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A summary of the seminar:

Smart cement with 0.38 water-to-cement ratio was modified with iron oxide nanoparticle (NanoFe2O3) to have better sensing properties so that the behaviour can be monitored at various stages of construction and during the service life of wells. A series of experiments evaluated the piezoresistive smart cement behaviour with and without NanoFe2O3 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 behaviour. When oil well cement (Class H) was modified with 0.1% of conductive filler (CF), the piezoresistive behaviour of the hardened smart cement was substantially improved without affecting the setting properties of the cement. During the initial setting, the electrical resistivity changed with time based on the amount of NanoFe2O3 used to modify the smart oil well cement.

A new quantification concept has been developed to characterise the smart cement curing based on electrical resistivity changes in the first 24 hours of curing. An addition of 1% NanoFe2O3 increased the compressive strength of the smart cement by 26% and 40% after 1 day and 28 days of curing respectively. The modulus of elasticity of the smart cement increased with the additional of 1% NanoFe2O3 by 29% and 28% after 1 day and 28 days of curing respectively. A nonlinear curing model was used to predict the changes in electrical resistivity with curing time.

The piezoresistivity of smart cement with NanoFe2O3 was over 750 times higher than the unmodified cement depending on the curing time and nanoparticles content. Also, the nonlinear stress-strain and stress-change in resistivity relationships predicted the experimental results very well. Effects of curing time and NanoFe2O3 content on the model parameters have been quantified using a nonlinear model (NLM).

Short bio of the speaDr Ahmed Salih Mohammedker:

Dr Mohammed received his BSc in Building and Construction Engineering Department – University of Technology- Bagdad- Iraq (2000) and an MSc in Building and Construction Engineering-Geotechnical Engineering– University of Technology- Bagdad- Iraq (2003). He worked as an engineer in Qandil Swedish Organization and department of special projects in Kurdistan government from 2003 to 2005. He joined the Civil Engineering Department– University of Sulaimani – Kurdistan – Iraq as a faculty from 2005 to 2009.

He received a PhD in Civil Engineering/Geotechnical Engineering at Civil and Environmental Engineering Department at the University of Houston -Houston-Texas, the USA on December 2014 with GPA of 3.75/4 and a Postdoctoral fellow researcher in Civil Engineering/ Geo-Material Engineering at Civil and Environmental Engineering Department at University of Houston -Houston-Texas, USA. He has researched in the areas of petroleum engineering, materials engineering and geotechnical engineering. His cutting edge research was in the areas of development of hydraulic fracturing and smart cement for oil well application related to preventing disaster in the Gulf of Mexico.