Research paper Fabrication of kaolin-based cement plug for CO 2 storage wells Naim M. Faqir a,1 , Salaheldin Elkatatny b , Mohammd Mahmoud b , Reyad Shawabkeh a, ⁎ a Department of Chemical Engineering, King Fahd University Petroleum and Minerals, Dhahran 31261, Saudi Arabia b Department of Petroleum Engineering, King Fahd University Petroleum and Minerals, Dhahran 31261, Saudi Arabia abstract article info Article history: Received 24 October 2016 Received in revised form 8 February 2017 Accepted 9 February 2017 Available online xxxx A new material from clay was developed that has a resistance to carbon dioxide flow in upstream for plugging CO 2 storage wells. Thermogravimetric and thermal stability of this material showed a minimal variation in weight loss with incremental heating up to 420 °C. Adsorption-desorption of CO 2 at various modeled tempera- ture showed an exothermic and spontaneous process with maximum adsorption capacity of 775 mg/g obtained at 640 psi (43.5 bar) and 50 °C. Higher pressure led to more storage capacity with physisorption hysteresis curves. Freundlich and BET models best fit the equilibrium adsorption data with average regression coefficient of 0.995. The new material can substitute the conventional cement plugs for upstream carbon sequestration and prevents the migration of the stored CO 2 through the cement plug to the surface. Also the developed new cement showed no chemical interaction which confirms the economical impact of using this cement to plug the CO 2 sequestra- tions wells. © 2017 Elsevier B.V. All rights reserved. Keywords: Treated kaolin material Construction Carbon dioxide storage Clay EGR and EOR 1. Introduction The implementation of carbon capture and sequestration in Enhanced oil (EOR) and gas (EGR) recovery has recently gained great interest in terms of recovery cost, feasibility, and environmental reme- diation. This emerging technology has dual advantages of reducing the emission of CO 2 into atmosphere and recovering the oil and gas that left after secondary processes. However, maintaining CO 2 in gas and oil wells is a challenge in CO 2 sequestration and EOR and EGR recovery. The downhole forces on the pumped cement between the casing and the drilled formation lead to failure of cement, and hence the well integrity can be affected. Furthermore, the prolong interaction between the stored CO 2 and the casted cement can lead to corrosion of embedded well tubular. This deterioration of the casted well is a major cause of cracking and channeling of the cement matrix resulted in early gas migration. Such problems can lead to early work over jobs or shutting-down some wells that resulted in losing its productivity. The previous work focused on CO 2 storage and its effect on enhanced gas recovery. Others studied the interaction of CO 2 with casting cement and provided solution for its deterioration effect on casted cement. Le Guen et al. (2009) and Pacala and Socolow (2004) showed that CO 2 se- questration is one of the most important techniques used to reduce the amount of greenhouse gases in order to protect the environment. Tarco and Asghari (2010) mentioned that CO 2 storage can be performed either in abundant or active wells. The key point in the sequestration operation is the assurance of per- manent storage of CO 2 within the selected formation. Two possible ways of CO 2 leakage after injection; one is the leakage through the cap rock and the other is the leakage through a low strength bond between cement and permeable formation. Another major challenge associated with CO 2 sequestration is the injection of low pH brine on casted wells durability (Abid et al., 2015). Agbasimalo and Radonjic (2012) conclud- ed that Portland cement class H tends to degrade by injecting low pH brine and the degree of degradation increased with the presence of the drilling fluid filter cake. Li et al. (2014) concluded that the cement tends to lose its mechanical integrity after long term exposure to sour gases. Bai et al. (2016) stated that both mechanical loading and chemi- cal corrosion of cement affect the cement bond with the formation. The special types of cement as the one contains high alumina can be used for high injection rate operation especially with the presence of sour gases. Condor and Asghari (2009) have used type 10 classes A and G cement that are recommended for plugging in oil and gas industry. They found that the permeability of cement cubes of both types initially de- creased and after a few months increased. This increase in permeability was observed to be fast and high as the temperature increased. The compressive strength reduced for both types after few months. A poor bonding between the cement and the holder was confirmed by measur- ing the shear and hydraulic bonding. These results confirmed that wellbore leakage is the easy pass for the CO 2 to escape out of the perme- able formation. Moreover, as the cement is exposed to CO 2 , a carbon- ation reaction and leaching occurs. These phenomena triggers cement degradation where the rate of leaching is faster than formation of calci- um silicate hydrate (Lesti et al., 2013). Applied Clay Science 141 (2017) 81–87 ⁎ Corresponding author. E-mail addresses: faqir@ju.edu.jo (N.M. Faqir), elkatatny@kfupm.edu.sa (S. Elkatatny), mmahmoud@kfupm.edu.sa (M. Mahmoud), rshawabk@kfupm.edu.sa (R. Shawabkeh). 1 Current address: Department of Chemical Engineering, University of Jordan, Amman, Jordan. http://dx.doi.org/10.1016/j.clay.2017.02.011 0169-1317/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Applied Clay Science journal homepage: www.elsevier.com/locate/clay