Gazpromneft-Khantos has started drilling the first horizontal well to explore the Bazhenov complex of the Palyanovsky deposit at the Krasnoleninsky field. This marks a new stage in Gazprom Neft’s study of shale oil deposits* at the field.
The depth of the first well exceeds 3,200 metres and the horizontal borehole extends approximately 300 metres. Three-stage hydraulic fracturing (fracking) will be performed at the deposits in order to increase efficiency. Overall, it is expected that four wells will be drilled during the new phase of the project in 2014-2015, increasing the length of the horizontal sections in consecutive stages and also increasing the number of fracking stages.
In 2013-2014, during the previous stage of the study of the Bazhenov complex deposits at the Palyanovsky field, Gazprom Neft drilled 5 controlled-directional wells, involving the use of fracking at four of these. Commercial oil flows were achieved in all of these wells, which continue to be in operation. Furthermore, these operations confirmed the possibility of effective fracking at the Bazhenov complex. The next stage of the project will determine the most effective method for extraction.
Work on a second Gazprom Neft project for developing shale oil deposits continues to take place at the Bazhenov-Abalak formation of the Southern-Priobskoye field. Gazpromneft-Khantos received the license for geological development of this horizon in March 2014. Geophysical analysis of the data has been conducted over the last six months, and specialized studies of the core samples were carried out, as well as additional studies of the 3-D seismic survey data. The first stage of the program has been planned, providing for the drilling of controlled-directional prospecting and appraisal wells during 2014-2015 in order to determine the horizon's potential, to specify its geological model, and to determine the appropriate extraction methods. Seismic studies of the deposits using the 3-D method are expected to continue in 2016, as well as the drilling of horizontal wells.
Vadim Yakovlev, First Deputy CEO of Gazprom Neft, said:
"The Bazhenov formation is an example of our work with non-traditional deposits, which is an area the Company is focused on developing. By implementing pilot projects we determine the optimal method for working with these resources in order to develop further projects effectively."
*Shale oil is present in the Bazhenov, Abalak and Frolov formations – Western Siberian rock formations with extremely low permeability, but high oil saturation.
The Bazhenov formation is a stratum of rock which has been identified in the central area of Western Siberia at depths of 2,000-3,000 metres. It covers an area of around 1 million square kilometres, but is comparatively thin – between 10 and 40 metres thick. According to some estimates, the oil reserves in the Bazhenov formation reservoir may reach 100-170 billion tonnes in Western Siberia alone.
The Abalak formation consists of marine shoreline or marine deposit rocks; it underlies the deposits of the Bazhenov formation with which it is sometimes in abrupt contact. The Abalak formation extends across the Krasnoleninsky arch, as well over as the Surgut oil and gas district and the Uvat region. The deposits within the boundaries of the Krasnoleninsky arch are 2,200-2,400 metres deep, and their total thickness varies from 20 to 90 metres.
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