57 1. Introduction As a proved, efficient enhanced oil recovery (EOR) technique, in-situ combustion (ISC) has a history of about a hundred year [1]. In recent years, it has been attracting more and more attentions due to its high efficiency, easily accessible injectant (air), and environmentally friendly properties, especially for heavy crudes recovery (heavy oil, bitumen, oil shale, etc.) [2,3]. In spite of these advantages, ISC technique has not been as widely implemented for EOR in the field as steam injection process. The main challenge is its complexity, which makes it difficult to predict, control, and adjust [4,5]. To increase its predictivity and controllability, many researches have been carried out from different aspects, such as: studies on the combustion of different types of oils, their SARA fractions, as well as pure hydrocarbons (alkanes, aromatics, etc.) to understand the complex combustion mechanism [6–13]; studies on the factors affecting the ignition as well as the establishment and propagation of combustion front, including reservoir temperature, pressure, rock composition, and water saturation, etc.[14–18]; the effect of catalysts on the combustion behavior of oils and the performance of ISC process [3, 6, 19-23]; and numerical simulation studies to optimize injection parameters and to predict the displacement efficiency and economic benefit [24–29]. These researches can help to understand the combustion mechanism and EOR mechanism, as well as to predict the efficiency of ISC process. However, the current studies and techniques fail to know where is the combustion front and how it is propagating once the combustion front is established in field application of ISC process. In this work, we investigated the effect of combustion process of heavy oil on the composition and magnetic properties of rock. In fact, recently we have found that changes in magnetic properties can give answer about the movement of combustion front [30]. By doing this, we can provide fundamental data for developing new techniques that can help to monitor combustion front on the ground. 2. Experimental Section 2.1. Materials Initial rock sample was provided by the Nurlat Oil Field and used for combustion tube experiments presented in our previous work [31]. It should be mentioned that initial rock sample does not contain oil. For combustion tube experiments, the rock sample and oil from Nurlat Oil Field were mixed in a specific ratio. After the combustion tube experiment, the reactor was cooled down for 12 - 15 hours, then the core model was carefully removed from the core holder while maintaining the model structure. The rock samples were collected by vials EFFECT OF IN-SITU COMBUSTION PROCESS ON THE MAGNETIC PROPERTIES AND COMPOSITION OF ROCK D.M. Kuzina*, Ch. Yuan, D.K. Nurgaliev, D.A. Emelianov, M.A. Varfolomeev, A.V. Bolotov, I.F. Minhanov Kazan Federal University, Kazan, Russia *E-mail: di.kuzina@gmail.com http://dx.doi.org/10.5510/OGP2021SI200568 A b s t r a c t In-situ combustion (ISC) is a proved, effective method for enhanced oil recovery (EOR). In our previous work, we studied the feasibility of ISC process for heavy oil recovery in Nurlat Oil Field (Tatneft oil company, Russia) regarding to oil recovery, in-situ oil upgrading, stability of combustion front, etc. In this work, we investigated the effect of ISC process on the rock properties and composition. We found that magnetic minerals can be in-situ formed in rock during combustion process of oils. The formation of magnetic minerals in rock depends on temperature, heating time, and oil environment. Based on the magnetic properties, the samples can be divided into the most heated, less heated, and non- heated ones with hydrocarbons. The changes in the magnetic properties of rock can be used for developing technologies for combustion front monitoring, which is very valuable for controlling ISC process and its adjustment. Keywords: Magnetic properties; Thermomagnetic analysis; Enhanced oil recovery; In-situ combustion; Rock. © 2021 «OilGasScientificResearchProject» Institute. All rights reserved. SOCAR Proceedings Special Issue No. 2 (2021) 057-064 Reservoir and Petroleum Engineering journal home page: http://proceedings.socar.az