Abstract
During last decades the air injection or the in situ combustion has found a wide application as a heavy oil IOR process in the world. The idea of the in-situ coal gasification process was initially suggested by Academician D.I. Mendeleev in 1888. In the 1930s Soviet scientists A.B. Sheinman and K.K. Dubrovai performed first attempts to initiate in-situ oxidation of oil in one of the Krasnodar region heavy oil fields. In the USSR successful heavy oil in-situ combustion (ISC) applications have been implemented at the Pavlova Gora field in Krasnodar and at Shodnitza field in Ukraine in the sixties. A review of the ISC heavy oil field application experience in the USSR will be given in this paper.
The Republic of Tatarstan has the largest in the Russian Federation resources of natural bitumen, ranging from 4 to 7 billion tons. Today the air injection process is conducted by the operator "Tatneft" on two field projects at Ashalchinskoye and Mordovo-Karmalskoye (MK) fields. Natural bitumen has been produced at MK field since 1978.
In this paper we will present results of our simulation study of the MK's ISC project. The simulation model of the pilot area including combustion and pyrolysis reactions, oxidation parameters was calibrated using available experimental data to match the production history of the field. The advanced dynamic gridding numerical solutions were used for modeling and history matching of the ISC process. Dynamic gridding allows achieving the accurate modeling and material balance calculations of the complex physical and chemical processes taking place at the combustion and displacement fronts in the reservoir under air injection. It allows the saving computer time required for the process modeling. Automatic history matching routines were used to properly calibrate matching parameters and to adjust the reservoir and the reaction characteristics of the simulation model.
The established simulation model can be used as a tool for the ISC process monitoring at the field. The model allows also to interpret and to evaluate the pilot results, to optimize its application and to predict the IOR potential.
