OTC-25842-MS Iron Nanoparticle Modified Smart Cement for Real Time Monitoring of Ultra Deepwater Oil Well Cementing Applications C. Vipulanandan, R. Krishnamoorti, and A. Mohammed, CIGMAT-University of Houston; V. Boncan, and G. Narvaez, Baker Hughes; B. Head, and J. M. Pappas, Research Partnership to Secure Energy for America Copyright 2015, Offshore Technology Conference This paper was prepared for presentation at the Offshore Technology Conference held in Houston, Texas, USA, 4 –7 May 2015. This paper was selected for presentation by an OTC program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Offshore Technology Conference and are subject to correction by the author(s). The material does not necessarily reflect any position of the Offshore Technology Conference, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Offshore Technology Conference is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of OTC copyright. Abstract Better controls during well drilling and cementing operation are critical to ensure safety during construc- tion and the entire service life of the wells. For a successful cementing operation determine the setting of cement in place length of cement supporting the casing and performance of the cement after hardening. At present there are no technologies available to monitor the cementing operations without using buried sensors that could weaken the cement sheath. In this study, smart cement with 0.38 water-to-cement ratio was modified with Iron nanoparticles (NanoFe) to have better sensing properties, so that its behavior can be monitored at various stages of construction and during the service life of wells. A series of experiments evaluated the smart cement behavior with and without NanoFe in order to identify the most reliable sensing properties that can also be relatively easily monitored. Tests were performed on the smart cement from the time of mixing to hardened state behavior. During the initial setting the electrical resistivity changed with time based on the amount of NanoFe used to modify smart oil well cement. A new quantification concept has been developed to characterize cement curing based on electrical resistivity changes in the first 24 hours of curing. When cement was modified with 0.1 percent of conductive filer (CF), the piezoresistive behavior of the hardened smart cement was substantially improved without affecting the rheological and setting properties of the cement. For the smart cement the resistivity change at peak stress was about 2000 times higher than the change in the compressive strain after 28 days of curing. The shear thinning behavior of the smart cement slurries with and without NanoFe at two different temperatures (25°C and 85°C) have been quantified using the new hyperbolic model and compared with another constitutive model with three material parameters, Vocadlo model. The results showed that the hyperbolic model predicated the shear thinning relationship between the shear stress and shear strain rate of the NanoFe modified smart cement slurries very well. Also the hyperbolic model has a maximum shear stress limit were as the other model did not have a limit on the maximum shear stress. Based on the hyperbolic model the maximum shear stresses produced by the 0 percent, 0.5 percent, and 1 percent of NanoFe at temperature of 25°C were 175 Pa, 224 Pa, and 298 Pa, respectively. The maximum shear stresses produced by the 0 percent, 0.5 percent, and 1 percent of NanoFe at temperature of 85°C were 349