First projects of the high-viscosity oil deposits development in the Republic of Tatarstan began in the 1970-ies with pilot projects implementation at two fields (Mordovo-Karmalskoye and Ashalchinskoye) with application and testing of in-situ combustion, steam-heat and steam-gas treatment methods in vertical wells.
All the works in this area did not overcome a pilot project status, since the efficiency of tested technologies was low, and the cost of high-viscosity oil (HVO) production significantly exceeded the cost of traditional production of high-viscosity oil.
Nonetheless, the HVO produced during the pilot operation was successfully used to obtain road bitumen at the oldest in Russia Shugurovsky refinery. 206 thousand tonnes of HVO were produced by the end of 2005, with an average daily production rate of one well amounting to 0.4 tonne per day.
The Mordovo-Karmalsky deposit consists of 3 land plots: the Northern, South-Western and Southern parts. Pilot operations of steam-heat, steam-gas, steam-air treatment and in-situ combustion have been carried out in this area since 1974. As the wells were drilled the and work was carried out, the maximum production of 21.6 thousand tonnes of oil was achieved in 1992 with 20.8 thousand tonnes produced through the application of the in-situ combustion technology with the stock involvement in the amount of 83 production wells. However, as can be seen on the graph, there was a decline in production due to the cessation of direct funding from the sources of the Ministry and the lack of special equipment ensuring the efficient and safe operation of the field.
1998 also witnessed drilling of a pair of wells for operation using a steam assisted gravity drainage, which was associated with the second peak of oil production. However, the flow rate did not exceed 5 tonnes per day. Currently, the deposit is in conservation.
The second field in Tatarstan, where high-viscosity bituminous oil is produced, is the Ashalchinskoye field.
This field development history began in 1987 with a pilot operation project on the steam-heat and steam-gas treatments. And, the year 2006 witnessed the beginning of the pilot work on the operation of horizontal wells with the application of the steam assisted gravity drainage method.
In February 2016, the HVO Production Department produced 1 million tonnes of high-viscosity oil, in February 2017 - 2 million tonnes, in October 2017 - 3 million tonnes of high-viscosity oil and 5 million tonnes in October 2018.
The application of the steam assisted gravity drainage (or SAGD) technology started with drilling three pairs of unique double wellhead wells ssytems opening to the surface. Initially pairs of wells were drilled from a vertical drilling rig BU-75. Further development of the project continued with the purchase of a Canadian made slanted Kremko 2000 drilling rig in 2009.
Subsequently, in 2014, slant rigs were involved in drilling horizontal wells with a slanted wellhead without opening to the surface with the aim of speeding the project execution rate.