degrade when exposed to heat (Skalle, 2011). Natural starch physical properties including rheological and viscoelastic characteristics are dependent on two distinct structural polysaccharide fractions, amylose and amylopectin (Charles et al., 2005).These fractions influenced two important physical behaviors of starch, gelatinization and retrogradation. When starch granules are heated in excess water with increase in temperatures, a point is reached where the polarization cross starts to disappear and the granules begin to swell irreversibly. These phenomena, associated with the disruption of granular structure, are called gelatinization. Hence, gelatinization can be described as the disruption of molecular orders (breaking of H-bonds) within the granule, along with irreversible changes in properties such as water uptake, granular swelling, crystallite melting, birefringence loss, starch solubilization and viscosity development (BeMiller and Whistle, 2009). Gelatinization of granules in excess water causes large changes in the rheological properties of the system and has a major influence on the behaviour and functionality of starch-containing systems. Different starches display different thermal transitions and swelling patterns. Post-gelatinization changes accompanying the restoration of molecular order in starch, which are collectively described by the term retrogradation, exert a major influence on starch utilization. Retrogradation defines the reassociation of gelatinized starch molecules resulting in more ordered structures. These ordered structures in turn influence starch physical properties such as the viscosity of gels